Science and Racket Sports IV

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Science and Racket Sports IV

Science and Racket Sports IV presents a selection of important contemporary research into the four core racket sport disciplines of tennis, badminton, squash and table tennis. It showcases the best of the peer-reviewed papers and keynote addresses presented at the Fourth World Congress of Science and Racket Sports, Madrid. Including contributions from many of the world’s leading racket sport scientists, researchers and practitioners, the book details cutting-edge research in six key areas:

• • • • • •

Physiology Biomechanics Sports medicine Psychology Performance analysis Pedagogy, sociology and coach education.

This invaluable collection touches on the most important issues within contemporary sport science, and explores the full range of theoretical, experimental and applied work within the study of racket sports. It is essential reading for all sports scientists, sports physicians, therapists and coaches working in this area. Adrian Lees is Professor of Biomechanics and Deputy Director of the Research Institute for Sport and Exercise Sciences at Liverpool John Moores University. As chair of the World Commission of Sports Biomechanics Steering Group for Science and Racket Sports, he has promoted the three previous Science & Racket Sports Congresses and associated books. Author of over 20 books and chapters, he is editorial board member for the Journal of Sports Sciences, and Fellow of the British Association of Sport and Exercise Sciences and the European College of Sports Sciences. David Cabello is Senior Lecturer in the Education Sciences Faculty at the University of Granada. Gema Torres Luque is Senior Lecturer at the Catholic University of Murcia, Spain. They co-organized the Fourth World Congress of Science and Racket Sports.

Fourth World Congress of Science and Racket Sports, 21–23 September, 2006 Held at the Spanish Olympic Centre, Madrid, Spain

Organizing Committee David Cabello (Chair) Fernando Calvo Marín Antonio Garde Olea Rogelio Chantada Lago Julián García Angulo Gonzalo de la Herrán Adrian Lees Emilio Lezana García Ángel Luis López de la Fuente Jesús Mardaras García Francisco Pradas de la Fuente Inmaculada Roldán Miranda Javier Sampedro Moliner David Sanz Rivas Gema Torres Luque Miguel de la Villa Polo

Scientiﬁc Committee David Cabello Alberto Carazo Prada Mike Hughes Jean-Francois Kahn Adrian Lees (Chair) Ian Maynard Ignacio Refoyo Román Inmaculada Roldán Miranda David Sanz Rivas Gema Torres

Science and Racket Sports IV

Edited by A. Lees, D. Cabello and G. Torres

First published 2009 by Routledge 2 Park Square, Milton Park, Abingdon, Oxon, OX14 4RN Simultaneously published in the USA and Canada by Routledge 270 Madison Avenue, New York, NY 10016 Routledge is an imprint of the Taylor & Francis Group, an informa business This edition published in the Taylor & Francis e-Library, 2008. “To purchase your own copy of this or any of Taylor & Francis or Routledge’s collection of thousands of eBooks please go to www.eBookstore.tandf.co.uk.” © 2009 A. Lees, D. Cabello and G. Torres for selection and editorial matter; individual chapters, the contributors All rights reserved. No part of this book may be reprinted or reproduced or utilized in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data A catalog record for this book has been requested ISBN 0-203-89487-1 Master e-book ISBN

ISBN 10: 0–415–43556–0 (hbk) ISBN 10: 0–203–89487–1 (ebk) ISBN 13: 978–0–415–43556–7 (hbk) ISBN 13: 978–0–203–89487–3 (ebk)

Contents

List of ﬁgures List of tables List of contributors Preface Introduction

x xii xv xxi 1

PART 1

Physiology of racket sports 1 Physiological testing in badminton

3 5

O. FAUDE, T. MEYER, M. FRIES AND W. KINDERMANN

2 Core temperature and hydration status in professional tennis players measured in live tournament conditions

14

A.J. PEARCE

3 Anaerobic performance during intermittent exercise and body composition in tennis players of diﬀerent biological and chronological ages

22

E. ZIEMANN AND T. GARSZTKA

4 Comparison of laboratory and on-court testing of aerobic ﬁtness in tennis players

29

R.W. MEYERS

5 A speciﬁc incremental test in tennis O. GIRARD, R. CHEVALIER, F. LEVEQUE, J.-P. MICALLEF AND G.P. MILLET

36

vi

Contents

6 Muscle ﬁbre type distribution and ﬁbre size of triceps brachialis in elite tennis players

44

J. SANCHÍS-MOYSI, A. GUADALUPE-GRAU, S. GUERRA, H. OLMEDILLAS, O. BERNALES, C. DORADO AND J.A.L. CALBET

7 Development of a tennis-speciﬁc fatigue-inducing protocol and the eﬀects of caﬀeine on performance

51

D.J. HORNERY, D. FARROW, I. MUJIKA AND W. YOUNG

8 Nutrition knowledge and nutrition habits of tennis coaches

58

B.R. MATKOVIC´ , B. MATKOVIC´ AND P. TUDOR-BARBAROS

9 Correlations of physiological responses in squash players during competition

64

J.R. ALVERO CRUZ, J. BARRERA EXPÓSITO, A. MESA ALONSO AND D. CABELLO

10 Field-based assessment of speed and power in junior badminton players

70

M.G. HUGHES

11 Energy expenditure measurement in badminton players during a training camp using doubly-labelled water

77

E. WATANABE, S. IGAWA, T. SATO, M. MIYAZAKI, S. HORIUCHI AND K. SEKI

12 Kinanthropometric proﬁle, body composition, somatotype and grip strength dynamometry in young high level tennis, badminton and table tennis players

83

F. PRADAS, E. MARTÍNEZ, P.E. ALCARAZ AND L. CARRASCO

13 Analysis of the somatotype, body composition and anthropometry in badminton players between 12 and 16 years

91

M. DE HOYO, B. SAÑUDO AND F. PARÍS

PART 2

Biomechanical and medical aspects of racket sports

97

14 Biomechanics of racket sports: developments and current status

99

A. LEES

Contents 15 Angular velocities in the tennis serve

vii 106

C. LÓPEZ DE SUBIJANA AND E. NAVARRO

16 Comparison of injuries between Slovenian table tennis and badminton players

112

M. KONDRICˇ , G. FURJAN-MANDIC´ , L. PETRINOVIC´ -ZEKAN AND D. CILIGA

17 Prevention of injuries and cardiovascular events in veteran table tennis players

118

J.-F. KAHN AND T. CHARLAND

18 Strategies and support mechanisms used by elite Australian female tennis players returning to the circuit from injury

124

A.J. PEARCE, J.A. YOUNG AND M.D. PAIN

19 The use of plantar supports in badminton and squash players

132

G.A. GIJÓN NOGUERÓN, M. GIJÓN NOGUERÓN AND D. CABELLO

20 Centre of gravity in paddle rackets: implications for technique

139

P.T. GÓMEZ PÍRIZ AND M.F. ÁLVAREZ

PART 3

Psychological aspects of racket sports

143

21 Anticipation and skill in racket sports

145

A.M. WILLIAMS

22 A perception-action perspective on learning and practice in racket sports

154

G.J.P. SAVELSBERGH, F. RIVAS AND J. VAN DER KAMP

23 Inﬂuence of training and task diﬃculty on eﬃciency of a forehand drive in table tennis

162

L. JOSPIN, V. FAYT AND S. LAZZARI

24 Tennis play simulator 1: psychomotor predispositions for tennis based on locomotor movements J. LAPSZO

169

viii

Contents

25 Tennis play simulator 2: speed of sequential ball-hitting movements under practice and competitive conditions

177

J. LAPSZO

PART 4

Performance analysis of racket sports

185

26 Computerized notational analysis and performance proﬁling in racket sports

187

M.D. HUGHES, M.T. HUGHES AND H. BEHAN

27 Playing patterns of world elite male and Austrian top male single’s badminton players

197

E. OSWALD

28 Comparison of the average game playing time in diﬀerent scoring systems in badminton

204

L. PETRINOVIC´ -ZEKAN, Zˇ . PEDISˇ IC´ , D. CILIGA AND M. KONDRICˇ

29 Feedback systems in table tennis

208

A. BACA AND P. KORNFEIND

30 Practice oriented match analyses in table tennis as a coaching aid

214

R. LESER AND A. BACA

31 Quantitative analysis of playing eﬃciency in squash

220

G. VUCˇ KOVIC´ , B. DEZˇ MAN, S. KOVACˇ ICˇ AND J. PERSˇ

32 A comparison of whole match and individual set data in order to identify valid performance indicators for real-time feedback in men’s single tennis matches

227

H.J. CHOI, P.G. O’DONOGHUE AND M.D. HUGHES

33 Variability in men’s singles tennis strategy at the US Open

232

P.G. O’DONOGHUE

34 Time analysis of three decades of men’s singles at Wimbledon H. TAKAHASHI, T. WADA, A. MAEDA, M. KODAMA, H. NISHIZONO AND H. KURATA

239

Contents

ix

PART 5

Pedagogy, sociology and coach education in racket sports

247

35 New perspectives and research applications in tennis

249

M. CRESPO

36 Sport identity of Polish badminton players in the context of other selected sport disciplines

255

M. LENARTOWICZ AND P. RYMARCZYK

37 Coach education: models, characteristics and views of Greek tennis coaches

262

N. GRIVAS AND K. MANTIS

38 Modern teaching methods for tennis: what do they have in common?

269

P.G. UNIERZYSKI AND M. CRESPO

39 Season-of-birth eﬀects on elite junior tennis players’ world rankings

275

P. G. O’DONOGHUE

40 Health-related habits of tennis coaches

282

B.R. MATKOVIC´ , B. MATKOVIC´ AND L. RUZˇ IC´

41 Integrated functional evaluation: a speciﬁc proposal for badminton

287

C. BLASCO, A. RUIZ AND R.P. GARRIDO

42 The social structure of racket sports practice in Spain

295

R. LLOPIS GOIG AND D. LLOPIS GOIG

Index

301

Figures

2.1 Core body temperature sensor pill 2.2 Measurement of a player in-match during change of ends 3.1 Directions of movement during the ‘PUST’ tennis-speciﬁc drill 4.1 Illustration of the calculation for the three intensities used 4.2 Representation of the Tan determination 5.1 Set-up of the speciﬁc incremental ﬁtness test for tennis players 7.1 Serve velocity and RPE over the duration of the protocol 10.1 Layout of the badminton half-court for the speciﬁc speed test 10.2 Scatter plot (and linear trend lines) for vertical jump height and agility test results in male and female players 15.1 The calibration system 15.2 Filming area location 15.3 The 28-point body model 16.1 Training and competitive status of top athletes (both games) 16.2 Location of injury (both games) 19.1 Orthotic compensator elements 20.1 Lines of application of the gravity force from two diﬀerent suspension points in a paddle racket 20.2 Distances from the COG to the proximal point and weight 21.1 Mean (± SE) percentage time spent viewing each ﬁxation location 23.1a Performance in the nine experimental conditions 23.1b HR in the nine experimental conditions 24.1 The tennis play simulator – version 1 25.1 The tennis play simulator 2 25.2 Proﬁles of tested psychomotor factors for the best player, the tested group and freely chosen player

16 17 24 31 32 38 56 72 74 107 108 108 113 114 134 140 142 147 166 166 171 179 181

Figures xi 25.3 The proﬁle of correlation coeﬃcients between tested psychomotor factors and sporting results ranking for tested group 27.1 Types of service strokes 27.2 Faults and points during the return 27.3 Types of strokes during the rally 27.4 Shot frequencies in diﬀerent areas 27.5 Distribution of too-short and optimal long strokes 27.6 Distribution of diﬀerent kinds of strokes before point 29.1 Setup for detection of ball impact positions 29.2 Computer screen presenting a series of ball impact positions 29.3 Left: Schematic presentation of the system for calculating impact time intervals. Right: complete system without PC/PDA 29.4 Presentation of impact time intervals 29.5 Feedback training using impact position detecting system 30.1 Flowchart of applied match analysis in table tennis 30.2 Data collection screen 30.3 Success and failure of player A when starting a rally with his own service 30.4 Video feedback screen 31.1 The court divided into 29 segments 33.1 Distribution of percentage net points for diﬀerent players 33.2 Relationship between the mean and SD for percentage net points 34.1 A comparison of time duration per point among match groups 34.2 A comparison of rally length per point among match groups 34.3 A comparison of time duration of ﬁrst service among match groups 34.4 A comparison of time duration of second service among match groups 34.5 A comparison of time duration of ground stroke among match groups 34.6 A comparison of time between points among match groups 41.1 Quantitative evaluation

182 199 200 201 201 202 203 209 210

211 211 212 215 216 217 218 222 235 235 241 241 242 243 243 244 292

Tables

2.1 Hydration status as measured by speciﬁc gravity 2.2 Hydration status as measured by changes in athlete body mass 2.3 Core temperature at match start, peak and mean temperature 2.4 Mean core temperature responses in ﬁve players 3.1 Anthropometric characteristics of subjects (chronological age) 3.2 Anthropometric characteristics of subjects (biological age) 3.3 Physiological characteristics in anaerobic capacity and anaerobic power in biological groups 3.4 Time of ‘PUST’ tennis drills in relation to biological age 4.1 Mean and correlation data for the variables assessed 5.1 Physiological values in tennis players 6.1 General subject characteristics 7.1 Comparative physiological responses between conditions 8.1 Questionnaire with the marked true or false answers 9.1 General data 9.2 Values are mean of lactate concentration, RPE Borg Scale and mean heart rate between winners and losers 9.3 Correlation between variables 10.1 Mean ± standard deviation results for ﬁtness test data 10.2 Correlation matrix for female subjects 10.3 Correlation matrix for male subjects 11.1 Physical characteristics of subjects 11.2 Analysis of subjects using DLW method in men 11.3 Analysis of subjects using DLW method in women 11.4 Result of dietary intake in men 11.5 Result of dietary intake in women 12.1 Biometric data in terms of racket sports practised 12.2 Skinfolds in terms of racket sports practised 12.3 Body composition in terms of racket sports practised

18 18 19 19 25 25 26 26 33 41 45 55 60 66 66 66 73 73 74 78 79 79 80 81 84 85 86

Tables 12.4 12.5 12.6 13.1 13.2 13.3 15.1 15.2 16.1 16.2 16.3 17.1 17.2 18.1 18.2 18.3 18.4 19.1 19.2 19.3 20.1 20.2

23.1 24.1 27.1 27.2 28.1 28.2 31.1 31.2 31.3 32.1

Somatotype in terms of racket sports practised Grip strength in terms of racket sports practised Muscle mass, arm perimeter and grip strength Analysis of the skinfolds and Σ in the 4 and 6 folds Information relative to the BMI and body composition Information relative to the somatotype Angular velocities from players A and B Maximum angular velocities key instances Percentage of injuries in muscles, tendons and joints Sum of all injuries reported by players (both games) Number of injuries reported by players (both games) Distribution of the veteran players according to their age group and gender Distribution of the injuries in veterans according to their age group Frequency of minor injuries to body parts Frequency of treatments sought for minor injuries Frequency of severe or chronic injuries to body parts Frequency of treatments sought for a severe or chronic injury Relation between the age of the players and the injuries sustained Relation between the morpho-structural alterations established and the most frequent injuries Relation of the orthopaedic elements of the support with the diﬀerent dynamic alterations Numbers in each category for distances (cm) of the COG to the proximal end of the racket Numbers in each category for percentage distance (cm) of the COG to the proximal end of the racket relative to racket length Temporal structure of the experimental procedure The correlation coeﬃcients of the tested factors with sporting results for the examined groups Basic statistics of the investigation Strokes per rally Descriptive parameters and conﬁdence intervals for mean playing time Diﬀerences between mean playing time Percentage of strokes executed by top world players and top Slovenian players by court segment Results by discriminant analysis in terms of percentage of strokes Standardized correlation coeﬃcients Summary of the winning and losing performances

xiii 87 87 87 93 93 93 109 109 114 114 115 119 120 126 127 128 129 135 135 136 141

141 164 174 198 199 206 207 223 223 224 229

xiv 32.2 33.1 33.2 35.1 39.1 39.2 39.3 39.4 39.5

40.1 40.2 40.3 41.1 42.1 42.2 42.3 42.4 42.5 42.6 42.7

Tables The results of the Wilcoxon Signed Ranks test Skewness and kurtosis of percentage net points Percentage of points where four players went to the net Research areas suggested for scientiﬁc research in tennis Numbers of 1987- and 1988-born tennis players achieving ITF junior ranking points in diﬀerent years Half year of birth of 1987- and 1988-born players with junior ranking points in each year Changes in the set of 1987- and 1988-born players achieving ranking points in 2003 and 2004 Changes in the set of 1987- and 1988-born players achieving ranking points in 2004 and 2005 World rankings of male and female players born in the ﬁrst and second halves of the year who had achieved ranking points in all three years Alcohol consumption of tennis coaches Smoking habits of tennis coaches Nutrition habits questionnaire List of quantitative evaluation Racket sports participation in Spain Change in participation (% of population) in racket sports in Spain Motivation for racket sports practice Racket sports practice according to sex Racket sports practice according to age Racket sports practice according to the highest education attainment Racket sports practice according to employment status

229 234 236 251 276 277 278 278

279 283 284 285 293 297 297 297 298 298 298 299

List of contributors

Alcaraz, P.E. Biomechanics Laboratory, Faculty of Physical Activity and Sport Sciences, Saint Antonio Catholic University of Murcia, Spain. Álvarez , M. F. Sevilla F.C., Spain. Alvero Cruz, J.R. Sports Medicine School, Department of Human Physiology and Sports Physical Education, Faculty of Medicine, University of Málaga, Spain. Baca, A. Department of Sport Science, University of Vienna, Wien, Austria. Barrera Expósito, J. Sports Medicine School, Department of Human Physiology and Sports Physical Education, Faculty of Medicine, University of Málaga, Spain. Behan, H. Badminton Association of England, Milton Keynes, UK. Bernales, O. Human Performance Laboratory, Department of Physical Education, University of Las Palmas de Gran Canaria. Blasco, C. Department of Physical Education, University of Valencia, Valencia. Cabello, D. Faculty of Education, University of Granada, Spain. Calbet, J.A.L. Human Performance Laboratory, Department of Physical Education, University of Las Palmas de Gran Canaria. Carrasco, L. Faculty of Educational Sciences, University of Sevilla, Sevilla, Spain. Charland, T. French Table Tennis Association, Paris, France. Chevalier, R. CREOPP, Faculty of Sport Sciences, France. Choi, H. J. Centre for Performance Analysis, School of Sport, University of Wales Institute, Cardiﬀ, UK. Ciliga, D. Faculty of Kinesiology, University in Zagreb, Zagreb, Croatia.

xvi

List of contributors

Crespo, M. Coaching and Development Department, International Tennis Federation, Roehampton, UK. Dez¯ man, B. Faculty of Sport, University of Ljubljana, Slovenia. Dorado, C. Human Performance Laboratory, Department of Physical Education, University of Las Palmas de Gran Canaria. Faude, O. Institute of Sports and Preventive Medicine, University of Saarland, Saarbrücken, Germany and the Olympic Training Center RheinlandPfalz/Saarland, Saarbrücken, Germany. Farrow, D. Australian Institute of Sport. Fayt, V. UFR STAPS Liévin, Université d’Artois, France. Fries, M. Institute of Sports and Preventive Medicine, University of Saarland, Saarbrücken, Germany and the Olympic Training Center RheinlandPfalz/Saarland, Saarbrücken, Germany. Furjan-Mandic´, G. University of Zagreb, Faculty of Kinesiology, Croatia. Garrido, R.P. General Hospital of Alicante, Alicante, Spain. Garsztka, T. Department of Kinesiology, University of Physical Education, Poznan´ , Poland, and the Polish Tennis Federation Warszawa, Poland. Gijón Noguerón, G.A. Health Science School, University of Malaga, Spain. Gijón Noguerón, M. Podiatric Clinic Hnos, Granada, Spain. Girard, O. UPRES - EA 2991, Faculty of Sport Sciences, University of Montpellier 1, France. Gómez Píriz, P.T. University of Sevilla, Spain. Grivas, N. University Sports Centre, National University of Athens, Greece. Guadalupe-Grau, A. Human Performance Laboratory, Department of Physical Education, University of Las Palmas de Gran Canaria. Guerra, S. Human Performance Laboratory, Department of Physical Education, University of Las Palmas de Gran Canaria. Horiuchi, S. Faculty of Human Sciences, Waseda University, Japan. Hornery, D.J. Australian Institute of Sport, University of Ballarat, Australia and Tennis Australia. de Hoyo, M. Department of Didáctica de la Expresión Musical, Plástica y Corporal, Universidad de Sevilla, Spain. Hughes, M.D. CPA, UWIC, Cyncoed, Cardiﬀ, UK.

List of contributors

xvii

Hughes, M.G. Cardiﬀ School of Sport, University of Wales Institute, Cardiﬀ. Cardiﬀ, UK and Badminton England, National Badminton Club, Milton Keynes, UK. Hughes, M.T. English Institute of Sport, North West Region, Manchester, UK. Igawa, S. Faculty of Sport Science, Nippon Sport Science University, Japan. Jospin, L. UFR STAPS Liévin, Université d’Artois, France. Kahn, J.-F. Laboratory of Physiology, University of Paris 6, France and ITTF, Renens, Switzerland. Kindermann, W. Institute of Sports and Preventive Medicine, University of Saarland, Saarbrücken, Germany. Kodama, M. National Institute of Fitness and Sports in Kanoya, Japan. Kondricˇ, M. Faculty of Sport,University in Ljubljana, Ljubljana, Slovenia. Kornfeind, P. Department of Sport Science, University of Vienna, Wien, Austria. Kovacˇicˇ, S. Faculty of Electrical Engineering, University of Ljubljana, Slovenia. Kurata, H. National Institute of Fitness and Sports in Kanoya, Japan. Lapszo, J. Academy of Physical Education and Sport, Gdansk, Poland. Lazzari, S. UFR STAPS Liévin, Université d’Artois, France. Lees, A. Research Institute for Sport and Exercise Sciences. Liverpool John Moores University, Liverpool, UK. Lenartowicz , M. Department of Sociology, The Józef Piłsudski University of Physical Education in Warsaw, Poland. Leser, R. Department of Sport Science, University of Vienna, Austria. Leveque, F. UPRES - EA 2991, Faculty of Sport Sciences, University of Montpellier 1, France. Llopis Goig, D. Altorendimiento.net, Spain. Llopis Goig, R. Departament of Sociology, University of Valencia, Spain. López de Subijana, C. Faculty of Physical Activity and Sport Sciences, Alcala de Henares University, Spain. Maeda, A. National Institute of Fitness and Sports in Kanoya, Japan. Mantis, K. Department of Physical Education and Sport Science, Democritus University of Thrace, Greece.

xviii

List of contributors

Martínez, E. I.E.S. Cabo de la Huerta, Alicante, Spain. Matkovic´, B. Faculty of Kinesiology, University of Zagreb, Croatia. Matkovic´, B. R. Faculty of Kinesiology, University of Zagreb, Croatia. Mesa Alonso, A. Sports Medicine School, Department of Human Physiology and Sports Physical Education, Faculty of Medicine, University of Málaga, Spain. Meyers, R.W. Cardiﬀ School of Sport, University of Wales Institute Cardiﬀ (UWIC), Cardiﬀ, UK. Meyer, T. Institute of Sports and Preventive Medicine, University of Saarland, Saarbrücken, Germany. Micallef, J.-P. UPRES – EA 2991, Faculty of Sport Sciences, University of Montpellier 1, France. Millet, G.P. ASPIRE, Academy for Sport Excellence, Doha, Qatar. Miyazaki, M. Faculty of Human Sciences, Waseda University, Japan. Mujika, I. Department of Research and Development, Athletic Club Bilbao, Spain. Navarro, E. Faculty of Physical Activity and Sport Sciences, Polytechnic University of Madrid, Spain. Nishizono, H. National Institute of Fitness and Sports in Kanoya, Japan. O’Donoghue, P. G. School of Sport, University of Wales Institute Cardiﬀ, Cyncoed Campus, Cardiﬀ, UK. Olmedillas, H. Human Performance Laboratory, Department of Physical Education, University of Las Palmas de Gran Canaria. Oswald, E. Department of Sport Science, University of Vienna, Auf der Schmelz 6A, A-1150 Wien, Austria. Pain, M.D. Department of Sport and Recreation, Victoria University, Melbourne, Australia. París, F. Department of Didáctica de la Expresión Musical, Plástica y Corporal, Universidad de Sevilla, Spain. Pearce, A. J. Centre for Aging, Rehabilitation, Exercise and Sport (CARES), Victoria University, Melbourne, Australia. Pedisˇic´, Zˇ . Faculty of Kinesiology, University in Zagreb, Zagreb, Croatia. Persˇ, J. Faculty of Electrical Engineering, University of Ljubljana, Slovenia. Petrinovic´-Zekan, L. Faculty of Kinesiology, University in Zagreb, Zagreb, Croatia. Pradas, F. Faculty of Health and Sport Science, University of Zaragoza, Huesca, Spain.

List of contributors

xix

Rivas, F. Spanish Badminton Federation, Madrid, Spain. Ruz¯ ic´, L. Faculty of Kinesiology, University of Zagreb, Croatia. Ruiz, A. Badminton Spanish Federation and University of Alicante, Alicante, Spain. Rymarczyk, P. Department of Sociology, The Józef Piłsudski University of Physical Education in Warsaw, Poland. Sanchís-Moysi, J. Human Performance Laboratory, Department of Physical Education, University of Las Palmas de Gran Canaria. Sañudo, B. Department of Didáctica de la Expresión Musical, Plástica y Corporal, Universidad de Sevilla, Spain. Sato, T. Faculty of Sport Science, Nippon Sport Science University, Japan. Savelsbergh, G.J.P. Institute for Fundamental and Clinical Human Movement Sciences, Vrije Universiteit Amsterdam, The Netherlands and theInstitute for Biophysical and Clinical Research into Human Movement, Manchester Metropolitan University, UK. Seki, K. Faculty of Sport Science, Waseda University, Japan. Takahashi, H. National Institute of Fitness and Sports in Kanoya, Japan. Torres Luque, Gema, Catholic University of Murcia, Spain. Tudor-Barbaros, P. Faculty of Kinesiology, University of Zagreb, Croatia. Unierzyski, P. University School of Physical Education, Poznan, Poland. Van der Kamp, J. Institute for Fundamental and Clinical Human Movement Sciences, Vrije Universiteit Amsterdam, The Netherlands and the Institute of Human Performance, University of Hong Kong, Hong Kong. Vucˇ kovic´, G. Faculty of Sport, University of Ljubljana, Slovenia. Wada, T. National Institute of Fitness and Sports in Kanoya, Japan. Watanabe, E. Faculty of Human Health Science, Hachinohe University, Aomori, Japan. Williams, A.M. Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK. Young, W. University of Ballarat, Australia. Young, J. A. Department of Sport and Recreation, Victoria University, Melbourne, Australia. Ziemann, E. Department of Physiology, Academy of Physical Education and Sport, Gdan´ sk, Poland, and the Polish Tennis Federation Warszawa, Poland.

Preface

The meeting of the Fourth World Congress of Science and Racket Sports was held at the Spanish Olympic Centre, Madrid, 21–23 September 2006 and was hosted by the Spanish Badminton Association. The Congress was held in parallel with the World Badminton Championships which together with the presence of many coaches from the badminton world, provided a strong applied ﬂavour to the Congress. The World Congress of Science and Racket Sports series began in 1993 with the ﬁrst Congress being held at Runcorn, UK. The second was held at the National Sports Centre, Lilleshall, UK in 1997, and the third in Paris in 2003. They are a part of the academic programmes initiated by the World Commission of Science and Sports which, over the last three decades, has promoted applied sports science congresses on swimming, football, golf, cycling, cricket and winter sports. The broad aim of these congresses is to bring together scientists whose research work is concerned with particular sports, and practitioners in these sports who are interested in obtaining current information about scientiﬁc aspects. The aims of each congress are thus broadly similar and so when the opportunity arose to hold the congress in conjunction with a major World Championship this was welcomed. The scientiﬁc programme consisted of a series of keynote lectures, podium communications and poster presentations. The result was a well-attended congress with participants from every continent who were able to interact across the scientiﬁc disciplines and across the various racket sports. The organizers are indebted to the Spanish Badminton Federation and Madrid Town Hall whose sponsorship of the event ensured its success. The organizers are also grateful for the co-operation and support given by the following organizations and institutions: Spanish Sport Council – Ministry of Education Community of Madrid Spanish Olympic Committee University of Granada National Institute of Physical Education – University of Madrid

xxii

Preface Catholic University of Murcia World Badminton Federation Spanish Tennis Federation Spanish Tennis Table Federation Spanish Paddle Federation Spanish Squash Federation High Performance Publisher.

Introduction

This volume is the fourth in the Science and Racket Sport series and contains papers presented at the Fourth World Congress of Science and Racket Sports which was held at the Spanish Olympic Centre, Madrid, Spain, from 21–23 September 2006. Each manuscript has been subject to peer review by at least two expert referees and editorial judgement before being accepted for publication. This review process has ensured that there is consistency and a high level of scientiﬁc quality across all papers. We are particularly indebted to those anonymous reviewers without whose help this volume could never have been completed on time. The volume contains 42 papers covering all four racket sports, although several address issues which have application across all racket disciplines. The papers are organized into ﬁve scientiﬁc parts, each part representing a theme of the Congress and in most cases introduced by one of the keynote lectures. The choice of location of papers in a section was at the discretion of the editors and it is acknowledged that some papers could ﬁt happily into more than one section. A choice had to be made and it should be remembered that this choice was an attempt to aid the reader rather than to categorize work, which in many cases represents the best of interdisciplinary research. The sections and papers indicate current research in the racket sports and provide markers for the topics that researchers are currently addressing. Less than half of the papers presented at the Congress are included due to non-submission or rejection due to lateness or inadequate scientiﬁc merit. Nevertheless those contained within are a reasonable reﬂection of the topics covered within the Congress programme. The editors are grateful to the contributors for their painstaking preparation of the manuscript and their willingness to comply with the publisher’s guidelines and deadlines. We are also indebted to them for rapid and helpful responses to queries raised in the editing process. It is our aim that the papers in this volume should function as an up-todate reference for researchers in the racket sports and yield important current information for racket sport practitioners. The material may motivate others

2

Introduction

to embark on research programmes prior to the Fifth World Congress of Science and Racket Sports. Adrian Lees David Cabello Gema Torres

Part 1

Physiology of racket sports

1

Physiological testing in badminton O. Faude, T. Meyer, M. Fries and W. Kindermann

Introduction Badminton is a racket sport that involves intermittent, high-intensity exercise. Professional badminton requires a high level of technical skill, tactical competence and physical capacity. From a physiological point of view it is of primary interest to know the cardiovascular and metabolic demands of badminton. The aim of this report is to give an overview of characteristics and physiological demands of badminton match-play. In addition, consequences for physiological testing in badminton are presented and implications for the design of training programmes are outlined.

Characteristics of badminton match-play Match characteristics The size of a badminton court is 6.70 × 5.18 m (single) or 6.70 × 6.10 m (double), respectively. Since the rally point scoring system has been introduced, a match usually lasts between 20 min and an hour. Average match duration in the World Championship 2006 in Madrid was 33.6 min for womens’ and mens’ singles, respectively (www.internationalbadminton.org/ results.asp). Liddle et al. (1996) analysed ten elite male badminton players during competition and observed that they covered a total distance of 1862 m during singles and 1108 m during doubles matches. These distances are covered with frequent changes in speed and direction including distinct accelerations and decelerations. During one rally, professional players reach maximal velocities of about 4 m.s−1 over a maximal distance of 8 m (Kollath et al., 1987). In racket sports, there may be considerable diﬀerences in the temporal structure of the game (Docherty, 1982; Glaister, 2005). Mean rally times in squash, badminton, and tennis range from 5 to 10 s, the work to rest ratios are reported to vary between 1:1 (squash) and 1:5 (tennis). Average rally and rest time intervals in badminton during international tournament matches were reported to be 6.4 s and 12.9 s, respectively, with an average of 6.1 shots played per rally (Cabello and Gonzalez-Badillo, 2003). More than 80 per cent

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of all rallies are shorter than 10 s (Liddle et al., 1996; Cabello and GonzalezBadillo, 2003). Stroke frequency (SF) and eﬀective playing time (EPT) seem to be slightly higher in badminton (SF = 0.93 shots per second, EPT = 33 per cent, Cabello and Gonzalez-Badillo, 2003) compared to tennis (SF = 0.75 shots per second, EPT = 25 per cent, Smekal et al., 2001).

Physiological characteristics Knowledge about cardiovascular, metabolic and respiratory demands in certain types of sports provides the basis for adequate performance assessment and evidence-based design of training regimens. There are only a few published studies of physiological characteristics in badminton. Most of these studies were focused on heart rate data and blood lactate measurements during badminton competition. Docherty (1982) reported heart rate (HR) values of 80–85 per cent of the predicted maximal heart rate (HRmax) during badminton competition. More recent studies observed average values of 86 per cent (Majumdar et al., 1997), 91 per cent (Cabello and Gonzalez-Badillo, 2003) and 93 per cent HRmax (Liddle et al., 1996) during singles matches. These values demonstrate a high average intensity during badminton match-play. Blood lactate concentrations during high-level badminton matches were recorded between 3.8 and 4.7 mmol*l−1 (Majumdar et al., 1997; Weiler et al., 1997; Cabello and Gonzalez-Badillo, 2003). Weiler et al. (1997) analysed catecholamine concentrations during badminton training and high level competition. Although blood lactate concentrations were higher during the analysed training programme the relation between catecholamine and lactate concentrations was higher during real competition. This ﬁnding may reﬂect the greater psychological stress of the subjects during match-play. In addition to heart rate monitoring and blood lactate determinations, ambulatory gas exchange measurements oﬀer the opportunity to evaluate the physiological proﬁle of discipline-speciﬁc performance directly (Meyer et al., 2005a). Majumdar et al. (1997) estimated oxygen uptake (VO2) during badminton matches using heart rate data as well as the HR–VO2 relationship obtained during treadmill running and arrived at the conclusion that mean VO2 was about 57 per cent of maximal oxygen uptake (VO2max). Faccini and Dal Monte (1996) observed an average VO2 during badminton match-play of 35.7 ml.min−1 .kg−1 corresponding to 60.4 per cent VO2max in seven nationally ranked male Italian players. These values are higher than those observed during singles tennis match-play in six male players who reached an average VO2 of 25.6 ml.min−1 .kg−1 (~54 per cent VO2max, Ferrauti et al., 2001). Similar average VO2 values with considerable interindividual diﬀerences (VO2 ranging between 20 and 87 per cent VO2max) were reported by Smekal et al. (2001) in 20 male tennis players of the two highest leagues in Austria. These studies, however, reported average and maximal physiological values but no measures reﬂecting the sport-speciﬁc exercise dynamics.

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In our own approach, 12 internationally ranked badminton players (eight women, four men, VO2max = 50.3 ± 4.1 ml.min−1 .kg−1 (women) and 61.8 ± 5.9 ml.min−1 .kg−1 (men), respectively) were studied during a simulated badminton match of 2 × 15 min with ambulatory gas exchange (breath-bybreath) and heart rate measurements as well as the determination of blood lactate concentrations before, after 15 min and at the end of the match. Match characteristics were similar to those obtained by Cabello and GonzalezBadillo (2003) and, therefore, it is tenable that the observed data may adequately reﬂect real badminton conditions. Mean VO2, HR and blood lactate concentrations during the matches was 39.6 ± 5.7 ml.min−1 .kg−1 (73.3 per cent VO2max), 169 ± 9 beats.min−1 (89.0 per cent HRmax) and 1.9 ± 0.7 mmol.l−1, respectively. In one single subject, VO2 and HR during matchplay varied between 45 and 100 per cent VO2max and 78 and 100 per cent HRmax (unpublished data). The results of this descriptive study revealed a high average intensity of badminton match-play. Considerable ﬂuctuations in several physiological variables represent the intermittent nature of the game. The ﬁndings demonstrate the importance of alactacid as well as aerobic energy production in badminton. A well-developed aerobic endurance capacity seems to be necessary for a fast recovery between rallies or intensive training workouts. In contrast, anaerobic/lactacid capacity seems to be of minor importance.

Physiological testing The characteristics of badminton match-play suggest that a well-developed endurance capacity as well as the ability to generate high velocities over short distances (Kollath et al., 1987) are probably decisive in competititve high-level badminton. Therefore, important parameters may be endurance performance and speed abilities. Endurance and speed testing Maximal oxygen uptake (VO2max) is probably the most widely accepted single parameter for the estimation of endurance capacity in healthy subjects (Shephard et al., 1968). The VO2max values of competitive badminton players were reported to be in a range from 45 to 53.3 ml.min−1 .kg−1 (female subjects, Miao and Wang, 1988; Gosh et al., 1993;) and 55.7 to 63.4 ml.min−1 .kg−1 (male players, Faccini and Dal Monte, 1996; Majumdar et al., 1997; Miao and Wang, 1988), respectively. These values are comparable to male tennis players (57.3 ml.min−1 .kg−1, Smekal et al., 2001) and slightly lower than those of professional soccer players (50–75 ml.min−1 .kg−1, Stolen et al., 2005). Although VO2max is a generally accepted criterion for endurance capacity, there are several concerns with regard to the use of VO2max in the diagnosis of endurance performance. For instance, there are some methodological aspects which should be critically considered when using VO2max (Meyer et al., 2005b).

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In addition to the mode of exercise (e.g. running or cycling) and the protocol used to reach VO2max, it is important that subjects spend a suﬃcient degree of maximal eﬀort. This should be proven by objective parameters (e.g. VO2 plateau, maximal heart rate, and maximal blood lactate concentrations). Furthermore, it is questionable if VO2max is sensitive enough to detect slight but relevant diﬀerences or changes in endurance capacity in high-level athletes (Coyle et al., 1991). There is evidence that submaximal (lactate or ventilatory) thresholds give more exact information about the endurance capacity of diﬀerent individuals in homogenous groups (Coyle et al., 1991). Unfortunately, a review of the scientiﬁc literature on lactate and ventilatory thresholds will result in a variety of diﬀerent ‘threshold concepts’. In our working group the model of the individual anaerobic threshold (IAT) (Stegmann et al., 1981) has been developed. Several studies have shown that it estimates the maximal lactate steady state well (McLellan and Jacobs, 1993; Urhausen et al., 1993). It has been established for testing endurance capacity in various sports, mainly endurance and diﬀerent team sports. The German national badminton team in the mid-1990s reached average IAT values of 14.7 km.h−1 (Weiler et al., 1997; Weiler et al., 1996). German national squad soccer players at the same time had slightly lower values (~14.3 km.h−1, Meyer et al., 2000). In addition to endurance performance, Weiler et al. (1997) compared speed abilities of elite badminton players of diﬀerent nations using a 5 × 30 m sprint test, as it is often used in various game sports (e.g. soccer, Kindermann et al., 1998; Stolen et al., 2005). It was observed that elite Indonesian players (N = 7, top 15) were faster than the German team squad players, particularly over the ﬁrst 10 m. Because sprinting distance in one direction is never more than 8 m during badminton match-play (Kollath et al., 1987), Weiler et al. (1997) compared the 5 × 30 m sprint test with 10 × 10 m maximal sprinting. The authors did not ﬁnd any relevant diﬀerences between groups for the 5-m and 10-m split times. Therefore, a 10 × 10 m test may be similarily appropriate for testing straight sprint abilities of badminton players. Badminton-speciﬁc testing of endurance and agility Badminton players do not run in a straight direction for long distances. They play on a small-sided court with frequent changes in running direction. A limitation of testing general endurance capacity and ‘straight speed abilities’ might be that the speciﬁc musculature and movement patterns are not engaged suﬃciently. Therefore, it seems justiﬁed to use more discipline-speciﬁc approaches to assess endurance and speed abilities in badminton players. Chin et al. (1995) as well as Coen et al. (1998) employed an incremental ‘on-court’ test to evaluate badminton-speciﬁc endurance. A similar test protocol recently has been used in elite squash players (Girard et al., 2005). The test is designed as a stepwise increasing exercise test as it is common in routine sports medical context. Speed and direction are given by computerized

Physiological testing in badminton

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ﬂashing light signals placed on a board (six lights for four corners and two sides). The lights ﬂash up in a randomized order with a regulated frequency. Intensity is controlled by the frequency of the lights ﬂashing. From the lactate-workload plot it is possible to determine an individual anaerobic threshold. Chin et al. (1995) compared the rank order (based on objectice physiological assessment on the ﬁeld and on subjective impressions of the trainers) of 12 Hong Kong national team players with the results of this speciﬁc endurance test (4 mmol.l−1 anaerobic threshold). They found a signiﬁcant correlation of r = 0.65 and, therefore, concluded that this ﬁeld test allows a reasonable estimate of players’ discipline-speciﬁc ﬁtness levels and should be included as a means of on-court conditioning. A similar conclusion was obtained by Coen et al. (1998) who compared IAT determined from a graded running test and from the incremental ‘on-court’ test. A signiﬁcant correlation (r = 0.58) between IAT determined from both tests was observed although considerable inter-individual deviations were present. Therefore, it was concluded that the badminton-speciﬁc test gives detailed information on badminton-speciﬁc endurance capacity. This information allows assessors to monitor badminton-speciﬁc endurance training on the court. Because speciﬁc and general endurance capacity do not inevitably give intra-individually consistent results, complementary testing seems reasonable. Speed abilities with quick turns, decelerations and accelerations usually are determined by agility tests. Up to now, there are no published data on agility testing in high-level badminton players. Gabbett et al. (2006) described a socalled ‘T-Test’ for testing agility in 26 young, talented volleyball players. Players must run as quickly as possible along the agility course, which consists of four cones placed 5 m apart in the shape of an inverted T. This test seems appropriate for badminton, too (sprints of 5 to 10 m with quick turns). However, there are some concerns regarding the term ‘agility’. In a current review Sheppard and Young (2006) stated that there is no general agreement on a precise deﬁnition of agility within the sport science community. The authors proposed to deﬁne agility as ‘a rapid whole-body movement with change of velocity or direction in response to a stimulus’. Additionally, it is unclear which trainable components may enhance agility. From a theoretical point of view, the ability to accelerate, decelerate, and change direction rapidly might be an important prerequisite in badminton. Therefore, it seems appropriate to establish standardized and scientiﬁcally validated agility tests for badminton. Future research should evaluate adequate test procedures to obtain valid and reliable test results as well as reference values for high-level badminton players.

Implications for badminton training As it can be deduced from the characteristics of badminton match-play, aerobic and alactacid energy production form the dominant metabolic pathways

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during badminton match-play. Therefore, a fast resynthesis of phosphocreatine (PCr) stores between rallies seems to be an important factor for optimal physical performance. Tomlin and Wenger (2001) suggested that a welldeveloped aerobic ﬁtness enhances recovery from high-intensity intermittent exercise, particularly through an increased aerobic response during exercise as well as an enhanced PCr regeneration during breaks. Therefore, it can be assumed that an appropriate endurance capacity is necessary to allow for a fast recovery between rallies or intensive training workouts. Furthermore, it might be appropriate to reproduce the intermittent nature of badminton match-play in training sessions to improve alactacid pathways. Up to now, there is only one study of a training period with regard to improvements in physical ﬁtness in badminton players. Gosh et al. (1993) followed ﬁve female badminton players (age: 13–14 years) over a three-week training camp, which was dominated by speciﬁc on-court training at intensities in the range of 78 to 90 per cent of maximal heart rate. After the training camp they observed a 6 per cent and a 9 per cent increase in VO2max and ventilatory anaerobic threshold, respectively. As sample size was quite small and subjects were very young, the generalizability of these results to high-level athletes will have to be further evaluated. In our own study, we followed 40 international badminton players (mean age: 21.5 years) during a two months’ period of intensiﬁed training at the Badminton World Training Centre in Saarbrücken (unpublished data). The training programme focused on athletic and ﬁtness training. Athletes trained six days per week, twice each day for a total of 21.5 hours per week on average. About 32 per cent of this training consisted of technique and coordination training, for instance low-intensity multifeeding and footwork. About half of the total training amount was speciﬁc conditioning, including high-intensity multifeeding, footwork and matches. About 20 per cent of the total time was spent for general conditioning as well as weight and power training. A total of 17 female and 23 male players completed a graded running test at the onset as well as at the end of the training camp. Within this two months’ period subjects improved their IAT up to values comparable to those found in national squad members in badminton and soccer (females: +0.7 km.h−1, males: +0.6 km.h−1). It can be concluded that intensive badminton training with an emphasis on athletics and ﬁtness considerably improves endurance capacity of badminton players within two months. Some studies also evaluated the blood lactate responses during diﬀerent badminton-speciﬁc training programmes. For instance, Gosh et al. (1993) observed lactate levels during badminton training between 3.2 and 6.2 mmol.l−1. The highest lactate values were found during training without a shuttlecock (‘shadow play’). Weiler et al. (1997) reported individual lactate values between 3.4 and 10.5 mmol.l−1 (mean: 6.7 mmol*l−1) at the end of an intensive on-court training programme (1 vs. 2, 2 × 5 min with 10 min rest). Similarly, Majumdar et al. (1997) recorded lactate levels between 8.0 and

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10.5 mmol.l−1 during ﬁve diﬀerent on-court training programmes (‘shadow play’ and ‘multishuttle’ with various work-to-rest ratios). These results suggest that energetic requirements of typical intensive on-court training programmes are met with considerable contribution of lactacid pathways. Therefore, it seems obvious that metabolic pathways are trained even though they may be of minor importance in badminton match-play.

Conclusions and perspectives In summary, badminton match-play is characterized by high intensity, intermittent actions separated by short rest periods. The average intensity is about 70 per cent VO2max. Energy requirements are mainly met by aerobic and alactacid metabolic pathways. Therefore, a well-developed endurance capacity as well as good speed abilities over short distances with quick turns may be the most important performance prerequisites for badminton. The use of scientiﬁcally validated physiological tests is the basis for an evidence-based ﬁtness assessment and for rational training recommendations. Future research should focus on the evaluation of test procedures for badminton-speciﬁc endurance capacity and speed abilities. Badminton training regimens should be designed to induce the development of a suﬃcient endurance capacity. Additionally, it may be advisable to reproduce the intermittent nature of the sport, particularly with regard to alactacid energy production to improve badminton speciﬁc metabolic pathways. Future perspectives might be seen in ambulatory gas exchange measurements during typical training sessions to describe metabolic processes in more detail (Meyer et al., 2005a).

References Cabello, D. and Gonzalez-Badillo, J.J. (2003). Analysis of the characteristics of competitive badminton. British Journal of Sports Medicine, 37, 62–66. Chin, M.K., Wong, A.S., So, R.C., Siu, O.T., Steininger, K. and Lo, D.T. (1995). Sport speciﬁc ﬁtness testing of elite badminton players. British Journal of Sports Medicine, 29, 153–157. Coen, B., Urhausen, A., Weiler, B., Huber, G., Wiberg, F. and Kindermann, W. (1998). Speciﬁc performance diagnostics in badminton. International Journal of Sports Medicine, 19, S22 (Abstract). Coyle, E.F., Feltner, M.E., Kautz, S.A., Hamilton, M.T., Montain, S.J., Baylor, A.M., Abraham, L.D. and Petrek, G.W. (1991). Physiological and biomechanical factors associated with elite endurance cycling performance. Medicine and Science in Sports and Exercise, 23, 93–107. Docherty, D. (1982). A comparison of heart rate responses in racquet games. British Journal of Sports Medicine, 16, 96–100. Faccini, P. and Dal Monte, A. (1996). Physiologic demands of badminton match play. American Journal of Sports Medicine, 24, S64–S66. Ferrauti, A., Bergeron, M.F., Pluim, B.M. and Weber, K. (2001). Physiological

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responses in tennis and running with similar oxygen uptake. European Journal of Applied Physiology, 85, 27–33. Gabbett, T., Georgieﬀ, B., Anderson, S., Cotton, B., Savovic, D. and Nicholson, L. (2006). Changes in skill and physical ﬁtness following training in talent-identiﬁed volleyball players. Journal of Strength and Conditioning Research, 20, 29–35. Girard, O., Sciberras, P., Habrard, M., Hot, P., Chevalier, R. and Millet, G.P. (2005). Speciﬁc incremental test in elite squash players. British Journal of Sports Medicine, 39, 921–926. Glaister, M. (2005). Multiple sprint work: physiological responses, mechanisms of fatigue and the inﬂuence of aerobic ﬁtness. Sports Medicine, 35, 757–777. Gosh, A.K., Goswami, A., and Ahuja, A. (1993). Evaluation of a sports speciﬁc training programme in badminton players. Indian Journal of Medical Research, 98, 232–236. Kindermann, W., Coen, B. and Urhausen, A. (1998). Leistungsphysiologische Maßnahmen im Fußball und Handball. [Performance diagnostics in soccer and handball]. Deutsche Zeitschrift für Sportmedizin, 49, 56–60. Kollath, E., Bochow, W. and Quade, K. (1987). Kinematische Wettkampfanalyse im Badminton. [Kinematic competition analysis in badminton]. Leistungssport, 21–25. Liddle, S.D., Murphy, M.H. and Bleakley, W. (1996). A comparison of the physiological demands of singles and doubles badminton: a heart rate and time/motion analysis. Journal of Human Movement Studies, 30, 159–176. McLellan, T.M. and Jacobs, I. (1993). Reliability, reproducibility and validity of the individual anaerobic threshold. European Journal of Applied Physiology, 67, 125–131. Majumdar, P., Khanna, G.L., Malik, V., Sachdeva, S., Arif, M. and Mandal, M. (1997). Physiological analysis to quantify training load in badminton. British Journal of Sports Medicine, 31, 342–345. Meyer, T., Ohlendorf, K. and Kindermann, W. (2000). Longitudinal analysis of endurance and sprint abilities in elite German soccer players. Deutsche Zeitschrift für Sportmed, 51, 271–277. Meyer, T., Davison, R.C. and Kindermann, W. (2005a). Ambulatory gas exchange measurements: current status and future options. International Journal of Sports Medicine, 26 Suppl 1, S19–27. Meyer, T., Scharhag, J. and Kindermann, W. (2005b). Peak oxygen uptake. Myth and truth about an internationally accepted reference values. Zeitschrift für Kardiologie, 94, 255–264. Miao, S.K. and Wang, S.W. (1988). The measurement of aerobic, anaerobic capacity and extremital strength of Chinese top badminton players. Abstracts New Horizons of Human Movement, 3, 252. Shephard, R.J., Allen, C., Benade, A.J., Davies, C.T., Di Prampero, P.E., Hedman, R., Merriman, J.E., Myhre, K. and Simmons, R. (1968). The maximum oxygen intake. An international reference standard of cardiorespiratory ﬁtness. Bulletin of the World Health Organization, 38, 757–764. Sheppard, J.M. and Young, W.B. (2006). Agility literature review: classiﬁcations, training and testing. Journal of Sports Sciences, 24, 919–932. Smekal, G., von Duvillard, S.P., Rihacek, C., Pokan, R., Hofmann, P., Baron, R., Tschan, H. and Bachl, N. (2001). A physiological proﬁle of tennis match-play. Medicine and Science in Sports and Exercise, 33, 999–1005.

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Stegmann, H., Kindermann, W. and Schnabel, A. (1981). Lactate kinetics and individual anaerobic threshold. International Journal of Sports Medicine, 2, 160–165. Stolen, T., Chamari, K., Castagna, C. and Wisloﬀ, U. (2005). Physiology of soccer: an update. Sports Medicine, 35, 501–536. Tomlin, D.L. and Wenger, H.A. (2001). The relationship between aerobic ﬁtness and recovery from high intensity intermittent exercise. Sports Medicine, 31, 1–11. Urhausen, A., Coen, B., Weiler, B. and Kindermann, W. (1993). Individual anaerobic threshold and maximum lactate steady state. International Journal of Sports Medicine, 14, 134–139. Weiler, B., Urhausen, A., Coen, B., Weiler, S. and Kindermann, W. (1996). Sportsmedical performance diagnostics in badminton players. International Journal of Sports Medicine, 17, S20 (Abstract). Weiler, B., Urhausen, A., Coen, B., Weiler, S., Huber, G. and Kindermann, W. (1997). Sportmedizinische Leistungsdiagnostik (allgemeine Laufausdauer und Sprintvermögen) und Streßhormon-Messungen im Wettkampf bei Badmintonspielern der nationalen und internationalen Spitzenklasse. [Sportsmedical performance diagnosis (general endurance and speed) and stress hormone determination in competition in badminton players of national and international level]. Sportorthopädie – Sporttraumatologie, 13, 5–12.

2

Core temperature and hydration status in professional tennis players measured in live tournament conditions A.J. Pearce

Introduction The physiological demands of tennis are well published (see reviews by Kovacs, 2006 and Fernandez et al., 2006) and vary between standard of player (Bernardi et al., 1998), surfaces played on (Hughes and Clarke, 1995) and playing styles/strategies (Hughes and Moore, 1998). In addition to the physically demanding aspects of tennis, another major challenge presented to players is the environment. Heat, and dehydration in particular, present major obstacles to performance (Marks et al., 2004). Dawson et al. (1985) observed that professional tennis players, competing in year-round tournament calendars, participate in a wide variety of climatic conditions from cool and dry conditions to hot and/or humid conditions. For many players, life on the professional circuit is diﬃcult. Unlike major tournaments, such as the Grand Slams, where players may have a day’s rest in-between to recover from their matches (if they are only playing singles), for players participating in lower tiered events run by the International Tennis Federation (ITF) which includes Satellite, Challenger and Futures events, it is common to be playing on a daily basis. Adding further diﬃculty, timing of matches is unpredictable and in some cases a player may have to compete in several matches a day. For these players, issues of heat adaptation and hydration practices are important. The ITF and a number of National Tennis Federations have adopted policies for hot conditions whereby play will be suspended when the dry bulb globe temperature (ambient temperature) and wet bulb globe temperature (heat stress) reach a particular limit. These heat policies have been developed from generic sports medicine and military research data (Sparling and MillardStaﬀord, 1999; Bricknell, 1996). Given that these heat policies are based on generic data, and with recent cases of players suﬀering from heat stress during professional tournament play, the need to develop tennis-speciﬁc guidelines has been raised by the ITF Medical Commission. To date, research in thermoregulation and hydration practices speciﬁc to tennis has only been conducted under simulated tennis conditions (Dawson et al., 1985; Bergeron et al., 1991; Kavasis, 1995; Therminarias et al., 1995; McCarthy et al., 1998).

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Therefore the purpose of this study was to examine core temperature responses and hydration status measured in professional touring players during live tournament conditions.

Methods Participants All professional tennis players who entered ITF and Tennis Australia sanctioned professional tournaments in South Australia and Victoria, Australia, in 2004 and 2005 were invited to participate in the study. Eleven players (three male, eight female; aged between 19 and 30 years of age) participated. All methods were approved by Victoria University Human Ethics Committee and the ITF Medical Commission. Data were collected over three tournaments played on hard courts. Testing Measurement of environmental conditions (ambient temperature as measured by dry globe bulb temperature (DBGT); relative humidity (RH); and heat stress as measured by wet bulb globe temperature (WBGT)) were conducted using an environmental measurement monitor (Kestrel 3000, Nielsen-Kellerman, USA). For regional tournaments where continuous oncourt measurements were not taken, measurements were obtained from the Melbourne and Adelaide Bureau of Meteorology at the weather station closest to the tournament site. Hydration status was measured using a hand-held refractometer (Atago Co., Japan) presenting a measure of the player’s urine speciﬁc gravity (g.ml−1). Players provided a ‘clean-catch’ (mid-stream) sample pre- and postmatch. Body mass before and after the match were measured to the nearest 100 g using scales which were calibrated daily during the events. Each player’s internal core temperature was measured via ingestion of a CorTemp176 core body temperature sensor pill (Figure 2.1). The sensor pill transmitted the player’s core temperature and measured by CorTemp176 wireless telemetry system during the 90-s change of ends when players were seated. The measure of progressive core temperature was taken without disturbing the players during their rest time (Figure 2.2). Due to small numbers of subjects participating in the study, descriptive statistics are presented as means and standard deviations.

Results The time duration of matches recorded during the tournaments ranged from 50 min to 160 min. No players experienced any form of heat illness during the tournaments nor adverse aﬀects from swallowing the temperature

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Figure 2.1 Core body temperature sensor pill.

sensor. Of the 11 players participating, ﬁve progressed past the ﬁrst round, with three of these players participating in three or more consecutive rounds. Environmental conditions The environmental conditions varied throughout the three tournaments. On-court ambient temperature DBGT recorded during all tournaments ranged between 17 and 38°C. However, only one of the days, in all three tournaments, saw ambient temperature exceed 35°C. Heat stress, measured by WBGT, ranged from 10.8 to 29.0°C with WBGT exceeding 28.0°C on the same day as ambient temperature exceeded 35°C. Relative humidity ranged between 14 and 93 per cent. Hydration status: urine speciﬁc gravity and body mass Pre-match hydration measures ranged between 1.003 to 1.024 g.ml−1 (mean 1.014 ± 0.008 g.ml−1) with post-match measures ranging between 1.004 to 1.025 g.ml−1 (mean 1.012 ± 0.010 g.ml−1). Table 2.1 presents individual pre-match and post-match hydration levels. In ﬁve of the matches players presented with decreased hydration status post-match (range 0.004 to 0.013 g.ml−1), however, in four matches players presented with an increased hydration status post-match (range 0.005 to 0.017 g.ml−1). Three matches showed no change in hydration status. The change in body mass (Table 2.2) from before to after matches ranged

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17

Figure 2.2 Measurement of a player in-match during change of ends.

from 2.9 per cent deﬁcit to 2.0 per cent increase pre- and post-match (mean 0.09 ± 1.28 per cent deﬁcit). Analysis of individual matches showed that in ﬁve matches, players lost weight (range 0.27 per cent to 2.9 per cent of body weight). In eight matches players showed increased weight post-match (range 0.15 per cent to 2 per cent), and in two matches no change was observed. Core temperature measures All players experienced an increase in core temperature during the match ranging between 0.1 to 2.3°C (Table 2.3). Individual analysis showed little correlation between the ambient temperature and a player’s mean core temperature (r = −0.28). Four of the ﬁve players showed an overall trend of increased mean core

18

A.J. Pearce

Table 2.1 Hydration status as measured by speciﬁc gravity (g.ml−1) Subject

Round 1

Round 2

Round 3 Post

Pre

Round 4

Pre

Post

Pre

Post

Pre

Post

1 2 3 4 5 6 7

1.014 1.015 1.014 1.004 1.004 1.020 1.024

N/A 1.028 1.020 1.004 1.004 1.025 1.007

8 9 10 11

1.005 N/A N/A N/A

1.005

Out of tournament Out of tournament 1.020 1.025 Out of tournament Out of tournament Out of tournament 1.015* N/A 1.015 1.005 1.015* N/A 1.003 1.007 1.017 1.007 Out of tournament Out of tournament N/A Out of tournament Out of tournament 1.025* N/A 1.025 1.020 1.025* N/A

Notes: N/A refers to players unable to provide a urine sample * Rain delay aﬀected post-match hydration status results

Table 2.2 Hydration status as measured by changes in athlete body mass (kg). A negative number represents a loss in body mass; a positive number represents a gain in body weight Subject

Round 1

Round 2

1 2 3 4 5 6 7 8 9 10 11

N/A* 0.0 0.2 −0.2 0.2 −0.3 1.0 0.5 −1.4 −2.6 N/A*

Out of tournament Out of tournament 0.3 Out of tournament Out of tournament N/A* 0.0 Out of tournament −0.8 Out of tournament N/A*

Round 3

Round 4

Out of tournament

1.35 0.5

N/A* Out of tournament

Out of tournament 0.5

Notes: N/A refers to players did not provide body mass sample * Rain delay aﬀected post-match body weight results

N/A*

Core temperature and hydration status

19

Table 2.3 Core temperature at match start, peak and mean core temperature during player’s ﬁrst match across three tournaments Subject

Core temperature – match start (°C)

Core temperature – peak (°C)

Core temperature – mean (°C)

1 2 3 4 5 6 7 8 9 10 11

37.2 38.1 37.9 37.6 38.3 37.1 38.4 37.7 37.3 36.4 37.3

39.5 38.6 38.5 37.8 39.1 37.8 38.5 37.8 38.7 37.4 39.6

38.5 38.4 38.0 37.7 38.8 37.3 38.4 37.7 38.0 36.6 38.1

Table 2.4 Mean core temperature responses in ﬁve players who progressed past the ﬁrst round Subject

Round 1 (°C)

Round 2 (°C)

Round 3 (°C)

3 6 7 9 11

38.04 36.82 38.44 37.99 N/A

37.43 38.00 38.57 38.76 38.15

Out of tournament 38.22 39.68 Out of tournament 36.44

Round 4 (°C)

38.68 Out of tournament 38.59

Note: N/A – not available.

temperature in the preceding day’s matches (Table 2.4). Of the nine matches where core temperature was recorded, seven caused an increase in mean core temperature compared to the previous day’s match.

Discussion This study is the ﬁrst to present core temperature and hydration status data from professional tennis players under live competitive tournament playing conditions. All players who participated in the study were provided with a personalized report of their hydration status and core temperature results from the matches) played. The results suggest that despite inadequate pre-match and during-match hydration status in some players, players involved in ‘singular’ matches (where players are playing in their ﬁrst match and/or only play one round)

20

A.J. Pearce

did not present with extremely elevated core body temperatures. Players who progressed through several rounds showed an increased mean core temperature compared to their previous match (in all but two matches) notwithstanding on-court environmental conditions. Given the nature of professional tennis tournaments where players are not fully aware of when they are playing (organizers schedule matches in order of play on each court rather than to time), standardization issues such as providing a urine sample, and the ingestion of the temperature sensor contributed to missed data points. Further, several athletes who initially volunteered for the study withdrew prior to the tournament or in the initial stages of their ﬁrst match due to injury. Studies simulating tennis play (Dawson et al., 1985; Bergeron et al., 1995; McCarthy et al., 1998) have shown decreases in body weight that suggest dehydration. However, in this study an increase in body mass and improvement in hydration status was observed in a number of players. Four players started their matches in a dehydrated state, deﬁned by Stuempﬂe and Drury (2003) as urine speciﬁc gravity >1.020, and hydratied during changeovers in the match. Despite numerous articles on athlete hydration in the coaching and sports science literature (Groppel, 2002; Mannie, 2004; Armstrong, 2006), eight of the eleven players participating in the study admitted they were unaware of their hydration status or admitted they did not prepare properly. Core temperature results from single and/or ﬁrst round matches were similar (or slightly lower) to those reported by Dawson et al. (1985) and Therminarias et al. (1995), being 38.4°C in college and intermediate level players respectively. The trend of increasing mean core temperatures in players in progressive matches needs to be further explored. Further study and data collection of players’ core temperature and hydration status needs to be conducted under live tournament conditions where valuable ranking points and prize money are at stake. More importantly research must continue with a view to obtaining thermoregulatory data on days of extreme and stressful heat as the current study was limited in the actual temperature range in which data were collected. This would allow for meaningful and speciﬁc evidence-based data to assist the ITF, WTA/ATP and tennis federations in determining and regulating player heat stress, and the development of appropriate and tennis-speciﬁc heat policies.

Acknowledgments Funding for the study was provided by the International Tennis Federation and Smartplay (Sports Medicine Australia, Victoria Branch).

References Armstrong, L.E. (2006). Nutritional strategies for football: counteracting heat, cold, high altitude and jet lag. Journal of Sports Sciences, 24, 723–741.

Core temperature and hydration status

21

Bergeron, M.F., Maresh, C.M., Kraemer, W.J., Abraham, A., Conroy, B. and Gabaree, C. (1991). Tennis: a physiological proﬁle during match play. International Journal of Sports Medicine, 12, 474–479. Bergeron, M.F., Armstrong, L.E. and Maresh, C.M. (1995). Fluid and electrolyte losses during tennis in the heat. Clinics in Sports Medicine, 14, 23–32. Bernardi, M., De Vito, G., Falvo, M.E., Marino, S. and Montellanico, F. (1998). Cardiorespiratory adjustment in middle-level tennis players: Are long term cardiovascular adjustments possible? In Science and Racket Sports II (edited by A. Lees, I. Maynard and T. Reilly), London: E&FN Spon, pp. 20–26. Bricknell, M. (1996). Heat illness in the army in Cyprus. Occupational Medicine, 46, 304–312. Dawson, B., Elliott, B.C., Pyke, F. and Rogers, R. (1985). Physiological and performance responses to playing tennis in a cool environment and similar intervalised treadmill running in a hot climate. Journal of Human Movement Studies, 11, 21–34. Fernandez, J., Mendez-Villanueva, A. and Pluim, B.M. (2006). Intensity of tennis match play. British Journal of Sports Medicine, 40, 387–391. Groppel, J. (2002). Heating up – plan for play in extreme conditions. ADDvantage, 26, 6–7. Hughes, M. and Clarke, S. (1995). Surface eﬀect on elite tennis strategy. In Science and Racket Sports (edited by T. Reilly, M. Hughes and A. Lees), London: E&FN Spon, pp. 272–278. Hughes, M. and Moore, P. (1998). Movement analysis of elite level male ‘serve and volley’ tennis players. In Science and Racket Sports II (edited by A. Lees, I. W. Maynard, M. Hughes and T. Reilly), London: E&FN Spon, pp. 254–259. Kavasis, K. (1995). Fluid replacement needs of young tennis players. In Science and Racket Sports (edited by T. Reilly, M. Hughes and A. Lees), London: E&FN Spon, pp. 21–27. Kovacs, M.S. (2006). Applied physiology of tennis performance. British Journal of Sports Medicine, 40, 381–386. McCarthy, P.R., Thorpe, R.D. and Williams, C. (1998). Body ﬂuid loss during competitive tennis match-play. In Science and Racket Sports II (edited by A. Lees, I.W. Maynard, M. Hughes and T. Reilly), London: E&FN Spon, pp. 52–55 Mannie, K. (2004). Tip from the trenches. Coach and Athletic Director, 74, 12. Marks, B.L., Angelopoulos, T.J., Shields, E., Katz, L.M., Moore, T., Hylton, S., Larson, R. and Wingo, J. (2004). The eﬀects of a new sports drink on fatigue factors in competitive tennis athletes. In Science and Racket Sports III (edited by A. Lees, J.-F. Kahn and I.W. Maynard), London: Routledge, pp. 9–14. Sparling, P.B. and Millard-Staﬀord, M.L. (1999). Keeping sports participants safe in hot weather. Physician and Sports Medicine, 27, 9. Stuempﬂe, K.J. and Drury, D.G. (2003). Comparison of 3 methods to assess urine speciﬁc gravity in collegiate wrestlers. Journal of Athletic Training, 38, 315–319. Therminarias, A., Dansou, P., Chirpz, M.F., Eterradossi, J. and Favre-Juvin, A. (1995). Cramps, heat stroke and abnormal biological responses during a strenuous tennis match. In Science and Racket Sports (edited by T. Reilly, M. Hughes and A. Lees), London: E&FN Spon, pp. 28–32.

3

Anaerobic performance during intermittent exercise and body composition in tennis players of diﬀerent biological and chronological ages E. Ziemann and T. Garsztka

Introduction Tennis is a sport characterized by a variety of demands on the human body, all depending on the level of play. Tennis requires coordination, agility, speed, quickness, cardio-respiratory endurance, local muscle endurance, strength and power. Each aspect becomes more important at higher levels of play. The somatic characteristics of body size, structure and composition are substantial determinants of athletic success. The training process of a tennis player should develop each ﬁtness component and metabolic pathway, especially the anaerobic lactic and alactic system. Furthermore the training load may be modiﬁed by age and game style. A player’s game style and physical characteristics will have an impact on the type of conditioning the player should perform. At 14 years, girls can start an individualized physical conditioning programme according to their game style and physical characteristics recommended by the International Tennis Federation. Boys may begin such a programme soon thereafter. The question is whether biological or chronological age is more important for performance and training. The focus of this study was to assess the inﬂuence of body size and composition on anaerobic performance of tennis players from diﬀerent age groups during intermittent workloads. We have investigated the relationship between anaerobic power and anaerobic capacity and body composition (fat mass, fat-free mass). Anaerobic capacity and power are usually tested in the laboratory using advanced equipment. On the court it is possible to control several features of physical ability (coordination, agility, speed and so on) but a correlation between laboratory results and the athlete’s tennis stroke rating have been shown to be poor (Kovacs, 2006). The purpose of our study was to investigate the relationship between selected physiological responses during laboratory and on-court test.

Anaerobic performance

23

Methods Participants Eighteen male tennis players, all members of the Polish Tennis Federation, took part in this study. They were ranked among the highest in their age categories. The subjects were separated into four groups depending on their chronological age. Preliminary testing Body composition was estimated by bio-electrical impedance using Tanita Body Fat Monitor/Scale Analyser TBF-300 on the ﬁrst testing day. Then subjects performed supra-maximal 15-s Wingate tests on a cycle ergometer (Monark Sprint Bike 884E) following the procedure of Bar Or (Bar Or, 1978, 1987). This exercise was completed four times with 45-s rest between tests. Before the ﬁrst Wingate test the participant performed a warm-up lasting 3 min. Then the subject pedalled as rapidly as possible for 15-s and against resistance of 0.74 N⭈kg−1 body mass. During the test we measured the following values: total work, maximal power output, fatigue index, time to peak power and time of sustained peak power. Experimental testing Two days later a tennis-speciﬁc drill (Figure 3.1) was performed. The drill was labelled ‘PUST’, an acronym derived from the Polish language words describing the movements performed. These movements were similar to those made during a tennis match (run, forehand, backhand, volley and smash). This exercise was performed with a tennis racket in hand but without a tennis ball. The elapsed time was measured by timing gates. This tennis drill was repeated six times with a 30-s break after each drill (Garsztka, 2003). Environmental conditions The laboratory test was performed in ambient conditions of 20–22 °C, and 60 per cent humidity. The ﬁeld test was performed in ambient conditions of 19–21 °C and 65 per cent humidity. Statistics Statistical analysis was performed by using Statistica 6.0 for Windows. Data are presented as mean values ± standard deviation (SD). Diﬀerences between groups and between each test was evaluated by RIR Tukey test. Signiﬁcance was set at P < 0.05 Correlations were computed by the Pearson Product Moment.

24

E. Ziemann and T. Garsztka

Figure 3.1 Directions of movement during the ‘PUST’ tennis-speciﬁc drill.

Results Body composition The anthropometric data of subjects are shown in Tables 3.1 and 3.2. Fat mass ranged from 10 to 18 per cent. The group of 17 year olds had the highest per cent fat mass and total amount of fat (kg). There was signiﬁcant diﬀerence in fat mass observed between the 17 and 15 year olds. Anaerobic performance The anaerobic performance results tests are presented in Table 3.3. The smallest diﬀerence between ﬁrst and last anaerobic test was observed in the group of 16-year-old tennis players. The anaerobic capacity and anaerobic power during the last trial were 11 per cent and 9.5 per cent lower respectively than in the ﬁrst test. A signiﬁcant negative correlation between lean body mass and values of total work J⭈kg−1 was noticed only for the 15 year olds during the second and third tests (r = −0.92, r = −0.92) respectively. There were no other signiﬁcant correlations between anaerobic performance measures and body composition in the other groups. Body mass for the 18 and 16 year olds was correlated

Anaerobic performance

25

Table 3.1 Anthropometric characteristics of subjects (chronological age) Subjects Mass (kg) Age 18 N=4 Age 17 N=5 Age 16 N=4 Age 15 N=5

Height (m)

Fat (%) FM (kg)

77.0±4.4 1.84±0.067 14.2±4.7 11.3±3.9 76.5±12

FFM (kg)

FFM/ FM

BMI

63.6±3.5* 6.4±2.9 22.1±0.6

1.80±0.068 18.4±5.4 14.5±5.0* 61.9±8.0

64.8±9.4 1.77±0.061 14.3±4.1

9.4±4.0

63.3±3.5 1.76±0.051 11.0±1.6

7.0±1.2* 56.1±3.1

5.1±3.3 23.4±2.8

53.3±5.5* 6.0±2.8 20.6±2.1 8.2±0.8 20.2±1.4

Notes: Values are mean range ± SD, N – number of subjects, BMI – Body Mass Index, FM – fat mass, FFM – free fat mass * 17–15 P<0.05 Values signiﬁcantly diﬀerent

Table 3.2 Anthropometric characteristics of subjects (biological age) Subjects

Mass (kg)

Height (m)

Fat (%)

FM (kg)

FFM (kg))

Age 18 N=9 Age 17 N=2 Age 16 N=2 Age 15 N=5

77.7±8.2

1.83±0.050

16.9±4.2*

13.4±4.3*

63.6±5.3

66.5±5.2

1.79±0.056

13.5±2.1N

9.05±1.8N

54.7±0.4

66.2±2.8

1.75±0.007

12.5±2.1

8.3±0.8

57.8±3.7

60.1±5.1

1.72±0.027

10.0±1.7*N

5.9±1.3*N

53.9±4.2

Notes: * 18–15 P < 0.03 N 17–15 P < 0.02

with the fatigue index during the third and fourth test. In these groups there were positive correlations r = 0. 9 and r = 0.97 between those results. The biological age (Cieslik and Kaczmarek, 1994) of these tennis players was determined for comparison with chronological age. The chronological age was not the same as the biological age in every case. Many tennis players had a higher biological age compared to their chronological age. In players whose biological age was 18, a positive correlation between body mass and total anaerobic work J⭈kg−1 (r = 0.76 r = 0.75) and anaerobic power W⭈kg−1 (r = 0.75, r = 0.77) was observed in the ﬁrst and the second tests. A similar correlation was also noticed in 15-year-old boys but only during the ﬁrst test. PUST performance Table 3.4 shows the elapsed time for the speciﬁc tennis drill by repetition. There were no signiﬁcant diﬀerences between biological age groups. The

141±2.3* 136±8.5 122±6.6 116±12*

11.2±0.6⭈ ⭈ 10.6±0.9 9.6±0.7⭈ ⭈ 9.2±0.7⭈ ⭈ 10.5±1.6 10.1±0.7 9.3±0.7 8.72±0.9

145±9.2* 137±5.9 133±2.1 128±5.1*

(J⭈kg−1) 10.5±0.5⭈ ⭈ 10.0±0.4 9.8±0.1 9.5±0.2⭈ ⭈

(W⭈kg−1)

16-year-old group

138±5.6 132±7.5 125±3.5 117±8.4

(J⭈kg−1)

9.122±0.2

9.346±0.5 9.228±0.4 9.226±0.4

Age 18

Age 17 Age 16 Age 15

Time 1 (s)

9.427±0.6 9.102±0.4 9.111±0.3

9.234±0.6

Time 2 (s)

9.393±0.4 9.229±0.4 9.231±0.4

9.162±0.2

Time 3 (s)

9.265±0.6 9.227±0.4 9.225±0.5

9.332±0.3

Time 4 (s)

9.431±0.7 9.147±0.4 7.358±0.3

9.457±0.4

Time 5 (s)

9.375±0.4 9.158±0.4 9.185±0.5

9.377±0.6

Time 6 (s)

9.416±0.9 9.175±0.4 9.204±0.4

9.283±0.3

Time (average)

11.0±0.3⭈ ⭈ 10.0±0.3⭈ ⭈ 9.4±0.3⭈ ⭈ 9.0±0.4⭈ ⭈

(W⭈kg−1)

15-year-old group

Values signiﬁcantly diﬀerent determined by Tukey test *1–3 P < 0.005, *1–4 P < 0.0007, ⭈ ⭈1–3 P < 0.03, ⭈ ⭈1–4 P < 0.008, ⭈1–4 P < 0.04 *1–4 P < 0.003 *1–4 p < 0.007, ⭈ ⭈1–4 P < 0.007, ⭈ ⭈1–2 P < 0.001, ⭈ ⭈1–3 P < 0.0001, ⭈ ⭈1–4 p < 0.0001, ⭈ ⭈2–3 P < 0.03, ⭈ ⭈2–4 P < 0.0009

150±7.3* 141±8.3 128±6.7* 121±7.0*

(J⭈kg−1)

(W⭈kg−1)

(J⭈kg−1)

(W⭈kg−1)

17-year-old group

18-year-old group

Table 3.4 Time of ‘PUST’ tennis drills in relation to biological age

Notes: 18 years 17 years 16 years 15 years

Test 1 Test 2 Test 3 Test 4

No. of test

Table 3.3 Physiological characteristics in anaerobic capacity and anaerobic power in biological groups (total work expressed in (J⭈kg−1) and power expressed in (W⭈kg−1))

Anaerobic performance

27

PUST scores were regressed against anaerobic power and capacity variables (Wingate test). The correlation was strongest for the biological 18 year olds for anaerobic power at every repetition (r = −0.85, r = −0.60, r = −0.62, r = −0.74, Figure 3.1). Similar correlations were observed between anaerobic capacity expressed in total work and average time of PUST (r = −0.92, r = −0.76, r = −0.64, r = −0.82).

Discussion and conclusion The testing of physical abilities related to performance and competition should indicate the eﬀectiveness of training. Tennis match-play is primarily characterized by variety of short duration intermittent workloads of the body’s muscular system with extensive and intensive work phases. Earlier analyses by Kovacs (2004) have shown that mean duration of work and rest periods during a tennis match are 5–10-s and 10–20-s respectively. The energy requirements for a tennis match depend on the length and intensity of the rally. International Tennis Federation investigators determined that the anaerobic (alactic) system provides 70 per cent and lactic 20 per cent of all energy expenditure (Crespo and Miley, 1998). The restoration of the phosphagen compounds from one performance to another is thus of obvious importance. The replenishment of the muscle phosphagen store is rapid (75 per cent of PCr used during exercise was restored within 1 minute of rest) after maximal eﬀort. The rest time during a game lasts approximately 20-s between points and 90-s between changeovers. This time is too short for complete whole phosphagen store replenishment leading to a surge in demand for anaerobic metabolism. In our study, anaerobic power and capacity were measured during the Wingate test. Fox and Matthews (1974) suggested a training interval for improving the ATP/PC energy system using a work–rest ratio of 1:3. That is the reason for using the 15-s followed by 45-s rest in the Wingate test. We investigated the correlation between these anaerobic performances and a speciﬁc tennis drill (PUST). We evaluated anaerobic power (ATP-CP system) through power, power relative to body mass and time to sustain and approach maximum power output; and anaerobic capacity (glycolitic energy system) through total work, work relative to body mass and fatigue index. We observed signiﬁcant and strong correlation between the Wingate and PUST tests for only one group whose biological age was 18 years. We observed that body composition inﬂuenced anaerobic performance. In young players this correlation was negative. The higher the body mass, the lower the anaerobic capacity during repeated exercise. This relationship may lead to undesirable performance results in a tennis match. Nevertheless, players with lower technical ability may favourably compensate their performance through a high level of anaerobic capacity. Some authors (Houtkooper and Going, 1994) associated the higher values of FFM/FM [Free Fat Mass/Fat Mass] with the better performance of men. In our investigation this

28

E. Ziemann and T. Garsztka

relationship was conﬁrmed only in groups with the highest amount of fat. Body mass can be inﬂuenced by regular training for sport, resulting in changes in body composition. Training is associated with a decrease in fatness and with an increase in fat-free mass. We observed these changes in body composition in all biological age groups, with the exception of the oldest group, but correlation between anaerobic performance during lab test and speciﬁc tennis drill was the strongest in each repetition. High levels of body mass in 18-year-old tennis players increased the fatigue index. The issue of correlation between training, biological and chronological age and anaerobic performance is current and insuﬃciently explained (Maﬀulli et al., 2001). Although early studies suggested that regular exercise increases the rate of growth and in particular height and mass, the results are limited (Malina, 1994). Physical activity is not the same as regular training. Training programmes are ordinarily speciﬁc. In our research, tennis player groups trained from 14 to 18 hours per week. The results of the training process was that 10 boys out of the whole research group had a higher biological age than chronological. In summary, we concluded that training enhanced the biological age of teenage tennis players.

References Bar-Or, O. (1978). A new anaerobic capacity test-characteristic and application. Proceedings of the 21st World Congress of Sport Medicine. Brazil, 1–27. Bar-Or, O. (1987). The Wingate Anaerobic test: an update on methodology, reliability and validity. Sports Medicine, 4, 381–394. Cies´ lik, J. and Kaczmarek, M.D. (1994). Dziecko Poznan´ skie ’90 [Child from Poznan´ ’90]. Poznan´ : Bogucki Wydawnictwo Naukowe. Crespo, M. and Miley, D. (1998). ITF Advanced Coaches Manual, 9, 148–150 Garsztka, T. (2003). Relacja pomiedzy obciaz· eniemi treningowymi, a meczowymi w tenisie Konferencja Wychowanie Fizyczne i Sport w badaniach naukowych. [Relationship between training work-load and match responses. Conference on Physical Education and Sport], AWF Poznan´ . Fox, E.L. and Mathews, D.K. (1974). Interval Training: Conditioning for Sports and General Fitness. Philadelphia: W.B. Saunders. Houtkooper, L.B. and Going, S.B. (1994). Body composition: how should it be measured? Does it aﬀect sport performance? Sports Science Exchange, 7, 1–8. Kovacs, M. (2004). A comparison of work/rest intervals in men’s professional tennis. Medicine and Science, 3, 10–11. Kovacs, M.S. (2006). Applied physiology of tennis performance. British Journal of Sports Medicine, 40, 381–386. Maﬀulli, N., Ming Chan, K., Macdonald, R., Malina, R.M. and Parker, A. W. (2001). Sports Medicine for Speciﬁc Ages and Abilities. Edinburgh: Churchill Livingstone. Malina, R.M. (1994). Physical growth and biological maturation of young athletes. Exercise and Sport Science Reviews, 22, 89–433.

4

Comparison of laboratory and on-court testing of aerobic ﬁtness in tennis players R.W. Meyers

Introduction The modern game of tennis is characterized by 200–600 explosive eﬀorts over a match that may last up to six hours (Richers, 1995), utilizing speciﬁc movement patterns which diﬀer depending on the tactical situation and court surface. It is clear that the player must be conditioned to meet the speciﬁc aerobic, strength and power demands of these matches in order to maintain the required work rate over such an extended period. Davey et al. (2003) has also indicated that in conditions of fatigue, hitting accuracy decreases by as much as 81 per cent, further illustrating the importance of the physical requirements of the game on the potential match outcome. Bergeron et al. (1991) suggested that despite the repeated explosive eﬀorts, the overall metabolic response to tennis match-play was comparable to continuous exercise at moderate intensity. Furthermore, literature has suggested that during singles match-play plasma lactate values range from 2.3–5.9 mmol.l−1 and VO2 ranges between 53–73 per cent VO2max (Bergeron et al., 1991; Christmass et al., 1995; Reilly and Palmer, 1995). This ﬁnding was further supported by Dansou et al. (2001) who suggested that approximately 60 per cent of VO2max was achieved for 80 per cent of the match, and that in spite of the intermittent nature of activity during the sport, the game of tennis induces moderate aerobic energy expenditure. In light of these ﬁndings, it would seem the evaluation of aerobic ﬁtness is important for tennis players. Coyle (1995) further suggested that performance in prolonged, continuous aerobic activity was highly related to measurements of blood lactate threshold, although VO2max did provide an upper limit of aerobic capacity. Therefore, it could be suggested that measurements of ‘aerobic endurance’ (i.e. anaerobic/blood lactate threshold) may be more suitable than measurements of ‘aerobic power (i.e. VO2max) for sports such as tennis where VO2max is rarely reached, and eﬃciency and economy of movement may be more important. Studies in tennis have entailed comparisons of various physiological measures during on-court activities and laboratory testing protocols (Girard et al., 2006; Smekal et al., 2000); however these authors used on-court maximal,

30

R.W. Meyers

incremental exercise, rather than intermittent, sustained exercise evident in tennis match-play. Furthermore, the measurement of the lactate threshold has traditionally been assessed through maximal, incremental performance tests, which lacks speciﬁcity to tennis performance in match-play. Hence, the use of sustained lactate threshold tests to evaluate maximal lactate steady state (Billat et al., 2003) could be more speciﬁc to tennis due to the sub-maximal nature of the sport. Therefore, the aim of this study was to produce an intermittent test for aerobic ﬁtness that was speciﬁc to tennis and would allow the comparison of sub-maximal physiological responses between laboratory and on-court conditions.

Method Eight male university level tennis players (age 20.9±1.6 yrs, height 1.78±0.1 m, mass 76.7±7.2 kg, VO2max 59.5±6.1 ml.kg.min−1) volunteered to participate in four separate testing protocols. Each subject was required to complete a maximal laboratory test and a maximal on-court test which were used to inform the intensities for the sub-maximal laboratory test and sub-maximal on-court test. The order of these tests was kept the same for all participants, and each was separated by a minimum of 24 hours. Stature and mass were measured during the ﬁrst laboratory visit via a pre-calibrated ﬁxed stadiometer (Holtain, UK) and digital weighing scales (Seca 770, Germany) in minimal clothing. The maximal laboratory test required the participants to complete an incremental test to exhaustion on a motorized treadmill (H/P/Cosmos, Quasar, Germany), whilst connected to a breath-by-breath gas analysis system (Oxycon Pro, Jaeger, Germany) set at a 5-s sampling rate. Following a standardized 3-min warm up, the test began at 7 km.h−1 at a 4 per cent gradient for a period of 2 min 45 s, followed by a 15-s blood sampling period. After each 3-min stage, the treadmill speed was increased by 1.5 km.h−1 until volitional exhaustion. Heart rate response was monitored (Polar S610i, Kempele, Finland) at a 5-s sampling rate throughout the protocol. Blood lactate concentration was determined using a blood analysis system (Biosen C-Line, EFK Diagnostics, Netherlands). The results were used to form a lactate proﬁle and anaerobic threshold was determined using the methods laid out by Cheng et al. (1992). Results from the maximal laboratory test were utilized to establish three exercise intensities for the sub-maximal laboratory test, as illustrated in Figure 4.1. These corresponded to the anaerobic threshold (Tan) calculated via D-max (Cheng et al., 1992), a value equivalent to 50 per cent of the diﬀerence between the AT and the ﬁnal lactate value added to Tan (Tan +50 per cent ∆), and a value equivalent to 100 per cent of the diﬀerence between Tan and the ﬁnal lactate value deducted from Tan (Tan −100 per cent ∆). These three intensities were used to determine the exercise intensity for three, 8-min

Comparison of laboratory and on-court testing

31

Figure 4.1 Illustration of the calculation for the three intensities used during the submaximal laboratory test and sub-maximal on-court test from the maximal laboratory test and maximal on-court test lactate proﬁle.

stages on a motorized treadmill at a constant 4 per cent gradient. Heart rate was monitored throughout the protocol and blood samples were taken at 4-min intervals throughout each 8-min stage. The participants were then required to complete a maximal on-court test. The test comprised of up to 23 levels, each of which was divided into three stages. Each of these stages comprised of nine speciﬁc movements around the court including eight lateral movements across the baseline and one towards the net. Each movement had to be completed in time with a computer generated tone (Test Tone Generator, Timo Esser, Germany) that was played via a CD stereo (JVC RVNB10, UK). At the end of each movement, the participant was instructed to have one foot placed in a speciﬁc area in time with the tone, and an appropriate stroke was shadowed. The exact nature of the stroke was not speciﬁed, and each participant was instructed to perform a stroke as if in a match-play situation, according to the position on the court and the time permitted by the test. Each stage of nine movements was separated by a 10-s rest period. Each level (comprising three stages) was separated by an additional 5-s rest period with each level being incrementally faster until volitional exhaustion. Similar test principles have been used in an aerobic test for badminton players designed by Hughes et al. (2002). Blood samples were taken at the end of each odd numbered level, and heart rate was recorded throughout. Following the same process as the laboratory testing, the results from the

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maximal on-court test were used to calculate Tan via D-max, Tan +50%∆, and Tan −100%∆ as the three sub-maximal intensities. These intensities were used to determine the movement speed for the three, 8-min stages of the sub-maximal on-court test. This test followed the same format as the maximal on-court test with respect to the rest periods, except the intensities were kept the same throughout each of the 8-min stages. For both the sub-maximal laboratory test and sub-maximal on-court test, the movement speed (Vmax), heart rate (HR) and percentage maximum heart rate (per cent HRmax) were calculated at Tan. This was achieved by plotting the lactate levels from 4-min and 8-min blood samples. This provided a point at which the two lines crossed, which is representative of a maximal lactate steady state (MLSS) measurement (Billat et al., 2003) modiﬁed for the speciﬁc demands of tennis, as illustrated in Figure 4.2. An analysis of the relationships and diﬀerences between the MLSS data achieved during the maximal and sub-maximal laboratory and on-court tests was then made using Pearson’s correlation and paired t-tests, respectively. P values are reported with all statistical analyses with a signiﬁcance level set at 0.05.

Results The maximal laboratory test elicited signiﬁcantly higher (P=0.0001) maximum heart rate than the maximal on-court test (206±8 beats⭈min−1 vs. 197±6 beats⭈min−1, respectively). This trend was also demonstrated with the mean heart rate at the Tan assessed via D-max, with signiﬁcantly higher (P=0.003) values shown during maximal laboratory test (179±6 beats⭈min−1 vs. 172±7 beats⭈min−1, respectively). The per cent maximum heart rate at Tan was not signiﬁcantly diﬀerent between the maximal laboratory test and

Figure 4.2 Representation of the Tan determination during the sub-maximal laboratory test and sub-maximal on-court test.

Comparison of laboratory and on-court testing

33

maximal on-court test (86.9±3.1 per cent vs. 87.4±2.5 per cent, P=0.613, respectively). The results also indicated no signiﬁcant correlation (r=0.497, P=0.210) between movement speeds at the Tan assessed via D-max in the maximal laboratory test and maximal on-court test. A signiﬁcant relationship was shown between HR D-max in both conditions (r=0.817, P=0.013). There was a signiﬁcant correlation (r=0.712, P=0.048) between VO2max and time to exhaustion in the maximal laboratory test, yet the correlation only approached signiﬁcance between VO2max and time to exhaustion in the maximal on-court test (r=0.673, P=0.067). Furthermore, no signiﬁcant correlation existed between the time to exhaustion during maximal laboratory test and maximal on-court test (r=0.573, P=0.138). The sub-maximal on-court test elicited signiﬁcantly higher mean heart rate at Tan (174±11 beats⭈min−1 vs. 156±9 beats⭈min−1, P=0.005) and per cent maximum heart rate at Tan (88.3±4.5 per cent vs. 76.1±5.2 per cent, P=0.0004). Lactate levels at Tan were not signiﬁcantly (2.57±0.74 mMol.l−1 vs. 3.03±0.91 mMol.l−1, P=0.329) diﬀerent between the two sub-maximal test conditions. Table 4.1 reports that Blood (lac) at Tan was found to be not signiﬁcantly correlated between the sub-maximal laboratory test, and submaximal on-court test. This trend was evident with heart rate at the anaerobic threshold, percentage maximum heart rate at the anaerobic threshold and speed at the anaerobic threshold with no signiﬁcant correlation between sub-maximal laboratory and on-court testing conditions.

Discussion These data suggest that none of the variables assessed during sub-maximal testing were signiﬁcantly correlated between the laboratory and on-court conditions. Furthermore, many variables were shown to be signiﬁcantly diﬀerent between laboratory and on-court test protocols. The maximal laboratory test and maximal on-court test were primarily used to determine appropriate exercise intensities for the sub-maximal laboratory test and sub-maximal on-court test. However, some of the results from these tests are of interest. The VO2max was found to be signiﬁcantly Table 4.1 Mean and correlation data for the variables assessed during the submaximal laboratory test and sub-maximal on-court test, including blood lactate concentration (Blood (lac)), heart rate at Tan (HR), maximum heart rate at Tan (%HRmax) and movement speed at Tan (V)

Blood (lac) HR %HRmax V

Sub-maximal laboratory test

Sub-maximal on-court test

r value

P value

2.57±0.74 mMol.l−1 156±9 beats⭈min−1 76.1±5.2% 8.3±0.8 km.h−1

3.03±0.91 mMol.l−1 174±11 beats⭈min−1 88.3±4.5% 0.896±0.117 move.s−1

−0.004 0.372 0.444 0.162

0.993 0.364 0.270 0.701

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correlated with time to exhaustion during maximal laboratory test, yet not signiﬁcantly correlated to time to exhaustion during maximal on-court test. This may suggest that factors other than VO2max may have more of an inﬂuence on performance capability during a maximal on-court testing. The heart rates at the anaerobic threshold from the sub-maximal on-court test are comparable to those reported by Christmass et al. (1995) during play. They reported an average of 82.8 per cent maximal heart rate (excluding change of ends) during a 90-min game of singles, compared to 88.3 per cent reported in the current study. This ﬁnding suggests Tan assessed during the submaximal on-court test may also produce a physiological response comparable to singles match-play. The comparison of laboratory and on-court sub-maximal testing elicited signiﬁcantly diﬀerent heart rates and percentage maximum heart rates at the anaerobic threshold, with both values being signiﬁcantly higher during the sub-maximal on-court test. There was also no signiﬁcant correlation between heart rate and percentage maximum heart rate in the diﬀerent sub-maximal testing conditions. Movement speed at Tan was also found to be not signiﬁcantly correlated between the two sub-maximal conditions. The results from this study may be explained by a combination of factors, including the intermittent nature of the maximal on-court test which facilitates recovery during the non-active periods, and the additional physiological loading experienced with the on-court activity that requires multiple changes of direction accompanied with repeated acceleration and deceleration and the eccentric/concentric muscular loading patterns. Furthermore the ecological validity of the on-court protocol to movement in a tennis match-play environment may result in the participants eliciting a diﬀerent movement eﬃciency and economy than during laboratory testing. These results highlight the diﬀerent physiological responses arising from laboratory and on-court testing protocols presented in this paper. The results from the sub-maximal on-court testing are of particular importance due to the speciﬁcity of the testing protocol to tennis performance.

Conclusion The implications of these ﬁndings are that the sub-maximal on-court test could provide physiological loading which is similar to that reported in the literature regarding tennis match-play, yet equivalent laboratory and on-court tests give diﬀerent and unrelated results in terms of performance and physiological responses. Therefore it could be suggested that laboratory testing should not necessarily be used to infer tennis related performance, and that the sub-maximal on-court testing presented in this paper may be a viable way to assess tennis speciﬁc aerobic ﬁtness. However, it is suggested that both laboratory and on-court testing protocols could be used as valuable elements of an aerobic ﬁtness testing battery in order that measures of general and tennis speciﬁc physiological responses may be obtained.

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35

References Bergeron, M.F., Maresh, C.M., Kraemer, W.J., Abraham, A., Conroy, B. and Gaharee, C. (1991). Tennis: a physiological proﬁle during match play. International Journal of Sports Medicine, 12, 474–479. Billat, V.L., Sirvent, P., Py, G., Koralsztein, Micallef, J.-P. and Mercier, J. (2003). The concept of maximal lactate steady state: a bridge between biochemistry, physiology and sports science. Sports Medicine, 33, 407–426. Cheng, B., Kuipers, H., Snyder, A.C., Keizer, H.A., Jeukendrup, A. and Hesselink, M. (1992). A new approach for the determination of ventilatory and lactate thresholds. International Journal of Sports Medicine, 13, 518–522. Christmass, M.A., Richmand, S.E., Cable, N.T. and Hartmann, P.E. (1995). A metabolic characterisation of single tennis. In Science and Racket Sports (edited by T. Reilly, M. Hughes and A. Lees), London: E&FN Spon, pp. 3–9. Coyle, E.F. (1995). Integration of the physiological factors determining endurance performance ability. Exercise and Sport Sciences Reviews, 23, 25–63. Dansou, P., Oddou, M.F., Delaire, M. and Therminarias, A. (2001). Aerobic expenditure during a tennis match. Science and Sports, 16, 16–22. Davey, P.R., Thorpe, R.D. and Williams, C. (2003). Simulated tennis match play in a controlled environment. Journal of Sport Sciences, 21, 459–467. Girard, O., Chevalier, R., Leveque, F., Micallef, J.-P. and Millet, G.P. (2006). Speciﬁc incremental ﬁeld test for aerobic ﬁtness in tennis. British Journal of Sports Medicine, 40, 791–796. Hughes, M.G., Andrew, M. and Ramsay, R. (2002). A sport-speciﬁc endurance performance test for elite badminton players. Journal of Sports Sciences, 21, 277–278. Reilly, T. and Palmer, J. (1995). Investigation of exercise intensity in male singles lawn tennis. In Science and Racket Sports (edited by T. Reilly, M. Hughes and A. Lees), London: E&FN Spon, pp. 10–13. Richers, T.A. (1995). Time-motion analysis of the energy systems in elite and competitive singles tennis. Journal of Human Movement Studies, 28, 73–86. Smekal, G., Pokan, R., Von Duvillard, S.P., Baron, R., Tschan, H. and Bachl, N. (2000). Comparison of laboratory and ‘on-court’ endurance testing in tennis. International Journal of Sports Medicine, 21, 242–249.

5

A speciﬁc incremental test in tennis O. Girard, R. Chevalier, F. Leveque, J.-P. Micallef and G.P. Millet

Introduction Aerobic ﬁtness is important for tennis players which enables them to generate power repeatedly for explosive stroke production and rapid court movements during extended matches (Lees, 2003). Currently a variety of test procedures are used to evaluate the exercise capacity of tennis players and prescribe the appropriate on-court training intensity. This evaluation involves laboratory and ﬁeld tests. The standard test for assessing aerobic ﬁtness is the direct measurement of the player’s maximal oxygen uptake (VO2max) while running to exhaustion on a treadmill in a laboratory environment. In addition, two speciﬁc ventilatory changes that correspond to the ventilatory threshold (Tvent) and the respiratory compensation point (RCP) have been widely used in the sport science literature (Santos and Giannella-Neto, 2004). These reproducible ventilatory breakpoints appear to provide useful markers to characterize training eﬀects, evaluate physical ﬁtness and identify training intensity zones that are distinguished by meaningful diﬀerences in sympathetic stress load, motor unit involvement and duration of fatigue (Foster and Cotter, 2006). However, during treadmill testing, the modes of exercise tests (continuous activity) often cannot simulate the speciﬁc demands of tennis (intermittent activity) and do not reﬂect the speciﬁc muscular involvement of both lower and upper limbs with respect to the stop, start and change of direction in movement patterns (Fernandez, 2005). Recent eﬀorts have been made to develop ﬁeld tests in tennis in order to determine the exercise capacity or technical performance of players with an acceptable accuracy under standardized conditions (Vergauwen et al., 1998; Smekal et al., 2000; Davey et al., 2002). However, because these tests require expensive equipment – that is a ball machine, video, radar – (Vergauwen et al., 1998; Smekal et al., 2000; Davey et al., 2002), or only simulate rallies from the baseline (Smekal et al., 2000) or do not reﬂect precisely time intervals of tennis play (Davey et al., 2002), they cannot be routinely used to evaluate an individual player’s ﬁtness level accurately in a context close to the game. Accordingly, the aims of this study were to: (a) develop a tennis-speciﬁc

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37

incremental ﬁtness test including some elements of tennis play; (b) compare physiological responses recorded during this ﬁeld test with those observed during an incremental treadmill test. We hypothesized that the physiological responses diﬀer because of the diﬀerent movement patterns between the tennis speciﬁc (combined use of arms and legs) and treadmill (forward running only) tests.

Methods Subjects Nine male junior competitive tennis players (mean ± SD, age 16.0 ± 1.6 years; height 1.798 ± 0.094 m; body mass 65.3 ± 11.9 kg; training frequency 8.2 ± 3.1 hour.week−1) of regional to national level volunteered and gave written informed consent to participate in this study, which had local ethics committee approval. Study protocol All subjects carried out two incremental protocols to exhaustion in a randomized order: a treadmill test (non-speciﬁc) and a tennis ﬁtness test (sportspeciﬁc). Each test was conducted under standard environmental conditions (temperature ~20 °C, relative humidity ~50 per cent) at the same time of day. Experimental procedures Treadmill testing The incremental treadmill test (TT) to exhaustion was performed on a motorized treadmill (S 2500, Medical development, France) and consisted of an initial 3-min continuous workload of 9 km.h−1 followed by increases of 0.5 km.h−1 every minute (0 per cent incline). Each stage was composed of a 45-s running period followed by 15 s of active recovery during which subjects had to walk at 5 km.h−1. The test ended with voluntary exhaustion of the subjects. Field testing A tennis speciﬁc incremental ﬁeld test (FT) was developed in which subjects repeated displacements replicating the tennis game at an increasing speed on the court. Each stage consisted of seven shuttle runs, performed from a central basis to one of the six targets located around the court, alternated with 15-s of active recovery (Figure 5.1). Sets of seven rallies included two forward (oﬀensive), three lateral (neutral) and two backward (defensive) courses performed randomly. When a subject arrived at the target, he was instructed to mime a powerful stroke as in oﬃcial competition before moving back to

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Figure 5.1 Set-up of the speciﬁc incremental ﬁtness test for tennis players. The position of forward (black cones), lateral (grey cones) and backward (white cones) targets are indicated. See Methods for further details.

baseline after each drive. Movement velocities and directions were controlled by visual and sound feed-backs from a PC computer. Brieﬂy, a speciﬁcsoftware was used in order to sound simultaneously a tune and project a picture of a player moving around the target to reach. These velocities and sequences of movement were calculated from data collected during oﬃcial competitions (unpublished data). Test reliability of the FT was determined in four subjects performing two ﬁtness tests within one week. Physiological measurements During the TT (CPX/D; MedGraphics, Saint Paul, Minnesota, USA) and FT (K4b2; Cosmed, Rome, Italy), the following gas exchange data were measured using breath-by-breath gas analysers which were calibrated prior to each test using the manufacturers’ recommendations: VO2, carbon dioxide production (VCO2), respiratory exchange ratio (RER = VCO2/VO2), minute ventilation (VE), breathing frequency, and tidal volume. Heart rate (HR) values were recorded for 5 s by a HR monitor with the athletes wearing a chest belt (S810, Polar, Kempele, Finland). Ratings of perceived exertion (RPE) were recorded using the Borg 6–20 scale and 25-µl capillary blood samples were taken from the ﬁngertip and analysed for blood lactate concentrations ([La]) by using the Lactate Pro (LT-1710, Arkray, Japan) portable analyser at the point of volitional fatigue.

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39

In both tests, the gas samples were averaged every 15 s. The highest values for VO2 and HR over 15 s were regarded as VO2max and heart rate (HRmax). Four criteria were used to determine maximal eﬀorts : 1 2 3 4

a plateau or levelling oﬀ in VO2, deﬁned as an increase of less than 1.5 ml.min−1 .kg−1 despite progressive increases in exercise intensity a ﬁnal RER of 1.1 or above a ﬁnal HR above 95 per cent of the age-related maximum a ﬁnal [La] above 8 mmol.l−1.

Time to exhaustion (Te, s) was recorded in each test. Determination of Tvent and RCP Ventilatory threshold was determined using the criteria of an increase in VE/ VO2 with no increase in VE/VCO2 and the departure from linearity of VE, whereas RCP corresponded to an increase in both VE/VO2 and VE/VCO2 (Santos and Giannella-Neto, 2004). Each physiological variable corresponding to Tvent, RCP, and maximal load was expressed in absolute terms and relative to VO2max and HRmax. Statistics Data obtained at Tvent, RCP and maximal load were compared between FT and TT, using paired sample t-tests. P < 0.05 was determined as statistically signiﬁcant.

Results Reproducibility No diﬀerence was found in Te (1479 ± 68 v 1454 ± 103 s; CV = 1.2 per cent), VO2 (57.4 ± 6.4 v 58.2 ± 6.5 ml.min−1 .kg−1; CV = 1.0 per cent), HR (194.3 ± 6.7 v 187.3 ± 1.2 beats.min−1; CV = 2.6 per cent), [La] (8.0 ± 2.8 v 7.4 ± 2.1 mmol.l−1; CV = 5.2 per cent) and RPE (17.3 ± 1.2 v 16.7 ± 1.5 points; CV = 2.8) between the two FTs performed within four days (n = 4). Comparisons of Te , [La] and RPE Values of Te (1666 ± 188 v 1491 ± 64 s; 10.5 per cent) were higher (P < 0.05) in TT than in FT. Mean values of [La] (2.2 ± 0.5 v 2.2 ± 0.6 and 10.6 ± 4.3 v 10.7 ± 3.0 mmol.l−1) and RPE (9.0 ± 2.1 v 8.6 ± 2.1 and 17.7 ± 1.0 v 18.5 ± 0.9 points) measured before and after exercise did not diﬀer between TT and FT, respectively.

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Physiological variables at Tvent , RCP and maximal load At Tvent and RCP, VCO2 and RER, values were signiﬁcantly higher in FT than in TT (Table 5.1). It is of interest to note that per cent HRmax and per cent VO2max at VT and RCP were not diﬀerent between FT and TT. Again, VO2, VCO2 and RER values measured at maximal loads were signiﬁcantly higher in FT than in TT.

Discussion The physiological demands in racket games such as tennis are highly inﬂuenced by the fact that players have to accelerate, decelerate, change direction, move quickly, maintain balance and generate optimum stroke production repeatedly (Lees, 2003). In these activities, exercise testing on a treadmill (i.e. running) is not speciﬁc for muscles involved and therefore inadequate to evaluate the speciﬁc demands of the sport (Smekal et al., 2000; Fernandez, 2005). As a consequence, we designed a speciﬁc incremental ﬁtness test for tennis players including some technical characteristics (i.e. performed on a tennis court; similar displacement technique to that of competition; incertitude of the motion direction; mime of ball strokes) and compared the physiological-perceptual responses with an incremental treadmill test. The FT had a high reproducibility illustrating that this test is sensitive and valid to detect diﬀerences between players as well as seasonal changes in ‘tennis ﬁtness’. Submaximal intensities The lack of diﬀerence in physiological variables (per cent HRmax and per cent VO2max) at Tvent and RCP between the two tests lead us to suggest that treadmill testing remains the ‘gold method’ to detect ventilatory breakpoints in order to deﬁne intensity areas for tennis on-court aerobic exercises. Surprisingly, only limited data are available regarding Tvent and RCP values in tennis players since VO2max has traditionally been considered as the ‘gold standard’. There is increasing evidence that the ventilatory breakpoints may be a better predictor of submaximal endurance performance. This is especially true in tennis where the performance is multifaceted, involving technical, tactical, psychological and physiological factors (Lees, 2003). The intensity at Tvent and RCP found in the present study for junior competitive tennis players is higher than that generally reported for physically active subjects (80 v 90 per cent of HRmax and 50 v 80 per cent of VO2max at Tvent and RCP, respectively) (Foster and Cotter, 2006). According to König et al. (2001), the high Tvent and RCP values could reﬂect the ability to tolerate high intensity exercise during tennis competitions. These values of ventilatory breakpoints are, however, lower than the values (88 v 95 and 85 v 91 per cent of the HRmax and VO2max for Tvent and RCP, respectively) reported recently in elite squash players tested

44.2 ± 5.5 42.8 ± 6.3 0.96 ± 0.04 58.0 ± 10.9 158.8 ± 9.3 38.1 ± 10.2 1.62 ± 0.56 69.4 ± 8.1 83.6 ± 5.1

43.4 ± 5.8 38.6 ± 4.9* 0.89 ± 0.02*** 64.2 ± 8.4 161.1 ± 9.2 40.5 ± 9.0 1.74 ± 0.52 73.5 ± 6.1 83.0 ± 2.8

53.8 ± 5.5 56.0 ± 7.4 1.04 ± 0.04 78.6 ± 14.0 174.9 ± 5.4 43.8 ± 8.7 1.88 ± 0.63 84.4 ± 6.5 92.1 ± 2.1

FT

FT

TT

RCP

VT

Notes: * P < 0.05; ** P < 0.01; *** P < 0.001 for diﬀerences between FT and TT

VO2 (ml.min−1 .kg−1) VCO2 (ml.min−1 .kg−1) RER VE (litres.min−1) HR (beats.min−1) Bf (breaths.min−1) Vt (litres) % VO2max % HRmax

Variables

50.5 ± 7.6 47.9 ± 7.0** 0.95 ± 0.04** 87.3 ± 14.5* 179.3 ± 9.3 53.3 ± 13.7** 1.85 ± 0.56 85.5 ± 8.7 92.3 ± 2.1

TT

63.8 ± 5.7 74.5 ± 7.5 1.18 ± 0.07 117.1 ± 17.4 190.0 ± 5.2 62.5 ± 8.7 2.24 ± 0.6 – –

FT

Max

58.9 ± 5.3* 58.7 ± 5.5*** 1.03 ± 0.04*** 115.1 ± 14.5 194.1 ± 7.7 67.4 ± 11.4 2.07 ± 0.5 – –

TT

Table 5.1 Physiological values in tennis players corresponding to the ventilatory threshold (VT), respiratory compensation point (RCP) and maximum work load (Max) in tennis ﬁeld (FT) and treadmill (TT) tests (n = 9)

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similarly to that of the present test but with time intervals speciﬁc to the squash game (shorter resting periods between stages: 10 s; longer stage durations: 9 simulations of ball hitting) (Girard et al., 2005). The discrepancies between these studies are mainly the result of the training status of the subjects. Maximal loads At maximal loads [La] and RPE responses were similar in both tests, which diﬀers from previous ﬁndings reporting higher [La] values following treadmill than ﬁeld testing (Smekal et al., 2000). A possible explanation could be the intermittent design of the present treadmill test contrasting with previous protocols with a continuous load proﬁle. Indeed, it is well established that lactate can be oxidized locally or transported from production sites to oxidative muscle ﬁbres for subsequent oxidation during recovery periods (Brooks, 1986). Maximal oxygen uptake (VO2max) values measured in the FT or the TT are in a similar range or slightly higher than those reported previously (50–60 ml.min−1 .kg−1) in players of similar standard (König et al., 2001). This conﬁrms that a high aerobic power is a pre-requisite in tennis to sustain an elevated level of technical, tactical, physiological and psychological capacity for several hours. Of interest also is the fact that the VO2, VCO2 and RER values were signiﬁcantly higher in the FT than in the TT at maximal loads, suggesting that VO2max values derived from laboratory testing were not relevant for an accurate estimate of ﬁtness in tennis players. Although the design of the two tests was intermittent in nature, it is noteworthy that during the FT, players were asked to perform repeated speciﬁc displacements in all directions with changing pace. These speciﬁc patterns included accelerations, decelerations, changeovers as well as upper arm involvement in holding the racket and miming stroke actions. On the contrary, running on a treadmill was characterized by a steady pace and little or no lateral movement. As suggested by Smekal et al. (2000), one may therefore assume that greater muscle mass was involved during the FT and that muscles were recruited at a higher rate than during the TT which may have in turn increased VO2 in the FT. Practical applications The potential beneﬁts of the proposed ﬁeld test are important. First, it places a speciﬁc demand upon the player and would therefore be an appropriate test to be included into a training routine. Second, it involves movement patterns that are more speciﬁc to training and competition and therefore has the potential to increase players’ motivation when they have to hit the ball. Again, the progressive increase in load proﬁle appears to be a strong point. This test may also be beneﬁcial when the weekly training time is limited.

A speciﬁc incremental test in tennis

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Finally, this test can be combined with the training of sport-speciﬁc technical elements and easily administrated to players of various standards as it requires limited equipment (six cones, a meter and portable PC including the software of the test). Therefore, it can be routinely used to indicate an alteration or improvement in the player’s physical performance with maintaining a simple design. Furthermore, it can be easily performed at diﬀerent periods of the season wherever the player may be. It may be also used to judge the eﬃciency of diﬀerent training regimens or to analyse the eﬀects of factors that could aﬀect tennis performance (i.e. supplementation, drinking regimens).

Conclusions To conclude, ﬁeld and laboratory tests appear to be complementary and have diﬀerent uses in tracking ﬁtness changes in tennis players. Coaches and conditioning experts should use the present speciﬁc ﬁtness test for tennis players as an additional item for training purposes. This test, which is reproducible and speciﬁc to tennis play, provides information on a player’s individual ﬁtness level and can be easily administrated.

References Brooks, G.A. (1986). The lactate shuttle during exercise and recovery. Medicine and Science in Sports and Exercise, 18, 360–368. Davey, P.R., Thorpe, R.D. and Williams, C. (2002). Fatigue decreases skilled tennis performance. Journal of Sports Sciences, 20, 311–318. Fernandez, J. (2005). Speciﬁc ﬁeld tests for tennis players. Medicine and Science in Tennis, 10, 22–23. Foster, C. and Cotter, H.M. (2006). Blood lactate, respiratory, heart rate markers on the capacity for sustained exercise. In Physiological Assessment of Human Fitness (edited by P.J. Maud and C. Foster), Champaign, IL: Human Kinetics, pp. 63–76. Girard, O., Sciberras, P., Habrard, M., Hot, P., Chevalier, R. and Millet, G.P. (2005). Speciﬁc incremental test in elite squash players. British Journal of Sports Medicine, 39, 921–926. König, D., Huonker, M., Schmid, A., Halle, M., Berg, A. and Keul, J. (2001). Cardiovascular, metabolic, and hormonal parameters in professional tennis players. Medicine and Science in Sports and Exercise, 33, 654–658. Lees, A. (2003). Science and the major racket sports: a review. Journal of Sports Sciences, 21, 707–732. Santos, E.L. and Giannella-Neto, A. (2004). Comparison of computerized methods for detecting the ventilatory thresholds. European Journal of Applied Physiology, 93, 315–324. Smekal, G., Pokan, R., von Duvillard, S.P., Baron, R., Tschan, H. and Bachl, N. (2000). Comparison of laboratory and ‘on-court’ endurance testing in tennis. International Journal of Sports Medicine, 21, 242–249. Vergauwen, L., Spaepen, A.J., Lefevre, J. and Hespel, P. (1998). Evaluation of stroke performance in tennis. Medicine and Science in Sports and Exercise, 30, 1281–1288.

6

Muscle ﬁbre type distribution and ﬁbre size of triceps brachialis in elite tennis players J. Sanchís-Moysi, A. Guadalupe-Grau, S. Guerra, H. Olmedillas, O. Bernales, C. Dorado and J.A.L. Calbet

Introduction Tennis is an excellent exercise model to study muscle plasticity in response to chronic exercise. Tennis players submit their dominant-arm to a huge amount of physical activity compared to their contralateral arm (Pirnay et al., 1987; Tsuji et al., 1995). In consequence, the muscle mass of the dominant arm is about 20 per cent higher than that of the non-dominant arm in elite tennis players (Sanchis Moysi et al., 1998). Although it is reasonable to assume variations in the relative contribution of the muscle groups to the overall muscle hypertrophy of the dominant arm, to our knowledge, the relative contribution of the size of individual muscles has not been investigated in tennis. Studies using electromyography have shown that triceps brachialis plays an important role in power generation in the diﬀerent tennis strokes (Chow et al., 1999; Miyashita et al., 1980; Van Gheluwe and Hebbelinck, 1986). The knowledge of the morphological adaptations of triceps brachialis in elite tennis players could be useful for designing more speciﬁc and eﬃcient strength-training programmes for tennis players. The aim of this study was to assess the eﬀect of tennis participation on the ﬁbre size of triceps brachialis muscle of the dominant compared to that of the non-dominant arm and its relationship with the overall muscle mass of the dominant arm.

Methods Participants Four elite tennis players (23.0 ± 1.0 year, mean ± SEM) from the Canary Islands volunteered and gave written informed consent to participate in this study, which had local ethics committee approval. All the tennis players had been training and participating in professional tennis competitions during, at least, the previous four years (24 ± 9 hours per week). Three players were right-handed and one left-handed. One of the right-handed players played a ‘two hands’ backhand while the other three players played the ‘one hand’

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backhand stroke. Table 6.1 summarizes the general characteristics of these tennis players. Materials Muscle biopsies were taken from lateral aspect of the triceps brachialis (short head) of both arms. A section of the muscle samples was cut oﬀ, mounted in embedding medium, and frozen in isopentane cooled to its freezing point in liquid nitrogen and stored at −80 °C until further analysis. In serial transverse muscle sections, ﬁbre types were stained for myoﬁbrillar ATPase as described previously (Brooke and Kaiser, 1970). In addition, the lean mass of the dominant and non-dominant arm was determined using dual-energy x-ray absorptiometry (DXA) (QDR-1500, Hologic Corp., Waltham, MA), as previously described (Sanchis-Moysi et al., 2004). The lean mass of the arm was assumed to be equivalent to the muscle mass of the arm (Calbet et al., 1998). From the whole body scans the percentage of body fat was also determined (Sanchis Moysi et al., 1998). Table 6.1 summarizes the main characteristics of the subjects. Statistical analysis Data were analysed using the SPSS mainframe statistical program. Side-toside comparisons were carried out using a one-tailed Student’s t-test. Statistical signiﬁcance was set at P < 0.05 level. Results are presented as means ± standard error of the mean.

Results and discussion Marked diﬀerences existed between the dominant and the contralateral arm for muscle mass (3606 ± 76 versus 3154 ± 268 g, P < 0.001). This result is in concordance with previous studies carried out in our laboratory that showed a 10–20 per cent more muscle mass in the dominant compared with the contralateral arm in elite tennis players (Calbet et al., 1998; Sanchis Moysi et al., 1998). The increased lean mass of the dominant arm and particularly the relative higher hypertrophy of the triceps brachialis can only be explained as a consequence of the mechanical demand sustained by this muscle, since

Table 6.1 General subject characteristics (mean ± SD) Age (years) Total body mass (kg) Height (m) Total body fat (%)

23.0 ± 1.0 74.1 ± 8.8 1.839 ± 0.06 11.8 ± 10.3

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any other genetic, nutritional or hormonal mechanism is also acting on the contralateral arm which has smaller ﬁbres. Compared to the non-dominant arm the type 1, 2a and 2x muscle ﬁbres were hypertrophied in the dominant arm by 36 per cent (4018 ± 457 and 5472 ± 556 µm2), 31 per cent (6185 ± 1015 and 8109 ± 1542 µm2) and 39 per cent (5333 ± 1389 and 7430 ± 1370 µm2), respectively. The mean area of all muscle ﬁbres was 33 per cent higher in the dominant than in the non-dominant arm (P < 0.05). Although we cannot compare our results with other studies, since there are no published data on muscle ﬁbre type and cross-sectional areas of lateral aspect of the triceps brachialis in either tennis players or other athletes, the values obtained in this study for cross-sectional areas are similar to that reported, for example, in the long head of the triceps brachialis in cross-country skiers (Calbet et al., 2005). The inter-arm diﬀerence in lean mass (14 per cent) was smaller than the diﬀerence in cross-sectional area of the triceps brachialis (33 per cent), emphasizing the relative importance of this muscle in tennis players. In the last three decades, studies using cinematography and electromyography have shown that an elbow extension movement, with participation of triceps brachialis occurs in most tennis strokes. For example, during the service stroke the triceps brachialis muscle contributes to the active acceleration of the racket prior to ball impact (Van Gheluwe and Hebbelink, 1986). In the forehand stroke, the triceps display strong activity during ball impact in order to counteract the maximal contraction of biceps brachialis and brachioradialis (Van Gheluwe and Hebbelinck, 1986). The backhand stroke demands the extension of the elbow joint approximately 40° from the backswing position to impact as a means of generating racket speed (Elliott et al., 1989), this movement implies the participation of triceps brachialis in both the one-hand and the two-hands backhand stroke (Roetert and Ellenbecker, 1998). The triceps muscle also shows a high electrical activity during the forward swing phase of the forehand and the backhand volleys, being greater during the backhand volley (Chow et al., 1999). In this study we provided direct morphological evidence showing the importance that this muscle has for racket actions in tennis players. The fact that the magnitude of hypertrophy of the muscle ﬁbres of the lateral aspect of the triceps brachialis is more than twice the mean increase in muscle mass also suggests that this muscle is submitted to an overload likely higher than that supported by other muscles of the arm. The muscle cross-sectional area and the ﬁbre type determines the power production of a muscle (Aagaard and Andersen, 1998). It seems reasonable to assume a relationship between the triceps brachialis hypertrophy and morphology of the dominant arm and the increased maximal strength of elbow extension movement found on the dominant arm of tennis players (Cohen et al., 1994; Kibler and Chandler, 1989). As a consequence, this muscle hypertrophy could also contribute to impel higher ball velocities during the tennis serve (Bencke et al., 2002; Pugh et al., 2003). However, the

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inﬂuence of muscle strength on ball speed in tennis has generated some controversy, since it may depend on more factors than just the strength of the musculature recruited in each speciﬁc action (Ellenbecker, 1991; Elliott et al., 1990). It has been reported that tennis practice is not associated with a signiﬁcant increment in total lean mass in professional tennis players compared to a non active population of the same age (Calbet et al., 1998). Nevertheless, tennis players have a greater chance of satisfactorily meeting tennis requirements if they increase their maximal dynamic strength (MDS) as a way to enhance the peak force developed during ball strokes (König et al., 2001; Sanchis Moysi, 2004). Supporting this idea several studies show that strength training can improve racket and ball speed (Kraemer et al., 2000, 2003). In agreement, a recent study has focused on the inﬂuence of triceps brachialis morphology on shot-put performance (Terzis et al., 2003). This showed that despite the fact that it is commonly accepted that shot-put performance is mainly determined by the ability of the lower body to produce power, isokinetic torque of the elbow extensors, type II ﬁbre area of triceps brachialis and estimated arm cross-sectional area of the arm signiﬁcantly correlated with shot-put performance. Tennis actions may generate several stimuli known to elicit muscle hypertrophy. For example to maintain the position of the racket a strong grip is needed in many instances. This strong grip is likely supported by an isometric contraction of elbow and ﬂexor and extensor muscles. It is well established that isometric contractions can elicit muscle hypertrophy (Kanehisa et al., 2002). Tennis practice increases the maximum grip strength (Kibler et al., 1988) and the maximal strength during the elbow extension movement in the dominant arm (Bencke et al., 2002; Cohen et al., 1994; Kibler and Chandler, 1989). A maximum grip strength of 600 N has been reported in the dominant arm in elite tennis players (Kibler and Chandler, 1989). The inter-arm diﬀerence in grip strength is around 30 per cent in female and 40 per cent in male competitive adult tennis players (Kibler et al., 1988; Kraemer et al., 2003). Moreover, diﬀerences between upper limb sides have been found in elite tennis players during an isometric maximal voluntary contraction in the elbow extension movement (Bencke et al., 2002). In addition to this strength gain, moderate but signiﬁcant correlations have been observed between ball speed in the tennis serve and both the grip strength (Cohen et al., 1994; Elliott, 1982) and the isokinetic extension torque measured at the elbow in elite tennis players (Pugh et al., 2003). It seems reasonable to contend that forceful muscle contractions during service and forehand strokes may also elicit forceful eccentric and concentric muscle actions which are also known to stimulate muscle hypertrophy (Seger et al., 1998). Overall, these studies support the view that swinging a tennis racket many times during training sessions and competition can be considered as a powerful stimulus for muscle hypertrophy in the dominant arm (Bencke et al., 2002). Our ﬁndings suggest that a moderate muscle hypertrophy of the dominant arm could also contribute to the strength gains of the dominant arm

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and the increase in ball velocity. Future studies will be needed to verify this hypothesis. In addition, other mechanisms could also contribute to the greater strength of the dominant arm of tennis players. It has been suggested that higher coordination of the neuromuscular system and increased muscle activation of speciﬁc muscles of the dominant arm involved in tennis strokes could also contribute to the impressive asymmetry in arm muscle strength in tennis players (Sanchis Moysi, 2004). The impact forces sustained by the dominant arm of the tennis players combined with the elevated tensions generated by the muscles that attach in the bones of the upper extremity also stimulate osteogenesis as a protective mechanism for the osseous structure. It is well documented that tennis practice increases the bone mineral content (BMC) and density (BMD) of the dominant arm (Sanchis Moysi et al., 1998; Sanchis-Moysi et al., 2004). The high BMC and BMD in the dominant arm of the tennis players is related to the arm muscle mass (Calbet et al. 1998) and several studies have reported that regional lean mass correlates with both regional BMC and regional BMD (Baumgartner et al., 1996; Nichols et al., 1995). Moreover, it has been shown recently that the myostatin-deﬁcient mice, which show increased muscle mass, also have a more pronounced osteotrophic response to exercise (Hamrick et al., 2006). Together these studies support the idea that both impact loading and muscle hypertrophy contribute to the enhancement of BMC and BMD in tennis players.

Conclusions We report for the ﬁrst time the eﬀect of long-lasting tennis participation on the structure of the lateral aspect of the muscle triceps brachialis in elite tennis players. Long-term participation in tennis is associated with marked muscle hypertrophy of all ﬁbre types in the lateral portion of the muscle triceps brachialis. The inter-arm diﬀerence in muscle mass was smaller than the diﬀerence in cross-sectional area of the triceps brachialis, emphasizing the relative importance of this muscle in tennis players.

References Aagaard, P. and Andersen, J.L. (1998). Correlation between contractile strength and myosin heavy chain isoform composition in human skeletal muscle. Medicine and Science in Sports and Exercise, 30, 1217–1222. Baumgartner, R.N., Stauber, P.M., Koehler, K.M., Romero, L. and Garry, P.J. (1996). Associations of fat and muscle masses with bone mineral in elderly men and women. American Journal of Clinical Nutrition, 63, 365–372. Bencke, J., Damsgaard, R., Saekmose, A., Jorgensen, P., Jorgensen, K. and Klausen, K. (2002). Anaerobic power and muscle strength characteristics of 11 years old elite and non-elite boys and girls from gymnastics, team handball, tennis and swimming. Scandinavian Journal of Medicine and Science in Sports, 12, 171–178.

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Brooke, M.H. and Kaiser, K.K. (1970). Three myosin adenosine triphosphatase systems: the nature of their pH lability and sulfhydryl dependence. Journal of Histochemistry and Cytochemistry, 18, 670–672. Calbet, J.A., Moysi, J.S., Dorado, C. and Rodriguez, L.P. (1998). Bone mineral content and density in professional tennis players. Calciﬁed Tissue International, 62, 491–496. Calbet, J.A., Holmberg, H.C., Rosdahl, H., van Hall, G., Jensen-Urstad, M. and Saltin, B. (2005). Why do arms extract less oxygen than legs during exercise? American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, 289, R1448–1458. Chow, J.W., Carlton, L.G., Lim, Y.T., Shim, J.H., Chae, W.S. and Kuenster, A.F. (1999). Muscle activation during the tennis volley. Medicine and Science in Sports and Exercise, 31, 846–854. Cohen, D.B., Mont, M.A., Campbell, K.R., Vogelstein, B.N. and Loewy, J.W. (1994). Upper extremity physical factors aﬀecting tennis serve velocity. American Journal of Sports Medicine, 22, 746–750. Ellenbecker, T.S. (1991). A total arm strength isokinetic proﬁle of highly skilled tennis players. Isokinetic and Exercise Science, 1, 9–21. Elliott, B.C. (1982). Tennis: the inﬂuence of grip tightness on reaction impulse and rebound velocity. Medicine and Science in Sports and Exercise, 14, 348–352. Elliott, B., Marsh, T. and Overheu, P. (1989). The topspin backhand drive in tennis. Human Movement Studies, 16, 1–16. Elliott, B., Ackland, T., Blanksby, B. and Bloomﬁeld, J. (1990). A prospective study of physiologic and kinanthropometric indicators of junior tennis performance. Australian Journal of Science and Medicine in Sport, 22, 87–92. Hamrick, M.W., Samaddar, T., Pennington, C. and McCormick, J. (2006). Increased muscle mass with myostatin deﬁciency improves gains in bone strength with exercise. Journal of Bone and Mineral Research, 21, 477–483. Kanehisa, H., Nagareda, H., Kawakami, Y., Akima, H., Masani, K., Kouzaki, M. and Fukunaga, T. (2002). Eﬀects of equivolume isometric training programs comprising medium or high resistance on muscle size and strength. European Journal of Applied Physiology, 87, 112–119. Kibler, B. and Chandler, J. (1989). Grip strength and endurance in elite tennis players. Medicine and Science in Sports and Exercise, 21 (Suppl. 2), 65. Kibler, W.B., McQueen, C. and Uhl, T. (1988). Fitness evaluations and ﬁtness ﬁndings in competitive junior tennis players. Clinics in Sports Medicine, 7, 403–416. König, D., Huonker, M., Schmid, A., Halle, M., Berg, A. and Keul, J. (2001). Cardiovascular, metabolic, and hormonal parameters in professional tennis players. Medicine and Science in Sports and Exercise, 33, 654–658. Kraemer, W.J., Ratamess, N., Fry, A.C., Triplett-McBride, T., Koziris, L.P., Bauer, J.A., Lynch, J.M. and Fleck, S.J. (2000). Inﬂuence of resistance training volume and periodization on physiological and performance adaptations in collegiate women tennis players. American Journal of Sports Medicine, 28, 626–633. Kraemer, W.J., Hakkinen, K., Triplett-Mcbride, N.T., Fry, A.C., Koziris, L.P., Ratamess, N.A., Bauer, J.E., Volek, J.S., McConnell, T., Newton, R.U., Gordon, S.E., Cummings, D., Hauth, J., Pullo, F., Lynch, J.M., Fleck, S.J., Mazzetti, S.A. and Knuttgen, H.G. (2003). Physiological changes with periodized resistance training in women tennis players. Medicine and Science in Sports and Exercise, 35, 157–168.

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Miyashita, M., Tsunoda, T., Sakurai, S., Nishizono, H. and Mizuno, T. (1980). Muscular activities in the tennis serve and overhand throwing. Scandinavian Journal of Sport Sciences, 2, 52–58. Nichols, D.L., Sanborn, C.F., Bonnick, S.L., Gench, B. and DiMarco, N. (1995). Relationship of regional body composition to bone mineral density in college females. Medicine and Science in Sports and Exercise, 27(2), 178–182. Pirnay, F., Bodeux, M., Crielaard, J.M. and Franchimont, P. (1987). Bone mineral content and physical activity. International Journal of Sports Medicine, 8, 331–335. Pugh, S.F., Kovaleski, J.E., Heitman, R.J. and Gilley, W.F. (2003). Upper and lower body strength in relation to ball speed during a serve by male collegiate tennis players. Perceptual and Motor Skills, 97(3 Pt 1), 867–872. Roetert, P. and Ellenbecker, T.S. (1998). Complete Conditioning for Tennis. Champaign, IL: Human Kinetics. Sanchis Moysi, J. (2004). Strength training maintains muscle mass and improves maximal dynamic strength in two professional tennis players. In Science and Racket Sports III (edited by A. Lees, J.-F. Kahn and I. W. Maynard), London: Routledge, pp. 82–89. Sanchis Moysi, J., Dorado García, C. and Calbet, J.A.L. (1998). Regional body composition in proﬀesional tennis players. In Science and Racket Sports II (edited by A. Lees, I. Maynard, M. Hughes and T. Reilly), London: E&FN Spon, pp. 34–39. Sanchis-Moysi, J., Dorado, C., Vicente-Rodriguez, G., Milutinovic, L., Garces, G.L. and Calbet, J.A. (2004). Inter-arm asymmetry in bone mineral content and bone area in postmenopausal recreational tennis players. Maturitas, 48, 289–298. Seger, J.Y., Arvidsson, B. and Thorstensson, A. (1998). Speciﬁc eﬀects of eccentric and concentric training on muscle strength and morphology in humans. European Journal of Applied Physiology and Occupational Physiology, 79, 49–57. Terzis, G., Georgiadis, G., Vassiliadou, E. and Manta, P. (2003). Relationship between shot put performance and triceps brachii ﬁbre type composition and power production. European Journal of Applied Physiology, 90, 10–15. Tsuji, S., Tsunoda, N., Yata, H., Katsukawa, F., Onishi, S. and Yamazaki, H. (1995). Relation between grip strength and radial bone mineral density in young athletes. Archives of Physical Medicine and Rehabilitation, 76, 234–238. Van Gheluwe, B. and Hebbelinck, M. (1986). Muscle actions and ground reaction forces in tennis. International Journal of Sports Biomechanics, 2, 88–99.

7

Development of a tennis-speciﬁc fatigue-inducing protocol and the eﬀects of caﬀeine on performance D.J. Hornery, D. Farrow, I. Mujika and W. Young

Introduction Tennis performance is multi-faceted, characterized by an intricate integration of physical attributes, perceptual skill and technical proﬁciency. The dynamics of the sport and the various styles adopted by players (e.g. baseline or serve and volley), ensures that there is no predetermined match intensity or duration. Similarly, variable environmental conditions challenge sustained performance excellence. Success at the elite level is often determined by one’s ability to resist fatigue. While subjective links between fatigue and the impairment of skill proﬁciency are common, there is a lack of uniform empirical support. The prevailing view of those investigators that have examined the eﬀects of fatigue on tennis skill and performance (Davey et al., 2002; Vergauwen et al., 1998) is that fatigue manifests itself in a number of forms, either centrally or through other homeostatic perturbations, for example hypoglycaemia, hyperthermia and dehydration. Several investigators have used experimental strategies, such as caﬀeine and carbohydrate supplementation, to oﬀset the development of fatigue and performance impairment, but methodological shortcomings (methods to induce fatigue, sensitivity of performance measures and measuring only performance outcomes) limit the weight of the ﬁndings (Burke and Ekblom, 1982; Struder et al., 1999; Vergauwen et al., 1998). Caﬀeine is a practical and legal supplement and has proven perceptual and motor stimulatory eﬀects (Lorist and Snel, 1997). With the intended purpose of preventing fatigue and aﬀording a competitive edge, caﬀeine usage by elite athletes (including professional tennis players) has recently increased. Little explorative research (speciﬁc to tennis) has been conducted to support implementation of caﬀeine to mitigate fatigue and enhance performance. Consequently, tennis players currently employ the supplement without evidence-based support for its usage. The purpose of this investigation was to build upon previous research (Davey et al., 2002; Ferrauti and Weber, 1998; Struder et al., 1999; Vergauwen et al., 1998) and examine the ergogenic potential of caﬀeine, using an

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ecologically valid fatigue protocol and a multifaceted approach to tennis performance assessment.

Methods Participants Twelve highly trained male tennis players (mean ± SD: age 18.3 ± 3.0 years, height 1.788 ± 0.085 m, body mass 73.95 ± 12.3 kg, sum of seven (Norton et al., 1996) skinfolds 62.3 ± 20.9 mm) participated in the investigation. Participants trained at least 15–20 hours per week and had at least ﬁve years of competitive tournament experience. Participants (and parents) received explicit details of the experimental protocol before voluntarily providing written informed consent. The study was reviewed and approved by the Australian Institute of Sport Ethics Committee and the University of Ballarat Ethics Committee. Testing protocol Participants performed a prolonged simulated tennis match, four sets (~2 hours 40 min), on four occasions. The four trials (1 × placebo-control and 3 × interventions), were performed in a single-blinded and counterbalanced manner. Trials were separated by 48 hours to 7 days. Dietary and exercise standardization was applied for 24 hours prior to each trial. Matches were conducted on an indoor hard court (Synthetic category 2, Rebound Ace, A.V. Syntec Pty. Ltd. Queensland, Australia). Thirty minutes prior to protocol commencement participants ingested a gelatine capsule containing caﬀeine, 3 mg.kg−1 of body mass (No-Doz® Awakeners, Key Pharmaceuticals Pty Ltd, Rhodes, Australia) or the placebo supplement (Polycose®, Ross Nutrition, Abbott Laboratories, Ohio, USA). Venous blood samples (10 ml) were extracted from a superﬁcial vein from the cubital fossa of the (non-playing) forearm. Samples were later centrifuged and the supernatant was analysed for prolactin (PRL) concentration using an Immulite (Diagnostic Products Corporation, Los Angeles, California, USA). Blood lactate (BLa), blood glucose and creatine kinase (CK) were analysed from capillary samples using a Lactate Pro (Arkray Factory Inc. Shiga, Japan), HemoCue (Angelholm, Sweden) and Reﬂotron (Roche Diagnostics, Indianapolis, Indiana, USA), respectively. Core body temperature (TC) was measured via short range telemetry, from a single use capsule, ingested at least three hours prior to testing, to a data logger BCTM3 (Fitsense Technology, USA). Heart rate (HR) was monitored using a Polar S610 (Polar Electro Oy, Finland) unit. The protocol commenced with the ball machine (SAM Millennium II, Maximum Sports, Victoria) projecting 17 tennis balls in a pre-programmed random sequence over a duration of 40 s. The balls landed approximately

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1.5 m to the left and right of the centre mark of the baseline, and at a depth approximating the midpoint between the baseline and service line. The participants’ role was to return the balls to designated areas at the opposite end of the court. Participants were given a diﬀerent hitting sequence prior to each game (e.g. cross court only, one shot to the left two shots to the right, and so on). On completion of the rally, participants rested at the baseline for 20 s, after which the next 40-s rally immediately commenced. This process continued until 10 rallies were completed (10 min). Thereafter, players served six ﬁrst serves then sat and recovered courtside for 90–120 s. During this time participants performed a computer-based return of serve test to examine perceptual skill and physiological variables were recorded (TC, HR, ratings of perceived exertion (RPE) and thermal sensation (Young et al., 1987)). Blood lactate and blood glucose was measured during set breaks only (every third break in play). Once all variables were recorded, participants were informed of the next hitting sequence then walked to the baseline and commenced the subsequent 10-min ground stroke assessment. Therefore, one ‘game’ (~ 13-min block) comprised groundstroke performance assessment (~ 10-min: 40-s rally, 20-s rest), ﬁrst serve analysis (~ 1-min) and perceptual skill test (~ 90–120-s, also recovery). Three completed games constituted one ‘set’ and four sets constituted the simulated match. The successive sets replicated the format of the ﬁrst set, with the only variation being the instructions to players regarding the direction balls were to be returned. Participants were instructed to attempt to maintain an intensity equivalent to that during match-play. Participants consumed Gatorade® Lemon Lime Placebo (Pepsico Australia Holdings Pty Ltd., Sydney, Australia) (approximately 14 ml.kg−1 .h−1) during each trial. Performance assessment Serve and groundstroke velocity and accuracy Two radar guns (Stalker Professional Sports Radar, Radar Sales, Plymouth, MN) were used to measure ﬁrst serve and forehand groundstroke velocity. The radar recording serve velocity was positioned on the centre of the baseline at the opposite end of the court to the server, aligned with the approximate height of ball contact (~ 2.2 m), and pointing down the centre of the court. The radar recording forehand groundstroke velocity was positioned on the forehand side of the court, behind the participant pointed at net height down the singles sideline. Accuracy scores were determined, using a 3, 2, 1, 0 scoring system, by counting the number of times the ball landed within the target areas at the intersection of the service line and centre line (serve) and the baseline and singles sidelines (groundstrokes). A total score, expressed as a percentage of the maximum, was recorded for each game.

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Serve kinematics First serve service actions were captured using a high-speed (100 frames per second) digital video camera (Phantom, USA), downloaded and converted to video ﬁles. The ﬁles were viewed using a sport analysis tool (Swinger Plus, Webbsoft Solutions) and divided into ﬁve distinct temporal phases (Phase 1: preparation to ball release; Phase 2: ball release to maximum height of the ball toss; Phase 3: maximum height of the ball toss to racket–ball impact; Phase 4: racket–ball impact to follow-through; Phase 5: entire serve sequence – preparation to follow-through). The duration of each phase was determined by counting the number of frames. Perceptual skill Participants viewed 12 clips, displayed on a laptop computer screen, of a professional player serving. The footage was captured from the perspective of a player attempting to return the serve. The participant was instructed to assume the role of a receiving player and attempt to anticipate the direction of a serve from the footage shown. Two temporal occlusion conditions were presented to manipulate the time available to the participant to predict the direction of the serve. One condition presented the complete service action, including ball ﬂight (T2), while the other condition occluded the vision at the point of racket–ball contact (T1). Participants used the computer mouse to click on the side of the service box they believed was the intended service direction. A response accuracy percentage was then generated from the 12 trials presented (six randomly ordered trials of each occlusion condition). Statistical analyses The experiment used a repeated measures design (with each participant undertaking one trial under each condition), with longitudinal data collected throughout each trial. The data were analysed using linear mixed modelling, with provision for ﬁxed eﬀects of trials and time, random eﬀects for participants, and either constant correlation or autoregressive correlation between the random errors within each trial. Where overall signiﬁcant diﬀerences were detected, subsequent Bonferroni-adjusted post-hoc analyses were conducted to determine the pattern of signiﬁcance. Results are reported as mean ± standard deviation (SD), unless stated otherwise, and signiﬁcance was identiﬁed where P < 0.05.

Results Protocol eﬀects Signiﬁcant eﬀects of time (P < 0.05) were revealed for increasing levels of TC, HR, RPE, thermal sensation, CK, and decreasing blood glucose over the

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duration of the simulated match. Table 7.1 illustrates some selected physiological responses and comparisons between conditions. The velocity of ﬁrst serves (P < 0.05) and groundstrokes (P < 0.05) and groundstroke accuracy (P < 0.05) signiﬁcantly deteriorated over time. The racket-arm acceleration phase of the serve (Phase 3) slowed signiﬁcantly (P < 0.05) over the duration of the protocol. Condition eﬀects Caﬀeine supplementation did not elicit any signiﬁcant physiological responses, but there was a trend for reduced RPE towards the later stages of the protocol. Participants served signiﬁcantly (P < 0.01) faster in the fourth set under the caﬀeine condition (165 ± 15 km.h−1) compared to the placebo (159 ± 15 km.h−1). Figure 7.1 illustrates the reduction in serve velocity over time (placebo condition) and the signiﬁcant diﬀerence between conditions during the fourth set. The temporal analysis of the serve revealed trends for caﬀeine to facilitate racket-arm acceleration phases (Phase 2, P=0.052; Phase 3, P<0.05 condition by time interaction). No other performance measure differed signiﬁcantly between the experimental conditions, i.e. perceptual skill, serve and groundstroke accuracy and groundstroke velocity.

Discussion This investigation built on previous attempts and conﬁrmed that the proﬁciency of outcome and process performance skills, integral to tennis success, is compromised during prolonged match-speciﬁc exercise. The prolonged simulated match elicited physiological and performance responses equivalent to those observed during tennis competition and simulated scenarios. In this instance, only moderate physiological strain was experienced, relative to the duress that has been reported under more challenging playing conditions (Bergeron, 2003; Therminarias et al., 1994). The more commonly reported Table 7.1 Comparative physiological responses between conditions. Values presented are mean ± SD. Core temperature, HR, thermal sensation and blood glucose were averaged over the duration of the protocol

Core temperature (°C) Heart rate (beats⭈min−1) Thermal sensation Blood glucose (mmol⭈l−1) Creatine kinase Pre (u⭈l−1) Creatine kinase Post (u⭈l−1) Prolactin Pre (u⭈l−1) Prolactin Post (u⭈l−1)

Placebo

Caﬀeine

37.6 ± 0.5 154 ± 14 5.5 ± 0.7 5.5 ± 1.5 220.6 ± 135.5 314.5 ± 120.3 254.8 ± 90.9 258.2 ± 108.8

37.7 ± 0.4 156 ± 14 5.4 ± 0.7 5.3 ± 0.7 214.1 ± 121.5 347.2 ± 174.4 243.6 ± 56.5 313.1 ± 189.4

56

D.J. Hornery et al.

Figure 7.1 Serve velocity and RPE over the duration of the protocol. A signiﬁcant diﬀerence between conditions appeared in the fourth set for serve velocity only. Values presented are mean ± SE.

homeostatic disruptions (dehydration, thermal strain, hypoglycaemia or cardiovascular stress) were not induced in this investigation. Instead, it is suggested that the production of creatine kinase and prolactin underscored performance impairment. These ﬁndings implicate both muscle trauma and central fatigue as mechanisms challenging sustained performance proﬁciency and encourage further exploration of the area. Another key ﬁnding to emerge was that caﬀeine played a facilitative role in execution of the serve, speciﬁcally, increased serve velocity and augmented kinematics. These responses became more pronounced towards the latter stages of the prolonged simulated match where fatigue-associated performance deﬁcits are most likely to occur. Consistent with previous literature none of the other performance variables were enhanced through caﬀeine supplementation. Nor did caﬀeine lead to any physiological beneﬁts (Ferrauti and Weber, 1998; Vergauwen et al., 1998). Previous investigators have reported fatigue resistance and enhanced cognition with caﬀeine supplementation (Lorist and Snel, 1997). This investigation examined this issue through the application of a computer-based sport-speciﬁc perceptual skill test and did not reveal enhanced perceptual skill for the players. It was reasoned that the simulated match scenarios may

Tennis-speciﬁc fatigue and eﬀects of caﬀeine

57

not have elicited equivalent central demands to that experienced in real game situations (Royal et al., 2006). Additionally, the high ecological validity of the test setting may have reduced the sensitivity of the test to pick up any changes in perceptual skill. In conclusion, caﬀeine supplementation appears to oﬀer ergogenic properties to some skills imperative to tennis performance; however, further investigation is warranted (Ferrauti and Weber, 1998; Vergauwen et al., 1998). Diﬃculties associated with the conduct of ﬁeld-based testing such as the lack of attentional resource demands associated with simulated match conditions and measurement sensitivity need to be overcome before a true indication of the eﬀects of caﬀeine on tennis performance can be elucidated. Future researchers are encouraged to persist with the incorporation of both process and outcome measures of tennis performance.

References Bergeron, M.F. (2003). Heat cramps: ﬂuid and electrolyte challenges during tennis in the heat. Journal of Science and Medicine in Sport, 6, 19–27. Burke, E.R. and Ekblom, B. (1982). Inﬂuence of ﬂuid ingestion and dehydration on precision and endurance performance in tennis. Athletic Trainer, 17, 275–277. Davey, P.R., Thorpe, R.D. and Williams, C. (2002). Fatigue decreases skilled tennis performance. Journal of Sports Sciences, 20, 311–318. Ferrauti, A. and Weber, K. (1998). Metabolic responses and performance in tennis after caﬀeine ingestion. In Science and Racket Sports II (edited by A. Lees, I.W. Maynard, M. Hughes and T. Reilly), London: E&FN Spon, pp. 60–67. Lorist, M.M. and Snel, J. (1997). Caﬀeine eﬀects on perceptual and motor processes. Electroencephalography and Clinical Neurophysiology, 102, 401–413. Norton, K., Whittingham, N., Carter, L., Kerr, D. and Gore, C. (1996) Measurement techniques in anthropometry. In Anthropometrica (edited by K. Norton and T. Olds). Sydney: University of New South Wales Press, pp. 25–75. Royal, K., Farrow, D., Mujika, I., Halson, S., Pyne, D. and Abernethy, B. (2006). The eﬀects of fatigue on decision making and shooting skill performance in water polo players. Journal of Sports Sciences, 24, 807–815. Struder, H.K., Ferrauti, A., Gotzmann, A., Weber, K. and Hollmann, W. (1999). Eﬀect of carbohydrates and caﬀeine on plasma amino acids, neuroendocrine responses and performance in tennis. Nutritional Neuroscience, 1, 419–426. Therminarias, A., Dansou, P., Chirpaz, M.-F., Eterradossi, J. and Favre-Juvin, A. (1994). Cramps, heat stroke and abnormal biological responses during a strenuous tennis match. In Science and Racket Sports (edited by T. Reilly, M. Hughes and A. Lees), London: E&FN Spon, pp. 28–31. Vergauwen, L., Brouns, F. and Hespel, P. (1998). Carbohydrate supplementation improves stroke performance in tennis. Medicine and Science in Sports and Exercise, 30, 1289–1295. Young, A.J., Sawka, M.N., Epstein, Y., Decristofano, B. and Pandolf, K.B. (1987). Journal of Applied Physiology, 63, 1218–1223.

8

Nutrition knowledge and nutrition habits of tennis coaches B.R. Matkovic´, B. Matkovic´ and P. Tudor-Barbaros

Introduction The nutrition of athletes has been of interest to scientists for decades and since the origins of sports competitions questions about what to eat and what to drink in order to improve performance have been raised. Today there is scientiﬁc evidence that adequate dietary habits inﬂuence to a large extent an athlete’s health, body composition, and energetic pathways during training as well as during competition and recovery (Barr, 1999; American Dietetic Association, 2000; Bernardot, 2000; Wilmore and Costill, 2004; www.ais.org.au/ nutrition, 2005; www.hsph.harvard.edu/nutritionsource/ vitamins.html, 2005). Athletes should be well informed about the food groups, energy intake and daily meal schedules. As previous investigations have shown, athletes obtain most of their knowledge about nutrition from their coaches, especially physical conditioning coaches (Angel and Gillespie, 1990; Conkle and Tishler, 1992; Burns et al., 2004). The major aim of this study is to determine the level of knowledge about nutrition and dietary habits in tennis coaches. A further aim of this paper is to establish the relation between knowledge of nutrition and dietary habits.

Methods The sample consisted of 49 tennis coaches from Croatia. Knowledge about sports nutrition and dietary habits was assessed by means of questionnaires. The questionnaires were constructed based on the results of previous studies conducted at the Faculty of Kinesiology (Matkovic´ et al., 2006) and the results from international studies (Conkle and Tishler, 1992; Paugh, 2005). The questionnaire that provided information about knowledge in sports nutrition consisted of items determining the general knowledge about nutrition, nutritional ingredients needed for providing adequate energy levels in sports, items about supplements, meal schedule before training and competition and recovery, and items testing knowledge about the importance of liquids, dehydration and rehydration during and after training and competition.

Nutrition knowledge of tennis coaches

59

Dietary habits of the subjects were determined by items regarding the number of meals per day, skipping meals, intake of particular food subgroups based on the food pyramid, liquid intake and vitamin and mineral supplements intake, specially those used usually in sports. Surveys were anonymous and the data obtained were analysed by statistical software STATISTICA for WINDOWS. The correlations between nutritional knowledge and dietary habits were examined by means of Pearson’s correlation coeﬃcient.

Results and discussion The questionnaire and the number of correct and incorrect answers are presented in Table 8.1. According to the results obtained, it can be concluded that the level of knowledge about nutrition is not satisfactory. From the total of 1078 correct answers, the tennis coaches obtained 814 or 75.5 per cent accuracy, with a range of 5 to 49 correct answers. There were only seven statements on which the whole sample gave a correct answer. A closer look at the diﬀerent statements in the questionnaire suggest there is a deﬁcit in coaches’ knowledge. This lack can probably be connected to the fact that no single coach attended all of the nutrition courses and that the sources of information for nutritional facts that they use are not always scientiﬁcally justiﬁed. Most of their knowledge comes from diﬀerent popular magazines. Although in recent years there is a signiﬁcant growth in the literature relating to diﬀerent aspects of sports nutrition, it seems that tennis coaches are not interested in this type of source. It seems that proteins are the nutrient about which tennis coaches have the least knowledge. This ﬁnding is in accordance with the previous investigation conducted on Croatian basketball and alpine skiing coaches (Matkovic´ et al., 2006). Almost half of them take proteins for their main energy source and believe that athletes, compared to sedentary people, need as much as triple the amount of this nutrient even though they know very little about protein metabolism. They do know that amino acids are among the most used supplements (Lacey and Pritchett, 2003; Lombardo, 2004), frequently from the recommendation of their coaches. It would be expected that persons who are advocating the use of this supplementation know about the possible problems or side eﬀects that could endanger the health of the player. Vitamins and minerals are also frequently used as supplements (Burns et al., 2004). The statements on these nutrients had just a few incorrect answers. It is surprising that 40 per cent of coaches consider vitamins and minerals as sources of energy. With regard to supplementation, 40 per cent of tennis coaches think that there is no success in sport without dietary supplements. There are very few false answers about weight loss. This is surprising because tennis is not a sport where players and coaches have problems with keeping their weight within certain limits as in some other sports, like gymnastics or wrestling (American Dietetic Association, 2000; Ray and Fowler,

60

B.R. Matkovic´, B. Matkovic´ and P. Tudor-Barbaros

Table 8.1 Questionnaire with the marked true (T) or false (F) answers and the number of correct and incorrect answers Answers Correct Not correct 1. Proteins are the main energents

F

25

24

2. Muscle glykogen depots can aﬀect exercise available energy

T

44

5

3. Excess protein intake overload kidney and liver 4. Athletes need three times more proteins than sedentary persons

T F

30 4

19 45

5. Athletes need more carbohydrates than sedentary persons

T

39

10

6. Thirst is not an adequate indicator of water needed during exercise

T

25

24

7. Fluids should be ingested before, during and after exercise

T

34

15

8. Skipping meals is justiﬁed when it is necessary to promote a fast weight loss

F

49

0

9. Very fast weight loss associated to very restrictive diets can negatively aﬀect exercise performance

T

49

0

10. Weight loss with a very restricitve diet is mostly due to water loss

T

34

15

11. Calcium deﬁciency can lead to bone fractures and osteoporosis

T

49

0

12. Intake of mixtures of speciﬁc amino acids can cause a nutritional disbalance (one amino acid could compete with another)

T

8

41

13. Citric fruits are the only sources of vitamin C in food F

49

0

14. To eat after a competition is only important if the athlete is hungry

F

39

10

15. Balanced diet is necessary only before the competition

F

43

6

16. The last main solid meal should be taken with a 3–4 hour interval before the competition

T

49

0

17. Hydration and carbohydrate repletion should begin as soon as possible after the competition

T

43

6

18. It is impossible to win without supplements

F

29

20

19. Fruits and vegetables are good sources of vitamins and minerals

T

49

0

20. Excess vitamin and mineral consumption can be toxic

T

49

0

21. Vitamin D could be produced by the body

T

45

4

22. Vitamins and minerals are sources of energy

F

29

20

Nutrition knowledge of tennis coaches

61

2004). Probably this is a consequence of the fact that the problem of controlling body mass is present in everyday life and it is not only a question of sport nutrition but is connected with the quality of life. The coaches showed that they knew how to deal with meal schedules related to training/competitions. In contrast, understanding recovery and rehydration was not so good. Recovery is a very complex process in which nutrition and rehydration have a very important role. It is necessary to restore glycogen deposits in muscles and in the liver, replenish water and minerals lost by sweating and synthesize muscle proteins. Consumption of a carbohydrate-rich meal as soon as possible after exercise is recommended, providing at least one gram of carbohydrate per kilogram of an athlete’s body weight (Ivy et al., 1988; Inge, 2001; Welsh et al., 2002; Jentjens and Jeukendrup, 2003). Tennis players should consume ﬂuid at every opportunity they have, but recovery is a period to replenish the loss of water and electrolyte (Maughan et al., 1996; Shirreﬀs et al., 1996) and not to overconsume ﬂuids (Noakes, 2003). At this stage it is very important to take into consideration that thirst is not a good measure of dehydration and, unfortunately, almost half of the coaches surveyed were not familiar with this. The dietary habits questionnaire consisted of 18 questions (Paugh, 2005). These questions included food intake, dieting, skipping meals, consumption of diﬀerent beverages and vitamin and mineral supplementation. Answers ranged from always (4) to never (1) and the possible range for scores was from 18 to 72. Coaches obtained 48.6 points on average. It seems that coaches, like athletes, have very busy schedules so they skip some meals in their daily routine, but breakfast is not the one usually skipped. Coaches are rarely dieting and they do not seek much nutritional information nor are they recording what they eat. A positive relationship was found between dietary habits and nutritional knowledge. Coaches who had a better understanding of nutrition had also better nutrition habits. This fact was also established in some previous investigations (Paugh, 2005; Matkovic´ et al., 2006).

Conclusion It was concluded that despite relatively good nutritional knowledge, there is some incompleteness about very important nutrition facts. This is the reason why sport nutritionists should be included in coaching teams. Such a person would be the one to help in the education of coaches, athletes and parents, to diagnose dietary habits and to suggest necessary changes, all for the purpose of better sport results and preserving health (Lacey and Pritchett, 2003). A good level of knowledge could contribute to good dietary habits.

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References American Dietetic Association. (2000). Position of the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine: nutrition and athletic performance. Journal of the American Dietetic Association, 100:1543–1556. Angel, J.B. and Gillespie, C. (1990). Nutritional knowledge of athletic trainers. Alabama State Association for Health, Physical Education, Recreation and Dance (ASAHPERD) Journal, 13, 18–20. Barr, S.I. (1999). Eﬀects of dehydration on exercise performance. Canadian Journal of Applied Physiology, 24, 164–172. Benardot, D. (2000). Nutrition For Serious Athletes: An Advanced Guide to Foods, Fluids, and Supplements for Training and Performance. Champaign IL: Human Kinetics. Burns, R.D., Schiller, R., Merrick, M.A. and Wolf, K.N. (2004). Intercollegiate student athlete use of nutritional supplements and the role of athletic trainers and dietitians in nutrition counseling. Journal of the American Dietetic Association, 104, 246–249. Conkle, T.H. and Tishler, A.G. (1992). Sports nutrition knowledge assessment of physical educators and coaches. Annual meeting of the Mid-South Educational Research Association, 11–13 November 1992, Knoxville, Tennessee. Inge, K. (2001). Nutrition: the competitive edge. In Tennis Medicine for Tennis Coaches (edited by M. Crespo, B. Pluim and M. Reid), London: ITF Ltd, pp: 111–112. Ivy, J.L., Katz, A.L., Cutler, C.L., Sherman, W.M. and Coyle, E.F. (1988). Muscle glycogen resynthesis after exercise: eﬀect of time of carbohydrate ingestion. Journal of Applied Physiology, 64, 1480–1485. Jentjens, R. and Jeukendrup, A.E. (2003). Determinants of post-exercise glycogen synthesitss during short-term recovery. Sports Medicine, 33, 117–144. Lacey, K. and Pritchett, E. (2003). Nutrition care process and model: ADA adopts road map to quality care and outcomes management. Journal of the American Dietetic Association, 103, 1061–1072. Lombardo, J.A. (2004). Supplements and athletes. Southern Medical Journal, 97, 877–879. Matkovic´, B., Knjaz, D. and Cigrovski, V. (2006). Znanje trenera o sportskoj prehrani. [Sport nutrition knowledge of coaches]. Hrvatski sˇportsko medicinski vjesnik, 21, 3–8. Maughan, R.J., Leiper, J.B. and Shirreﬀs, S.M. (1996). Rehydation and recovery after exercise. Sport Science Exchange, 9, 1–5. Noakes, T.D. (2003). Overconsumption of ﬂuids by athletes. British Medical Journal, 327, 113–4. Paugh, S.L. (2005). Dietary habits and nutritional knowledge of college athletes. Unpublished PhD Thesis. California University of Pennsylvania. Ray, T.R. and Fowler, R. (2004). Current issues in sports nutrition in athletes. Southern Medical Journal, 97, 863–866. Shirreﬀs, S.M., Taylor, A.J., Leiper, J.B. and Maughan, R.J. (1996). Post-exercise rehydration in man: eﬀects of volume consumed and drink sodium content. Medicine and Science in Sports and Exercise, 28, 1260–71. Welsh, R.S., Davis, J.M., Burke, J.R. and Williams, H.G. (2002). Carbohydrates and

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physical/mental performance during intermittent exercise to fatigue. Medicine and Science in Sports and Exercise, 34, 723–31. Wilmore, J.H. and Costill, D.L. (2004). Physiology of Sport and Exercise. Champaign, IL: Human Kinetics. www.ais.org.au/nutrition (last accessed 2/11/2005). www.hsph.harvard.edu/nutritionsource/vitamins.html (8 of 12) (last accessed 6/6/ 2005).

9

Correlations of physiological responses in squash players during competition J.R. Alvero Cruz, J. Barrera Expósito, A. Mesa Alonso and D. Cabello

Introduction Physiological and perceptual responses to playing in squash competition are not well-known. Laboratory testing is commonly used to determine metabolic proﬁle of players, to evaluate physiological training-induced changes and/or determine appropriate training intensities. In racket sports such as squash, success is largely dependent on technical, tactical and motor skills (Lees, 2003). Squash is a moderate-to-high intensity intermittent exercise. Players are active 50 to 70 per cent of the playing time and 80 per cent of the time the ball is in play 10 s or less. The rest intervals ﬁt a normal distribution with an average duration of 8 s. Heart rate increases rapidly in the ﬁrst minutes of play and remains stable at approximately 160 beats.min−1 for the whole match regardless of players’ competitive levels (Montpetit, 1990). In sports with intermittent activity such as squash, physiological demands imposed on the players during competition cannot be simulated in controlled laboratory settings and it is important to consider the physiological characteristics of the game, including the many dynamic leg movements (repeated accelerations, decelerations, turns and jumps), arm (shoulder internal rotation, forearm pronation, wrist ﬂexion) and other movements made during real match-play. Only limited data on squash play performance exists in literature. Some studies have monitored cardio-respiratory responses in incremental treadmill test versus speciﬁc incremental test (Girard et al., 2005) and physiological characteristics (VO2max, anaerobic thresholds, running speed) of squash players (Chin et al., 1995; Steininger and Wodick, 1987). The maximal oxygen consumption (VO2max), anaerobic threshold (ventilatory thresholds, VT), and respiratory compensation point, are not able to explain the performance in competition and these are not suﬃcient for a valid estimate of competition ﬁtness (Steininger and Wodick, 1987; Girard et al., 2005). The aim of this study was to evaluate the relationship between several physiological variables (anthropometric, mean heart rate, lactate levels, ratings of perceived exertion (RPE) and training variables) considered important in the course of several matches in squash players.

Physiological responses in squash players 65

Methods Participants Thirteen healthy experienced male squash players volunteered for this investigation and written informed consent was obtained from each participant. The protocol was approved by the University of Malaga Ethical Committee (Spain). Preliminary testing Anthropometric variables used to estimate body composition included the sum of four skinfolds (triceps, subscapular, ileospinal and abdominal), body fat and the Heath-Carter anthropometric somatotype (Carter and Heath, 1990), which was derived according to ISAK’s methodology (Norton and Olds, 1996). Experimental testing Measurements of heart rate were continuously recorded (Polar 610i, 710i, Polar Electro Oy, Finland), lactate levels (Dr Lange LP20 Miniphotometer, Berlin, Germany) were determined from 20 µl of a hyperhemized blood drawn from the earlobe in the ﬁrst minute after the end of the match. Ratings of perceived exertion (RPE) were recorded by modiﬁed Borg scale of 0–10 (Chen et al., 2002), the total game time (s) and the loser (L = 0) or winner (W = 1) in a total of 25 matches. Statistics Statistical analyses were conducted using a SPSS version 14.0 and a MedCalc Statistical Software. The results are expressed as mean (SD). Paired t-tests were used to determine signiﬁcant diﬀerences between variables. Pearson product moment correlations were used to examine the relationships among variables (anthropometric, mean heart rate, lactate levels, RPE and training variables), and P < 0.05 was considered signiﬁcant.

Results Table 9.1 shows descriptive data for age, height, weight, percentage of body fat, Heath-Carter somatotype components, BMI and training characteristics Signiﬁcant diﬀerences were found between winner (W) and loser (L) on the Borg Scale and for lactate levels (Table 9.2). No signiﬁcant diﬀerences were found between HR mean for W and L or in variables like percentage of fat, BMI, somatotype components, age, mass, height, training years and week training unit sessions. Signiﬁcant correlations (Table 9.3) were found between

66

J.R. Alvero Cruz et al. Table 9.1 General data (n = 13) age, height, mass, percentage of fat, BMI, somatotype components and training data

Age (years) Height (cm) Mass (kg) % fat mass BMI (kg/m2) Endomorphy Mesomorphy Ectomorphy Training sessions (week) Training (years)

Mean

SD

31.93 173.61 75 15.05 25.19 3.58 5.75 1.23 5.98 9.59

11.21 7.02 5.88 2.76 2.06 1.3 1 0.97 4.36 9.18

Table 9.2 Values are mean (SD) of lactate concentration (mMol.l−1), RPE Borg Scale and mean heart rate (bpm) between winners and losers Variables

Winner

Loser

Lactate (mM.l−1) Borg Scale (0–10) HRmean (beats.min−1)

3.41 (1.58) 5.5 (2.3) 167 (12)

6.54 (2.86) 7.6 (2.43) 175 (9.6)

diﬀ

95% CI

t

2.11

0.1309 to 4.099 1.1971 to 5.069

– 3.34 – 2.20

–

–

–

3.13

df

P<

23

0.0028

23

0.037

–

ns

Table 9.3 Correlation between variables P< / r =

Borg Scale (RPE)

Winner–Loser

Mean HR

Lactate Borg Scale Winner–Loser Mean HR Play time

0.65**

−0.57** −0.418**

0.44* 0.727** −0.356

Play time 0.479* 0.00 0.33

Notes: * P < 0.05 ** P < 0.001

lactate concentrations and the Borg Scale, W or L and mean HR. Other correlations were found: weak training sessions were inversely related with percentage of fat (r = −0.423; P < 0.035) and endomorphy (r = −0.54; P < 0.005) and directly with ectomorphy (r = 0.42; P < 0.034), and regional ranking was related to percentage of fat (r = −0.48; P < 0.01) and endomorphy (r = 0.47; P < 0.018).

Physiological responses in squash players 67

Discussion In squash, maximal oxygen uptake has traditionally been considered the key factor in aerobic performance, and this sport is largely dependent on some technical motor abilities. Limited data are available in relation to competition parameters, and only a few publications are available on sport speciﬁc ﬁtness tests, and other sports (Green et al., 2006; Seiler and Sjursen, 2004). The results of the present study show a tight relationship between variables that are related with ﬁtness as mean heart rate, lactate levels, competition time and the ratings of perceived exertion. The basic anthropometric variables of our players are in agreement with Chin (Chin et al., 1995) and Girard (Girard et al., 2005) in relation to mass, height and percentage of body fat. The total amount of training is related to a smaller percentage of fat and endomorphy. Somatotype components and percentage of fat mass do not present signiﬁcant relationships with performance. The relationship between lactate and RPE, lactate and mean heart rate are direct (r = 0.44 and r = 0.65) and this suggests that RPE is a sensitive variable of acute exercise and dependent on intensity. High values of perceived exertion (Borg Scale) and lactate levels are inversely related to a win or loss. We can conﬁrm that lower RPE level, lactate and mean heart rate are associated with a win and it is an expression of a lower relative intensity. Finally, RPE is a sensitive variable to training-induced threshold changes (Hetzler et al., 1991). In our study this relationship could be due to the fact that the collection of RPE was after exercise and is associated with the perception of overall eﬀort, that ﬁnally picks up a sensation of a maintained steady-state exercise. In other studies signiﬁcant increases in RPE occurring concurrently with signiﬁcant decreases in blood lactate have been found during later stages of exercise, revealing a divergence in relationships indicating that lactate does not serve as a strong RPE mediator during 60-min of workload cycling (Green et al., 2006). These results show that physiological and competition responses can be a decisive factor that may make a diﬀerence between success and failure in squash tournaments. So we should consider them in order to plan training. Blood lactate levels between winners and losers suggest diﬀerent grades of metabolic contribution over the course of repeated short and intense workouts. (Montpetit, 1990). The blood lactate concentration remains stable despite a continued lactate production and elimination, due to a steady workload although there are short rest intervals. The change of blood lactate concentrations from the middle to the end of the match is nearly constant, suggesting that lactate production and elimination are balanced. Other exercise circumstances such as longer duration, steady workload and repeated exercise bouts may alter these associations (Green et al., 2006; Weltman et al., 1998; Seiler and Sjursen, 2004). The use of blood lactate measurements for prediction of exercise performance, training control and their changes is

68

J.R. Alvero Cruz et al.

recommended (Billat, 1996) and proposed as a physiological marker that is valuable for intensity regulation (Weltman, 1995; Weltman et al., 1998) The changes in mean heart rate and lactate levels during competitive squash are important and may be regulated for duration and intensity of match and competitor level. The rating of perceived exertion is a dependent variable of heart rate and lactate concentration. Also, the lactate levels and mean heart rate are dependent variables of a RPE and these responses are in agreement with Green (Green et al., 2006). Garcin and Billat (2001) showed that RPE responses attest to intensity as well as duration of exercise. Although the perception of eﬀort remains a critical tool, the good relation with heart rate and lactate suggest other ways to control perceived intensity. More investigations are necessary to demonstrate the relationship between these parameters and their changes with the speciﬁc training and their eﬀect in the competition results. Future studies aim to investigate the physiological and perceptual responses to competition after training intervention in diﬀerent aerobic–anaerobic zones. We consider that interval-training methods are important to improve squash performance and the convenience of the use of RPE, lactate and heart rate levels to quantify training and competition intensity. The key ﬁndings of this study are the close relationships between lactate, mean heart rate and rating scale of perceived exertion in response to competition and their possible modiﬁcation of these variables by means of speciﬁc training. These training sessions have to be designed on the basis of physiological data recorded during response to competition and training.

Conclusions This study indicates that the performance level of squash matches seems to have a strong association between variables such as the mean heart rate, lactate level and rating of perceived exertion. These variables should be utilized in the planning of training in order to design exercises with a similar response. These results also seem to demonstrate that the relative intensity of the game of squash in winners is characterized by aerobic lactate and mean heart rate levels. These physiological variables of competition are possibly modiﬁed by speciﬁc training.

References Billat, V.L. (1996). The use of blood lactate measurements for prediction of exercise performance an control of training. Sports Medicine, 22, 157–175. Carter, J.E.L. and Heath, B.H. (1990). Somatotyping: Development and Applications. Cambridge: Cambridge University Press. Chen, M.J., Fan, X. and Moe, S.T. (2002). Criterion related validity of the Borg ratings of perceived exertion scale in healthy individuals: a meta-analysis. Journal of Sports Science, 20, 873–899.

Physiological responses in squash players 69 Chin, M.K., Wong, A.S., So, R.C., Siu, O.T., Steininger, K. and Lo, D.T. (1995). Sport speciﬁc ﬁtness testing of elite badminton players. British Journal of Sports Medicine, 29, 153–157. Garcin, M. and Billat, V. (2001) Perceived exertion scales attest to both intensity and duration. Perceptual Motor Skills, 93, 661–667. Girard, O., Sciberras, P., Habrard, M., Hot, P., Chevalier, R. and Millet, G.P. (2005). Speciﬁc incremental test in squash players. British Journal of Sports Medicine, 39, 921–926. Green, J.M., McLester, J.R., Crews, T.R., Wickwire, P.J., Pritchett, R.C. and Lomax, R.G. (2006). RPE association with lactate and heart rate during high intensity interval cycling. Medicine and Science in Sports and Exercise, 38, 167–172. Hetzler, R.K., Seip, R.L., Boutcher, S.R., Pierce, E., Snead, D. and Weltman, A. (1991). Eﬀect of exercise modality on ratings of perceived exertion at various lactate concentrations Medicine and Science in Sports and Exercise, 23, 88–92. Lees, A. (2003). Science and the major racket sports: a review. Journal of Sports Science, 21, 707–73. Montpetit, R.R. (1990). Applied physiology of squash. Sports Medicine, 10, 31–41. Norton, K. and Olds, T. (1996). Anthropometrica. Sidney: Southwood Press. Seiler, S. and Sjursen, J.E. (2004). Eﬀect of work duration on physiological and rating scale of perceived exertion responses during self-paced interval training. Scandinavian Journal of Medicine and Science in Sports, 14, 318–325. Steininger, K. and Wodick, R.E. (1987). Sports-speciﬁc ﬁtness testing in squash. British Journal of Sports Medicine, 21, 23–26. Weltman, A. (1995). The Blood Lactate Response to Exercise. Champaign, IL: Human Kinetics, Weltman, A., Weltman, J.Y., Kanaley, J.A., Rogol, A.D. and Veldhuis, J.D. (1998). Repeated bouts of exercise alter the blood lactate-RPE relation. Medicine and Science in Sports and Exercise, 30, 1113–1117.

10 Field-based assessment of speed and power in junior badminton players M.G. Hughes

Introduction Badminton is a sport where fast, explosive movements and high levels of agility are essential for competitive success at the elite level. The assessment of ﬁtness for badminton should therefore include tests which reﬂect these performance demands. Badminton England’s programme of ﬁtness assessment for elite junior players was established in 2001 and has required players to perform ﬁeld tests for speed, agility, power and aerobic ﬁtness (Hughes, 2006). Although there are examples of aerobic ﬁeld tests for Badminton players in the scientiﬁc literature (Chin et al., 1995; Hughes and Fullerton, 1995; Hughes et al., 2002; Wonisch et al., 2003) no such test procedures have been reported for power, agility or speed. For the ﬁtness assessment of players, it is often desirable to assess for general, as well as sport-speciﬁc, physical abilities. The Badminton England ﬁtness test batteries include a combination of general tests for speed and power as well as a sport-speciﬁc, speed (‘agility’) test. Due to the lack of established ﬁeld tests for power in badminton players, the lower-body power tests involves assessment of jump performance, as used in many other sports (Gore, 2000). The speed and agility tests both require repeated movements within a badminton court but only the agility test required a badminton-speciﬁc movement pattern. Previous analysis of data from senior, elite players performing the same tests (Hughes and Bopf, 2005) showed that performance in the agility test was not related to performance in the jump tests for groups of either male or female players. Similarly, performance in the general speed test was only related to performance in the agility test for female, but not male, players. Hughes and Bopf (2005) concluded that the jump tests should not be used to make inferences about badminton-speciﬁc movement speed in senior players. The present study addressed the same issue but the analysis was performed on junior players where developmental considerations may show that diﬀerent conclusions should be drawn. For the junior programme of testing, where high numbers of players are routinely assessed, it is important to know whether there are associations

Field-based assessment of speed and power

71

between test types. For example, if a jump test was a predictor of speed or agility, rationalization of the test programme could be appropriate. Additionally, establishing the relationships between these variables may be useful in advising about future training for the optimization of speed, power or agility for individual players. Therefore the purpose of the present study was to investigate the relationships between results for ﬁeld tests for lower body power, speed and agility in a group of junior, elite badminton players.

Methods Participants At the time of testing all subjects were part of the England World Class Potential squad. There were 43 male subjects (mean ± SD, age and body mass: 16.9 ± 1.1 years, 70.5 ± 7.3 kg, respectively) and 49 female subjects (mean ± SD, age and body mass: 16.8 ± 1.3 years, 61.8 ± 7.8 kg, respectively). Test procedures Jump tests Jump tests were performed using vertical jump and standing long jump procedures. Vertical jump was measured using Vertec (JumpUSA, CA, USA) apparatus. Preparatory counter-movement was allowed and the dominant hand was raised in execution of the test jump. The standing long jump was measured from the front of the feet (taken as zero point) to the back of the foot which travelled the least distance upon landing. The best performance from at least four attempts was recorded as the test result. General speed test For the performance of this test, players stood astride the central line of a court and were required to make ten lateral movements at maximum speed across the court. Five shuttlecocks were placed, feathers downwards, on the outside line of each side of the court (i.e. ten shuttles in total). Each set of ﬁve shuttlecocks were spread out over a distance of around 50 cm. Players were instructed to knock one shuttle from its position with their racket for each lateral movement. They thus moved from forehand to backhand side knocking one shuttle for every movement made. Once the tenth shuttle had been hit, the test time was taken when the player crossed the central line for the last time. The best time from at least two attempts was taken as the test result.

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Badminton-speciﬁc speed (‘agility’) test This test required a total of eight movements in an ordered sequence in all directions around the court (see Figure 10.1; from points 1 to 4, twice in succession). This test used badminton-speciﬁc ‘shadow play’ movements around the court, starting from a central base. For position 1, players were required to replicate an overhead forehand shot while placing a foot in the box marked on Figure 10.1. At position 2, players had to touch a post (around 1.2 m high) positioned on the inner tramline, 1.5 m back from the front service line. At position 3, players had to hit a shuttle that was resting on the net tape, 0.5 m in from the inner tramline. Finally, at position 4, players had to hit a shuttle that was placed on the inner tramline 1.5 m back from the front service line before returning to their central base. Once this sequence had been performed twice, the test-time was taken when the player returned to the central base. The best time from at least two attempts was taken as the test result. Body composition Body composition was predicted from the measurement of four skinfold sites using the procedures of Durnin and Wormesley (1974).

Figure 10.1 Layout of the badminton half-court for the speciﬁc speed test. (See text for details; set-up shown is for right-handed player only).

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73

Data analysis The most recent, complete set of data for each player was taken for analysis. Separate Pearson’s product moment correlations were established for the results of male and female players. Statistical signiﬁcance was accepted at P < 0.05.

Results The mean results for the ﬁtness tests are given in Table 10.1. Correlation analyses The correlation matrices for these data are shown in Tables 10.2 (female data) and 10.3 (male data). These data show that for female players, all of the physical test results were highly correlated. Similarly, body fat results were related to jump test performances and general speed test results, but not to performance in the agility test. For the male players, the jump tests were interrelated and the jump test results were also correlated to general speed test performance. The agility test results were only related to performance in the general speed test. Table 10.1 Mean ± standard deviation results for ﬁtness test data

Predicted body fat (%) Vertical jump height (m) Standing long jump (m) General speed test (s) Agility test (s)

Males (n = 43)

Females (n = 49)

10.9 ± 3.4 0.63 ± 0.06 2.42 ± 0.14 14.9 ± 0.7 11.7 ± 0.8

23.9 ± 3.5 0.49 ± 0.05 1.96 ± 0.18 16.4 ± 0.9 13.3 ± 1.0

Table 10.2 Correlation matrix for female subjects Age Body mass % Fat Vertical jump Long jump General speed Agility

0.36* 0.21 0.13 0.20 −0.31* −0.39**

Body mass

0.70** −0.21 −0.16 0.34* 0.01

% Fat

−0.50** −0.37** 0.48** 0.10

Notes: * denotes signiﬁcant correlation (P < 0.05) ** denotes signiﬁcant correlation (P < 0.01)

Vertical jump

Long jump

General speed

0.74** −0.70** −0.49**

−0.64** −0.60**

0.67**

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Table 10.3 Correlation matrix for male subjects Age Body mass % Fat Vertical jump Long jump General speed Agility

0.42** 0.16 0.29 0.51** −0.46** −0.39**

Body mass

0.69** 0.06 0.34* −0.13 −0.19

% Fat

−0.05 −0.08 0.07 −0.02

Vertical jump

Long jump

General speed

0.62** −0.44** −0.29

−0.41** −0.23

0.65**

Notes: * denotes signiﬁcant correlation (P < 0.05) ** denotes signiﬁcant correlation (P < 0.01)

Discussion The key ﬁndings of this study were that, like senior players, the jump test results of juniors were related closely to general speed test performance, but not always to speed in a badminton-speciﬁc agility test. For female players, the badminton agility test performance was related to performance in the other speed and jump tests. In contrast, for male players, agility-test performance was not signiﬁcantly correlated to jump test performance. The performance level of the players assessed in this study was very high. The mean results for all tests with these junior players are within 5 per cent of equivalent data for the senior players whose data were analysed by Hughes and Bopf (2005). Bearing in mind the age of these players, and the fact that they were well habituated to the test procedures in these tests, it would seem

Figure 10.2 Scatter plot (and linear trend lines) for vertical jump height and agility test results in male and female players.

Field-based assessment of speed and power

75

that these data were representative of the players’ limits of performance in these tests of ﬁtness. A number of factors ought to be considered about the nature of this study and its analysis before conclusions can be made about its ﬁndings. First, the ﬁndings of this study should not be generalized to a wider population as the sample whose data are analysed here were the product of a national squad selection process. For example, the fact that the trends within the data for males were slightly diﬀerent to those of the female group could be a product of preferential selection of diﬀerent charactermbistics for the two genders. In this case, it could be that the strong relationships between the speed, agility and power results are attributed to a selection policy that favours females who were generally athletic. Similarly, the weaker correlation between agility scores for the males and the speed and jump tests could be attributable to selection based on badminton movement speed, as opposed to more general attributes. Second, limitations of the statistical analysis could also help to explain these ﬁndings. Correlation is always strengthened when a population is relatively heterogeneous for the variables being analysed. The standard deviation of agility scores for females was slightly higher than for the males, but this was roughly proportional to the magnitude of the values, suggesting that the data for the males and females were not contrasting in terms of heterogeneity. The outcomes of this study may have implications for the preparation, identiﬁcation and ﬁtness assessment of junior badminton players. In terms of ﬁtness assessment, these data support the ﬁndings from senior players (Hughes and Bopf, 2005) that performance in the jump test, although thought to reﬂect lower body power, is not necessarily predictive of badminton speciﬁc speed-agility. In junior females, however, performance in the jump test and speed tests may be predictive of badminton speed-agility. Caution should be exercised in using results from the jump tests to make inferences about more dynamic badminton activities. It should be acknowledged that jumping is an integral activity in elite badminton and, irrespective of any lack of association with speciﬁc movement speed, very high levels of leg power are essential for success in the sport. On the evidence gathered with the English players analysed, jump test performance is not always correlated to speed on court. For these junior players, results from the general speed test correlated strongly with the agility task: a ﬁnding that was not seen with senior male players. With reference to the preparation of players, these ﬁndings highlight the importance of the movement technique that is required for this sport. Male players with good jump test performances were not necessarily the fastest on the agility task. These ﬁndings are consistent with the outcomes of the similar analysis with senior male and female players (Hughes and Bopf, 2005). Finally, in terms of identiﬁcation of talented players, a balance needs to be drawn between desirable sport-speciﬁc and general characteristics. Particularly with reference to young players, appropriate training should be devised which compensates for the relative deﬁciencies in a player’s ﬁtness proﬁle that are identiﬁed by a programme of ﬁtness testing such as this.

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Conclusion In summary, performance in a jump test is not necessarily predictive of oncourt speed in junior badminton players. While performance in a general speed test seems to relate to a badminton speed-agility task in these junior players, the same trend may not be present once the male players reach senior level. The present data suggest that the factors that correlate with on-court movement speed may diﬀer between male and female junior players.

References Chin, M.-K., Wong, A.S.K., So, R.C.H., Siu, O., Steiniger, K. and Lo, D.T.L. (1995). Sport speciﬁc ﬁtness testing of elite badminton players. British Journal of Sports Medicine, 29, 153–157. Durnin, J.V. and Wormesley, J. (1974). Body fat assessed from total body density and its estimation from skinfold thicknesses. British Journal of Nutrition, 32, 77–97. Gore, C.J. (2000). Physiological Tests for Elite Athletes: Australian sports commission. Champaign, IL: Human Kinetics. Hughes, M.G. (2006). Fitness Testing Procedures. Milton Keynes, UK: Badminton England. Hughes, M.G. and Bopf, G. (2005). Relationships between performance in jump tests and speed tests in elite Badminton players. Journal of Sports Sciences, 23, 194–195. Hughes, M.G. and Fullerton, F.M. (1995). Development of an on-court aerobic test for elite badminton players. In Science and Racket Sports (edited by T. Reilly, M. Hughes and A. Lees), London: E&FN Spon, pp. 51–54. Hughes, M.G., Andrew, M. and Ramsay, R. (2002). A sport-speciﬁc, endurance performance test for elite badminton players. Journal of Sports Sciences, 21, 277–278. Wonisch, M., Hofmann, P., Schwaberger, G., von Duvillard, S.P. and Klein, W. (2003). Validation of a ﬁeld test for the non-invasive determination of badminton-speciﬁc aerobic performance. British Journal of Sports Medicine, 37, 115–118.

11 Energy expenditure measurement in badminton players during a training camp using doubly-labelled water E. Watanabe, S. Igawa, T. Sato, M. Miyazaki, S. Horiuchi and K. Seki Introduction The quantity of physical activity and energy expenditure of badminton players have been studied in general using heart rate monitoring. There are many research reports concerning the physical activity of a game of badminton (Seki et al., 1982; Araragi et al., 1999; Cabello et al., 2003). In order to obtain good results in an international match, it is necessary to prepare for the target game. For that purpose, we need to understand the habitual energy consumption (in training camp, on tour, during competition games and so on) that a player expends. Energy expenditure can be measured under ﬁeld conditions using the doubly-labelled water method (DLW). The DLW method has been validated with respiratory gas analysis in several animals species and recently in humans. The technique has the advantage that total energy expenditure (TEE) can be measured in free-living subjects with minimal interference with only the periodic sampling of urine or saliva. Subjects can take part freely in their daily activities, even during an experimental period. It has been standardized in a workshop where all users in the ﬁeld of human energy metabolism were represented (Prentice, 1990). In recent years studies for not only general populations, but also athletes have increased (Hunter et al., 2000; Naoyuki et al., 2000; Hyong-Ryul et al., 2003). The purpose of this study is to examine the total energy expenditure for badminton players. In this study, the doubly-labelled water method was used to estimate energy expenditure of the badminton players in a training camp. Simultaneously, a nutrition investigation was also conducted.

Methods Subjects were 17 badminton players (seven men, ten women) who participated in the six-day training camp of the Thomas and Uber cup at the Japan Institute for Sports Sciences (JISS) in 2004. Before the training camp, we explained the purpose of this study to both players and coaches. Subjects gave informed consent to participate in this institutionally approved study.

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Measurements were performed without changing their practice schedule so that it did not become a burden to players and staﬀ. Practice was performed as usual. Each player was asked for one urine sample every morning. Their activity, including the urine sampling time, was recorded in the questionnaire by the players. Food intake was recorded using the nutritional administration system ‘I-dietitian’. When a training camp was over, we collected all the samples, results of meal contents and questionnaires. Urine samples were analysed using the DLW method. With regard to energy intake, the I-dietitian output record data were summed to give the amount of energy, protein, lipid, carbohydrates, calcium, iron and vitamins A, B1, B2 and C.

Results Physical characteristics and the results using DLW Physical characteristics of subjects are shown in Table 11.1. As a result of the analysis of DLW, in men the water turnover was 5.94 l.day−1, TEE was 4685.5 kcal.day−1, and the percentage of fat was 11.9 per cent. In women, the water turnover was 4.12 l.day−1, energy expenditure was 3238.7 kcal.day−1, and the percentage of fat was 20.09 per cent (Tables 11.2 and 11.3). Results of dietary intake The energy intake in men was 3326.2 kcal/day, in women it was 2450.2 kcal/ day. The PFC ratio in men was 16.3:25.7:58.0, in women it was 18.0:30.8:51.1 (Tables 11.4 and 11.5).

Discussion and conclusion The mean data presented excluded the data that needed retesting due to unusually high values. Generally, the result of energy expenditure measurement using the DLW method tended to be higher than the energy intake. The results of this study also showed large values of about 1300 kcal in men, 800 kcal in women. Because it was not possible in this study to investigate Table 11.1 Physical characteristics of subjects Men

Age (yr) Height (cm) Weight (kg) BMI (kg/m2)

Women

Mean

SD

Mean

SD

23.6 171.3 66.1 22.5

1.9 3.6 5.1 1.2

24.5 163.7 56.1 20.9

3.8 4.4 4.4 0.9

Energy expenditure in badminton players

79

Table 11.2 Analysis of subjects using DLW method in men Subject

TBW (kg)

rCO2 (mol/day)

TEE (kcak/day)

% fat

Water turnover (l/day)

1 2 3 4 5 6 7

46.2 – 41.3 37.3 41.9 49.8 38.0

37.0 – 44.9 47.7 107.1 26.1 29.8

4672 – 5672 6026 13521 3294 3758

5.9 – 15.8 12.1 18.3 8.1 17.6

5.0 – 5.6 7.4 – 5.4 6.3

Mean SD

42.50 5.375

11.92 4.98

5.94 0.94

37.11 9.35

4684.54 1179.75

* *

**

Notes: * Needing retest ** Except for retest value

Table 11.3 Analysis of subjects using DLW method in women Subject

TBW (kg)

rCO2 (mol/day)

TEE (kcak/day)

% fat

Water turnover (l/day)

1 2 3 4 5 6 7 8 9 10

31.8 30.2 32.2 30.9 32.0 35.9 34.1 34.6 37.5 32.1

60.6 20.8 22.9 28.5 30.6 390.7 59.8 32.2 21.6 29.5

7654 2630 2889 3600 3857 49312 7547 4068 2731 3727

18.0 20.8 18.5 14.7 20.6 18.3 19.6 17.0 22.4 23.6

3.1 3.0 4.6 3.4 4.6 3.7 5.8 5.1 5.3 3.9

*

Mean SD

32.48 2.59

3238.69 548.05

20.09 3.15

4.12 0.85

**

25.65 4.36

* * *

Notes: * Needing retest ** Except for retest value

snacks in enough detail, it is thought that the value may be lower than other studies of energy intake due to under-estimation. The PFC ratio suggests the necessity for dietary counselling, because the lipid ratio was over 30 per cent in woman. There were no data to compare for men, but these data will act as a baseline for future studies. Because every player in this training camp had a diﬀerent menu, it is thought that an energy consumption between players diﬀered greatly. In addition, in order to compete for Olympic selection, players left the training camp early to attend an international match. However, this method hardly restricted a player’s schedule and was not a burden. Energy expenditure and the information about lifestyle were acquired. This awareness can be expected

E (kcal)

2864 – 3047 3680 3941 3090 3335

3326.15 412.62

Subject

1 2 3 4 5 6 7

Mean SD

142.44 14.41

151.6 – 130.3 132.1 164.4 128.6 147.7

Protein (g)

99.40 17.50

84.1 – 78.0 111.8 121.9 91.0 109.7

Lipid (g)

Table 11.4 Result of dietary intake in men

505.55 125.73

362.5 – 448.6 531.2 533.6 431.7 725.7 1136.76 183.36

1389 – 907 1110 1020 1075 1320

Carbohydrate (g) Ca (mg)

15.76 1.70

17 – 17 16 16 12 16

Iron (mg)

2788.24 1493.20

3862 – 5282 1872 1474 1722 2517

A (µ g)

2.22 0.24

2.56 – 2.11 2.17 2.35 1.84 2.33

B1 (mg)

2.68 0.40

3.34 – 2.70 2.39 2.63 2.19 2.81

B2 (mg)

510.23 123.40

301.8 – 471.0 611.0 624.0 465.7 588.0

C (mg)

E (kcal)

2701 1684 2423 3118 2801 2371 2242 2544 2500 2118

2450.23 393.14

Subject

1 2 3 4 5 6 7 8 9 10

Mean SD

109.46 17.00

101.4 84.5 96.1 133.0 138.9 111.3 110.7 115.1 110.7 92.9

Protein (g)

83.25 18.95

81.2 49.4 73.8 118.9 98.1 75.7 87.7 94.7 86.8 66.4

Lipid (g)

Table 11.5 Result of dietary intake in women

310.43 47.97

373.6 224.6 335.5 372.7 337.4 305.9 250.3 306.3 309.2 288.9 880.35 226.73

798 635 584 933 1394 839 1063 890 802 867

Carbohydrate (g) Ca (mg)

12.72 1.84

10 12 10 14 16 12 14 13 12 14

Iron (mg)

2615.17 1648.21

999 2684 1103 3351 5474 1671 1202 3555 1231 4882

A (µ g)

1.64 0.32

1.67 1.60 1.64 2.19 2.03 1.68 1.20 1.83 1.29 1.32

B1 (mg)

2.18 0.58

1.50 2.03 1.43 2.6 3.44 2.10 2.04 2.46 1.82 2.4

B2 (mg)

335.41 112.57

398.2 306.1 212.9 506.8 367.5 333.2 182.0 486.9 205.3 355.3

C (mg)

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to improve the self-management of the player. By improving speed and accuracy of analysis, it would be considered to be one of the more eﬀective methods to use in the sports ﬁeld.

Acknowledgements We thank the 17 subjects, their coaches, JISS staﬀ and students of Waseda University, for cheerfully participating in this study. This study was supported by a grant from JISS and Nippon Badminton Association. A scholarship fund was oﬀered by JISS and Nippon Badminton Association.

References Araragi, K., Oomori, M. and Iwata, H. (1999). Measurement of energy consumption, constituent of blood, and amount of nutrition in the high strength training period of elite badminton players. Acta Scholae Medicinalis Universitatis in Gifu, 47, 215–227 (in Japanese). Cabello, D. and González-Badillo, J.J. (2003). Analysis of the characteristics of competitive badminton. British Journal of Sports Medicine, 37, 62–66. Hunter, G.R., Wetzstein, C.J., Fields, D.A., Brown, A. and Bamman, M.M. (2000). Resistance training increases total energy expenditure and free-living physical activity in older adults. Journal of Applied Physiology, 89, 977–984. Hyong-Ryul, K., Sang-Jik, L., Jong Hoon, P., Naoyuki, E., Kunio, Y., Kouzou, T. and Shinichi S. (2003). Measurement of total energy expenditure by the doubly labelled water method during a competitive season in Korean professional football league players. Japan Journal of Physical Education and Health Sport Science, 48, 717–723 (in Japanese). Naoyuki, E., Jian-Ying, F., Miwako, H., Shinichi, S. and Jones, P.J.H. (2000). Total energy expenditure of elite synchronized swimmers measured by the doubly labelled water method. European Journal of Applied Physiology, 83, 1–6. Prentice, A.M. (editor) (1990). The Doubly-Labelled Water Method for Measuring Energy Expenditure: Technical Recommendations for Use in Humans. A consensus report by the IDECG working group. Vienna: International Atomic Energy Agency. Seki, K., Onozawa, H. and Miyazaki, M. (1982). Variation of heart-rate playing a game of badminton players in the all-Japan education staﬀ meeting. Research of Physical Education of Waseda University, 14, 35–43 (in Japanese).

12 Kinanthropometric proﬁle, body composition, somatotype and grip strength dynamometry in young high level tennis, badminton and table tennis players F. Pradas, E. Martínez, P.E. Alcaraz and L. Carrasco Introduction Kinanthropometric proﬁle, body composition and somatotype have become very popular terms among athletes and coaches in recent decades. The body composition of elite athletes has also received a great deal of attention from the scientiﬁc community due to its importance in competitions. In fact, there are many studies which deﬁne the anthropometric proﬁle and/or body composition in diﬀerent sports (Bloomlied and Sigererseth, 1965; Behnke and Royce, 1966; Costill, 1967; Hanson, 1973; Burke, 1980; Haymes and Dickenson, 1980; Baxter-Jones et al., 1995; Damsgaard et al., 2001; Pradas et al., 2003; Carrasco et al., 2005). In addition, muscle strength has been identiﬁed as other important element for ﬁtness for the racket player (Chandler, 1998). However, there are few comparisons of anthropometric characteristics and body composition in young high-level tennis, badminton and table tennis players. Neither are there many reports concerning grip strength dynamometry. In fact, there are only a few comparisons of grip strength between genders (Beenakker et al., 2001; Luna et al., 2005). It is important to carry out a complete evaluation of racket sports players, for comparative purposes. Thus, the purpose of this study was to deﬁne anthropometric, body composition, somatotype and grip strength proﬁles in high-level young tennis, badminton and table tennis players.

Methods Twenty-eight male (age = 16 ± 1; body mass = 63.2 ± 10.9 kg; height = 1.74 ± 0.059 m) and 22 female (age = 16 ± 1; body mass = 56.2 ± 7.8; height = 1.636 ± 0.054 m) players participated in the study. Experienced assessors used a Holtain skinfold callipers (Holtain, Crymych, UK) to determine skinfold values. All skinfolds were measured on the right side of the body and were

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determined as described by the Spanish Anthropometric Group (Esparza, 1993). The equations of De Rose and Guimaraes (1980) were used in the determination of body composition for both males and females. Grip force was measured using a grip dynamometer (Grip-D, T.K.K. 5401, Japan) with a grip span of 5.0 cm for all participants. Standard statistical methods were used for the calculation of means, standard deviations (SD) and Pearson correlation coeﬃcients (r). Multivariate analysis of variance (MANOVA) with a post hoc Bonferroni test of honestly signiﬁcant diﬀerences (SPSS 13.0, SPSS Inc., Chicago, IL) was used to compare the three racket sports. Signiﬁcance was set at P < 0.05.

Results Tables 12.1 to 12.6 represent biometric data, body composition, somatotype and dynamometric strength concerning the sport performed. The relationships between muscle mass, arm circumference and dynamometric strength for both hands are also included. No signiﬁcant diﬀerences were found between the sports studied in any of the player’s biometric data (Table 12.1). Signiﬁcant increases were found in triceps skinfold between tennis and badminton players (P = 0.04 and P = 0.009, respectively) compared with table tennis players. Furthermore, signiﬁcant increases were established in subscapular and illiocristal skinfolds when badminton players were compared with table tennis and tennis players. Likewise, there were signiﬁcant diﬀerences in abdominal skinfold, sum of four and six skinfolds, fat mass, and thigh perimeter (Tables 12.2 and 12.3). When somatotype was analysed in terms of racket sports practised, signiﬁcant diﬀerences were found between table tennis and badminton players in the endomorphic component and was higher in the badminton players (Table 12.4). Table 12.5 shows that there were no signiﬁcant diﬀerences for dynamometric strength between the hands in terms of racket sports practised. A high relationship was shown between muscle mass and grip strength in Table 12.1 Biometric data in terms of racket sports practised (BMI = Body mass index) Body mass (kg)

Height (m)

BMI (kg⭈m−2)

Table tennis n = 18

56.6 ± 6.1

1.672 ± 0.07

20.2 ± 1.5

Tennis n = 15

60.9 ± 8.6

1.714 ± 0.083

20.8 ± 1.6

Badminton n = 17

63.0 ± 13.7

1.700 ± 0.077

21.8 ± 3.7

15.3* ± 3.5

16* ± 6.7

Tennis n = 15

Badminton n = 17

13.6*† ± 5.5

10.1 ± 1.9

9.3 ± 2.2

Su

9.7 ± 3.8

14 ± 19.7

Sup

21.8*† ± 10.5 12.3 ± 6.5

17 ± 4.4

12.9 ± 4.8

Il

21.9* ± 12.3

18.1 ± 5.6

14.1 ± 5.5

Ab

22.2 ± 8.9

22.9 ± 6

23.3 ± 6.6

Th

14 ± 6

13.4 ± 2.7

12.7 ± 4.6

Sh

89.1 ± 17.8

82.9 ± 28.2

Σ6

63.8* ± 29.5 100* ± 42.7

53.2 ± 12.6

48.2 ± 23

Σ4

Notes: Tr = triceps; Su = subscapular; Il = illiocristal; Sup = suprailliac; Ab = abdominal; Σ4 = sum of four skinfolds (Tr, Su, Sup and Ab); Σ6 = sum of six skinfolds (Tr, Su, Sup, Ab, thigh and shank)

12.5 ± 4.3

T. Tennis n = 18

Tr

Skinfolds (mm)

Table 12.2 Skinfolds in terms of racket sports practised

10.2* ± 4.7 10.7 ± 1.7

Badminton n = 17

27.7 ± 5.3

27.3 ± 3.8

25.5 ± 2.2

MM

14.7 ± 3.4

14.3 ± 2.4

13 ± 1.7

RM

27.8 ± 3.4

27.5 ± 2.5

27.8 ± 2

48.7 ± 6.6

46.5 ± 4.9

47.6 ± 3.1

5.3 ± 0.3

5.3 ± 0.4

36.6* ± 3.8 5.3 ± 0.4

35.6 ± 2.2

34.1 ± 2.4

6.3 ± 0.5

6.4 ± 0.4

6.4 ± 0.5

Biep

Bie

Sh

Ar

Th

Diameters (cm)

Perimeters (cm)

9.5 ± 0.9

9.4 ± 0.5

9.1 ± 0.6

Bic

Notes: FM = fat mass; OM = osseous mass; MM = muscle mass; RM = residual mass; Bie = bistyloid diameter; Biep = biepicondylar diameter; Bic = bicondylar diameter; * = signiﬁcant diﬀerences from table tennis players

10.6 ± 1.4

8.5 ± 1.8

Tennis n = 15

10.1 ± 1.5

7.9 ± 3.1

OM (kg)

T. Tennis n = 18

FM

Table 12.3 Body composition in terms of racket sports practised

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87

Table 12.4 Somatotype in terms of racket sports practised Endomorphic

Mesomorphic

Ectomorphic

Table tennis n = 18

3.1 ± 0.9

3.8 ± 0.8

3.3 ± 0.9

Tennis n = 15

3.5 ± 0.7

3.5 ± 0.8

3.2 ± 0.7

Badminton n = 17

4.1* ± 1.6

4.0 ± 1.2

2.9 ± 1.6

Note: * = signiﬁcant diﬀerences from table tennis players

Table 12.5 Grip strength in terms of racket sports practised Grip strength (N) Right

Left

Table tennis n = 18

342.0 ± 56.8

300.9 ± 56.8

Tennis n = 15

363.6 ± 79.4

327.3 ± 76.4

Badminton n = 17

349.9 ± 95.1

328.3 ± 85.3

Table 12.6 Muscle mass, arm perimeter and grip strength Muscle mass (kg) Total n = 50

26.8* ± 4.0

Grip strength (N)

Arm perimeter (cm)

Right

Left

351.8* ± 76.4

318.5* ± 72.5

27.7* ± 2.7

Note: * = Signiﬁcant correlation between the three variables; P < 0.01

both right and left hands. In the same way, an elevated statistical signiﬁcance was noticed when these last variables were related to the circumference of the arm (Table 12.6).

Discussion The current study deﬁnes the kinanthropometric proﬁle, body composition, somatotype and grip strength dynamometry in young high-level tennis, badminton and table tennis players.

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Signiﬁcant diﬀerences were shown between badminton and table tennis in several players. Also, signiﬁcantly higher values were evidenced in the endomorphic component in badminton with respect to table tennis players. Similar data were found by Baxter-Jones et al. (1995) in body fat percentages. This last study indicated a signiﬁcantly lower body fat percentage in gymnasts (P < 0.05) compared with junior football and tennis players. However, Baxter-Jones et al. (1995) did not show signiﬁcant diﬀerences in the anthropometric variables studied. These data are in contrast to other works. Damsgaard et al. (2001) found signiﬁcant diﬀerences in the sum of skinfolds for female athletes in four sports (swimming, tennis, handball and gymnastics). Furthermore, Leone et al. (2002) found signiﬁcantly higher values in female adolescent tennis players compared to female adolescent artistic skaters in anthropometric variables. Fleck’s (1983) study of body composition data of various groups of elite American athletes concluded that extremely low percentage fat values were not a necessity for success in many sports. In general, athletes involved in sports where their body weight is supported in some manner tend to have higher percentage fat values than athletes involved in extreme aerobic or extreme anaerobic type sports. It seems that competitive badminton is less anaerobic than competitive table tennis (Lees, 2003) which could explain the lower percentage fat in table tennis players. Grip strength is importance for holding and controlling the racket. Sharp (1998) suggested that, in elite squash players, a range of 400–450 N for men and 300–350 N for women is required to ensure that the racket is held ﬁrmly during play. In the current study the mean grip strength of male and female athletes was 351.8 ± 76.4 N, which led us to consider that these racket players were strong enough to be resistant to fatigue. Actually, signiﬁcant diﬀerences were not found between tennis, badminton and table tennis players in grip strength dynamometry for this range of age. Finally, and as expected, a signiﬁcantly high relationship (P < 0.01) was found between muscle mass, grip strength, and the circumference of the arm in the whole sample studied.

Conclusions For the athletes studied in this work, it is concluded that several of the skinfold (subscapular, ileocrestal and abdominal, sum of four and six skinfolds), fat mass percentage, thigh circumference and endomorphic components were signiﬁcantly higher in badminton players compared to table tennis players. In addition, no signiﬁcant diﬀerences were found between tennis, badminton or table tennis players in grip strength dynamometry for this age range.

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89

References Baxter-Jones, A.D.G., Helms, P., Maﬀulli, N., Baines-Preece, J.C. and Preece, M. (1995). Growth and development of male gymnasts, swimmers, soccer and tennis players: a longitudinal study. Annals of Human Biology, 22, 381–394. Beenakker, E.A.C., van der Hoeven, J.H., Fock, J.M. and Maurits, N.M. (2001). Reference values of maximum isometric muscle force obtained in 270 children aged 4–16 years by hand-held dynamometry. Neuromuscular Disorders, 11, 441–446. Behnke, A.R. and Royce, J. (1966). Body size, shape and composition of several types of athletes. Journal of Sports Medicine and Physical Fitness, 6, 75–88. Bloomlied, J. and Sigererseth, P.O. (1965). Anatomical and physiological diﬀerences between sprint and middle distance swimmers at the university level. Journal of Sports Medicine and Physical Fitness, 5, 76–81. Burke, E.R. (1980). Physiological characteristics of competitive cyclists. Physician and Sports Medicine, 8, 79–84. Carrasco, L., Martínez, E. and Nadal, C. (2005). Perﬁl antropométrico, somatotipo y composición corporal de jóvenes piragüistas [Anthropometric proﬁle and body size of young canoeists]. Revista Internacional de Medicina y Ciencias de la Actividad Física y el Deporte, 20, http://cdeporte.rediris.es/revista/revista20/ artpalistas19b.htm (accessed 1 April 2008). Centeno, R.A., Naranjo, J. and Guerra, V. (1999). Estudio cineantropométrico del jugador de bádminton de élite juvenil [Anthropomteric study of badminton players aged below 17]. Archivos de Medicina del Deporte, 16, 115–119. Chandler, T.J. (1998). Conditioning for tennis: preventing injury and enhancing performance. In Science and Racket Sports II (edited by A. Lees, I. Maynard, M. Hughes and T. Reilly), London: E&FN Spon, pp. 77–85. Costill, D.L. (1967). The relationship between selected physiological variables and distance running performance. Journal of Sports Medicine, 7, 61–66. Damsgaard, R., Bencke, J., Matthiesen, G., Petersen, J.H. and Müller, J. (2001). Body proportions, body composition and pubertal development of children in competitive sports. Scandinavian Journal of Medicine and Science in Sports, 11, 54–60. De Rose, E.H. and Guimaraes, A.C. (1980). A model for optimization of somatotype in young athletes. In Kinanthropometry II (edited by M. Ostin, G. Buenen, J. Simons), Baltimore: University Park Press, pp. 177–188. Esparza, F. (1993). Manual de Cineantropometría [Kinathropometric Manual]. GREC-FEMEDE, Pamplona. Fleck, S.J. (1983). Body composition of elite American athletes. The American Journal of Sports Medicine, 11, 398–403. Hanson, J. (1973). Maximal exercise performance in members of the U.S. Nordic ski team. Journal of Applied Physiology, 35, 592–595. Haymes, E.M. and Dickenson, A.L. (1980). Characteristics of elite male and female ski racers. Medicine and Science in Sports and Exercise, 12, 153–158. Lees, A. (2003). Science and the major racket sports: a review. Journal of Sports Sciences, 21, 707–732. Leone, M., Lariviere, G. and Comtois, A.S. (2002). Discriminant analysis of anthropometric and biomotor variables among elite adolescent female athletes in four sports. Journal of Sports Sciences, 20, 443–449. Luna, E., Martín, G. and Ruiz, J. (2005). Handgrip dynamometry in healthy adults. Clinical Nutrition, 24, 250–258.

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Pradas, F., Vargas, M.C. and De Teresa, C. (2003). A comparative study of anthropometric proﬁle in top-level table tennis young players. In III World Symposium on Education, Physical Activity and Health (edited by the Faculty of Educational Sciences), Melilla: University of Granada, pp. 94–102. Sharp, N.C.C. (1998). Physiological demands and ﬁtness for squash. In Science and Racket Sports II (edited by A. Lees, I. Maynard, M. Hughes and T. Reilly), London: E&FN Spon, pp. 3–13.

13 Analysis of the somatotype, body composition and anthropometry in badminton players between 12 and 16 years M. de Hoyo, B. Sañudo and F. París

Introduction The study of the dimensions and composition of the human body is one of the criteria on which sports specialization is based. The analysis of the body composition is well established nowadays due to the fact that the percentage of muscle tissue, bone tissue and adipose tissue which the human body contains can be quantiﬁed. It has been used for accessibility, simplicity of application, reproducibility and economy (Ramirez and Iglesias, 2006). With the somatotype we can follow the changes that occur during the growth of children and control the intensive training in children so that it produces normal and desirable eﬀects for their correct and adequate development (Gómez et al., 2002). The aim of this work was to determine the body composition and the anthropometric proﬁles of the badminton players of the infant and cadet categories of the Andalusian Community.

Material and method Subjects A total of 108 subjects were analysed (n1 = 54 boys; n2 = 54 girls), with ages between 12 and 16 years, as a descriptive and cross-sectional study. The study took place during the ‘Andalusian Championship’, celebrated in Punta Umbría in April, 2006. Procedure The skinfolds (bicipital, subescapular, tricipital, pectoral, axial, supraspinal, abdominal, thigh, leg and suprailiac) were measured in triplicate with a Holtain Skinfold Caliper (Holtain Ltd., Dyfed, UK) with a range from 0 to 48 mm, graduation of 0.2 mm and constant pressure of 10 g.mm−2. A calliper with a range of 140 mm was used to measure bone diameters. A metric tape Harpenden Anthropometric Covers of Holtain Ltd. was used for measuring muscular circumference.

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Measurements were conducted as recommended by the Manual de Cineantropometría (Esparza, 1993) and the manual of the International Society for Anthropometry and Kinesiology (ISAK, 2001). Two experimenters took each measurement separately. The technical error of measurement (TEM) was calculated with a tolerance of 5 per cent for cutaneous skinfolds and 2 per cent for the rest of the measurements. Body mass was measured using the SECA scale (SECA, Hamburg, Germany) using the method described by Canda and Esparza (1999). Height was obtained with a Holtain stadiometer (Holtain Ltd., Dyfed, UK), following the protocol described by Marfell-Jones (1991). Body composition was quantiﬁed following the protocol of De Rose and Guimaraes (1980), referenced in Esparza (1993). The equation proposed by Slaughter et al. (1988), validated in studies with children between 8 and 18 years, was used for the estimation of the percentage of adipose mass. Finally, the somatotype of the badminton players was determined following the model proposed by Carter (2002). Statistical analysis Data were analysed by SPSS 13.0 for Windows. Only values having a correlation coeﬃcient satisfying P < 0.05 were considered statistically signiﬁcant.

Results The average mass was 55.47 ± 12.42 kg (boys: 58.23 ± 14.15 kg; girls: 53.06 ± 9.87 kg). Average height was 1.62 ± 0.108 m (boys: 1.666 ± 0.119 m; girls: 1.596 ± 0.008 m). The diﬀerences between sexes were statistically signiﬁcant (P < 0.05) With reference to the cutaneous tissue, the girls presented, with the exception of the pectoral fold, higher absolute values (Table 13.1) than the boys. With reference to the summation of six skinfolds (Σ6p), the diﬀerences were statistically signiﬁcant between boys and girls (P < 0.001). Nevertheless, in case of the summation of four skinfolds (Σ4p) it was found to be P < 0.10. This result indicates that there exists certain diﬀerences between method of calculation used. Boys had larger muscular circumferences than the girls at the waist (P < 0.001) and arm (P < 0.05). Diﬀerences found in the biepicondylar diameters and bistyloid were signiﬁcant (P < 0.001), but not signiﬁcant in femoral condyles (P < 0.10). With reference to the somatotype, an average of 16.25 ± 8.30 per cent was found for the endomorphic body, of 43,83 ± 6,90 per cent for the ectomorphic and 17.41 ± 3.00 per cent for the mesomorphic, the residual percentage being of 22.50 ± 1.61 per cent. The information relative to both genders is presented in Table 13.2. Boys presented average values of mesomorphy and ectomorphy greater

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Table 13.1 Analysis of the skinfolds and Σ of the 4 and 6 folds

Boys Girls

Boys Girls

Media SD Media SD

Media SD Media SD

Triceps

Subesc.

Biceps

Pectoral

Axilar

12.53 4.75 15.92 4.97

9.23 4.02 10.55 3.55

6.51 3.02 8.21 3.15

6.48 3.24 6.33 5.84

7.84 4.2 9.10 3.80

Ileo

Supra.

Abdom.

thigh

Leg

Σ6P

Σ4P

14.65 7.36 17.36 6.53

11.24 6.67 12.49 5.52

16.59 10 18.96 7.87

16.01 6.54 22.42 7.87

15.32 5.78 18.93 5.2

80.78 34.50 101.33 29.21

49.38 23.97 57.92 20.58

Note: Σ6P (triceps, subscapular, supraspinal, abdominal, thigh and leg) Σ4P (triceps, subscapular, supraspinal and abdominal)

Table 13.2 Information relative to the BMI and body composition

Boys Girls

Media SD Media SD

BMI

% Fat

% Lean

% Bone

% Residual

20.79 3.39 20.7 2.91

9.79 5.27 22.08 6.03

48.01 5.23 4.13 6.2

18.08 3.15 16.75 2.7

24.1 0 20.9 0

Note: BMI = Body Mass Index

Table 13.3 Information relative to the somatotype Total

Media SD

Boys

Girls

Endo

Meso

Ecto

Endo

Meso

Ecto

Endo

Meso Ecto

3.66 1.33

4.14 2.56

2.85 1.41

3.26 1.43

4.36 2.39

3.1 1.49

4 1.14

3.93 2.70

2.63 1.29

Note: Endo. = endomorphy; Meso. = mesomorphy; Ecto. = ectomorphy

than those of the girls, but in endomorphy, it was lower than for the girls (Table 13.3). A statistically signiﬁcant diﬀerence between the genders was found (P < 0.05).

Discussion and conclusions This study deﬁnes the anthropometric and body composition proﬁles of young Andalusian badminton players according to gender. Both for adults and children, a BMI equal or greater than 25 kg.m−2 is considered as

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overweight, whereas a value greater than 30 kg.m−2 implies obesity (Dietz and Billizzini, 1999). Using this criterion, 13 per cent of the boys and 11 per cent of the girls were overweight. With reference to the girls an adipose tissue percentage above 22.5 per cent represents overweight (Hoeger, 1989) and a value greater than 27.5 per cent indicates obesity. In accordance with this, 44 per cent of the girls were overweight or obese. The results of this study for BMI were similar to that obtained by other investigators and has shown that the BMI does not seem to be a parameter that diﬀerentiates teenagers of diﬀerent genders. There are few kinanthropometry studies that have been performed on badminton players and even fewer for the ages considered in this paper. However, the authors have found some publications which have been carried out for people of similar age but for other specialities and also for sedentary populations. In this sense, a study in which a wide group of students of ﬁve Spanish provinces was analysed, the percentages of fat found in 13- and 14-year-old girls were greater than those corresponding to boys of the same age. These results are quite consistent with those found in the present study. With reference to the somatotype, it can be stated that the results follow a direct relation with the typical features of boys and girls for these ages. According to Gómez et al. (2002) the boys reached a more endomesomorphic model in early maturity, whereas the girls had a major trend to endomorphy in adolescence, this trend appearing in the male closer to the adult age, though both men and women tend toward endomorphy with age. When the somatotype proﬁling is compared with that of other authors (Gómez et al., 2002; Michels, 1996; Rubio and Franco, 1995; Rubio et al., 1993; Téllez et al., 2002) a very similar proﬁle is found, both in girls and boys.

References Canda, A. and Esparza, F. (1999). Cineantropometría [Kinanthropometry]. In Valoración del deportista: aspectos biomédicos y funcionales, Pamplona, Spain: FEMEDE. Carter, J.E.L. (2002). The Heath-Carter Anthropometric Somatotype. Instruction Manual. San Diego, CA: San Diego State University. De Rose, E.H. and Guimaraes, A.C. (1980). A model for optimization of somatotype in young athletes. In Kinanthropometry II (edited by M. Ostin, G. Buene and J. Simona), Baltimore: University Park Press. Dietz, W.H. and Bellizzini, M.C. (1999). Introduction: the use of body mass index to assess obesity in children. American Journal of Clinical Nutrition, 70, 123–125. Esparza, E. (1993). Manual de Cineantropometría [Kinanthropometry Manual]. Pamplona, Spain: FEMEDE. Gómez, J.R., Berral, C.J., Viana, B., Leiva, A., Ibnziaten, A. and Berral, F.J. (2002). Un estudio de somatotipo en adolescentes de 10 a 14 años [A somatotype study in teenagers (10–14 years)]. Medicina del Ejercicio, XVII (1–2), 22–34. Hoeger, W. (1989). Lifetime Physical Fitness and Wellness. Englewood Cliﬀs, NJ: Morton.

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ISAK (2001). International Standards for Anthropometric Assessment. Unerdale: ISAK. Marfell-Jones, M. (1991). Guidelines for Athlete Assessment in New Zealand Sport. Kinanthropometric Assessment. Michels, G. (1996). Aspectos antropométricos de escolares de 10 a 14 años de Córdoba y provincia Anthropometric proﬁle of schoolchildren (10–14 years). PhD thesis, Faculty of Medicine, University of Córdoba, Spain. Ramírez, E. and Iglesias, M.C. (2006). Estudio antropométrico de los jugadores portugueses de balonmano de edades comprendidas de 15 a 16 años [Anthropometric study of Portugese handball players (15 and 16 years)]. Actas del I Congreso Internacional de Ciencias del Deporte. Pontevedra, Spain. Rubio, F.J. and Franco, L. (1995). Estudio descriptivo antropométrico y de forma física de escolares integrados en programas deportivos de iniciación [Descriptive anthropometric and ﬁtness study in schoolchildren’s introductory sports programmes]. Apunts, 32, 33–40. Rubio, F.J., Franco, L. and Peral, R. (1993). Valoración de la forma física mediante el test de banco de Astrand en los niños integrados en programas de deportes de iniciación [Fitness evaluation of children’s introductory sport programmes by Astrand’s test]. Actas del V Congreso Nacional de FEMEDE, Pamplona, Spain: FEMEDE. Slaughter, M.H., Lohman, T.G., Boileau, R.A., Horswill, R.J., Stillman, M.D., Van Loan, M.D. and Bemben, D.A. (1988). Skinfold equations for estimation of body fatness in children and youth. Human Biology, 60, 709–23. Téllez, A., Martí, A., Martínez, J., Parra, J.C., Villodres, M.C. and Fernández, C.F. (2002). Antropometría y grado de maduración en nadadores [Anthropometric and maturing grade of swimmers]. Archivos de Medicina del Deporte, XIX (87), 29–35.

Part 2

Biomechanical and medical aspects of racket sports

14 Biomechanics of racket sports Developments and current status A. Lees

Introduction The goal of sports biomechanics is to study the mechanical functioning of the human system within a sports context in order to understand how to enhance performance and reduce injury. When applied to racket sports (badminton, squash, table tennis and tennis) the topics which have been most frequently addressed in the literature are the analysis of technique, the kinematic (motion) and kinetic (force) analysis of racket skills. The scope of these applications have been inﬂuenced by the availability and development of technology and associated computer related analysis methods. A brief historical survey of technological developments illustrates how important they have been to the understanding of the biomechanics of performance. The earliest application of motion analysis technology to racket sports occurred in the 1960s when cine cameras became available for common use and were used to provide ﬁlm clips of racket skills for observation. The 1970s saw the development of methods for making measurements from ﬁlm images. This process of ‘digitization’ enabled simple calculations to be made of variables such as joint and racket head speed. In the 1980s multi-camera systems were used to get images from two or more views and analytical procedures (developed in the aerial surveying ﬁeld a decade earlier) were applied by sports biomechanists to obtain three dimensional (3D) data from sports skills. Application to racket sports occurred in the 1990s, which also saw the development of methodology for calculating 3D kinetics of skills such as the tennis serve. The cine camera has subsequently declined in popularity due to the advent of two other systems. The ﬁrst was the video camera which during this time became cheaply available and was, and still is, used for observation and simple 2D analyses. In recent years, integrated observation systems have been developed which have provided valuable tools for the practising coach. The second, opto-electronic systems developed in the last decade, have been used by sports biomechanists to rapidly capture 3D motion data and perform 3D kinematic and kinetic analyses. This technology is now beginning to be applied to the racket sports. It appears that we have experienced a period of rapid development and are on the edge of a period of

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extensive application. A review of past and present applications is timely to prepare us for that future.

Observation of technique High speed cinematography and video have enabled clear descriptions of the sequence of joint actions used in the performance of skills. In racket sports the most popular skill analysed is the fast overhead shot or serve in tennis. These actions require the generation of high racket head speed and is achieved by a sequence of trunk and upper limb motions. The trunk rotates initially away from the direction of the stroke (retraction phase) and then towards the direction of the stroke (action phase). During retraction, the upper arm at the shoulder is abducted and externally rotated, the lower arm at the elbow ﬂexed and supinated, and the hand at the wrist extended and radially ﬂexed. During the action phase the shoulder continues to abduct and to horizontally adduct, the upper arm internally rotates, the forearm pronates and the wrist ﬂexes. This description of events has been helpful to coaches to understand the sequential nature of rotations involved in skills of this type and to clinicians who have appreciated the importance of joint ﬂexibility and ranges of motion demanded by the performance of these skills. In addition to understanding the sequence of events, observation can also help understand the purpose of actions made. For example, one of the purposes of the jump smash in badminton is to gain extra height at contact with the shuttle so that a sharper angle of descent into the opponent’s court can be achieved. Observation of some skilled but sub-elite players indicate that their general action is sound but their timing is in error, as at the moment of impact they have landed back on the ground, thus failing to use the height generated during the jump. Similar observations can indicate the success of positioning, for if a player is poorly positioned they make contact with the shuttle at a lower height than would be possible if their positioning was optimal.

Movement principles Movement principles are statements that deﬁne how a movement should take place and are based on sound mechanical or biological principles. There are many principles that can be stated (see Lees, 2002, for a discussion of this issue) but there are four which apply easily to racket sports. The ﬁrst is known as range of motion. This describes how performance can be enhanced by increasing the range of motion during the retraction and action phases of a skill. This is seen clearly in fast shots like the overhead smash in badminton or the serve in tennis. During these movements the player ‘winds up’ thus increasing the distance that the ‘un-winding’ action can go though. The increased range of motion increases the acceleration path of the racket head and means that muscle force can be applied over a greater

Biomechanics of racket sports 101 distance enabling more muscle energy to be used. This principle is also inﬂuenced by ﬂexibility and joint ranges of motion, those with more mobile joints are able to generate a greater range of motion. Thus, ﬂexibility training is important. A second principle is the proximal-to-distal sequence associated with actions, like the tennis serve, which require high end point speed. The basic statement of the principle is that the more proximal joints (i.e. to the centre of gravity of the body) act ﬁrst with the more distal joints acting later in sequence. The velocity created by the larger slower proximal segments provide a platform on which the lighter more distal segments operate. This is clearly seen in the overhead smash and in the general sequence of action as noted under the observation section. In particular it is worth noting that segment rotations about the longitudinal axis are also important and in practice these are diﬃcult to observe and measure, and their timing may not always follow the strict sequence implied by the proximal-to-distal principle. Marshall and Elliott (2000) commented that the traditional concepts of proximal-to-distal sequencing may be inadequate to describe the full complexity of racket shots, due to the longitudinal rotation of segments, although the concept is helpful for a general understanding. The third principle is referred to as a velocity lever and is evident again in the power shots. This principle explains why the longitudinal rotations of the arm segments are important in racket sports. If the racket is held perpendicular to the forearm and the forearm is rotated, the racket head moves through a much greater distance than the hand because it has a greater radius of rotation about the longitudinal axis of the forearm. As in force levers, which try to magnify the force applied, the velocity lever magniﬁes the velocity of the end of the lever (i.e. the racket head). The ﬁnal principle is the stretch–shorten cycle which describes the characteristics of muscle when initially stretched and then allowed to rapidly shorten again. The basis of this principle is that during the stretch, the muscle is pre-loaded so that when it starts to shorten it is able to generate its highest level of force immediately at the start of the shortening phase, rather than having to build that force up more gradually, as would occur in a normal concentric contraction. It is thought that there are other factors that might also contribute to this eﬀect (see Elliott, 2006, for a fuller discussion).

Kinematic applications As mentioned in the Introduction, the kinematic analysis of racket sports skills has developed along with technological advances in high-speed imaging. The most recent and important developments have been in threedimensional (3D) kinematic analyses. The ﬁrst studies that applied 3D analyses to racket sports established some basic data for joint ﬂexion angles, joint ﬂexion–extension angular velocities, linear joint velocities and racket and ball speeds for a number of tennis skills. It is not possible to detail all of this

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information but some of the skills analysed are the tennis serve (Elliott et al., 1986; Papadopoulis et al., 2000; van Gheluwe et al., 1987), the tennis backhand drive (Elliott et al., 1989a), the tennis forehand drive (Elliott et al., 1989b; Knudson, 1990), the tennis volley (Elliott et al., 1988), and the forehand drive in squash (Elliott et al., 1996). There are limited 3D data on skills in other racket sports like badminton or table tennis. The 3D kinematic methods referred to above have been developed to analyse rotations about the longitudinal axis of the forearm and upper arm during fast shots like the serve in tennis and the smash in badminton. In order to investigate these more complex 3D characteristics of movement, a specialized marker system and analysis method are required. The ﬁrst attempt to do this was reported by van Gheluwe et al. (1987) who attached several markers to the wrist, elbow and upper arm and from the reconstructed 3D location of these markers they were able to quantify the magnitude of rotation of the upper arm and forearm. Using a similar approach, Tang et al. (1995) investigated the kinematics of the badminton forehand smash. They reported on forearm pronation, wrist ﬂexion–extension and ulnar and radial deviation and found that, although there was considerable wrist joint motion about its two axes of rotation, the most important movement in this shot was pronation of the forearm. A method for obtaining the contribution of all rotations of the arm segments to racket speed was presented by Sprigings et al. (1994). A series of markers were used to deﬁne segment positions and orientations which allowed a full 3D description of segment rotations including ﬂexion– extension, abduction–adduction and internal–external rotation of the upper arm, lower arm and hand. This method showed that in the tennis serve the greatest contribution to ﬁnal speed of the racket head was upper arm internal rotation (29 per cent), followed by wrist ﬂexion (25 per cent), upper arm horizontal adduction (23 per cent), forearm pronation (14 per cent) and forward movement of the shoulder (9 per cent). These results, though, contradict the earlier reports with regard to the importance of forearm pronation. This method was used by Elliott et al. (1995) to investigate the tennis serve in more detail. They reported the same order of importance as above although the percentages diﬀered slightly. They also reported that the elbow extension played a negative role (−14 per cent) by reducing the forward velocity of the centre of the racket at impact. A 3D kinematic analysis has recently been reported by Gordon and Dapena (2006) using similar, but not identical, methods. Methodologically they questioned the ability of 3D kinematic analyses to fully quantify joint and segment rotations close to impact, and their error analysis suggested that some of the segment rotation data, in particular, should be treated with caution. However, within the limits of their analysis they were able to demonstrate that the most important sequential contributions made by joint rotations during the action phase were twist of the lower trunk, twist rotation of the upper trunk relative to the lower trunk, shoulder abduction, elbow

Biomechanics of racket sports 103 extension, ulnar deviation rotation, second twist of the upper trunk relative to the lower trunk and wrist ﬂexion. While some of these rotations were similar to those reported by earlier studies, there are also some diﬀerences. It is clear that the methodology is still developing and that a consensus as to exactly what might be happening in detail during the serve is still to be achieved. Gordon and Dapena provide some very useful illustrations of the rotations they refer to and will be of particular value to the coach as well as the scientist.

Kinetic applications The uncertainties experienced in the detailed 3D kinematics noted above, also aﬀect the 3D kinetics. There are fewer studies that explore the 3D kinetics of racket skills but their value is that they provide an insight into the overall pattern of joint moments which in general terms relate to both performance and injury. Elliott et al. (2003) have presented shoulder and joint torque data for the tennis serve from male and female Olympic competitors with respect to two aspects of technique – the extent of backswing and the level of knee ﬂexion. These latter two technique factors have been implicated in injury. They reported highest torque levels in male players for shoulder horizontal adduction (108 Nm). The next highest value was in elbow varus (78 Nm), shoulder internal rotation (71 Nm) and elbow ﬂexion torque (37 Nm). The respective values for female players were lower (by between 30 and 50 per cent) at 69, 58, 48 and 18 Nm respectively. At the position of maximal internal rotation, all of these joint torques were close to maximum values suggesting that the joints are at their greatest risk of injury close to this position. In the forehand drive in male tennis players, Bahamonde and Knudson (2003) reported peak torques in shoulder horizontal adduction (91 Nm), elbow varus (62 Nm) and shoulder internal rotation (52 Nm). These peak torques were similar, but a little lower, to those reported by Elliott et al. (2003) for the serve, suggesting less risk of overuse injury in the forehand drive than in the serve.

The lower limb Research in racket sports has tended to ignore the lower limb in favour of the upper limb. However, the ground–foot interface has an important bearing on performance as well as injury. The actions used (e.g. side-stepping, running foot plant and lunging) generate unusual force proﬁles that can inﬂuence both performance and injury. The peak vertical ground reaction forces in the lateral movement of tennis players has been reported up to 2.5 body weights (van Gheluwe and Deporte, 1992) and 3.5 body weights for a running forehand foot plant (Stiles and Dixon, 2006). For the badminton lunge, Lees and Hurley (1995) reported vertical forces up to 1.5 body weights and noted that less skilled players

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generated the higher forces. Simpson et al. (1992) found that the technique used to plant the foot has a marked eﬀect on loading and ankle movement and so it may be that less skilled players lack the movement skills to reduce the load they experience and as a result, would be more susceptible to injury. This interesting ﬁnding has never been followed up but it would be another example of where technique is important for reducing the load experienced by players. Stiles and Dixon (2006) also investigated the inﬂuence of tennis surface on the impact forces generated during the running foot plant but found, surprisingly, that there was no diﬀerence between three tennis surfaces of diﬀerent cushioning properties (carpet, acrylic, artiﬁcial turf). The authors speculated that players were adjusting to the surfaces although there was little evidence in their joint kinematic data. Subject variability seemed to be an important factor masking possible eﬀects and this ﬁnding warrants further investigation.

The future Technological advances have yielded analysis systems that are currently able to quantify many of the biomechanical variables relevant to racket sports. These have been developed and applied mainly in tennis with much less attention paid to other racket sports. A good general understanding has been gained of performance in racket sports and much of this is transferable to other sports. There are still some methodological issues to be satisfactorily developed (for example appropriate 3D kinematic analysis around impact) and extended (into satisfactory 3D kinetic analysis) but these solutions are likely to be available soon. Applications to a wider range of racket sports and skills is likely to be important in the near future, along with the use of advanced technology to answer questions regarding the eﬃcacy of particular equipment, surfaces and techniques used by players.

References Bahamonde, R.E. and Knudson, D. (2003). Kinetics of the upper extremity in the open and square stance tennis forehand. Journal of Science and Medicine in Sport, 6, 88–101. Elliott, B. (2006). Biomechanics and Tennis. British Journal of Sports Medicine, 40, 392–396. Elliott, B.C., Marsh, T. and Blanksby, B. (1986). A three dimensional cinematographic analysis of the tennis serve. International Journal of Sports Biomechanics, 2, 260–271. Elliott, B.C., Overheu, P.R. and Marsh, A.P. (1988). The service line and net volleys in tennis: a cinematographic analysis. Australian Journal of Science and Medicine in Sport, 20, 10–18. Elliott, B.C., Marsh, A.P. and Overheu, P.R. (1989a). The topspin backhand drive in tennis: a biomechanical analysis. Journal of Human Movement Studies, 16, 1–16.

Biomechanics of racket sports 105 Elliott, B.C., Marsh, T. and Overheu, P.R. (1989b). A biomechanical comparison of the multisegment and single unit topspin forehand drives in tennis. International Journal of Sports Biomechanics, 5, 350–364. Elliott, B.C., Marshall, R.N. and Noﬀal, G.J. (1995). Contributions of upper limb segment rotations during the power serve in tennis. Journal of Applied Biomechanics, 11, 433–442. Elliott, B.C., Marshall, R.N. and Noﬀal, G.J. (1996). The role of the upper limb segment rotations in the development of racket-head speed in squash. Journal of Sports Sciences, 14, 159–165. Elliott, B., Fleisig, G., Nicholls, R. and Escamilla, R. (2003). Technique eﬀects on upper limb loading in the tennis serve. Journal of Science and Medicine in Sport, 6, 76–87. Gordon, B.J. and Dapena, J. (2006). Contributions of joint rotations to racket speed in the tennis serve. Journal of Sports Sciences, 24, 31–49. Knudson, D. (1990). Intra-subject variability of upper extremity angular kinematics in the tennis forehand drive. International Journal of Sport Biomechanics, 6, 415–421. Lees, A. (2002). Technique analysis in sports: a critical review. Journal of Sports Sciences, 20, 813–828. Lees, A. and Hurley, C. (1995). Forces in a badminton lunge. In Science and Racket Sports (edited by T. Reilly, M. Hughes and A. Lees), London: E.&F.N. Spon, pp. 186–189. Marshall, R.N. and Elliott, B.C. (2000). Long axis rotation: the missing link in proximal-to-distal sequencing. Journal of Sports Sciences, 18, 247–254. Papadopoulis, C., Emmanouilidou, M. and Prassas, S. (2000). Kinematic analysis of the service stroke in tennis. In Tennis Science and Technology (edited by S. Haake and A.O. Coe), Oxford: Blackwell, pp. 383–388. Simpson, K.J., Shewokis, P.A., Alduwaisan, S. and Reeves, K.T. (1992). Factors inﬂuencing rearfoot kinematics during a rapid lateral braking movement. Medicine and Science in Sports and Exercise, 24, 586–594. Sprigings, E., Marshall, R., Elliott, B. and Jennings, L. (1994). A 3-D kinematic method for determining the eﬀectiveness of arm segment rotations in producing racket head speed. Journal of Biomechanics, 27, 245–254. Stiles, V.H. and Dixon, S. J. (2006). The inﬂuence of diﬀerent playing surfaces on the biomechanics of a tennis running forehand foot plant. Journal of Applied Biomechanics, 22, 14–24. Tang, H.P., Abe, K., Katoh, K. and Ae, M. (1995). Three dimensional cinematographic analysis of the badminton forehand smash: movements of the forearm and hand. In Science and Racket Sports (edited by T. Reilly, M. Hughes and A. Lees), London: E.&F.N. Spon, pp. 113–120. van Gheluwe, B. and Deporte, E. (1992). Friction measurements in tennis on the ﬁeld and in the laboratory. International Journal of Sport Biomechanics, 8, 48–61. van Gheluwe, B., de Ruysscher, I. and Craenhals, J. (1987). Pronation and endorotation of the racket arm in a tennis serve. In Biomechanics X-B (edited by B. Jonsson), Champaign, IL: Human Kinetics, pp. 666–672.

15 Angular velocities in the tennis serve C. López de Subijana and E. Navarro

Introduction The serve has turned into a fundamental stroke in tennis. It is one of the most diﬃcult shots to learn correctly. The act of throwing the ball with one hand and then hitting it with the racket arm, supposes a complex eye–hand and intersegment coordination (Bahamonde, 2002). The speed of the ball in the tennis serve has been recorded at up to 249 km.h−1 (69.2 m.s−1) by the player Andy Roddick in the 2004 season (www.daviscup.com). A high velocity combined with a good percentage of serves in court, guarantees higher probabilities of winning a match (Brody, 2003). Haake et al. (2000), proved that when the speed of the tennis serve was higher than 160 km.h−1, the errors in the opponent’s return increased signiﬁcantly. The serve has been one of the most studied strokes in tennis. Of the studies which have considered the angular velocity as a reference parameter (Van Gheluwe et al., 1987; Sprigings et al., 1994; Elliott et al., 1995; Ito et al., 1995; Wang et al., 2000; Fleisig et al., 2002; Elliott et al., 2003; Fleisig et al. 2003), the most complete studies were presented by Elliott et al. (2003) and Fleisig et al. (2003). The sample in both cases was taken from the Sydney 2000 Olympic Games with the best three serves performed by the tennis players on the central court. Fleisig et al. (2003) showed that the angular velocity sequence was: ﬁrst the knee extension, then the upper arm external rotation, trunk tilt, thorax rotation (longitudinal axis), pelvis rotation (longitudinal axis), elbow extension, wrist ﬂexion and ﬁnally upper arm internal rotation. Lopez de Subijana and Navarro (2005) analysed the ﬂat tennis serve from two female top level tennis players taking the kinetic energy as the main parameter. Both players showed a proximal to distal kinetic chain. The maximum kinetic energy peaks were from the lower limbs, to the trunk, the upper arm, the lower arm and ﬁnally the hand–racket segment. In all, the tennis shots sequences were stable. The aims of this study were twofold; ﬁrst to quantify and compare the angular velocities of tennis serves from two female top level tennis players,

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and second to analyse if those angular velocities followed the kinetic energy chain previously found.

Methods Three dimensional (3D) photogrammetry was used to obtain data. The participants were two professional female tennis players who volunteered and gave written informed consent and with local ethics committee approval. They were between 40 and 60 WTA in the world ranking. They previously underwent a speciﬁc warm-up activity. Performances were recorded with two synchronized high-speed cameras at 125 Hz. The camera location varied during the event as one of the players was right-handed and the other, left-handed. A 2-m length cube was used as calibration system and also to deﬁne the three axes: x, y and z (Figure 15.1). A total of 15 ﬂat tennis serves, which landed in an aiming area were recorded (Figure 15.2). All shots were manually digitized. To get the 3D coordinates the DLT algorithm was applied. The mechanical model was adapted from Clauser et al. (1969) considering the body deﬁned by 28 points (Figure 15.3). All segments were deﬁned as bars except for ﬁve solids (pelvis, thorax, upper arms and racket). The inertial parameters were taken from De Leva (1996). Data were ﬁltered with quintic spline functions The manual digitization mean error was 0.016 m, similar to Fleisig et al. (2003) who found 0.014 m.

Figure 15.1 The calibration system.

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Figure 15.2 Filming area location.

Figure 15.3 The 28-point body model.

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Results and discussion A preliminary qualitative analysis identiﬁed two diﬀerent techniques related to movements at the feet and the swing. Player A used a ‘foot back’ technique and an ‘abbreviated’ swing and player B used a ‘foot up’ technique and a full swing. The ﬁnal sample included 12 and 14 ﬂat serves from players A and B. All landed in the target area. The ball speed measured after ball–racket impact was 41.9 ± 1.6 m.s−1 for player A and 38.1 ± 1.2 m.s−1 for player B (mean ± SD). This result agrees with Fleisig et al. (2003) and Elliott et al. (2003), who registered 41.5 m.s−1 for the three best tennis serves from 12 female tennis players at the 2000 Sydney Olympic Games. The angular velocities about the ‘z’ axis are shown in Table 15.1. Player A used more ﬂexion and extension about the ‘y’ axis, as her technique produced less rotation about the ‘z’ axis. The angular velocities found in player B were similar to Fleisig et al. (2003). That study registered 440°.s−1 ± 90° at the thorax, 870°.s−1 ± 120° at the pelvis and 1370°.s−1 ± 730 at the upper arm. The data showed increased variability the closer the body segment was to the racket and to impact time. Player A reached a higher angular velocity in upper arm internal rotation. Elliot et al. (2003) showed that at high speeds the loads at the shoulder joint were higher than desirable and could cause overload injuries. The time of maximum angular velocities of the segments before impact are shown in Table 15.2. These key events represented the temporal sequence of segment rotations. In previous studies (Lopez de Subijana and Navarro, 2005 and 2006), these players showed a kinetic energy chain of the body segments from proximal to distal. Therefore, the maximum kinetic energy of the lower limbs came ﬁrst, then the trunk, the upper arm, the lower arm and ﬁnally the hand–racket that peaked just prior impact. Table 15.1 Angular velocities from players A and B, in °.s−1 Player

A B

Maximum angular velocity (mean ± SD) Upper Arm

Pelvis

Thorax

1962 ± 486 1404 ± 506

197 ± 23 416 ± 51

405 ± 46 618 ± 55

Table 15.2 Maximum angular velocities key instances (s) where t=0 represents impact

Thorax rotation Pelvis rotation Upper arm internal rotation

A (mean ± SD)

B (mean ± SD)

−0.135 ± 0.014 −0.088 ± 0.037 −0.006 ± 0.018

−0.090 ± 0.027 −0.027 ± 0.034 −0.021 ± 0.011

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In the angular velocities about the ‘z’ axis, it was noticed that the thorax participated ﬁrst, before the pelvis and ﬁnally the upper arm. These events (with t=0 representing impact) were thorax rotation −0.075 ± 0.018 s; pelvis rotation −0.048 ± 0.028 s. and upper arm internal rotation −0.010 ± 0.018 s. Due the high variability of upper arm internal rotation this event could occur in a diﬀerent order, resulting in a diﬀerent sequence as shown by Flesig et al. (2003). This fact indicated that the angular velocity could only be considered as a descriptive parameter as its information is only about one axis and it could not be considered as a part of a stable kinetic chain, as its order could be easily altered.

Conclusions This study showed the diﬀerence in technique when it is determined exclusively by a rotation about one axis. Player A reached higher upper arm angular velocities than in recent studies. This fact was not due to higher previous rotation of the body segment, so it could be based on her muscle power. Player B was more similar to those in recent studies. This player had a more natural technique and she had higher body segment rotation about the ‘z’ axis in consequence. On the other hand the angular velocity must be considered as a descriptive parameter, since it doesn’t show a stable sequence of events, and it doesn’t allow the intra- and inter-individual analysis of the shot throughout the movement. In the assessment of the high-level tennis player, the individual shot features and not the general description of the serve should be considered.

References Bahamonde, R.E. (2002). The role of trunk angular momentum in the tennis serve. In Scientiﬁc Proceedings: Applied Programme. XXth International Symposium on Biomecanics in Sports: Tennis (edited by K. Gianikellis, B. Elliott, M.M. Reid, M. Crespo and R.E. Bahamonde), Caceres (Spain): University of Caceres, pp. 14–19. Brody, H. (2003). Serving Strategy. ITF Coaching and Science Review, 31, December, 2–3. Clauser, C.E., McConville, J.T. and Young, J.W. (1969). Weight, Volume and Center of Mass of Segments of the Human Body. NTIS, Springﬁeld. De Leva, P. (1996). Adjustments to Zatsiorsky-Seluyanov’s segment inertia parameters. Journal of Biomechanics, 29, 1223–1230. Elliott, B.C., Marshall, R.N. and Noﬀal, G.J. (1995). Contributions of upper limb segment rotations during the power serve in tennis. Journal of Applied Biomechanics, 11, 433–442. Elliott, B., Fleisig, G., Nicholls, R. and Escamilla, R. (2003). Technique eﬀects on upper limb loading in the tennis serve. Journal of Science and Medicine in Sport, 6, 76–87.

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Fleisig, G., Nichols, R., Escamilla, R. and Elliot, B. (2002). Kinematics and kinetics of the high velocity tennis serve. Medicine and Science in Sports and Exercise, 34, supl. 1, 105. Fleisig, G., Nichols, R., Escamilla, R. and Elliot, B. (2003). Kinematics used by world class tennis players to produce high-velocity serves. Sports Biomechanics, 2, 17–30. Haake, S., Rose, P. and Kotze, J. (2000). Reaction time-testing and Grand Slam Tie-break data. In Tennis Science and Technology (edited by S.J. Haake and R. Coe), Oxford: Blackwell Science, pp. 269–276. Ito, A., Tanabe, S. and Fuchimoto, T. (1995). Three dimensional kinematic analysis of the upper limb joint in tennis ﬂat serving. In XVth Congress of the International Society of Biomechanics (edited by K. Hakkinen), July 2–6, University of Jyvaskyla, pp. 424–425. Lopez De Subijana, C. and Navarro, E. (2005). The kinetic chain performed by top tennis players. In International Congress on Physical Activity and Sport at the XXIth Century (edited by E. Gymnos), Madrid: The European University of Madrid, pp. 619–625. Lopez De Subijana, C. and Navarro, E. (2006). The kinetic chain performed by high performance tennis players. In Proceedings of the XXIV International Symposiom on Biomechanics in Sport (edited by H. Schwameder, G. Strutzenberger, V. Fastenbauer, S. Lindinger and E. Müller), Salzburg, Austria: University of Salzbburg, pp. 367–370. Sprigings, E., Marshall, R., Elliott, B. and Jennings, L. (1994). A three dimensional kinematic method for determining the eﬀectiveness of arm segment rotations in producing racquet-head speed. Journal of Biomechanics, 27, 245–254. Van Gheluwe, B.V., Ruysscher, I.D. and Craenhals, J. (1987). Pronation and endorotation of the racket arm in the tennis serve. In Biomechanics X-B (edited by B. Johnson), Champaign, Il: Human Kinetics, pp. 667–672. Wang, L., Wu, C. and Su, F. (2000). Kinematics of trunk and upper extremity in tennis ﬂat serve. In Tennis Science and Technology (edited by S.J. Haake and A.O. Coe), Oxford: Blackwell Science, pp. 395–400.

16 Comparison of injuries between Slovenian table tennis and badminton players M. Kondricˇ , G. Furjan-Mandic´, L. Petrinovic´-Zekan and D. Ciliga

Introduction Table tennis and badminton are two of the most popular sports in the world and two of the most common sports for people aged from 7 to 99 not only as recreational sport, but also as sport for rehabilitation. Table tennis and badminton are ideal sports for young and old because of their extremely low risk of injury (Kondricˇ and Furjan-Mandic´, 2003) and the very low incidence of acute and chronic injuries. There are hardly any injuries reported in recreational table tennis (Weber, 1982; Scott, 1992; Hochenbichler, 1992). Jørgensen and Winge (1987) reported that in badminton there are more overuse injuries (74 per cent) than acute injuries (26 per cent). The potential risk of injuries in sport seems to increase for all levels of athletes with increasing participation, intensity and demands, as well as longer training periods. The number of top athletes in Slovenia is increasing leading to a problem of sport injuries. Physicians are required to take part in the rehabilitation process, advising for training and helping athletes to get back to practising sport as well as helping to decrease the risk of potential injuries. As a result, sport physicians must be fully acquainted with the strains athletes are exposed to in a particular sport. In addition they must have the knowledge of patho-physiology of sport injuries (Dervisˇevic´ and Hadzˇ ic´, 2002). As with any other sport, there are some injuries that are typical of table tennis and badminton. For eﬀective prevention, it is important to understand the functional anatomy and patho-physiology of injuries of diﬀerent tissues. For injury prevention it is also necessary to understand the importance of excessive load and how these loads are distributed, sports-injury mechanisms and the biochemical response of body tissues to impact and overuse (Kondricˇ and Furjan-Mandic´, 2003). Sports medical examinations of table tennis and badminton players should not merely be an additional examination by a primary care physician. A physician must have, in addition to expertise in anatomy and physiology of the human body, also a profound knowledge of various loads, which often reach the limit or even exceed an athlete’s physiological capabilities. A good

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knowledge of these factors and appropriate measures taken to solve them is a pre-requisite to prevent a number of injuries, or at least to decrease the injury incidence and severity in table tennis and badminton. The incidence of injury levels needs to be reduced and it can be achieved by concentrating more on preventative measures. The aim of this study is therefore to point out the factors that can prevent a number of injuries.

Methods Within this project, 43 top Slovenian athletes (17 table tennis players and 26 badminton players) were questioned. At the time when the questionnaires were distributed, these athletes had an international or national ranking (as per Slovenian Olympic Committee criteria). For the purpose of this study, a questionaire of 42 questions pertaining to sport injuries among top Slovenian athletes was used. Data was processed by SPSS software. Basic descriptive statistical parameters were calculated (mean, standard deviation and frequency).

Results and discussion A total of 50 questionnaires were mailed to top Slovenian athletes, among which 23 are table tennis players and 27 badminton players. The questionnaires were mailed to those athletes who were listed in the publication by the Slovenian Olympic Committee ‘Announcements: List of categorized athletes in the Republic of Slovenia’, and whose medical records were at the same time at the clinic of sports medicine CMSˇ in Ljubljana. According to the instructions provided, 43 athletes returned the questionnaires. The average age of the athletes questioned was 21.5 years. Data from the analysis are given in Figures 16.1 and 16.2 and Tables 16.1 to 16.3. Participation in competitive sports places the athlete in a situation in which injuries are possible at any given time. Based on the results of this study risk factors can be identiﬁed and injury prevention measures planned accordingly. Traditionally, table tennis has been associated with a low injury rate and the

Figure 16.1 Training and competitive status of top athletes (both games).

M. Kondricˇ et al.

114

Figure 16.2 Location of injury (both games) for foot, ankle, shank, knee, hip, spine, trunk, forearm and shoulder respectively.

same holds for badminton. However, the number, distribution and nature of injuries within table tennis and badminton have not been well deﬁned due to poor injury deﬁnition reporting. The highest number of injuries (23.3 per cent, Figure 16.1), as expected, are shoulder girdle injuries. However, it is interesting that the number of these injuries is far higher in table tennis than in badminton. The higher number of injuries in table tennis is a result of short, abrupt and extremely rapid movements, particularly in forehand strokes (Kondricˇ et al., 2003). Table 16.1 Percentage of injuries in muscles, tendons and joints per individual sport

Table tennis Badminton Together

Muscles

Tendon

Joint

52.9 23.1 34.9

17.6 26.9 23.3

5.9 7.7 7.0

Table 16.2 Sum of all injuries reported by players (both games) Frequency Valid

Missing Total

Percent

Valid Percent

1 muscle 2 tendon 3 joint 4 others

15 10 3 2

34.9 23.3 7.0 4.7

50.0 33.3 10.0 6.7

TOTAL

30

69.8

100.0

System

13

30.2

43

100.0

Cum. Percent 50.0 83.3 93.3 100.0

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Table 16.3 Number of injuries reported by players (both games) Frequency Valid

Missing Total

Percent

Valid Percent Cum. Percent

1 In practice 21 2 In competition 3 4 During other sports 3 activities 5 Others 3

48.8 7.0 7.0

70.0 10.0 10.0

70.0 80.0 90.0

7.0

10.0

100.0

Total

30

69.8

100.0

System

13

30.2

43

100.0

As many table tennis players experience pain only during speciﬁc skill execution, normal physical testing of the shoulder is often not suﬃcient to reproduce the table tennis player’s pain. Therefore, functional testing must be used in order to identify the pain-provoking position with estimation of the force, direction and magnitude of muscle activity. There are more injuries that occur during a training period (Table 16.3). The result is not expected as the number of risk factors increases – such as the opponent, violation of fair play, increased motivation – and consequent over-enthusiasm. This is particularly interesting because it possibly indicates inadequate warm-up, lack of stretching exercises prior to practising and similar. Unfortunately, even at major events such as World or European championships, it is evident that some top athletes are either not familiar or are not well informed about proper warm-up and stretching. Although there are few studies focused on the medical aspects of table tennis, Shida et al. (1994) reported 25.1 per cent injuries of waist (lumbago), 15.7 per cent of shoulder and 14.1 per cent of knee joint. Many of reported disorders were referable to the speciﬁc nature of the practice. After treatment, more than 95 per cent of players were able to resume the game. Jørgensen and Winge (1987) reported 74 per cent overuse and 26 per cent acute injuries on Danish badminton players. They also reported that there was 2.9 injuries per 1000 playing hours. Azarbal et al. (2004) found that 17.7 per cent of badminton players had a history of medial elbow pain during training reﬂecting a history of medial elbow injury including medial epicondylitis, ulnar nerve injury, medial collateral ligament injury, medial elbow intra-articular pathology, or any combination of these causes. The most frequent injuries in table tennis and badminton pertain to muscle tissues (Tables 16.1 and 16.2), followed by tendon injuries. These records more or less correspond to the epidemiology of sport injuries records in the international literature. In percentage terms, the shoulder joint injuries are ranked highest, which is consistent with epidemiology studies. The shoulder is the most ﬂexible body part and therefore most vulnerable.

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In both racket sports, the trunk is signiﬁcantly involved in all strokes players perform. There are various sites around the hip that are weak as a consequence of open physeal plates. Quite large pieces can be pulled oﬀ, particularly with sudden unexpected loads. The anterior-inferior iliac spine tends to go in badminton when the front leg is suddenly blocked. Because of these abrupt blocking movements, the percentage of ankle injuries is as high as 9.3 per cent. Spine injuries (7.0 per cent) more or less pertain to lower back pain or overuse injuries. Overuse injury to the pars interarticularis is quite common in the young athlete (Pizzutillo, 1985). Because of fast lateral movements in table tennis and all round movements in badminton, the integrity of the foot is essential, as shoe support and orthotic devices cannot be used to modify poor foot biomechanics. A high percentage of injuries of ankle and foot joints (11.6 per cent in badminton), indicates that badminton players should pay more attention to choosing appropriate footwear to avoid those injuries. Some players are more prone to overuse injuries and this is usually related to anatomic or biomechanical factors. Imbalances between strength and ﬂexibility around certain joints predispose to injury.

Conclusions The poor recognition, localization and reporting of pain by table tennis and badminton players can often delay access to appropriate and timely intervention to prevent injury. The ﬁrst requirement for eﬀective management of table tennis and badminton injuries is therefore prevention, based on an understanding of the factors involved in overuse injuries generally and table tennis injuries speciﬁcally. The high repetition of activity necessary to develop and perfect table tennis and badminton skills produces the potential for chronic overuse injury. Poor technique, coupled with the anomalies of growth and improper equipment, produce skill errors, which may result in an increased stress on the musculoskeletal tissues and produces pain in response to micro trauma or overload. To minimize the pain response, the body adopts compensatory mechanisms, which ultimately add to the skill errors, and the never-ending cycle of overload is established. The most frequent injuries in table tennis and badminton pertain to muscle tissues, followed by tendon injuries. In addition, the database records obtained in such studies contribute to health care planning and organization for top Slovenian athletes, who inevitably require a better and qualitative medical supervision primary care physicians could oﬀer.

References Azarbal, M., Adybeik, D., Ettehad, H. and Arash Kia, M. (2004). A survey of elbow injuries in badminton players. The Internet Journal of Orthopedic Surgery, 2.

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www.ispub.com/ostia/index.php?xmlFilePath=journals/ijos/vol2n1/elbow.xml (last accessed 2 April 2008). Dervisˇevicˇ , E. and Hadzˇ ic´, V. (2002). Knee and shoulder injuries in comparison with other sport injuries in high proﬁle sportsmen in Slovenia a prospective study. In Book of Abstracts (edited by E. Di Pietro), Citta di Castello: A.C. Graﬁsche. Hochenbichler, A. (1992). Sportverletzungen und überlastungsyndrome im Leistungssport Tischtennis [Sports injuries and overloading syndromes in competitive table tennis]. Munich: Jørgensen, U. and Winge, S. (1987). Epidemiology of badminton injuries. International Journal of Sports Medicine, 8, 379–82. Kondricˇ , M. and Furjan-Mandic´, G. (2003). Zakonitosti kondicijskih programov v treningu namiznotenisˇkega igralca [Rules for designing physical preparation in table tennis]. Top Spin (Ljubljana), 2, 3–6. Kondricˇ , M., Furjan-Mandic´, G. and Medved, V. (2003). Myoelectric and neuromuscular features of table tennis forehand stroke performance with balls of diﬀerent sizes. In Science and Racket Sports III (edited by A. Lees, J.-F. Kahn and I.W. Maynard), London: Routledge, pp. 121–126. Pizzutillo, P.D. (1985). Spondylolisthesis: etiology and natural history. In The Pediatric Spine (edited by D.S. Bradford and R.M. Hensinger), New York: Thieme, pp. 395–402. Scott, M.J. (1992). ITTF questionnaire of elite athletes at 41st World Table Tennis Championships. International Journal of Table Tennis Sciences, 1, 191–193. Shida, Y., Shida, S., Suzuki, S., Hurakami, H., and Youza, N. (1994). Injuries and systematic disorders of table tennis players. International Journal of Table Tennis Sciences, 2, 121–122. Weber, K. (1982). Analyse der körperlichen Beanspruchung in den verschiedenen Rückschlagspielen unter dem Aspekt der Präventiv- und Leistungsmedizin [Analysis of physical demands in the diﬀerent racket sports under the aspect of the preventive and sports medicine]. In Training im Sportspiel 4 (edited by R. Andersen and G. Hagedorn), Ahrensburg: International Sportspielsymposium, pp. 111–133.

17 Prevention of injuries and cardiovascular events in veteran table tennis players J.-F. Kahn and T. Charland

Introduction There are many arguments based on medical and/or scientiﬁc recommendations which underline the positive eﬀects on health of regular physical activity during life as opposed to the negative eﬀects of a sedentary way of life (Haskel, 1991). If it cannot be denied that a well conducted sporting activity can have beneﬁcial eﬀects (Blair et al., 1992; Marks, 2006), it also cannot be denied that it can carry some risks. The notion of risk is present in any sporting activity, including racket sports, and in most cases, for a given discipline, the probability of occurrence of an injury increases as the intensity of the practice increases on the one hand, and as age increases on the other. A great number of works have already been published about the physiological and biomechanical aspects of diﬀerent racket sports, mainly in young and/or in elite players. With respect to the induced pathologies, practically all the publications deal with traumatic injuries, i.e. bone, joint, ligament and muscle injuries (Kibler and Chandler, 1994; Petschnig et al., 1997; Pluim, 2004). However, data on cardiovascular events in racket sports and their prevention are relatively scarce (Northcote et al., 1986; Reilly and Halsall, 1994). Concerning table tennis, to our knowledge no study has ever been conducted to make an inventory of all injuries aﬀecting players above 40 years (veterans). The few results presented here represent the initial step of an enquiry dealing with the diﬀerent kinds of injuries found in veteran table tennis players in France. The main objective of this study is to deﬁne the risk proﬁles of older players in order to propose preventive measures (Chandler, 1998).

Methods In France, every competitor has the obligation to get annually a valid playing licence delivered by the appropriate national association, a medical certiﬁcate delivered by a physician and an individual insurance. The present preliminary enquiry is based on consulting insurance claim reports collected during the 40 months period between 3 January 2003 and 8 May 2006. Only the reports of injuries having occurred on the site of practice (table tennis halls and

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outdoor grounds for training camps), and having necessitated medical care have been taken into consideration. The incomplete reports, the broken glasses and road accidents have been discarded.

Results During 40 months more than 500 insurance claim reports were received by the insurance company working with the French Association. A total of 441 players suﬀered more or less serious injuries, and among them 142 (32 per cent) were aged at least 40 years (mean ± SD, 50.7 ± 9.3 years). There were 12 women (8.5 per cent) aged 48.8 ± 9.6 years, and 130 men (91.5 per cent) aged 50.9 ± 9.3 years (Table 17.1). Among the 142 injuries, 125 were traumatic injuries and 17 were cardiovascular events of which 15 lead to the death of the player in a few minutes (Table 17.2). Joint injuries (32) were mainly represented by ankle and knee sprains, but there were also patella and glenohumeral dislocations and low back injuries. Concerning muscle injuries (25), there were 21 partial ruptures of the gastrocnemius muscle (‘tennis leg’) of which one was in a female player, three were partial ruptures of the tight posterior muscles, and one was a partial rupture of the biceps brachii muscle. The largest number of cases have been obtained with the rupture of Achilles tendon (29); among them, only one occurred in a woman. Fractures (20) concerned elbows, wrists, ankles, feet and teeth. In the group ‘miscellaneous’ there were three falls without serious outcome, one rupture of the patellar tendon, two short losses of consciousness, one cranial traumatism, and a dozen minor injuries (bumps against the table or with a racket, etc.) All of the fatal cardiovascular events occurred in competition except one during a training session.

Table 17.1 Distribution of the veteran players according to their age group and gender N

%

Male/Female

V1 (40–49 yr)

85

60

V2 (50–59 yr)

31

22

V3 (60–69 yr)

20

14

V4 (70–79 yr)

6

4

142

100

Total

M = 77 F=8 M = 29 F=2 M = 18 F=2 M=6 F=0

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Table 17.2 Distribution of the injuries in veterans according to their age group

Joints Rupture of Achilles tendon Tennis leg Fractures Miscellaneous Cardiovascular events Total

V1 (%)

V2 (%)

V3 (%)

V4 (%)

22 (68.8) 16 (55.2) 21 (84.0) 13 (65.0) 8 (42.1) 5 (26.7)

7 (21.9) 9 (31.0) 4 (16.0) 2 (10.0) 5 (26.3) 4 (20.0)

3 (9.3) 3 (10.3) 0 (0.0) 4 (20.0) 4 (21.0) 6 (40.0)

0 (0.0) 1 (3.5) 0 (0.0) 1 (5.0) 2 (10.6) 2 (13.3)

85 (59.9)

31 (21.8)

20 (14.1)

6 (4.2)

Total (%) 32 (22.5) 29 (20.4) 25 (17.6) 20 (14.1) 19 (13.4) 17 (12.0) 142 (100)

Discussion The practice of table tennis by older players oﬀers diﬀerent advantages: there is no direct contact with the opponent, and there are no heavy loads to move (the racket mass is between 160 and 210 g, and the mass of the ball is 2.7 g). It maintains, and even improves, a sense of rhythm, visual strategies, eye– brain coordination, reaction time and so on (Ripoll, 1989). Moreover, being an indoor activity, it can be played the whole year round. However, the reality indicates that there is also a probability of occurrence of more or less serious injuries. One third of all injuries collected arose in players aged more than 40 years (veterans) while this age group represents only one ﬁfth of all players. With respect to muscle and tendon injuries: even with regular standard table tennis training twice a week, the total muscle mass decreases with age and leg muscles become more fragile (Jansen et al., 2000). In the case of loss of balance, for example, during a quick lateral step, which is a very frequent situation in table tennis, the leg muscle weakness increases the risk of falling. Besides, with age there is a decrease in muscle and tendon elasticity and an increased stiﬀness, and the combined muscle and tendon unit becomes more fragile. Since it is impossible for a player to control the intensity of the force generated by a given muscle group, especially the calf muscles during a sudden displacement of the whole body to try to catch the ball, there is a strong risk of total or partial rupture of either the gastrocnemius muscle or the Achilles tendon. In the present preliminary report, muscle and tendon injuries account for nearly 39 per cent of all injuries, and they have lead to an incapacity of the player of about a month, and a total temporary working

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disability of up to three months. Even if full recovery can be obtained, the personal and economical (professional) consequences are high. There is a progressive decline in bone mass of about 0.10 to 0.15 per cent per year until the age of 50 years. Beyond 50 years the reduction in bone mass increases especially in post-menopausal women. The regular practice of a physical activity can slow down the decrease in bone density, however it cannot completely stop it (Copeland, 2004). The result is that the bone fragility increases as people get older, which explains the high frequency of bone fractures (14.3 per cent of all injuries). They mainly occur during falls due to a less eﬃcient control of the motor coordination and balance. In some cases however, the falls did not result in fractures but in joint injuries (22.8 per cent). Again these injuries have been followed by a more or less long period of immobilization and a total or partial working disability period. Cardiovascular events may have been less numerous (12.0 per cent of all injuries), but they were more serious since in 15 cases out of 17, players have died within a few minutes despite immediate attempts to resuscitate. Two main risk factors were identiﬁed: gender and age. All cardiovascular events occurred in male players; their mean age was 59.0 ± 9.3 years (range: 43–73 years). In one case, it has been found that a player who died had a history of arterial occlusive disease of the legs. As for skeletal muscles, one of the consequences of ageing is the decrease in heart performance. Among others, it translates into a lowering of the maximal heart rate of which the mean theoretical value changes from 200 beats.min−1 at 20 years of age to 160 beats.min−1 at 60. From there on, the decreased heart rate during exercise is accompanied by a decrease in cardiac output, and thus by a reduced oxygen transport to the active muscles, including the cardiac muscle itself. The insuﬃcient heart oxygenation can be worsened by an already existing hypertension, or in a player whose resting blood pressure is within the normal limits, by a sudden increase in blood pressure due to a strong and sustained catecholamine excretion. Such a situation is frequently found in players under pressure (high level of psychophysical stress) and who intensively ﬁght in order to win a game (Baron et al., 1992). Moreover recordings made during play show that during a rally there is a sharp increase in heart rate and its value is close to the maximum. It is likely that these marked and uncontrolled reactions are at the origin of most cardiovascular events having occurred during play, either in competition or in a training session. The age category which is the most prone to injury has been the V1 group, whatever the kind of injury. A plausible explanation is that the ‘youngest veterans’ (V1) were not totally conscious of the weakness of their muscle and central and peripheral nervous system capacities, and they continued to play as if they were 10 or 15 years younger. Therefore it is possible that they have been more exposed than the oldest to the risk of a traumatic injury. Further to these preliminary observations, simple and eﬃcient measures can be taken in order to limit the occurrence of injuries and even to prevent most of them.

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All players, whatever their age and their level of play, should undergo a systematic assessment of their health status and physical abilities at least once every year. In particular, the medical check-up must be oriented towards the detection of cardiovascular risk factors. If an abnormality is detected, everything must be undertaken to explore it and to treat it, and when necessary the patient must be encouraged to modify his way of life (e.g. to lose weight, to stop smoking, etc.). In order to limit exercise intensity, it could be advisable to avoid any competition (ﬁghting) spirit. The second measure is the maintenance of a good physical condition. Training must be carried out the whole year, with a warm-up and a cool-down phase, and the physical load must be adapted. Since table tennis is characterized by a succession of short periods of intense activity separated by incomplete recovery periods, it is recommended that players maintain their endurance abilities through walking, running or cycling. In order to ﬁght against the decrease in muscle mass and force, veteran players must be encouraged to regularly make adapted strength training. During or just after an exercise, any unusual shortness of breath with regard to the exercise intensity and/or duration, or any other abnormal sensation (sudden dizziness, unexplained pain, suﬀocation, transient loss of vision, etc.) must lead to an immediate interruption of the ongoing activity and for a medical examination to be carried out with the utmost urgency. Last but not least, it is necessary to have a balanced diet, correct hydration (Evans, 1992; MacLaren, 1998) and periods of rest.

Conclusion An adapted practice of table tennis by veteran players may delay and momentarily lessen the negative eﬀects of the ageing process. However, it must be kept in mind that the probability of occurrence of a leg muscle/tendon injury or a serious cardiovascular event increases as age increases. Therefore it is recommended to detect and to treat cardiovascular risk factors, to have regular activity, including endurance and strength training, at a moderate level without too much competitive spirit.

References Baron, R., Petschnig, R., Bachl, N., Raberger, G., Smekal, G. and Kastner, P. (1992). Catecholamine excretion and heart rate as factors of psychophysical stress in able tennis. International Journal of Sports Medicine, 13, 501–505. Blair, S.N., Kohl, H.W., Gordon, N.F. and Paﬀenberger, R.S. (1992). How much physical activity is good for health? Annual Review of Public Health, 13, 99–126. Chandler, T.J. (1998). Conditioning for tennis: preventing injury and enhancing performance. In Science and Racket Sports II (edited by A. Lees, I. Maynard, M. Hughes and T. Reilly), London: E&FN Spon, pp. 77–85. Copeland, J.L. (2004). Anabolic hormones in aging women: eﬀects of supplementation vs. physical activity. Canadian Journal of Applied Physiology, 29, 76–89.

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Evans, W.J. (1992). Exercise, nutrition and aging. Journal of Nutrition, 122, 796–809. Haskel, W.L. (1991). Dose response relationship between physical activity and disease risk factors. In Sport for All (edited by P. Oja and R. Telama), Amsterdam: Elsevier, pp. 125–133. Jansen, I., Heymsﬁeld, S.B., Wang, Z. and Ross, R. (2000). Skeletal muscle mass and distribution in 468 men and women aged 18–88 yr. Journal of Applied Physiology, 89, 81–88. Kibler, W.B. and Chandler, T.J. (1994). Racquet sports. In Sports Injuries, Mechanisms, Prevention and Treatment (edited by F. Fu), Baltimore: Williams and Wilkins. MacLaren, D.P.M. (1998). Nutrition for racket sports. In Science and Racket Sports II (edited by A. Lees, I. Maynard, M. Hughes and T. Reilly), London: E&FN Spon, pp. 43–51. Marks, B.L. (2006). Health beneﬁts for veteran (senior) tennis players. British Journal of Sports Medicine, 40, 460–476. Northcote, R.J., Flannigen, C. and Ballantyne, D. (1986). Sudden death and vigorous exercise: a study of 60 deaths associated with squash. British Heart Journal, 55, 198–203. Petschnig, R., Wurnig, C., Rosen, A. and Baron, R. (1997). Stress fracture of the ulna in a female table tennis tournament player. Journal of Sports Medicine and Physical Fitness, 37, 225–227. Pluim, B. (2004). Physiological demands and injury in racket sports: diﬀerences and similarities. In Science and Racket Sports III (edited by A. Lees, J.F. Kahn and I.W. Maynard), London: Routledge, pp. 61–69. Reilly, T. and Halsall, D.L. (1994). Physiological eﬀects of squash participation in diﬀerent age-groups and levels of play. In Science and Racket Sports (edited by T. Reilly, M. Hughes and A. Lees), London: E&FN Spon, pp. 44–48. Ripoll, H. (1989). Uncertainty and visual strategies in table tennis. Perceptual and Motor Skills, 68, 507–512.

18 Strategies and support mechanisms used by elite Australian female tennis players returning to the circuit from injury A.J. Pearce, J.A. Young and M.D. Pain Introduction Elite athletes in many sports recognize that injury endangers their sporting career, and often it is how well an injury is managed, not only medically but psychologically, that aﬀects their sporting longevity and success. In studies of athletes’ returning to sport from an injury, Smith et al. (1990) found that the most seriously injured group experienced signiﬁcantly more tension, depression, anger and less vigour than college norms, a mood disturbance that lasted one month. Johnston and Carroll (1998) reported a regained conﬁdence in competitive and recreational athletes after return to sport from injury before regaining their previous performance levels. Poor performance upon return from injury often resulted in initial stages of depression, further eroding conﬁdence and performance. Chase et al. (2005) examined the mental and physical strategies used by competitive gymnasts to overcome fear of injury or re-injury. Ten themes emerged from the data analyses including ‘mental preparation’ (with strategies such as ‘thought stopping’ and imagery to deal with pressure), ‘coach’s inﬂuence’, ‘positive self communication’, ‘good luck objects’ (e.g. lucky earrings and hair ties to help build conﬁdence), ‘peer support’, ‘physical preparation’ (e.g. breaking the skill into component parts), ‘routine of action’ (e.g. sticking to the same warm-up activities), ‘thinking of past successful performances’ and ‘bribe’ (i.e. thinking of a reward to gain if gymnast completed the diﬃcult routine). For athletes who were not adapting to the threat of injury or re-injury, Chase et al. (2005) recommended coaches and parents look for signs of avoidance that, if not countered, may result in the athlete retiring prematurely. Research by Young et al. (2006) into the retirement experiences of elite female tennis players revealed a high degree of frustration with Australia’s governing body of tennis, Tennis Australia (TA) in terms of the perceived lack of support and recognition for the country’s former players. Thus, the aim of this study was to further explore issues of player welfare so as to provide the basis for improvement of psychosocial outcomes for players.

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Further, Podlog and Eklund (2005) have suggested that having enforced time oﬀ due to an injury may result in the athlete gaining ‘a renewed perspective’ on their life, and consequently, this study sought to also examine this issue.

Methods Approval of the study, conforming to the Code of Ethics of the World Medical Association (Declaration of Helsinki), was granted by the Board of Management of TA. For the purposes of the study, and based on Devonport et al.’s (2005) suggestion to develop ‘measures grounded in the athlete’, a questionnaire was devised to allow players to relate experiences in their own words regarding satisfaction with the speed of identiﬁcation of the injury, the eﬃcacy of the treatment sought, the eﬀect it had on their mental state and the perceived support by the national governing body (TA). A letter of invitation, including consent form, and an anonymous questionnaire were posted to the players (both competitive and retired) with a self-addressed stamped envelope. The questionnaire was developed by the investigators in response to the speciﬁc areas of interest as deﬁned by TA and consisted of 21 closed and open-ended questions asking players to recount: (a) minor and severe/chronic injuries sustained and how the injury aﬀected their tournament participation; (b) the frequency and type of treatment sought for their injury; (c) attitudinal changes that occurred following minor and severe/chronic injury; and (d) their beliefs about precautions that limited exposure to injury. Descriptive data are reported using frequencies. Qualitative data were content analysed, where possible, for key themes and phrases, or reported verbatim in the words of the subjects.

Results Fifty-ﬁve participants voluntarily consented to take part in the study; 26 were active on the circuit, and 28 were retired (average retirement was seven years). Of the 26 who were still playing, 24 were not contemplating retiring in the foreseeable future (i.e. within two years), and two players were thinking of retiring within one year. The average number of years participants had been on the professional women’s tennis circuit was 4.3 years. The average Women’s Tennis Association singles ranking was 501 (three in the top 100, 16 in the top 500), and the average doubles ranking was 325 (three in the top 100, 25 in the top 500). Minor injuries Examining the eﬀect of minor injuries (described as ‘niggling’ or ‘shortterm’) on a players’ career (Table 18.1), the degree to which a player’s tennis career had been negatively aﬀected (i.e. hampered ability to train and play) by

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minor injuries was given an average score of 3.8 (signifying ‘hampered, but not extensively’ on a 1–10 point rating scale). On a rating scale of 1 to 10 (1 = never withdrawn due to minor injury, 10 = withdrawn from 10 or more tournaments due to the eﬀects of a minor injury), an average score of 2.8 was obtained, indicating that the average player had withdrawn from one to three tournaments due to minor injuries. The types of treatments sought to overcome these injuries were extensive. Table 18.2 shows the frequency of treatment options undertaken by players, assisting their recovery from minor injuries. Many players sought advice from the doctor and trainer (physiotherapist) on-site at tournaments, some then followed up with their own doctors for their minor injuries. Following a minor injury, self-treatment was also very popular. Sport psychologists were sought to help overcome problems arising from the injury, with goal setting and self-talk being the main skills taught. As well, talking to others, usually those well known to the player, was a strategy used to help with recovery from minor injuries. Severe/chronic injuries Severe or chronic injuries were those that prevented a player from competing for more than one month. The degree to which a player’s tennis career had been negatively aﬀected (i.e. it hampered their ability to train and play) by severe or chronic injuries was given an average score of 3.7 (signifying ‘hampered, but not extensively’ on a 1–10 point rating scale). Table 18.3 presents a summary of injured body areas. On a rating scale of 1 to 10 (1 = never withdrawn due to severe or chronic injury, 10 = withdrawn from 10 or more tournaments due to the eﬀects of a Table 18.1 Frequency of minor injuries to body parts (Note: players could nominate more than one injured body part) Area of body aﬀected

Frequency

Ankle Lower back Hip/Quad/Hamstring area Shoulder; Wrist Abdomen Neck/Upper back; Foot Knee; Shin Forearm; Elbow; Groin Calf/Achilles Upper Arm; Toes; Fingers; Hand

12 11 10 9 8 7 6 4 3 1

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Table 18.2 Frequency of treatments sought for minor injuries (Note: players could nominate in more than one category) Treatment Actively sought medical treatment from tournament doctor at the time of injury Actively sought medical treatment from tournament trainer at the time of injury Actively sought medical treatment from own doctor some time after

Frequency 16 42 20

Treated self (with no medical intervention): a) Took anti-inﬂammatory medication b) Rest, Ice, Compression, Elevation c) Rubbed on a heat gel (e.g. Dencorub) d) Treated with ice packs e) Strapped body part f) Took headache tablets

30 43 26 30 30 5

Used physiotherapy services Used chiropractic services Used massage Used acupuncture

40 12 35 9

Used a sport psychologist: a) mental images b) goal setting c) hypnosis/meditation d) self talk e) Other Used other support mechanisms: Friends or family (to distract from injury) Coach, manager, other ‘entourage’ staﬀ Other: a) Personal trainer b) Muscle manipulator c) Yoga d) Osteopath

5 10 3 9 Nil

16 11

1 1 5 1

severe or chronic injury), an average score of 2.8 was obtained, indicating that the average player in the sample had withdrawn from one to three tournaments due to severe or chronic injuries. The types of treatments were more varied (Table 18.4) with mixed success. Some players admitted to trying to return too soon from their injury, adding to their problems. Some thought their problems occurred initially from overtraining. Severe or chronic injuries were often treated on-site at the tournament and then followed up with

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Table 18.3 Frequency of severe or chronic injuries to body parts (Note: players could nominate more than one injured body part) Area of body aﬀected

Frequency

Shoulder Wrist Lower back Knee Abdomen Hip area (including Thigh and Hamstring) Hand; Elbow; Upper arm; Shin; Ankle; Foot Forearm; Neck/Upper back; Groin; Toes; Calf/Achilles; Fingers

8 7 6 5 3 2 1 Nil

appointments to the player’s own doctor. The injury sometimes required surgery, but at some stage of the players’ recovery, they self-treated, as well as received physiotherapy, massage and chiropractic services. Fewer players sought the services of a sport psychologist than they did for minor injuries. Talking to others was still an option to help recovery, but ‘talking to other players’ was admitted when a severe or chronic injury had occurred. With respect to ‘coming back from a severe or chronic injury’, players responded that a return to previous best form took less than six months in 12 cases, and more than six months in eight cases. For some (n = 9), previous good form was never regained after a serious or chronic injury. Of those retired (n = 25), 15 attributed their decision to do so to reasons other than their inability to recover from their injuries. Attitude perspectives Players’ perceptions as to changes in their ‘personal values’ as a direct result of being injured were explored. If they had been largely unaﬀected by injury, 42 per cent of players said they experienced a change in attitude, which mainly included an appreciation for life and family and friends outside of tennis and a change in training routine (such as more strength and conditioning and not overtraining). However, a greater number of players claimed their attitude to life was unaﬀected (at this stage of their life and career). Further, players did not suggest that the National Federation could have provided greater support during their recovery from injury. Players were happy to make recommendations to future players, and many of these recommendations centred on behaviours within the players’ own control such as: more stretching; maintaining strength and conditioning/ ﬁtness, not playing when injured; more sleep/rest; good nutrition; and having a ‘balance’ in their life (i.e. something other than tennis). Most of the recommendations were inexpensive to implement on a regular basis.

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Table 18.4 Frequency of treatments sought for a severe or chronic injury (Note: players could nominate in more than one category) Treatment Actively sought medical treatment tournament doctor at the time of injury Actively sought medical treatment tournament trainer at the time of injury Actively sought medical treatment from own doctor some time after Had surgery to correct the injury

Frequency 13 24 24 10

Treated self (with no medical intervention): a) Took anti-inﬂammatory medication b) Rest, Ice, Compression, Elevation c) Rubbed on a heat gel (e.g. Dencorub) d) Treated with ice packs e) Strapped body part f ) Took headache tablets

18 24 14 21 18 7

Used physiotherapy services Used chiropractic services Used massage Used acupuncture

24 8 18 6

Used a sport psychologist: a) Mental images b) Goal setting c) Hypnosis/meditation d) Self talk e) Other Used other support mechanisms: a) Friends or family (to distract from injury) b) Other players c) Coach, manager, other ‘entourage’ staﬀ Other: a) Went to hospital b) Osteopath c) Rehabilitation strengthening d) Unspeciﬁed

4 5 2 5 Nil

13 13 10

1 1 1 1

Discussion and conclusions The high level of frustration experienced by a perceived ‘lack of support’ from the National Federation (Young et al., 2006), and a raison d’être for further exploration of these issues in the current study, was not evident

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among this sample of current or newly retired players who generally believed that ‘destiny was in their own hands’. During their playing career, elite female tennis players in this study had been hampered by minor and severe/chronic injuries – almost to the same degree, in terms of tournaments missed – but diﬀerent body parts were injured. Lower limb injuries were more represented to a greater extent in the injuries classiﬁed as ‘minor’ (and many players attributed these to constantly playing on hardcourts), and shoulder, wrist and lower back injuries were the main body parts implicated in those classiﬁed as severe/chronic. Overtraining was frequently cited as the cause of a severe or chronic injury, however some injuries occurred from an initial acute injury, such as when the player tripped and fell (particularly with wrist injuries). In Podlog and Eklund’s (2005) study, the positive beneﬁts an athlete acquired after an injury may have arisen from the skewed sample of athletes who had returned from their sport (i.e. overcoming the injury). Their research did not include athletes who had become injured and had not returned to the sport (or, possibly, not chosen to complete the questionnaire). In the present study, less than half of the players thought there was a positive attitudinal change. Like the present study, Podlog and Eklund (2005) used retrospective recall, which can be open to bias (i.e. if players have successfully returned to sport, the eﬀects of their injury may be looked at ‘through rose-coloured glasses’) however, the present study also included players who were currently on the tennis circuit (47 per cent of the participants). Although psychological strategies were found to be useful among elite gymnasts in coping with fear (Chase et al., 2005), these skills were not cited frequently by tennis players in assisting them recover from minor or severe or chronic injuries. Players in this study were asked if they had seen a sport psychologist (with reference to some speciﬁc psychological skills listed), however, players were not asked if they used these skills to assist in their recovery (i.e. without needing to see a sport psychologist to do so). This issue could be explored in future research. Talking to others was a strategy players used to help overcome injury, however this research is unable to suggest if it was for a dissociative (i.e. to distract them by chatting about things other than the injury) or an associative purpose (i.e. ﬁnd out more information from others who may have suﬀered a similar injury). Players were more likely to talk to family, friends and a coach if suﬀering a minor injury, but included other players as well only if suﬀering a severe or chronic injury. In conclusion, the results have been presented to TA with recommendations to:

•

oﬀer touring players player-speciﬁc support (which includes ongoing medical assistance) to elite female players not currently eligible for support from other tennis-sponsored groups (e.g. Australian Institute of Sport scholarship holders);

Strategies and support mechanisms

• •

131

provide coach and player education sessions about appropriate levels of training; promote sport psychology skills (such as goal setting, self talk and imagery) to players of all abilities (via workshops) for use in all aspects of the tennis career (and life generally), but also to utilize them when recovering from injury.

Acknowledgements Funding for the study was provided by Tennis Australia. The authors would like to thank Ms Ros Kane for her administrative help with the project.

References Chase, M.A., Magyar, T.M. and Drake, B.M. (2005). Fear of injury in gymnastics: self-eﬃcacy and psychological strategies to keep on tumbling. Journal of Sport Sciences, 23, 465–475. Devonport, T.J., Lane, A.M. and Hanin, Y.L. (2005). Emotional states of athletes prior to performance-induced injury. Journal of Sports Science and Medicine, 4, 382–394. Johnston, L.H. and Carroll, D. (1998). The context of emotional responses to athletic injury: a qualitative analysis. Journal of Sport Rehabilitation, 7, 206–220. Podlog, L. and Eklund, R.C. (2005). Return to sport after serious injury: a retrospective examination of motivation and psychological outcomes. Journal of Sport Rehabilitation, 14, 20–34. Smith, A.M., Scott, S.G., O’Fallon, W.M. and Young, M.L. (1990). Emotional responses of athletes to injury. Mayo Clinical Proceedings, 65, 38–50. Young, J.A., Pearce, A.J., Kane, R. and Pain, M.D. (2006). Leaving the professional tennis circuit: exploratory study of experiences and reactions from elite female athletes. British Journal of Sports Medicine, 40, 477–83.

19 The use of plantar supports in badminton and squash players G.A. Gijón Noguerón, M. Gijón Noguerón and D. Cabello

Introduction The presence of minor foot malfunctions has rarely been the object of concern to society in general or to the athlete in particular. Only in cases of serious morphological alterations or injuries directly related to the foot is a treatment administered and most of the time this is limited to the surgical ﬁeld, ruling out the orthopodiatric ﬁeld as an alternative therapy (Hoy et al., 1994). Orthopodiatry applied to sport, through the use of plantar supports, may be of great help in the prevention of injuries, provided that its use is preceded by an appropriate biomechanical study (Cabello et al., 2002). The plantar supports cushion the pressure, increasing the contact surface and redistribute the loads throughout the foot, inﬂuencing the lower extremity and acting on all its structures: ankle, tibia, knee, hip and lumbar region; thus providing a force system to oppose the damaging forces, repositioning disordered structures and reducing the loads (Cabello and González-Badillo, 2003). In short, the purpose of a good support is to restore the muscular balances in the practice of sport (Céspedes et al., 1995). The biomechanical study, prior to the preparation of plantar supports, must take into account the analysis of a group of forces, pressures and levers of the lower extremities (Viladot, 2001) which will allow an accurate diagnosis of the characteristics of gait to be made, and at the same time establish an appropriate orthopodiatric treatment (Levy and Cortés, 2003). Movements made in each sports discipline have some speciﬁc biomechanical components; in the cases of badminton and squash, sideways displacements, sudden starts and stops are elements that diﬀer from normal gait, therefore, the design of plantar supports will have to consider not only the alterations to classical gait, but also to an individual’s own playing style (Cabello et al., 2004). It is also important in these cases to take into account some aspects, such as the kind of court or the type of footwear, which will determine certain corrections to be introduced throughout treatment. The use of plantar supports is becoming more and more widespread among athletes (Mejias, 1998), either to simply prevent unwanted movements

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or to treat osteoarticular or musculotendinous injuries (Jorgensen and Winge, 1990). After several years treating players from diﬀerent sports disciplines, we decided to monitor some badminton and squash players who came to our injury clinic in order to assess the consequences of using plantar supports in players, by studying the recovery process of an injured player (Cabello and Gijón, 2001). To this end, it was necessary to analyse the use of plantar supports, adapted through the Live Adaptation Technique, with a follow-up of the evaluation of the athletes treated.

Methods Participants The total number of players involved in this study was 18, of which 7 were badminton players and 11 squash players. Their ages ranged from 12 to 38 years. All had been subjected to treatment in our clinic over the last three years. Adaptation technique and materials employed The technical preparation of the plantar supports is known as the Live Adaptation Technique (LAT) (Céspedes et al., 1999). This technique originated in the preparation of comfort insoles for ski boots; having previously subjected the materials to a temperature of 80°C, they adapted the insole to the skier’s foot with a vacuum, providing a stronger hold and comfort and improving the adjustment of the ski boot. Afterwards, with the use of orthotic compensator elements (Figure 19.1), knowledge of gait disorders, such as heel supination, stress in midfoot pronation, cavus foot structure, and so on, they managed to form a plantar support using biomechanical criterion. This technique is currently becoming widespread and the development of a great variety of materials means that the podiatrist can choose, at any time, the most appropriate ones, for the requirements of each treatment (Gijón et al., 2006). The main components in the preparation of a plantar support through LAT are the thermo-conformed resins of PVC and polyester with a frame of textile gauze. This is combined in diﬀerent thickness and fused to 105°C for three minutes to provide the material with some physical features of resistance and grip capable of supporting a player’s traction during training and competition. The resins are combined with another group of materials, foams of acetyl vinyl acetate (EVA), with diﬀerent densities and hardness to provide the cushioning and stability that each athlete requires for his or her comfort.

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Figure 19.1 Orthotic compensator elements.

Diagnosis and treatment The most relevant data from the viewpoint of establishing a diagnosis are family history, injury history of the lower extremity, static examination and the biomechanical study of gait. The static examination allows, through visual examination, an analysis of the morpho-structural aspects of the lower extremity and its possible alterations. The biomechanical study allows us to establish the essential features and characteristics of the player’s gait (Viladot, 2001). This is accomplished through a ﬁrst examination of over-ground gait with ﬂuorolighting, in which the diﬀerent stances of the player can be analysed. An analysis of deviations in the sagittal and frontal planes is made running over a force platform and recording of gait with a video camera. Thus, we were able to make a correct diagnosis and assessment of the diﬀerent pathologies in players. The pathologies were treated with plantar supports prepared in PVC resins and polyester with EVA lining adapted with the LAT. For the follow-up the following parameters were established: (a) assessment of the pain caused by the injury on a 0–10 scale. It was considered both before the treatment and in the subsequent checkups; (b) injuries sustained once the treatment has been established, both related to the foot and lower extremity on which it could have had repercussions; (c) impact on the sports performance of the player throughout the season, subsequent to the establishment of the treatment. Once the treatment has been established, periodic checkups are ﬁxed for 15, 21 and 30 days, as well as for three and six months.

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Results After an appropriate examination, the following pathologies were detected: repeated sprain 33 per cent, fasciitis 28 per cent, periostitis 28 per cent and lower percentages of metatarsalgia, sesamoiditis and talalgia. Table 19.1 shows the distribution of these pathologies, according to the age of the players. As a result of the diagnoses established, 13 players (72 per cent) had cavus feet and among them, 10 (56 per cent) had varus or supinated feet, and three (17 per cent) associated with valgus or pronated feet. Only four players (22 per cent) had a valgus or pronated foot from the beginning of the gait stage. One of the players (5 per cent) had a normal foot (Table 19.2). For such injuries, diﬀerent supports were prepared to treat the structural alterations of the foot, not the pathologies, with biomechanical elements that correct the inadequate position of the foot (Table 19.3). In all cases we employed a central stabilizer element in order to provide the foot with a larger surface area and more control in total support as torsional movements take place at this moment, passing from the supination stage of backfoot to the pronation stage of mid-foot. In the cases of varus or supinated foot, we used an external side element of retention, with which it was possible to control excess supination in these feet. Likewise, a forefoot stabilizer was employed to control its propulsion stage, thus improving leverage through the ﬁrst radius. In the cases of valgus feet, Table 19.1 Relation between the age of the players and the injuries sustained Age

Sprain

Periostitis

12–18 19–22 23–26 27–30 31–34 35–38

3 2 1

4

Fasciitis

1 3 1

1

Metatarsalgia

Sesamoiditis

Talalgia

1 1 1

Table 19.2 Relation between the morpho-structural alterations established and the most frequent injuries Injury– Morphology

Sprain Fasciitis Periostitis Metatarsalgia Sesamoiditis Talalgia

Cavus-varus foot Cavus-valgus foot Normal foot Valgus foot

5

4 1 1 3

1

1

1 1

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Table 19.3 Relation of the orthopaedic elements of the support with the diﬀerent dynamic alterations Dynamic alterations

Central stabilizer element of mid-foot

External side element of retention

Front stabilizer element

Cavus-varus foot Cavus-valgus foot Normal foot Valgus foot

X X X X

X

X X X

Splint of 1st radius

X

the central stabilizer was strengthened in order to reduce the tension in the midfoot pronation. It was accompanied by a front stabilizer with splint of ﬁrst radius, which controlled the excess of pronation of the forefoot, facilitating the raising of the ﬁrst radius. In the cases of cavus feet, with sprain and periostitis pathologies, the change after a recovery of 21 days after the treatment was established, always complemented with physiotherapy treatment. In the subsequent checkups, relapses into these pathologies were not detected, but two of the cases showed metatarsalgia due to the excess of compensation of the external borders in the supports, so it was necessary to reduce such compensation. In the cases of valgus feet associated with pathologies such as faciitis or sesamoiditis caused by the musculotendinous tension of the feet, the recovery time was 30 days. In one of the cases, a patient with fasciitis, it was necessary to resort to surgical treatment to free the plantar fascia of tension. In the case of the player with the morphologically normal foot, the support helped kill the pain caused by the fasciitis in 15 days. Throughout the appropriate checkups, none of the players had relapses in their injuries, except for the case of the player with faciitis who required surgical treatment. As for the possible impact of the treatment on sports performance, the players reported more stability and less muscular fatigue obtained with the constant use of supports, which made it easier for them to adapt to the conditions of training and sports competition.

Discussion According to the results, it is necessary to state that there were more injuries of a musculotendinous nature than osteoarticular injuries, as highlighted by Kroner et al. (1990). With regard to the injuries in badminton players, these were mainly related to the age of the players; this aspect is comparable with other sports (Mejias, 1998; Crespo and Martín, 1994) in which the most frequent injuries are in children, with acute injuries such as ankle sprain being the most widespread. Injuries due to fatigue, periostitis, fasciitis or

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metatarsalgia (Hensley and Paup, 1979), are highlighted in older players (aged between 22 and 38), being also consistent with other reviewed works (Hoy et al., 1995). The existence of a morphological structure that predominates among the badminton and squash players, that of the cavus feet, is comparable to the data from athletes in general (Cabello and Gijón, 2001; Jorgensen and Winge, 1990). It has a direct impact on musculotendinous injuries, since these feet suﬀer from greater muscular tension (Gijón et al., 2006; Jorgensen and Winge, 1987). The impact of acute injuries on younger players, in contrast to fatigue injuries in experienced players (Crespo and Martín, 1994) is explained by the fact that young players with tensional morphological structures, such as cavus varus feet, have less stability (Hoy et al., 1995); however, they have not developed ﬁbrosis, characteristic of chronic or fatigue injuries, unlike older athletes whose feet have already developed ﬁbrosis, which has repercussions on the injuries closely related to repetitive actions. It was not possible to compare our results with the literature, so this data can be the basis for future studies on the use of plantar supports in athletes as a treatment for mulculotendinous injuries.

Conclusions The treatment of musculotendinous injuries in badminton and squash players with plantar supports has been eﬀective in a high percentage of players. The use of plantar supports in healthy players, in order to provide the foot with a larger surface area and more control, may help achieve a greater stability, while preventing the appearance of injuries.

References Cabello, D. and Gijón Noguerón, G. (2001). Estudio del pie del jugador de bádminton [Study of badminton players’s foot]. Apunts Medicina de L’esport, 36 (136), 23–27. Cabello, D. and González-Badillo, J.J. (2003). An analysis of the characteristics of competitive badminton. British Journal of Sport Medicine, 37, 18–25. Cabello, D., Gijón, G. and Gijón, M. (2002). El pie cavo-varo en el deporte: a propósito de un caso [The foot in sport: a case study]. Revista Española de Podología, 13(2),72–75. Cabello, D., Padial, P., Lees, A. and Rivas, F. (2004). Temporal and physiological characteristics of elite women’s and men’s singles badminton. International Journal of Applied Sports Sciences, 16, 1–12. Céspedes, T., Dorca, A. Sacristán, S. and Concustell, J. (1995). Técnica de aplicación directa de soportes plantares y prótesis de antepie [Direct application technique of plantar supports and forefoot prosthesis]. Revista Española de Podología, VI(5), 234–248. Céspedes, T., Dorca, A., Sacristán, S. and Concustell, J. (1999). Técnica de adaptación

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directa de ortesis sobre el pie: A propósito de varios casos [Direct adaptation technique of a foot orthotic]. Revista Española de Podología, 10 (6), 325–359. Crespo, M.A. and Martín, C. (1994). Afecciones traumáticas del deporte en los niños. Lesiones por uso y esfuerzo excesivo [Sport traumatic injuries in sport]. Archivos de Medicina del Deporte, 42, 153–164. Gijón, G., Gijón, M. and Amestoy, S. (2006). Fracturas de estrés del escafoides en deportistas de elite [Overstrain factors in elite players]. Salud del Pie: Revista Andaluza de Podologia, 39(2), 39–42. Hensley, L.D. and Paup, D.C. (1979). A Survey of badminton injuries. British Journal of Sports Medicine, 13, 156–160. Hoy, H., Linblad, B.E., Terkelsen, C.J. and Helleland, H.E. (1994). Badminton injuries: a prospective epidemiological and socioeconomic study. British Journal of Sports Medicine, 28, 276–279. Hoy, H., Terkelsen, C.J., Linblad, B.E. and Helleland, H.E. (1995). Badminton Injuries. In Science and Racket Sports II (edited by T. Reilly, M. Hughes and A. Lees), London: E&FN Spon, pp. 184–185. Jorgensen, U. and Winge, S. (1987). Epidemiology of badminton injuries. International Sport Medicine, 8, 379–382. Jorgensen, U. and Winge, S. (1990). Injuries in Badminton. Sports Medicine, 10, 59–64. Kroner, K., Schimidt, S.A., Nielsen, A.B., Jakobsen, B.W., Moller-Madsen, B. and Jensen, J. (1990). Badminton injuries. British Journal of Sports Medicine, 24, 169–172. Levy, A.E. and Cortés, J.M. (2003). Ortopodología y aparato locomotor: Ortopedia del pie y tobillo [Orthopaedics and locomotor system]. Barcelona: Masson. Mejias, M. (1998). Patología digital en el pie del futbolista [Finger pathology in football players]. Revista Española de Podologia, 9(8), 207–211. Viladot Voegeli, A. (2001). Lecciones básicas de biomecánica del aparato locomotor [Basic Biomechanical Lessons of the Locomotor System]. Barcelona: Springer.

20 Centre of gravity in paddle rackets Implications for technique P.T. Gómez Píriz and M.F. Álvarez

Introduction Controlling the location of the centre of gravity in implements used in racket sports is of great importance, particularly in those implements that, due to their weight, generate high levels of force on the joints. This may in turn inﬂuence technique and performance. In other sports disciplines, modiﬁcations to the centre of gravity location have enabled the best conditions for success to be created. It could be said that, as an implement’s weight increases (e.g. for a pole in vaulting) or a greater application of force or speed is required (e.g. in baseball or tennis), this control grows in relevance. The centre of gravity (COG), as a representative point (origin) for the gravitational force, is one of the key concepts of biomechanics. In racket sports it is important to take into account the distance from the COG to the handle, as this inﬂuences the movements made with the racket hand before, during and after the shot. This, along with the speed of the ball at the instant of impact and the speed with which the ball is intended to be sent will be important when playing shots, and may increase the risk of injury in the racket arm. Cross (1998) established a connection between these variables with regard to both the eﬀect produced on the joints and the trajectory of a tennis ball. His model used the relation between the COG and the impact point of the tennis ball. When the impact point goes through the COG the racket will translate; if they do not coincide, a moment of force will be generated, and the racket will both translate and rotate. With regard to paddle rackets, the Spanish Paddle Federation regulations state that the racket will not exceed 45.5 cm in length, 26 cm in width and 3.8 cm in thickness. There are no weight or COG speciﬁcations. Although paddle rackets have no reference to their COG, this parameter is supposed to be considered in their manufacture. Modiﬁcations to the weight of the racket takes place due to the demands and the objectives of play. Increasing the weight usually means putting more distance between the COG and its proximal point, which would generate a greater moment of force at the handle. These aspects are important in two situations (1) for beginners

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where bringing the COG closer to the proximal point will help technique and (2) its use to develop diﬀerent styles of play (i.e. more technical or more powerful) according to technical/tactical requirements. The speciﬁc objectives considered in this research are: ﬁrst, to establish a simple and easy procedure to obtain the COG; second to ﬁnd the COG of paddle rackets at amateur level of play for players of both sexes in the city of Sevilla; and third, to raise awareness of the importance of the COG in paddle rackets and its practical usefulness.

Methods The COG of a racket is determined by suspension. Regardless of the point of the racket from which it is hung, as the direction of gravitational force coincides with the COG, it will stop rotating. If done from two locations, the intersection point of both lines will be exactly at the COG of the racket (Figure 20.1). Images of the intersection point were taken with a 800×600 resolution digital camera Epson brand (L-100 model) resting on a tripod. The ATD Software (Analysis of the Sports Technique, Specialized Sports Training Centre of Granada v.1996) was used to digitize the images and obtain the COG and the distance from the proximal point to the intersection point of

Figure 20.1 Lines of application of the gravity force from two diﬀerent suspension points in a paddle racket.

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both straight lines (Figure 20.1). The weight of the racket was recorded using scales (Blauscal, AC-500 series). The sample consisted of 29 paddle rackets selected at random usually from amateur level players employed at diﬀerent clubs and gymnasiums in the city of Seville. A total of 17 models were tested that were used by men, and 12 by women. In order to control and give internal validity to the process, it was necessary to establish the reliability of the digitizer. The t-test for a trial sample showed a value of P=0.732, thus concluding that the mean detected was not statistically diﬀerent from the real value; therefore, the process was considered reliable within 0.77 per cent. For descriptive and inferential statistics (t-test for independent samples), the SPSS 11.5 software for Windows was used.

Results The COG from the proximal point (end of handle) ranged from 26.75 to 28.75 cm. The percentage of the total length of the racket was between 58.5 and 63 per cent. The frequency count of rackets in selected categories are indicated in Tables 20.1 and 20.2. The diﬀerence between males and females in the COG location relative to racket length and racket weight is given in Figure 20.2. After conducting a test for independent samples, no signiﬁcant diﬀerences were found between both groups in terms of gender or for the variable ‘COG distance to the proximal point’, or for the ‘weight’. It can be stated that, under the conditions of the research and even with the limits of the sample, there are no diﬀerences between rackets used by male and female players in these variables.

Discussion The results obtained provide information on an issue that was believed to be unimportant in the sport of paddle. The failure to recognize its importance Table 20.1 Numbers in each category for distances (cm) of the COG to the proximal end of the racket

Frequency

>26.75 27.0

27.25

27.5

27.75

28.0

28.25

28.5

<28.75

1

3

6

5

6

3

2

1

2

Table 20.2 Numbers in each category for percentage distance (cm) of the COG to the proximal end of the racket relative to racket length

Frequency

>58.5 59.0

59.5

60.0

60.5

61.0

61.5

62.0

62.5

<63.0

1

2

5

4

4

7

3

1

1

1

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Figure 20.2 Distances from the COG to the proximal point and weight in all the rackets used by male and female players.

may lead to injury, especially in players at risk (amateurs and children). At the same time it could improve certain aspects in high-level athletes. There are signs suggesting that the injuries in paddle involving the upper limbs may be related to this matter. Some shots would be more eﬀective with a COG closer to the handle, such as those involving technical ability, however it would be diﬀerent if applying a great power in the shot were the objective, in this case the COG would be better located further from the handle. Similar modiﬁcations would establish the characteristics of the rackets in persons who begin with little technical experience and poor development of the musculoskeletal system

Conclusions On the basis of what have been found, the following research conclusions have been determined: (1) The method employed may be considered as valid; (2) the distances and the percentage of the COG location with regard to the proximal point in the racket is the same for men and women; and (3) there are no diﬀerences with regard to the weight of rackets between sexes.

Reference Cross, R. (1998). The sweet spots of a tennis racquet. Sports Engineering, 1, 63–78.

Part 3

Psychological aspects of racket sports

21 Anticipation and skill in racket sports A.M. Williams

Introduction In sports such as squash, badminton and tennis, the ability to anticipate an opponent’s intentions is crucial to high level performance (Williams et al., 1999). The racket sports are played at tremendous speed, particularly at the highest level, such that the time available to respond often exceeds basic human information processing constraints related to reaction time and movement time. Although on occasion the costs associated with an incorrect anticipation judgement may outweigh the potential beneﬁts (James et al., 2005), typically, players do not have the luxury to react to an opponent’s stroke and consequently they must anticipate the type of stroke they will face before the ball or shuttle is struck. At very best, a decision must be made after viewing the initial portion of the ball or shuttle’s ﬂight path. It is now widely documented that skilled players in the racket sports demonstrate superior anticipation ability when compared to their less skilled counterparts. Moreover, over the last two decades or so, scientists have made signiﬁcant progress in identifying the mechanisms underpinning anticipation skill (for a review, see Williams and Ward, 2007). A number of perceptual-cognitive skills have been identiﬁed that contribute in varying degrees to anticipation skill. In this article, a brief overview of the important perceptual-cognitive skills that contribute to anticipation in the racket sports is provided. The implications of this research for performance enhancement are discussed, with particular reference to the development of perceptualcognitive training programmes in the racket sports.

The perceptual-cognitive skills underlying anticipation skill A number of diﬀerent perceptual-cognitive skills are assumed to support eﬀective anticipation in the racket sports. These skills are likely to be seamlessly integrated and to vary in importance from one situation to another depending on the unique constraints that exist at any given moment. An overview of some of the important perceptual-cognitive skills is provided next.

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Advance cue utilization One of the oldest and most robust ﬁndings in the literature is that skilled racket sport players are better than less-skilled individuals at picking up subtle information cues from an opponent’s postural orientation prior to the ball or racket being struck (for a review, see Williams et al., 1999). This skill has typically been examined using a temporal occlusion paradigm. Such an approach involves ﬁlming the task (e.g. return of serve in tennis or a forehand lob shot in badminton) from the perspective that the player would experience during an actual match. This ﬁlm is then played back to participants using a repeated-measures design with the recording being edited at varying time periods relative to ball- or shuttle-racket contact (e.g. 120 ms before, at contact, 120 ms after). The results have been very consistent, with skilled performers demonstrating superior accuracy, particular at the earlier occlusion conditions. Such ﬁndings have been observed in tennis (Goul et al., 1989; Jones and Miles, 1978), badminton (Abernethy, 1988) and squash (Abernethy, 1990). In comparison, fewer researchers have attempted to identify the speciﬁc sources of information that performers pick up when making such judgements. One hypothesis is that skilled players are able to pick up essential biological information from the relative motions between limbs rather than via a single cue or information source. In support of this latter argument, there is published research to show that the skilled player’s superiority over less skilled individuals when making such judgements is maintained even when action is presented as point-light rather than as ﬁlmed images (Abernethy et al. 2001; Ward et al., 2002). A related proposal is that skilled players are able to pick up multiple sources of information simultaneously using a more ‘global’ rather than ‘local’ processing strategy (Huys et al., in press). This latter ﬁnding may have signiﬁcant implications for improving understanding of how players attempt to disguise their intentions and in deciding how best to develop training programmes to facilitate anticipation skill in the racket sports. Visual search behaviour The ability to pick up relevant information from an opponent’s postural information is at least partly dependent on the player’s ability to orientate his/ her gaze towards relevant display features. The manner in which athletes move their eyes around the display in an eﬀort to extract pertinent information is refereed to as visual search behaviour. Typically, the search behaviours employed by athletes are assessed using a head-mounted corneal reﬂection system (see Williams et al., 1999). The ﬁndings indicate that skilled players employ more eﬃcient search behaviours than their less skilled counterparts (see Singer et al., 1998; Ward et al., 2002). Skilled players in the racket sports ﬁxate on diﬀerent areas of the display, for varying periods of time and in a

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diﬀerent order than less skilled athletes (for a detailed review, see Cauraugh and Janelle, 2002; Williams et al., 2004). The relative proportion of time spent ﬁxating diﬀerent areas of the display for high and low skill players when attempting to anticipate the direction of forehand drive shots in tennis is typically highlighted by our data in Figure 21.1. The high skill players spend more time viewing the head, shoulder and trunk regions compared to the low skill players, who spent a much higher proportion of time ﬁxating the racket. Pattern recognition Several researchers have demonstrated that skilled athletes are able to identify the patterns of play used by opponents more accurately than less skilled performers. If one can identify a pattern of play early in its development it should be feasible to accurately predict how the sequence will end, thereby facilitating anticipation. The importance of this skill has been demonstrated in team ball games such as basketball and soccer (Williams et al., 2006). It appears that skilled players are able to identify important cognitive and strategic information based on the relative positions and movements of a few select players. Unfortunately, there has been no attempt to identify such patterns of play in the racket sports, although it is likely that such information may be particularly important in the doubles events in tennis and badminton. This issue certainly merits further investigation in the racket sports. Knowledge of situational probabilities The diﬀerent perceptual-cognitive skills presented thus far primarily relate to a performer’s ability to process information present in the display as the

Figure 21.1 Mean (± SE) percentage time spent viewing each ﬁxation location for skilled and less skilled participants. Notes: H/S = head and shoulders; T/H = trunk and hips; A/H = arm and hand; L/F = leg and foot; R = racket; B = ball; R/BC = racket and ball contact area; UC = unclassiﬁed

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action unfolds. However, there is evidence to suggest that irrespective of this information skilled performers are able to generate accurate expectations or likelihood ratios in relation to the potential shots that may be played by an opponent in any given situation. The seminal work in this area was carried out by Alain and Proteau (1980) using squash, badminton and tennis players. Players were ﬁlmed performing a series of rallies during actual matches and after viewing the replays of these sequences were required to assign subjective probabilities to their opponent’s shots. Findings indicated that the skilled players’ initial anticipatory movements were strongly guided by their a-priori expectations in relation to shot probabilities. Unfortunately, despite the potential value of this type of work, there have been few published papers on this topic involving the racket sports (for a recent exception, see Crognier and Féry, 2005). In summary, as a result of the adaptations that occur following extended engagement in their sport skilled racket sports players develop perceptualcognitive skills that enable them to process information eﬀectively and adapt ‘on the ﬂy’ to the changing nature of any situation. These perceptual-cognitive skills develop as a result of the eﬀective storage of information in memory coupled with access to eﬃcient retrieval structures that enable skilled players to retrieve task-speciﬁc information in a ﬂexible manner so that they can rapidly adapt to situational demands (Ericsson and Kintsch, 1995). So, what are the implications for skill acquisition and training in the racket sports?

Implications for performance enhancement in the racket sports The key issue for those interested in developing anticipation skill in the racket sports is how the development of these perceptual-cognitive skills can be facilitated through practice and instruction. Although it is widely reported that such skills develop with extended engagement or experience in the speciﬁc sport (e.g. see Abernethy, 1988; Tenenbaum et al., 1996), there is now evidence to suggest that these skills are amenable to practice and instruction. The typical approach in this area has been to use ﬁlm-based simulation of the performance context, coupled with appropriate instruction and feedback in relation to task performance (e.g. see Williams et al., 2002; Smeeton et al., 2005). However, there have also been successful attempts to develop these skills using ﬁeld-based practices (e.g. see Singer et al. 1994; Williams et al., 2005). A brief overview of some of the key studies is provided next (for a detailed review of this literature, see Williams and Ward, 2003). Simulation training The vast majority of researchers have employed ﬁlm-based simulation techniques to train perceptual-cognitive skills in the racket sports, although most have focused on tennis with relatively few published papers involving badminton and squash (for exceptions, see Abernethy et al., 1998; Tayler

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et al., 1994). The usual approach is to employ similar ﬁlm footage to that used in the temporal occlusion approach. Players are then provided with instruction as to the important sources of information underlying anticipation skill, followed by the opportunity to practise using further ﬁlm sequences, often using progressively earlier occlusion periods, and feedback in relation to performance on the task (e.g. see Farrow et al., 1998; Scott et al., 1998). This type of training programme has been successful in improving performance on laboratory-based tests of anticipation skill, when compared to control conditions involving non relevant instruction, with some researchers also providing evidence that the observed improvements transfer to the ﬁeld-setting (e.g. see Smeeton et al., 2005). Field-based training A much smaller sample of researchers have used ﬁeld-based practices to try and train anticipation skill (e.g., Williams et al., 2005), although several have used a combination of ﬁlm- and ﬁeld-based practice and instruction (e.g., see Abernethy et al., 1998; Singer et al., 1994; Williams et al., 2002). In these latter studies the researchers have combined traditional video-based training with ﬁeld-based practices and drills intended to provide an opportunity for performers to link together perception and action in the actual performance setting. The ﬁndings from these studies have generally supported those reported using laboratory-based practice alone. However, there is scope for further research that compares the relative eﬀectiveness of laboratory- and ﬁeld-based practice; particularly given the potential beneﬁts of developing such skill practices as part of the player’s regular training regime (e.g. see Steinberg et al., 1998). Some questions that remain to be answered Although existing literature highlights the potential beneﬁts that may be gained from attempting to improve anticipation skill through perceptualcognitive training, numerous questions remain to be answered. For example, some of the questions still to be addressed include:

• • •

How do we create eﬀective simulations for training purposes? What are the respective merits of video simulation, virtual reality, and on-court training? How important is it for perception and action to be coupled together during practice? How and what type of information should be conveyed to the learner? How do we develop pattern recognition skills or knowledge of situational probabilities in the racket sports? What type of instruction is most eﬀective? What are the optimum frequency, duration and scheduling of perceptualcognitive training sessions?

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A.M. Williams Can imagery play a role in developing anticipation skill in the racketsports? What are the key time windows for developing perceptual-cognitive skills? At what age and skill level should we introduce perceptualcognitive training? What is the best way to assess the degree of transfer of learning from laboratory to ﬁeld settings?

Unfortunately, space precludes a detailed coverage of all these issues in this chapter, but a couple of areas are considered in greater detail below. Does the normal functional link between perception and action need to be maintained during training? Williams et al. (2005) examined whether ﬁeld-based perceptual-cognitive training that required the learner to physically respond to the action by attempting to return the serve (perception-action group) was more eﬀective than training that merely necessitated the learner to make a judgement as to an opponent’s intentions (perception only group). Participants who received technical instruction as to how to play forehand and backhand returns were included as controls. Anticipatory performance was assessed pre- and posttest using established on-court measures involving frame-by-frame video analysis. The perception-action and perception only training groups signiﬁcantly reduced their response times from pre- to post-test compared with the technical instruction control group. No signiﬁcant diﬀerences were observed between the perception-action and perception only training groups. Anticipation skill can be improved through appropriate instruction regardless of whether the learner has to physically respond to the action or merely make a perceptual judgment as to the likely destination of an opponent’s serve. If anticipation skill can be improved equally with or without an action response, then one possible implication is that video simulation training may be at least as eﬀective as on-court instruction, allowing coaches to make alternative use of on court practice time. The advantages of using video simulation rather than on-court practices for perceptual-cognitive training is that learning can occur at a self-regulated pace, in and outside of regular practice time, or when the performer is injured or fatigued. Video images can also be more easily manipulated for training purposes, providing greater ﬂexibility than that oﬀered by on-court practices, by, for example, highlighting or occluding relevant or irrelevant sources of information (see Williams and Ward, 2003). What type of instructional approach is most eﬀective for developing perceptual-cognitive skills? An issue that has attracted signiﬁcant research interest recently is what type of instruction is most eﬀective when developing these skills. For example,

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Smeeton et al. (2005) examined the relative eﬀectiveness of explicit instruction, guided discovery and discovery learning techniques in enhancing anticipation skill in young, intermediate level tennis players. The instruction was provided using ﬁlm-based simulation and a progressive occlusion technique, whereas performance was assessed using laboratory and on-court measures both pre- and post-intervention, as well as during acquisition and under transfer conditions designed to elicit high levels of anxiety. The three training intervention groups improved their performance from pre- to post-test compared with a control group, highlighting the beneﬁts of perceptual-cognitive training. Participants in the explicit and guided discovery groups improved their performance during acquisition at a faster rate than did the discovery learning group. However, the explicit group showed a signiﬁcant decrement in performance when tested under anxiety provoking conditions compared with the guided discovery and discovery learning groups. Although anticipation skill may be improved using ﬁlm-simulation coupled with all three types of instruction, guided discovery methods appear to provide greater expediency in learning and resilience under pressure.

Summary and conclusions The ability to successfully anticipate an opponent’s intentions is due to a number of underlying perceptual-cognitive skills. These include the ability to: a) pick up advance information from an opponent’s postural orientation at key moments prior to ball- or shuttle-racket contact; b) recognize evolving sequences or patterns of play as the action unfolds; c) use the visual system to search the display in an eﬀective manner in order to extract pertinent information; and d) accurately predict an opponent’s shot probabilities. Although these skills develop as a result of experience within the sport, there is empirical evidence to suggest that the acquisition of such skills can be facilitated through ﬁlm- and ﬁeld-based training coupled with appropriate instruction and feedback. Such training programmes should be used routinely for performance enhancement in the racket sports.

References Abernethy, B. (1988). The eﬀects of age and expertise upon perceptual skill development in a racquet sport. Research Quarterly for Exercise and Sport, 59 (3), 210–221. Abernethy, B. (1990). Expertise, visual search, and information pick-up in squash. Perception, 19, 63–77. Abernethy, B., Parks, S. and Wann, J. (1998). Training perceptual-motor skills in sport. In Training in Sport (edited by B. Elliott and J. Mester), Chichester, West Sussex: John Wiley&Sons, pp. 1–69. Abernethy, B., Gill, D.P., Parks, S.L. and Packer, S.T. (2001). Expertise and the perception of kinematic and situational probability information. Perception, 30, 233–252.

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Alain, C. and Proteau, L. (1980). Decision making in sport. In Psychology of Motor Behavior and Sport (edited by C.H. Nadeau, W.R. Halliwell, K.M. Newell and G.C. Roberts). Champaign, IL: Human Kinetics, pp. 465–477. Cauraugh, J.H. and Janelle, C. (2002). Visual search and cue utilisation in racket sports. In Interceptive Actions in Sport: Information and Movement (edited by K. Davids, G. Savelsbergh, S.J. Bennett, and J. Van der Kamp), Routledge: London, pp. 64–89. Crognier, L. and Féry, Y. (2005). Eﬀect of tactical initiative on predicting passing shots in tennis. Applied Cognitive Psychology, 19, 1–13. Ericsson, K.A. and Kintsch, W. (1995). Long-term working memory. Psychological Review, 102, 211–245. Farrow, D., Chivers, P., Hardingham, C. and Sachse, S. (1998). The eﬀect of videobased perceptual training on the tennis return of serve. International Journal of Sport Psychology, 29, 231–242. Goulet, C., Bard, C. and Fleury, M. (1989). Expertise diﬀerences in preparing to return a tennis serve: a visual information processing approach. Journal of Sport and Exercise Psychology, 11, 382–398. Huys, R., Cañal-Bruland, R., Hagemann, N. and Williams, A.M. 2006 (in press) The eﬀects of occlusion, neutralization, and deception of perceptual information on anticipation in tennis. Journal of Sport and Exercise Psychology, 28 (Suppl.), 44–45. James, N., Caudrelier, T. and Murray, S. (2005). The use of anticipation by elite squash players. Journal of Sports Sciences, 23, 1249–1250. Jones, C.M. and Miles, T.R. (1978). Use of advance cues in predicting the ﬂight of a lawn tennis ball. Journal of Human Movement Studies, 4, 231–235. Scott, D., Scott, L.M. and Howe, B.L. (1998). Training anticipation for intermediate tennis players. Behavior Modiﬁcation, 22, 243–261. Singer, R.N., Cauraugh, J.H., Chen, D., Steinberg, G.M., Frehlich, S.G. and Wang, L. (1994). Training mental quickness in beginning/intermediate tennis players. The Sport Psychologist, 8, 305–318. Singer, R.N., Williams, A.M., Frehlich, S.G., Janelle, C.M., Radlo, S.J., Barba, D.A. and Bouchard, L.J. (1998). New frontiers in visual search: an exploratory study in live tennis situations. Research Quarterly for Exercise and Sport, 69, 290–296. Smeeton, N.J., Williams, A.M., Hodges, N.J. and Ward, P. (2005). The relative eﬀectiveness of explicit instruction, guided-discovery and discovery learning techniques in enhancing perceptual skill in sport. Journal of Experimental Psychology: Applied, 11, 98–110. Steinberg, G.M., Chaﬃn, W.M. and Singer, R.N. (1998). Mental quickness training: drills that emphasize the development of anticipation skills in fast-paced sports. Journal of Physical Education, Recreation and Dance, 69, 37–41. Tayler, M.A., Burwitz, L. and Davids, K. (1994). Coaching perceptual strategy in badminton. Journal of Sports Sciences, 12, 213. Tenenbaum, G., Levy-Kolker, N., Sade, S., Liebermann, D.G. and Lidor, R. (1996). Anticipation and conﬁdence of decisions related to skilled performance. International Journal of Sport Psychology, 27, 293–307. Ward, P., Williams, A.M. and Bennett, S.J. (2002). Visual search and biological motion perception in tennis. Research Quarterly for Exercise and Sport, 73 (1), 107–112. Williams, A.M. and Ward, P. (2003). Perceptual expertise: development in sport. In

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Expert Performance in Sports: Advances in Research on Sport Expertise (edited by J.L. Starkes and K.A. Ericsson), Champaign, IL: Human Kinetics, pp. 220–249. Williams, A.M. and Ward, P. (2007). Perceptual-cognitive expertise in sport: exploring new horizons. In Handbook of Sport Psychology, 3rd edn (edited by G. Tenenabum and R. Eklund), New York: John Wiley and Sons, pp. 203–223. Williams, A.M., Davids, K. and Williams, J.G. (1999). Visual Perception and Action in Sport. London: E.&F.N. Spon. Williams, A.M., Ward, P., Knowles, J.M. and Smeeton, N.J. (2002). Perceptual skill in a real-world task: training, instruction, and transfer in tennis. Journal of Experimental Psychology: Applied, 8 (4), 259–270. Williams, A.M., Janelle, C.M. and Davids, K. (2004). Constraints on the search for visual information in sport. International Journal of Sport and Exercise Psychology, 2, 301–318. Williams, A.M., Ward, P., Allen, D. and Smeeton, N. (2005). Training perceptual skill using on-court instruction in tennis: perception versus perception and action. Journal of Applied Sport Psychology, 16 (4), 1–11. Williams, A.M., Hodges, N.J., North, J. and Barton, G. (2006). Perceiving patterns of play in dynamic sport tasks: investigating the essential information underlying skilled performance. Perception, 35, 317–332.

22 A perception-action perspective on learning and practice in racket sports G.J.P. Savelsbergh, F. Rivas and J. Van der Kamp

Introduction Competitive sports such as tennis and badminton require the players to receive and return a fast-moving ball or shuttle in one and the same action. Key to success is to intercept the ball at the right place at the right time and to apply the right amount of force to project it to the desired location. Because of the speed of the game together with the intrinsic limitations in the player’s movement times, it is hard to imagine that sportsmen can completely rely on ball/shuttle ﬂight information. Many have therefore concluded that information arising prior to ball ﬂight is pertinent for successful interception. Perceptual skill thus encompasses the ability to make accurate predictions from partial or incomplete advance sources of visual information (Poulton, 1957). In other words, the ability to anticipate future ball or shuttle position is a crucial skill in peak performance. In recent years, the anticipation capability of athletes with diﬀerent levels of expertise is studied by means of occlusion of visual information in the event and/or by recording the visual search behaviour of these players. The chapter discusses the players’ anticipation behaviour from a perception-action perspective. The aim is to illustrate that it is important to identify the visual information used and, to examine how diﬀerent levels of players use the visual information. This contribution will be concluded with some practical suggestion for coaching in racket sports.

Expertise and anticipation In recent years applied researchers have become increasingly interested in the study of skilled anticipation in interceptive tasks (Williams et al., 2004; Ward et al., 2002). There appear to be much evidence to support that experts are better able to identify what is needed to be done in sports like badminton (Abernethy, 1988; Abernethy and Russell, 1987), squash (Abernethy 1990; Abernethy et al., 2001) or tennis (Buckolz et al., 1988; Goulet et al., 1989; Williams et al., 2002). From the 1980’s onward, the occlusion technique has been dominant in studies of visual anticipation in sports. Players are presented with ﬁlm clips

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that displayed the opponent’s movements (e.g. serve) from the receiving party normal perspective (e.g. Abernethy and Russell, 1987; Jones and Miles, 1978). The ﬁlm clips selectively occluded either the opponent’s movements at various times (e.g. prior to, at or after the racket made contact with the ball), or various body parts of the opponent (e.g. head, trunk, arm, racket). Participants were thus presented with partial visual information and asked to predict the outcomes of ball ﬂight (e.g. landing location) or to identify the opponent’s action (e.g. type of stroke). Expert players were found to diﬀer from novices in terms of their ability to utilize early visual cues to either task. The main reasons for adopting the occlusion technique were theoretical and methodological. First, the occlusion technique ﬁtted neatly with the then leading theoretical paradigm of the information-processing approach. It was a basic assumption within the information-processing approach that perception is a process of assigning meaning to cues via some sort of inferential process. Second, it permitted a more rigorous control and replicability of the visual scene than ﬁeld studies. However, visual anticipation was investigated in isolation of action, the implicit (i.e. little explicit statements about the process(es) underlying anticipation were made) assumption being that a single perceptual representation or process supports anticipation. In the last decade or two the information-processing approach has come under attack. Proponents of the ecological approach (Gibson, 1979; Van der Kamp et al., 2003) regard visual perception as the detection of information, where information refers to (visual) information that is speciﬁc to environmental properties. Consequently skilled anticipation is not associated with the ability to process early visual cues but the ability to detect or pick up the information that speciﬁes the forthcoming event or guides the action. The ecological approach also fuelled concerns over the validity of the outcomes of the laboratory studies, primarily on the ground that the studies did not preserve the functional coupling between perception and action. In response, there has been a growing number of ﬁeld studies (e.g. Abernethy et al., 2001; Singer et al., 1998; Starkes et al., 1995).

The relevance of the functional coupling between perception and action The perception-action perspective oﬀers a useful starting point for understanding situation awareness in sport, as this issue is a core theme of this perspective: perceiving the environment by detecting those sources of information that are relevant for one’s actions. From this perspective, the control of movement is based on a continuous coupling to available perceptual information, which is presumed to evolve over time (Savelsbergh and Van der Kamp, 2000; Savelsbergh et al., 2004). In other words, from the perceptionaction perspective, visual information is assumed to be picked up in a continuous rather than discrete fashion. Hence, we will illustrate this core

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idea with two examples: one coming from soccer and one from racket sports, i.e. badminton. Visual search and locomotion behaviour in a soccer tactical position game In the ﬁrst example diﬀerences in locomotor and visual search behaviours were examined among a group of skilled amateur soccer players (Savelsbergh et al., 2006). The aim of the study was to examine what and how visual information is used in a complex game situation in soccer, not only with respect to tactical decision making, but also with respect to the way locomotion behaviour evolves during the participants’ actions. For that purpose, participants watched ﬁlm clips of a four-to-four position game, presented on a large screen. The task for participants was to take part in the game by choosing the best position for the reception of the ball passed by one of the players in the clip. A temporal occlusion paradigm was used: the clip stopped at 80 ms before foot-ball contact, at foot-ball contact or 80 ms after foot-ball contact by the passing player. Instead of using a binary response, such as a button press, the participants’ body movements are recorded by linked to a potentiometer to ensure continuous data sampling. This procedure allowed corrections to be made (and recorded) to the response in an on-going manner as the ﬂow of information changed across early and late time periods in the game situation. In addition to the locomotion behaviour, the visual search behaviour was recorded using a video-based eye-tracker system. Thus, participants’ locomotor and visual search behaviours were collected continuously throughout the presentation of the clip. A within-group comparison, based upon the participants’ interception score, was made. The high-score-group (i.e. participants that moved to the right location at the right time to receive the ball) had a signiﬁcant advantage (e.g. more correct interceptions) when information was available 80 ms after foot-ball contact. No such eﬀect was found for the low-score group (i.e. participants that moved to an incorrect location or arrived too late at the correct location). Additionally, the high-score group covered a greater distance than the low-score group both before and after the player passed the ball. This was independent of occlusion condition. No group diﬀerences were found for visual search behaviour. We conclude that the two groups used similar visual search strategies, but exploited the detected information diﬀerently to control locomotor behaviour. In relation to the use of the visual information, the study shows that there is a clear diﬀerence in performance level. Visually scanning the same ﬁxation locations but performing signiﬁcantly diﬀerent locomotion behaviour before, as well as after, foot-ball contact of the passing player, emphasizes that taking the movement pattern into account in visual search research is of the utmost importance. As a consequence of this ﬁnding, we studied in the racket experiment reported in

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the next section, both the gaze pattern (perception) and the locomotion behaviour of expertise and recreation badminton players. Perception-action coupling in badminton Abernethy and Russell (1987) examined how badminton players of diﬀerent standards perceived how to move. Participants were presented with ﬁlm clips of a player on a screen. The image could be occluded at diﬀerent times before and after shuttle-racket contact and at diﬀerent locations (e.g. arm, arm and racket, head). After the screen turned oﬀ, the participant had to mark on paper (i.e. schematic representation of a badminton court) the future landing position of the shuttle. The expert players were superior to their less skilled counterparts in predicting the future shuttle landing position. They appeared to be using information from the very ﬁrst occlusion period of the sequence (i.e. 167 to 83 ms prior to the racket-shuttle contact) from the arm and the racket, reducing signiﬁcantly their errors conversely to the novices. The researchers concluded that experts somehow conduct a kind of proximal-to-distal way of extracting information, which possess higher predictive potential. However, the movements of the player were not recorded. In line with the soccer study and keeping the connection between perception and action, we examined the visual search strategies and the movement control of the anticipatory and visual behaviour between diﬀerent strokes. Three kinds of forehand strokes were presented (i.e. drop shot, clear and smash) down-the-line and cross-court, providing us with a total of six diﬀerent directions per hitting location. The players were required to act as if they were actually playing a real match. Each ﬁlm clip included the whole player’s action sequence, since the player is waiting for the service until the shuttle touched the ﬂoor. The ﬁndings showed signiﬁcant diﬀerences between the two levels of expertise in the percentage of correct responses, that is, at the right shuttle landing location at the right time. Furthermore an signiﬁcant interaction between stroke and expertise were found that indicated that expert and novice badminton players diﬀered in the percentage of successful smashes and clears but not in drop shots. Based on this ﬁnding one could concluded that the drop shot does not diﬀerentiate between the level of players. However, the movement analyses revealed that the experts go more often to the right spot but also they covered the shortest possible distance between start and end location of the shuttle. From the perception-action perspective, both studies (football and badminton) show that there is a clear diﬀerence in performance level, that is, signiﬁcantly diﬀerent locomotion behaviour in relation to level of expertise. This emphasizes, ﬁrst, that the movement pattern analyses should be taken into account in visual search research. Second, during learning and practice, the visual information should be coupled to the desired movement behaviour.

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The next section deals with this issue followed by the implications for practice in racket sports.

The learning stages in perception-action coupling Savelsbergh and Van der Kamp (2000) proposed, analogous to ideas of Bernstein (1967), that during the process of learning to detect and use perceptual information to control movements three mutually overlapping phases of freezing, freeing and exploiting of perceptual degrees of freedom may be distinguished. The perceptual degrees of freedom refer to the fact that the environment provides us with multiple sources of information to which the required behaviour can be coupled. For instance, velocity information about an approaching object can be provided by the changing size of the object on our retina. But, there is also distance information in combination with object size, which informs us about the velocity of approach. In fact, there are multiple sources of information available in the sport setting. We will discuss only the ﬁrst two stages here, freeing and freezing. We argued that in the beginning of the learning, the player selects one of multiple information sources that will enable him to more or less successfully perform the task at hand. For instance, in the case of badminton, using distance information about the player to predict shuttle arrival time. With repetitive practice (e.g. constant interception of the shuttle that is hit from the same distance), the strength of the coupling (i.e. distance information to moving to correct arrival location) increases: the movement gets intricately tuned to information, which enhances the probability that this particular coupling re-occurs under the same set of circumstances. Eventually, this would result in a pruning of other potential couplings, and an increasing stability of the selected coupling. However, a change within the particular circumstances (hitting the shuttle from diﬀerent positions) during this early phase will disrupt the information-movement coupling. Because an alternative coupling is not available or too weak this could lead to a breakdown of action. Only after practice an (alternative) information-movement coupling, speciﬁc for the new set of local circumstances, will be established and strengthened. The second phase involves the freeing or releasing of perceptual degrees of freedom. During this phase, practice under diﬀerent sets of circumstances (e.g. shuttle is approaching with diﬀerent velocities, distances, locations etc.) eventually leads to a whole repertoire of possible information-movement couplings for a certain task (e.g. timing the arrival position of the shuttle by coupling it to information speciﬁc for distance, speed or time). Hence, if the local circumstances change, the actor will be able to realize an alternative coupling, without the need to learn it from scratch and without a complete breakdown of the action. In this stage, variability of practice is a must. In sum, we proposed that improvement in perceptual skill by learning to couple information to movement, may be captured by three mutually

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overlapping phases of freezing, freeing and exploiting of the available perceptual degrees of freedom. If we accept this description of the learning process, it has implication for practice.

Implications for coaching and practice in racket sport The proposal that the road to expertise is also characterised by a mastering of perceptual degrees of freedom has some important implications for the practice process. Coaches, instructors, and physical education teachers should consider the following points. First, the coupling of perception and action implies that speciﬁcity of practice is very important. That is to say, what should be learned during practice is to couple information and movement. For instance, during practice the game situation should be matched as close as possible. The visual information available during training should correspond with the information during the match. Second, in most sporting situations there is a redundancy of information and novices may develop strong sub-optimal couplings with less useful information. In order to help a player to discover the most optimal informationmovement coupling(s) during practice sessions, a coach should carefully design the practice environment (a set of circumstances) in which a speciﬁc coupling of information and movement is facilitated. In other words, a coach has to create a training environment whereby the player is ‘forced’ to tune to a speciﬁc information-movement coupling. We call such an environment a facilitative environment. Third, the coach can manipulate task constraints during practice in order to facilitate the discovery of preferred information-movement couplings. Fourth, the learning sequence is of great importance. From the perceptionaction perspective, the processes of learning serve to establish and further reﬁne information-movement couplings. We have argued that the learning process of coupling information to movement consists of a sequence of mutually overlapping phases. Practice under a similar set of circumstances will reﬁne or increase the strength of the coupling between distance information and positioning the racket. After reaching a certain degree of stability in performance, the second learning phase starts where alternative informationmovement couplings are explored (freeing). Practice will unavoidably take place under diﬀerent circumstances and will lead to a whole repertoire of information-movement couplings for the task. As a result, the performance of the player becomes much more ﬂexible and learns to adapt to changing conditions. In conclusion, particularly during the early phase of learning, speciﬁcity of practice is implied. In the ﬁrst instance, information is coupled only to movement under similar conditions. Hence, speciﬁcity of practice is needed. During later phases, however, practice should take place under changing conditions. That is, modifying the degree of uncertainty provides

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us with a facilitative environment so that the learner can explore alternative information-movement couplings. Under these conditions a repertoire of couplings can be formed and further exploited.

References Abernethy, B. (1988). The eﬀects of age and expertise upon perceptual skill development in a racquet sport. Research Quarterly for Exercise and Sport, 59, 210–221. Abernethy, B. (1990). Expertise, visual search, and information pick-up in squash. Perception, 19, 63–77. Abernethy, B. and Russell, D.G. (1987). Expert–novice diﬀerences in an applied selective attention task. Journal of Sport Psychology, 9, 326–345. Abernethy, B., Gill, D.P., Parks, S.L. and Packer, S.T. (2001). Expertise and the perception of kinematic and situational probability information. Perception, 30, 233–252. Bernstein, N.A. (1967). The Coordination and Regulation of Movements. Oxford: Pergamon Press. Buckolz, E., Prapavesis, H. and Fairs, J. (1988). Advance cues and their use in predicting tennis passing shots. Canadian Journal of Sport Sciences, 13, 20–30. Gibson, J.J. (1979). The Ecological Approach to Visual Perception. Boston, MA: Houghton Miﬄin. Goulet, G., Bard, C. and Fleury, M. (1989). Expertise diﬀerences in preparing to return a tennis serve: a visual information processing approach. Journal of Sport and Exercise Psychology, 11, 382–398. Jones, C.M. and Miles, T.R. (1978). Use of advances cues in predicting the ﬂight of a lawn tennis ball. Journal of Human Movement Studies, 4, 231–235. Poulton, E.C. (1957). On prediction in skilled movements. Psychological Bulletin, 54, 467–478. Savelsbergh, G.J.P. and van der Kamp, J. (2000). Information in learning to coordinate and control movements: is there a need for speciﬁcity of practise? International Journal of Sport Psychology, 31, 476–484. Savelsbergh, G.J.P., Van der Kamp, J, Oudejans, R.D.D. and M. Scott. (2004). Perceptual learning is mastering perceptual degrees of freedom. In Skill Acquisition in Sport: Research, Theory and Practice (edited by A.M. Williams and N. Hodges), London: Routledge, pp. 374–389. Savelsbergh, G.J.P., Onrust, O., Rouwenkost, A. and Van der Kamp, J. (2006). Visual search and locomotion behaviour in a four-to-four football tactical position game. International Journal of Sport Psychology, 37, 248–264. Singer, R.N., Williams, A.M., Frehlich, S.G., Janelle, C.M., Radlo, S.J., Barba, D.A., and Bouchard, X. (1998). New frontiers in visual search: an exploratory study in live tennis situations. Research Quarterly for Exercise and Sport, 69, 290–296. Starkes, J.L., Edwards, P., Dissanayake, P. and Dunn, T. (1995). A new technology and ﬁeld test of advance cue usage in volleyball. Research Quarterly for Exercise and Sport, 66, 162–167. Van der Kamp, J., Oudejans, R.R.D. and Savelsbergh, G.J.P. (2003). The development and learning of the visual control of movement: an ecological perspective. Infant Behavior and Development, 26, 495–515. Ward, P., Williams, A.M. and Bennett, S.J. (2002). Visual search and biological

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motion perception in tennis. Research Quarterly for Exercise and Sport, 73, 107–112. Williams, A.M., Ward, P., Knowles, J.M. and Smeeton, N.J. (2002). Anticipation skill in a real-world task: measurement, training and transfer in tennis. Journal of Experimental Psychology: Applied, 8, 259–270. Williams, A.M., Ward, P., Smeeton N.J. and Allen, D. (2004). Developing anticipation skills in tennis using on-court instruction: perception versus perception and action. Journal of Applied Sport Psychology, 16, 350–360.

23 Inﬂuence of training and task diﬃculty on eﬃciency of a forehand drive in table tennis L. Jospin, V. Fayt and S. Lazzari

Introduction The purpose of our study is to determine what characterises the eﬃciency of a player in table tennis. The ﬁrst term which comes to mind is ‘complexity’: complexity in the management of the ball–bat contact (Bootsma and Van Wieringen, 1990), complexity in the eﬀort management and complexity on the mental load (Baron et al., 1992). In other words, the complexity of the table tennis activity lies in the need for intercepting and returning balls as fast and as precisely as possible, while ensuring varied and fast displacements and choosing the best strategy to win the rally. An analysis of the table tennis activity in terms of motor skill organization points out that the player is confronted with an activity of trajectory perception and of ﬁne movement execution to control the ball–bat contact, the movement velocity, the movement accuracy and the drive direction. These stages (perception, decision and action) have to be accomplished within an important time constraint (200 ms) and following the tactical organization of the strokes. As mentioned, the informational constraints are high (quantity of information to be treated, perceptual uncertainty and time pressure, precision necessary for the execution) and led certain authors to deﬁne this activity as a bio-informational sport activity (Ripoll, 1989). Table tennis is also characterized by a rapid succession of short-term maximal or sub-maximal eﬀorts and short recovery phases. From a physiological point of view Lundin (1973) and Orfeuil (1982) characterized table tennis as an aerobic activity with an occasional anaerobic involvement. Consequently, a good aerobic capacity seems to be an essential factor to ensure the various and fast displacements needed during a rally. To go further into the analysis of the table tennis ability both these aspects, motor control and physiology, must be taken into account. Motor skill organization depends on the physical preparation and physical preparation sustain motor skill eﬃcacy. In activities where motor control and physiological involvement play a fundamental role, Durand (1992) used the expression ‘non optimal solicitation’ to describe the conﬂict between eﬃcacy and energetic solicitation.

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To characterize the eﬃciency of table tennis players, we choose to look at the training eﬀects both on performance and physiological demand when the intensity and the diﬃculty of the task vary. We hypothesize that a speciﬁc training programme allow players to gain in eﬃciency, that is, to increase their performance and to reduce the energetic demand. However, whatever the training eﬀects, we further hypothesized that eﬃciency remains inﬂuenced by task diﬃculty, with a negative correlation between these two parameters. In order to analyse at the same time the performance and the physiological involvement of participants in the task execution we retained two indicators: the percentage of success strictly linked to the capacity to organize movements to attain an imposed goal, and the heart rate, that is considered a good and easy-to-use indicator of energetic involvement (Astrand and Ryhming, 1954).

Method Participants Eleven students from the Faculty of Sport Science volunteered to participate in this study. They were all right-handed and they were considered as novices, having only 20 hours of trained practice behind them. Anthropometric characteristics such as age (23 ± 3.9 years), height (1.78 ± 0.051 m), mass (72 ± 8.2 kg), maximum heart rate (189 ± 2.6 beats.min−1) and heart rate at rest (58.1 ± 7.1 beats.min−1) were collected from the players. Heart rate at rest (HRrest) was measured whilst lying supine for 15 min and maximum heart rate (HRmax) was determined during a progressive, continuous and maximum test running around a track (Léger and Boucher, 1980). Experimental design Players were asked to perform a forehand drive as precisely as possible to attain a target (a circle of 21 cm of diameter) placed in the opponents halftable and as fast as possible to pass over a 75 cm high barrier placed at 2.50 m from the table. Balls were sent by a trainer following nine diﬀerent experimental conditions: three displacement conditions, each performed at three diﬀerent ball projection rate (60, 72 or 80 balls.min−1). The trainer followed the projection rhythm through a metronome earphone. Each condition lasted one minute. The three displacement conditions were: (1) task without displacement (WD), (2) task with a predictable displacement (PD) and (3) with an unpredictable displacement (UD). In the WD condition, balls were sent only on the right side of the player; in the PD condition, balls were sent alternately to the right hand side and middle of the player’s half court, in order to lead to lateral footwork; in the UD condition balls were randomly sent on the right hand side and middle of the player’s half court.

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Materials Heart rate (HR) was monitored during exercise every 5-s using a heart rate monitor (Accurex plus, Polar, Kempele, Finland) including a polar coded transmitter, an elastic belt and a receiver wristband. A Sony digital camcorder was employed to ﬁlm the players and to evaluate their performance ‘oﬀ-line’. Procedures The nine experimental conditions were tested before (pre-test) and after (post-test) a training period of three weeks, made up by nine sessions of 1:15 hours each (Table 23.1). Data analysis Heart rate (HR) and performance were recorded during exercises. The HR data were analysed using the Training Advisor Polar software. The maximal HR (HRex) obtained during exercise was expressed in absolute terms (beats.min−1) and relative to HRmax and to HRrest (Karvonen et al., 1983; Hiillorskorpi et al., 2003), which allow the determination of the relative eﬀort intensity (HRR). HRR = (HRex − HRrest)/(HRmax − HRrest)

...

(1)

Table 23.1 Temporal structure of the experimental procedure including a pre-test and a post-test sessions. During these sessions participants were evaluated in all the nine experimental conditions. Between the two evaluation sessions, nine training sessions took place: general description of the trainer’s interventions during the training sessions is reported Week

Session Phase

1

1

2

5

2 3 4 5 6 7 8 9 10 11

6

12

3 4

LegerBoucher Pre-test

Training sequences

9 task conditions 60 balls.min−1

Training

72 balls.min−1 80 balls.min−1

Post-test

9 task conditions

WD 1 general heating PD 2 speciﬁc heating UD 3 theoretical recall and demonstration WD 4 striking task (3 baskets) PD 5 work on power and eﬃcacy UD (2 baskets) WD 6 work of power and precision PD (2 baskets) UD 7 Evaluation (motivation)

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To evaluate performance, we retained six outputs classiﬁcation: (1) the target attained and the barrier passed (T + B), (2) only the target (T) or (3) only the barrier (B) attained, (4) the ball hit the opponent table neither attaining the target nor passing the barrier (O), (5) the ball hit by the player without reaching the opponent half-table (N), and (6) the ball not hit (NT). Using these six performance outputs, a global score of the performance was calculated and expressed as a percent relatively to the total attainable points for a subject, in order to compared conditions having diﬀerent numbers of projected balls. Three-way repeated measures ANOVA were performed on HRR and on performance score to analyse and quantify diﬀerences between the nine experimental conditions and to evaluate the improvements due to the speciﬁc training period. Statistical signiﬁcance was set at P < 0.05. All results are reported as mean ± standard deviation (SD).

Results Performance Performance score, obtained in the diﬀerent experimental conditions, showed that participants signiﬁcantly increased their performance after training in all the experimental conditions (F1,10 = 19.35, P = 0.001). Their mean score increased from 22 per cent to 32 per cent (Figure 23.1a). We found a signiﬁcant reduction in performance associated with the increase of task diﬃculty (F2,20 = 5.24, P < 0.05) and with the increase of intensity (i.e. ball projection rate) (F2,20 = 24.98, P < 0.001). Moreover, an interaction between the factors Task Diﬃculty and Projection Rate (F4,40 = 3.74, P < 0.05) underlined that the inﬂuence of the increasing projection rate on the performance was stronger for the easiest task (WD) than for the two other tasks. Before training, there was no signiﬁcant diﬀerence between experimental conditions, though a trend showed a decrease in performance associated with the increasing diﬃculty of the task. After training UD was signiﬁcantly lower than WD and PD (P < 0.05), reﬂecting with a negative trend the increasing diﬃculty of the task. Heart rate The analysis of HR showed a signiﬁcant eﬀect of the training (F1,10 = 7.79, P < 0.05): HR passed from 167 beats.min−1 during the pre-test to 162 beats.min−1 during the post-test. Training results in a slight decrease of HR in all the experimental conditions (Figure 23.1b). Another parameter aﬀecting HR was the diﬃculty of the task (F2,20 = 45.82, P < 0.001). Post-hoc analyses pointed out a signiﬁcant diﬀerence between WD and the two other conditions (P < 0.05) with signiﬁcantly lower

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Figure 23.1a Performance in the nine experimental conditions.

Figure 23.1b HR in the nine experimental conditions.

HR for the ﬁrst condition, while no diﬀerence was revealed between the two kinds of displacements. Projection Rate also inﬂuenced HR (F2,20 = 7.37, P < 0.05) showing an increase of HR with the increase of ball’s projection rate.

Discussion The main goal of our study was to analyse the eﬃciency of a table tennis player both from a physiological and a motor control point of view. In this kind of investigation, considered as a ‘non optimal solicitation’ activity (Durand, 1992), eﬃciency critically depends on the conﬂict between eﬃcacy (i.e. performance) and movement economy (energetic cost). Our analysis was based on the evolution of two major indicators of this conﬂict (HRR and score) due to training and concomitantly to diﬀerent level of diﬃculty (kind of displacement required) and intensity (ball projection rate) of the task. The

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basic hypotheses that lead this study was that training would induce an improvement of players’ eﬃciency (better performance with lower energy expenditure) and that this improvement would depend on task complexity (Durand, 1992). After the nine training sessions, we observed an increase in performance, with the score passing from 22 per cent to 32 per cent. This result supports the ﬁrst hypothesis, stating that learning leads to an increase in eﬃcacy. This result suggests that a better organization of movement patterns took place during training: the high movement variability of novices, made up essentially by a lower motor control organization (Jospin and Fayt, 2004), gradually evolved towards highly reproducible movements (Schmidt, 1982; Magill, 2004). Moreover, an improvement in displacement management may play a primary role in improving eﬃcacy, avoiding postural misplacements and incomplete and late information pick up (Abernethy, 1993; Ripoll, 1989), and allowing an optimal placement of players relatively to the table and balls (Arzel, 1994). Generally speaking, an increase in performance, due to a new movement organization, should lead to an optimization in terms of energy expenditure, induced by a more adapted muscular recruitment (Durand, 1992). The decrease in HRR that we evidenced in our study denotes that this change took place during training, allowing players to reduce their energetic involvement (Billat, 2003; Wilmore and Costill, 1998). In PD and UD conditions players evolved from an ineﬀective mobility, essentially made up by disorganized movements and useless muscular contractions, to a speciﬁcally organized mobility, allowing an adapted muscular recruitment. The more eﬃcient ‘anticipation’ capability of players, achieved through a better analysis and understanding of ball trajectories, allow them to have more versatile and controlled movements (Abernethy, 1993; Schmidt, 1982). Finally, the results obtained support the second hypothesis we formulated (i.e. improvement in eﬃciency depends on task complexity). The increasing in task constraints due to displacements and/or to ball projection rate seems inversely correlated with eﬃciency, both in terms of performance and of HRR. This result follows results found in previous studies on eﬃcacy (Fitts, 1954; Keele, 1968; Schmidt, 1982) and energetic cost (Durand, 1992).

Conclusion Results presented in this work suggested that training allows table tennis players to improve their ability through an increase in motor eﬃciency. This eﬃciency is made up both by a better eﬃcacy and by a decrease in the energetic involvement (Guthrie, 1935). This ‘economic’ parameter could be retained to precisely characterize motor abilities (Sparrow and Newell, 1998).

References Abernethy, B. (1993). Searching for the minimal essential information for skilled perception and action. Psychological Research, 55, 131–138.

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Arzel, G. (1994). Pour une pédagogie du développement des potentialités d’adaptation (approche clinique d’une pratique d’apprentissage) [On the pedagogy of the development potential for adaptation]. Le corps à l’école, apprentissage et développement. Dossier EPS, 22, pp. 20–27. Astrand, P.O. and Ryhming, I. (1954). A Nomogram for calculation of aerobic capacity from pulse rate during submaximal work. Journal of Applied Physiology, 7, 218–222. Baron, R., Petschnig, R., Bachl, N., Raberger, G., Smekal, G. and Kastner, P. (1992). Catecholamine excretion and heart rate as factors of psychophysical stress in table tennis. International Journal of Sports Medicine, 13, 501–505. Billat, V. (2003). Physiologie et méthodologie de l’entraînement. De la théorie à la pratique [Physiology and Methodology of Training: Theory and Practice] (2nd edn). Paris: De Boeck. Bootsma, R.J. and van Wieringen, P.C. (1990). Timing an attacking forehand drive in table tennis. Journal of Experimental Psychology: Human Perception and Performance, 16, 21–29. Durand, M. (1992). L’optimization de la performance. Etude dans des tâches constituant une sollicitation non optimale (2nd part) [Optimization of performance]. Revue S.T.A.P.S., 28, 41–57. Fitts, P.M. (1954). The information capacity of the human motor system in controlling the amplitude of movement. Journal of Experimental Psychology, 47, 381–391. Guthrie, E.R. (1935). The Psychology of Learning. New York: Harper. Hiilloskorpi, H.K., Pasanen, M.E., Fogelholm, M.G., Laukkanen, R.M. and Manttari, A.T. (2003). Use of heart rate to predict energy expenditure from low to high activity levels. International Journal of Sports Medicine, 24, 332–336. Jospin, L. and Fayt, V. (2004). Monitoring eﬀort during increasing level training exercises in table tennis. In Science and Racket Sports III (edited by A. Lees, J.-F. Kahn, and I. Maynard), London: Routledge, pp. 31–36. Karvonen, J. (1983). Physiological Follow-up of Endurance Runners. Report for the Finnish Sports Foundation. Keele, S.W. (1968). Movement control in skilled motor performance. Psychological Bulletin, 70, 387–403. Léger, L. and Boucher, R. (1980). An indirect continuous running multi-stage ﬁeld test, the Université de Montréal Track Test. Canadian Journal of Applied Sports Sciences, 5, 77–84. Lundin, A. (1973). Bordtennis, Idrotisfysiologi, rapport n°12. Stockholm: Tryig-Hanso. Magill, R.A. (2004). Motor Learning: Concepts and Applications (7th edn). Boston: McGraw-Hill. Orfeuil, F. (1982). Le Tennis de Table, Physiologie et Entraînement [Table Tennis: Physiology and Training]. Mémoire pour l’obtention du diplôme de Technicien supérieur de l’INSEP. Ripoll, H. (1989). Uncertainty and visual strategies in table tennis. Perceptual and Motor Skills, 68, 507–12. Schmidt, R.A. (1982). Motor Control and Learning: A Behavioral Emphasis. Champaign, IL: Human Kinetics Publishers. Sparrow, W.A. and Newell, K.M. (1998). Metabolic energy expenditure and the regulation of movement economy. Psychonomic Bulletin and Review, 5, 173–196. Wilmore, J.H., and Costill, D.L. (1998). Physiologie du sport et de l’exercice physique [Physiology of Sport and Physical Exercise]. Paris: De Boeck.

24 Tennis play simulator 1 Psychomotor predispositions for tennis based on locomotor movements J. Lapszo

Introduction Our study in table tennis (Lapszo, 1998) showed a strong correlation between the speed of ball-hitting movements, anticipation and behavioural ﬂuctuations tested in simulatory conditions with sporting results. On the basis of these ﬁndings we have developed a universal measurement system (Lapszo, 2002) which enables the testing of psychomotor eﬃciency in racket sports and ball games on the basis of fundamental and speciﬁc movement speed. In this study we present the application of the system to diagnose psychomotor eﬃciency in tennis. In a game of tennis we can diﬀerentiate between the locomotion used to hit the ball and locomotion after ball-hitting. These locomotor events have the character of fundamental movements for ballhitting. The movements are often called by coaches ‘foot work’. The speed of locomotor movements is related to ball-ﬂight anticipation. This anticipation consists of predicting the position towards which the ball is ﬂying and the execution of a movement to reach this position. In real play, anticipation is demonstrated by initiating the displacement of the body on the basis of how the opponent has hit the ball or from the early phase of the ball’s path. This information we have called anticipatory stimulus which indirectly indicates the place towards which the ball is ﬂying. The middle and ﬁnal phase of the ball’s path, directly indicating the spot, where the ball is ﬂying was called an orientation stimulus. In our experiment the locomotor movements were initiated by anticipatory and orientation stimuli and were called anticipatory and orientation locomotor movements respectively. Ball-ﬂight anticipation is based on anticipatory schema (Lapszo, 2000; Schmidt, 1975), which constitute the memorized relationships of the ways in which the ball was struck by the opponent and the places where the ball bounced on the tennis court. Creating the anticipatory schema in memory takes place in the learning process which inﬂuence behavioral ﬂuctuations caused by variations in attention concentration, motivation, arousal and resistance for disturbances (Hull, 1942). These ﬂuctuations determine the regularity in the learning process of anticipatory schema (Lapszo, 1998). The ability to react quickly and accurately in competitive conditions (play for points) seems also to

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be an important factor which can have an inﬂuence on sporting results in tennis. The aim of the research is to verify whether the developed universal diagnostic and training system (Lapszo, 2002) can be used to test the psychomotor predispositions speciﬁc to tennis on the basis of fundamental locomotor movements.

Method Participants Highly skilled male tennis players (6 senior, 6 junior and 5 younger junior) were participants. The average age of seniors was 23.6, juniors 17.2 and younger juniors 14.8 years respectively, and the period of tennis training was 13.4, 8.7 and 7.2 years respectively. Tennis play simulator 1 The tennis play simulator was designed in two versions (1 and 2). Both versions consist of a simulator proper, a controller and a computer. Version 1 was designated to test psychomotor eﬃciency speciﬁc to tennis on the basis of fundamental (locomotor) movements, while version 2 was on the basis of speciﬁc (ball-hitting) movements. In simulator 1 there are 14 lamps (anticipatory stimuli) on 12 stimuli boards (Figure 24.1) that simulate the spot where the ball is struck by one’s opponent. The lamps in ten tactile sensors (orientation stimuli) indicate the spot where the simulated ball is to be struck by the participant. Programming enables diﬀerent directions and the ball’s ﬂight speed to be simulated by creating constant pairs of lamps on the board and in the sensors (anticipatory schema) which are switched on sequentially with 0.5–1.5 s break. Psychomotor factors tested as predispositions for tennis In order to establish the psychomotor predispositions for tennis, the following factors were tested: the speed of anticipatory (‘brain’ and ‘body’ speed) and orientation (‘body’ speed) locomotion movements, the level of behavioural ﬂuctuations (the capability of optimizing attention concentration, motivation, arousal and resistance to disturbances), and the capability for anticipation and competitiveness. On the basis of the above factors, a psychomotor eﬃciency index was calculated which comprehensively expresses the psychomotor eﬃciency speciﬁc for tennis.

Tennis play simulator 1

171

Figure 24.1 The tennis play simulator – version 1 (with tactile sensors).

Anticipatory and orientation locomotion movements to ball-hitting The subject’s task was to perform locomotion movements to the places indicated indirectly by the lights on the boards (anticipatory locomotion movements) or directly by the lights in the sensors (orientation locomotion movements). The speed of particular movements was measured by the time that elapsed from when the light in the sensor lit to the instant the player touched the sensor. Accordingly, the shorter the time, the higher the speed. The speed of anticipatory and orientation locomotion movements was investigated in a series (tests) of 11 diﬀerent movements. The result of the whole test was the average speed of these 11 measurements. The tests of anticipatory movements were repeated ten times, while orientation movements were repeated six times. The order of movements in each test was diﬀerent but the same for the last four anticipatory and orientation movement elements of the test. The tests started ﬁve (anticipatory movements) and three (orientation movements) times from the right and left return positions. The results of the last four tests for each kind of movement were then averaged in order to obtain the ﬁnal speed of anticipatory (Ta) and orientation (To) locomotion movements to ball-hitting.

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The curves of anticipatory schema learning Learning curves were used to investigate behavioural ﬂuctuations (Lapszo, 1998). These curves illustrate the process by which the anticipatory schema develops. The results obtained in ten trials (tests) of anticipatory locomotion movement speed were approximated by the exponential learning curve (Woodworth and Schlosberg, 1966). The following formula of this curve was used: T(p) = (Tmax − Tp) × (1 − Is)(p − 1) + Tp, where p = serial number of the trial, T(p) = the result of the test as a function of the trial, Tmax = the lowest speed of anticipatory locomotion movements, Is = speed of learning, the increase in anticipatory movements speed in each trial (computed), and Tp = potential speed (the asymptote of the learning curve, computed). The statistical parameter R2 (Draper and Smith, 1973) showing the magnitude of the scatter around the learning curve was used as the index of behavioural ﬂuctuations If. The index of ball-ﬂight anticipation The increase in the speed of locomotion movements resulting from the ball-ﬂight anticipation was treated as an index of this anticipation (Ia). Ball-ﬂight anticipation is based on the association of a deﬁnite light (anticipatory stimuli) on the stimuli board with the position (place of location) of the sensor on the tennis court. The speeds of the anticipatory (Ta) and orientation (To) locomotion movements to ball-hitting were used to calculate the Ia index according to the following formula (Lapszo, 1998): Ia = (To − Ta)/To. This shows the relative extent to which the speed of displacement to the place towards which the ball is ﬂying increases as a result of ball-ﬂight anticipation. The simulated play for points: the index of capability for competitiveness The simulator enables playing for points. Programming the deﬁned speed of play (ball’s ﬁght speed) for a series of, for example, ﬁve movements, the performance of the series can be scored if the subject performed all ﬁve movements with the required speed or not. Too late in one of the ﬁve movements causes a loss of points. In this study, scoring was done using the standard tennis system of games and sets. Players in most cases had to perform four series of tests, consisting of ﬁve locomotion movements to win a game. The play was conducted to win one set (six games). The ratio of the number of lost to won games multiplied by the coeﬃcient of simulated play

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speed (the speed of ball’s ﬂight) was treated as an index of capability for competitiveness (Ic). The simulated play for points also enabled practising the speed of ‘foot work’ in competitive conditions, in which the level of motivation is usually higher than in practice conditions. Only junior groups participated in this test. The index of psychomotor eﬃciency In order to express psychomotor eﬃciency in a comprehensive way, the index of psychomotor eﬃciency Ipe was introduced. The index was calculated on the basis of the following formula Ipe = (If + Ia + Ic )*5/(Ta + To ). Index Ipe expresses psychomotor eﬃciency in one number, which corresponds to the speed of anticipatory (Ta ) and orientation (To) motor reacting and a capability for psychomotor state optimizing (If), anticipation (Ia) and competitiveness (Ic ) of particular players. By introducing this index we were interested whether it can be used to assess, in a comprehensive way, the psychomotor predispositions to achieve high sporting success in a tennis game. Statistics The relationships of the tested factors with sporting results were analysed on the basis on the Pearson’s correlation with the level of statistical signiﬁcance of P< 0.05.

Results Psychomotor predispositions for tennis Sporting predispositions constitute such psychomotor factors that have an inﬂuence on sporting results. In order to examine, whether the factors tested in this study (If, Ta, To, Ia, Ic, Ipe) are sporting predispositions for tennis we have correlated them with sporting results ranking for each age group separately. The rankings were determined independently by two coaches (separately for each group), who knew the sporting results of the tested players. The correlation coeﬃcients are presented in Table 24.1. All tested factors correlated with sporting results (although not all in all tested groups). In published studies the reaction and movement time (Keele, 1982) and anticipation (Meeusen, 1991) and attention concentration (Nettelton, 1986) did not diﬀer between highly and less skilled fast-ball games players. Our study has shown such diﬀerences although the tested groups were relatively small. We believe that a planned similar study with a participation of larger groups will support the results obtained in this study. We found the

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Table 24.1 The correlation coeﬃcients of the tested factors with sporting results for the examined groups Tested groups

N

Seniors

6

Juniors Younger juniors

6 5

Coeﬃcients of correlation Correlated factors

If

Ta

To

Ia

Ic

Ipe

Sporting results

−0.67

0.7

0.54

0.78

a

0.79

−0.56 x

0.66 0.67

x 0.55

0.75 0.7

1.0 0.97

0.77 0.73

Note: x = statistically insigniﬁcant coeﬃcients, a = not participated in the research, P < 0.05

strongest correlation (Table 24.1) between the index of capability for competitiveness (Ic) and sporting results. In an earlier study (Lapszo, 1998) on table-tennis the cluster analysis was used to classify players with respect to their level of aptitude (talent) for this game. In this study we used the index of psychomotor eﬃciency Ipe to assess the aptitudes for tennis. In all groups the correlation of sporting results with index Ipe was stronger than with other tested factors (except index Ic). The calculation of the index Ipe is more simple than cluster analysis and can be easily applied by coaches to assess the degree of psychomotor talent for tennis of advanced tennis players as well as of children that are novices to the game. The simulator could be used to diagnose and improve the psychomotor predispositions of tennis players at every competitive stage. The application of the tactile sensors in the simulator eliminate any inﬂuence of stroke technique on the speed of tested movements and inversely, the performed movements on stroke technique.

Discussion The strength of the correlation of particular factors with sporting results indicate the kind of psychomotor predispositions proﬁles of tested groups. We have found that seniors exhibit an anticipatory-concentration-speed proﬁle, juniors competitive-anticipatory-concentration proﬁle and that young juniors a competitive-anticipatory-speed proﬁle. The kind of psychomotor predisposition proﬁle shows what factors inﬂuence sporting results in groups of players of diﬀerent ages and having diﬀerent sport experience levels. Our study in table tennis (Lapszo, 1998) has shown that very talented players had all psychomotor predispositions at a very high level though not necessarily at the top level. To determine the level of tested psychomotor factors obtained by particular players, in comparison to other players or the whole group, the psychomotor proﬁles analysis can be used. The proﬁles constitute the graphic presentation (for example bar graphs) of all psychomotor

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predispositions in the same scale (Skorny, 1974). The proﬁles enable the identiﬁcation of strong and weak sides in the psychomotor proﬁles of tested players. The degree of the psychomotor strengths and weakness can be assessed on the basis of relative diﬀerences between particular factors in groups and individual proﬁles. The psychomotor proﬁles analysis can be useful when recruiting to tennis the most talented children, as well as identifying psychomotor strengths and weaknesses in players at any level of ability to individualize the practice process.

Conclusions The research presented using the tennis play simulator 1 has demonstrated that:

• • • • •

the tennis play simulator enabled the testing of several psychomotor factors related to tennis in simulated conditions; the tested psychomotor factors can be treated as predispositions for tennis; the index of psychomotor eﬃciency in a complex way expresses the level of talent for tennis; the strength of correlation of particular psychomotor factors with sporting results is diﬀerent for diﬀerent age groups; the capability for competitiveness has the strongest inﬂuence on sporting results in tennis.

This study has shown that the tennis play simulator 1 seems to be useful for sport researchers and coaches to test the psychomotor predispositions for tennis on the basis of locomotion movements that can be easily performed by people with or without previous experience playing tennis. The simulator can be applied to practice the speed of anticipatory and orientation locomotion movements (foot work) of advanced players in practice and combative (play for points) conditions without any interference from their ball-hitting techniques.

References Draper, N.R. and Smith, H. (1973). The Applied Regression Analysis (in Polish). State Scientiﬁc Publishers, pp. 196–234. Hull, C.L. (1942). Conditioning: outline of a systematic theory of learning. National Social Study of Education, 41 Yearbook, pp. 61–95. Keele, S.W. (1982). Component analysis and conceptions of skill. Human Motor Skills. London: Erlbaum, pp. 141–159. Lapszo, J. (1998). The method of research into the speed of speciﬁc movements and anticipation in sport under simulated conditions on the basis of table tennis. In Science and Racket Sports II (edited by A. Lees, I. Maynard and T. Reilly), London: E&FN Spon, pp. 135–141.

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Lapszo, J. (2000). Anticipatory model of human situation motor behaviours. In Current Research in Motor Control (edited by A. Raczek), Katowice: University School of Physical Education, pp. 134–139. Lapszo, J. (2002). Simulatory diagnostic and practice timer of movement speed, concentration and anticipation. Patent PL 183700. Warsaw Polish State Patent Oﬃce. Meeusen, H.J. (1991). On simplifying reality: implications for research on individual diﬀerences. Perceptual and Motor Skills, 73, 1055–1058. Nettleton, B. (1986). Flexibility of attention in elite athletes. Perceptual and Motor Skills, 63, 991–994. Schmidt, R.A. (1975). A schema theory of discrete motor skill learning. Psychological Review, 7, 225–259. Skorny, Z. (1974). The Methods of Research and Psychological Diagnostic (in Polish). Wroclaw-Warszawa-Krakow-Gdansk: Ossolinski National Publishers, pp. 90–91. Woodworth, R.S. and Schlosberg H. (1966). Experimental Psychology (in Polish). Warsaw: State Scientiﬁc Publishers.

25 Tennis play simulator 2 Speed of sequential ball-hitting movements under practice and competitive conditions J. Lapszo

Introduction The single ball-hitting movement in tennis has the character of sequential movements and consists of four separate, sequentially performed phases: split-step, displacement (locomotion) to hit the ball, ball-hitting proper and displacement after ball-hitting. The split-step prepares the muscles to move the body towards the ball as quickly as possible. The displacement to hit the ball is directed towards moving the body as fast as possible to the place where the ball is ﬂying. The purpose of the ball-hitting proper is to hit the ball to the opposite side of the court to score a point or cause the opponent to miss-hit the return. The purpose of displacement after the ball has been hit is to reach as quickly as possible the best position on the playing court to cover the possible lines (directions) of ﬂight of the returning ball. Contemporary tennis requires the ball-hitting movements to be performed very fast and with very high precision. The speed and precision of sequential ball-hitting movements is related to the anticipation of interception (Belisle, 1963), which consists of predicting the place or time (or both) where the ball will arrive and performing a movement coincident with the place and the time. This anticipation can be divided into the ball-ﬂight (place) and ballhitting (movement) anticipation (Lapszo and Kolodziejczyk, 1999). In the ﬁrst case, the anticipation consists of predicting the place where the ball is going and displacing the body to reach this place. In the second case, the anticipation is responsible for the spatial and temporal coincidence of the act of striking the ball with the path of the moving ball. We have diﬀerentiated anticipatory and orientation sequential ball-hitting movements. The anticipatory ball-hitting movements are initiated by the opponent’s ball-hitting movement or by the early phase of the ball’s path. This information is called the anticipatory stimuli. The middle or ﬁnal phase of the ball’s path have been treated as the orientation stimuli. The movements initiated by the orientation stimuli were called the orientation sequential ball-hitting movements. The anticipatory stimuli indirectly indicate the place in which the ball is ﬂying, while the orientation movements show it directly. The phase of the ball’s path just before and after bouncing on the tennis

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court can be regarded as a ball-hitting anticipatory stimulus, which allows the prediction of the shape (run in the space) and the speed of the ball-hitting movement proper. The ball-hitting anticipation enables hitting a ball in the optimal spot on the ball’s ﬂight trajectory to direct it toward the chosen place on the opposite side of the court with the highest precision. In other words, the ball-ﬂight anticipatory stimuli indicate where to run to reach a good position to hit the ball, while the ball-hitting anticipatory stimuli show how and when to hit the ball. The ball-ﬂight anticipation is based on memorizing the way in which the ball was struck by the opponent and the place where the ball ended up. Memorized experiences of this kind make up an anticipatory schema (Lapszo and Kolodziejczyk, 1999; Lapszo, 2000), the essence of which is similar to Schmidt’s motor schema (Schmidt, 1975). The ball-ﬂight anticipation is responsible for the instant of locomotion movement initiation while ballhitting anticipation is for precision of hitting the ball. The ball-ﬂight and hitting anticipations are unconscious (automatic) information processes. The concept of sequential ball-hitting movements, anticipatory and orientation stimuli, ball-ﬁght and hitting anticipation and anticipatory schema was used to design the tennis play simulator versions 1 and 2. The purpose of this paper is to present the construction of the tennis play simulator 2 (the version of the simulator, which allows the simulated ball-hitting movements to be performed with a tennis racket) and the research on psychomotor eﬃciency in tennis on the basis on the speed of orientation and anticipatory ball-hitting movements performed in practice and competitive conditions.

Methods Participants Eight highly-skilled American tennis players (four female and four male, average age 14.2 years) with an average of 6.1 years of special training in tennis participated in the study. One male player was located on the ATP list. Tennis play simulator 2 The simulator, used in the study, is a second (advanced) version of the tennis play simulator. Both versions of the simulator consist of a computer, a controller, and a speciﬁc simulator (Lapszo, 2002). The speciﬁc simulator-version 2 is presented in Figure 25.1. This simulator consists of: ten anticipatory stimuli lamps (red, yellow), three split step lamps (white), start (green) and end (blue) lamps, and ten sensors (with ten orientation stimuli lamps) enabling performance of ball strokes with a tennis racket in the manor of real play (eight base line strokes and two volleys). The computer enables the measurement tests to be controlled using a special computer language.

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Figure 25.1 The tennis play simulator 2.

Anticipatory stimuli lamps can emit the light in two colours: yellow and red. The yellow colour indicates ‘the ball is ﬂying cross court’, and the red one indicates ‘the ball is ﬂying down the line’. The following symmetric pairs of anticipatory and orientation (anticipatory schema) stimuli lamps were created in computer programme (Figure 25.1): 1,10–4,7; 2,9–2,9; 3,8–1,10; 4,7–3,8; 2,9–5, 6 (volleys), 5–7; 8 (service on forehand side), 6–3, 4 (service on backhand side). The players learned this anticipatory schema. In the anticipatory conditions, the ‘spilt step light’ was presented ﬁrst, next the light on the deﬁned board (anticipatory stimulus), and with delay (ball’s ﬂight) the light in the deﬁned sensor (orientation stimulus). In orientation conditions, ‘split step light’ comes on ﬁrst, and then the light in the sensor. The light on the board did not come on in these conditions. The players were instructed to perform the simulated ball hitting movements as in real play. Their task was to displace themselves as fast as possible in the direction of the proper sensor and hit the sponge ball located on the top of the ﬂexible stick (Figure 25.1) in response to anticipatory lights (anticipatory conditions) or lights in the sensors (orientation conditions). The speed of anticipatory and orientation ball-hitting movements were measured by the time elapsing from the instant of sensor activation to the instant of hitting the ball (on top of a ﬂexible

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stick) in the sensor. The tested movements were performed in six series. Each series of orientation and anticipatory ball-hitting movements consisted of six to eight movements started in the return position. Three series started from the right and three series from the left return position. The players performed the orientation and anticipatory ball-hitting movements in practice and competitive conditions. In the practice conditions, the players were only instructed to perform the movements as fast as possible. In the competitive conditions, the players were playing a game of six points in both orientation and anticipatory conditions. The speed of play was controlled by a special coeﬃcient (Csp) which determined the time in which the player had to perform the sequential ball-hitting movements. If the player performed all movements in a series in the required time she/he won a point. The following psychomotor factors were obtained in the presented research:

• • • •

speed of orientation (To) and anticipatory (Ta) ball-hitting movements in practice (To-pc, Ta-pc) and competitive (To-cc, Ta-cc) conditions – the speeds were averaged across all movements in the series and next across all series; coeﬃcients of the maximum speed of play in orientation (Msp-oc) and anticipatory (Msp-ac) conditions – the maximum value of coeﬃcient Csp, for which the players were able to win the points, if the index is larger the lower the speed of play; indexes of competitiveness in orientation (C-oc) and anticipatory (C-ac) conditions – the relative increase in orientation (To) and anticipatory (Ta) ball-hitting movements speed in competitive conditions in comparison to practice conditions; anticipation of the ball ﬂight in practice (A-pc) and competitive conditions (A-cc) – reﬂects the relative increase in sequential ball-hitting movements as a result of ball-ﬂight anticipation, the indexes A-pc and A-cc were calculated using the following formulas: A-pc = (To-pc − Ta-pc)/(To-pc) and A-cc = (To-cc − Ta-cc)/(To-cc);

•

•

speed endurance (Se), was tested in form of play for points (12) for the speed of play 30 per cent lower (larger Csp) than maximum speed (Msp), the index Se was calculated by the ratio of the number of lost to scored points multiplied by the coeﬃcient of the play speed Csp; smaller Se index means larger speed endurance; index of psychomotor eﬃciency (Ie), which was calculated on the basis of the following formula:

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Ie = [(C-oc + C-ac + A-pc + A-cc)/(To-pc + To-cc + Msp-oc + Ta-pc + Ta-cc + Msp-ac + Se)]*5; the index Ie expresses in comprehensive way the psychomotor eﬃciency; the larger the index the higher is the psychomotor eﬃciency related to tennis game. Statistics One-way ANOVA was used to assess the diﬀerences between factors. Relationship were tested by Pearson’s correlation. The level of signiﬁcance level was set at P < 0.05.

Results Psychomotor proﬁles The average values of tested factors are presented in a form of psychomotor proﬁles (Figure 25.2) that constitute the graphic presentation of the factors on the same scale (Skorny, 1974; Lapszo, 1998). In the same ﬁgure the proﬁles of the best player (located on the ATP list), the whole tested group and a freely chosen player (player 5) are shown. Higher speed (shorter time, Figure 25.2) of orientation (To) and anticipatory (Ta) ball-hitting movements and larger index of anticipation (A) were found in competitive than practice conditions (To-cc < To-pc, Ta-cc < Ta-pc, A-cc > A-pc, P < 0.02). The ﬁndings indicate that the play for points causes an increase in the speed of ball-hitting movements and anticipation in both conditions. The speed beneﬁt resulting from ball-ﬂight anticipation is much larger in competitive (A-cc, 71 per cent) than in practice (A-pc, 37 per cent)

Figure 25.2 Proﬁles of the tested psychomotor factors for the best player, the tested group and a freely chosen player (player 5).

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conditions. The indexes C-oc and C-ac show a relative increase in the speed of orientation (C-oc) and anticipatory movements (C-ac) as a result of an increase in motivation caused by playing for points. The increase in the speed was 0.05 (5 per cent, C-oc) in orientation conditions, while in anticipatory conditions it was 0.53 (53 per cent, C-ac). Also found were a higher speed (shorter time) of anticipatory (Ta) than orientation (To) ball-hitting movements in both practice and competitive conditions (Ta-pc < To-pc, Ta-cc < To-cc, P < 0.05). The research has shown that the best player obtained better results than group with respect to all tested factors while freely chosen player (player 5) demonstrated weak sides in his psychomotor proﬁles (Ta-pc, Ta-cc, C-ac, A-pc, A-cc, Se, Ie). Correlation of tested factors with sporting results Pearson’s correlation of the tested psychomotor factors obtained for particular players with their sporting results ranking was examined (Figure 25.3). All the tested factors strongly correlated with sporting results. Unfortunately, not all correlation coeﬃcients were statistically signiﬁcant because the number of tested players was not large (eight players). We found the strongest correlation for the maximum speed of play (Msp-ac, r = 0.97), index of competitiveness for anticipatory conditions (C-ac, r = 0.94) and index of psychomotor eﬃciency (Ie, r = 0.89).

Discussion The much higher anticipatory (Ta-pc, Ta-cc) than orientation (To-pc, To-cc) ball-hitting movement speed indicates that the ball-ﬂight anticipation in tennis enables players to reach the ball faster than relying on the orientation of the ball’s ﬁght. The speed of orientation ball-hitting movements mainly depends on motivation and on the motor (body) speed capability, which in turn depends on the proportion of the fast and slow ﬁbers in the muscles. The speed of anticipatory ball-hitting movements reﬂects the speed of information and motor processes in anticipatory motor reacting based on

Figure 25.3 The proﬁle of correlation coeﬃcients between tested psychomotor factors and sporting results ranking for tested group.

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anticipatory experience (anticipatory schema). Motivation is an energizing process of the human psychomotor system, directed on achieving a deﬁned goal (Schmidt, 1988). It was found that additional motivation resulting from the play for points caused a much higher increase in anticipatory (53 per cent) than orientation (5 per cent) ball-hitting movement speed. The increase in motivation causes much larger increases in eﬃciency of mental (perceptual, information and memory) than motor (execution) processes. We found strong correlations in all tested factors with sporting results. Keele (1982) and Meeusen (1991) found that movement time (motor speed) and anticipation do not diﬀerentiate highly proﬁcient from less skilled players. Our study has shown the diﬀerence (Figure 25.2) between ATP tournaments player and less skilled competitors with respect to motor speed, anticipation and other psychomotor factors tested. This research indicates that the tested factors reﬂect psychomotor capacities that are important in a contemporary tennis game. The obtained results support our earlier study (Lapszo, 1998) that showed a strong correlation with ball-hitting movement speed, anticipation, and concentration with sporting results in table tennis.

Conclusions The following conclusions can be drawn from the presented research:

• • • •

The simulator enabled testing of several psychomotor factors related to tennis in orientation and anticipatory, practice and competitive conditions. All tested psychomotor factors strongly correlated with sports ranking. The anticipatory ball-hitting movements are much faster than orientation movements. The speed beneﬁt (an increase in the speed of ball-hitting movements) of the ball’s ﬂight anticipation is larger in competitive (70 per cent) than practice (37 per cent) conditions.

References Belisle, J.J. (1963). Accuracy, reliability and refractoriness in a coincidenceanticipation task. Research Quarterly, 34, 271–281. Keele, S.W. (1982). Component analysis and conceptions of skill. Human Motor Skills. London: Erlbaum, pp. 141–159. Lapszo, J. (1998). The method of research into the speed of speciﬁc movements and anticipation in sport under simulated conditions on the basis of table tennis. In Science and Racket Sports II (edited by A. Lees, I. Maynard and T. Reilly), London: E&FN Spon, pp. 135–141. Lapszo, J. (2000). Anticipatory model of human situation motor behaviours. In Current Research in Motor Control (edited by J. Raczek). Katowice: University School of Physical Education, pp. 134–139. Lapszo, J. (2002). Simulatory, diagnostic and practice timer of movement speed,

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concentration and anticipation. Patent PL 183700. Warsaw: Patent Oﬃce of the Republic of Poland. Lapszo, J. and Kolodziejczyk, J. (1999). Psychomotor eﬃciency proﬁles of the members of the senior and junior polish national table tennis team. Acta of Bioengineering and Biomechanics, 1, 65–71. Meeusen, H.J. (1991). On simplifying reality: implications for research on individual diﬀerences. Perceptual and Motor Skills, 73, 1055–1058. Schmidt, R.A. (1975). A schema theory of discrete motor skill learning. Psychological Review, 7, 225–259. Schmidt, R.A. (1988). Motor Control and Learning. Champaign, IL: Human Kinetics Publishers. Skorny, Z. (1974). The Methods of Research and Psychological Diagnostic (in Polish). Wroclaw-Warszawa-Krakow-Gdansk: Ossolinski National Publishers.

Part 4

Performance analysis of racket sports

26 Computerized notational analysis and performance proﬁling in racket sports M.D. Hughes, M.T. Hughes and H. Behan

Introduction The ﬁrst hand notational analysis system published in Britain was for tennis (Downey, 1973). This system was never actually used to gather data due to its complexity but was signiﬁcant as it provided other researchers with a wealth of ideas for notational analysis (Hughes, 1998). Sanderson and Way (1977) reported a system for squash which seemed to be based on the work by Downey (1973). Their hand notation system was created to analyse successful and unsuccessful patterns of play in squash and was further developed by Sanderson (1983) to include symbols to represent shots that were placed upon a diagram of a court. However, it took ﬁve to eight hours to learn how to use this system, and a further 40–50 hours to analyse the data from one match. Because of the problems inherent in more sophisticated hand notation systems, computers were used to minimize learning time and process the data gathered. Hughes (1985) began this progression by computerizing the processing of the data gathered by hand with the system of Sanderson and Way. It is the aim of this paper to trace the development of computerized performance analysis through the examination, as a case study, of the maturation of the process across racket sports, which not only have the most advanced performance analysis support systems, but also have been clearly chronicled in research papers.

The development of analysis and technology in racket sports Diﬃculties with data entry and system learning time were reduced with the development of the digitization pad. Digitization pads are programmable, touch sensitive pads, over which one places an overlay with a graphic representation of the playing surface and aptly labelled keypad areas for the actions and the players (Hughes, 1994). A number of studies both in Britain and in the Notational Analysis Centre at University of British Columbia have used ‘Concept keyboards’ and ‘Power pads’ respectively. A voice interactive system (Taylor and Hughes, 1988) made the analysis

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systems easier to use for non computer-literate operators. They were able to demonstrate that a computer ‘non-expert’ was capable of using the system despite the sophistication of their study being limited by cost. Intuitively, this seems like the most ‘user friendly’ system, but there has been little advance in this area until recently (Cort, 2006). Concurrent with developments in how the data were entered into the computer, there were also advances in how the data were displayed postprocessing. Hughes and McGarry (1989) designed a program that presented the data in three-dimensional coloured histograms that could be rotated and viewed from diﬀerent angles. This made the results of the computer processing easier to understand. Another step forward in terms of data entry was the creation of a graphical user interface. This allowed the user to enter data by moving the mouse around the screen and clicking on icons representing the actions to be entered. Hughes and Clarke (1995) used this system for the analysis of strategies on diﬀerent playing surfaces at Wimbledon (grass courts) and the Australian Open (synthetic courts). They noted that there were signiﬁcantly shorter rallies at Wimbledon and indicated the importance of the serve on grass courts. Later O’Donoghue and Liddle (1998) analysed time factors in both the men’s and ladies’ games, for both grass and clay surfaces. In badminton, the European circuit was studied at the 1996 tournament (O’Donoghue and Liddle, 1998). Recent systems utilize the Windows environment and are interactive with a number of graphics packages making representation far clearer and easier to understand (Hughes, 1994). The developmental work by these researchers has now led to the current generation of generic analysis systems that are linked into digital video for easy retention of a video database and for editing and feedback purposes. Indeed, there are now a large number of commercial systems that are available for the notational analyst that can considerably enhance the power of feedback, through the medium of video replays and edited video clips. Some of the more successful were appraised by Hughes et al. (2002b).

Application of feedback in racket sports Hughes (1994) outlined four major areas within which feedback gathered via computerized notational analysis can be applied to racket sports as tactical evaluation, technical evaluation, movement analysis, and creating databases and modelling. Tactical evaluation Hughes and Robertson (1998) used computerized notational analysis to re-examine the patterns of play at the elite level and create a ‘structural archetype’ of elite squash. This in turn enabled the creation of a tactical model for the game at the elite level for men, it enumerated the structures of

Computerized notational analysis and performance 189 the rallies and games, shot distribution frequencies, or ratios, across the court, and the percentages of shots played in the four corners of the court, enabling individuals to compare their own patterns. Murray and Hughes (2001) reviewed the development, methodology and application of tactical performance proﬁles used with elite level male and female English squash players. The aim of the methodology (tactical performance proﬁles) was to provide the performers with quantitative analyses, highlighting their own, or an opponent’s, comparative strengths and weaknesses. It is very diﬃcult to quantify the eﬀect that these proﬁles may have upon the performance of the players, and to attribute transition of performance to the implementation of these proﬁles is speculative. However, considering that the world of elite sport (especially when on the playing ﬁeld or court) has multivariate inﬂuences then any singular attribution would be very diﬃcult to achieve. The verbal feedback from the players and coaches was both constructive and positive and has raised several issues around how we, as sports scientists, give our information to elite performers. Nevertheless, the process alone made the players more analytical and focused in their approach to matches and tournaments, which, arguably, is a singular positive eﬀect in itself. The process itself is one of analysis and, more importantly, of self-analysis and change. These experiences are presented as an exemplar of performance analysis from which some generic indicators of process for the performance analyst can be deﬁned. Technical evaluation Technique and tactics are inherently inter-dependent, so that research methods that deﬁne technical strengths and weaknesses of given players will also highlight the areas of tactical importance. Highlighting technical deﬁciencies or strengths in players can be of vital importance to coaches in their quest to improve players. The analysis systems used over the years (Hughes, 1985; Brown and Hughes, 1995) have been used to show the areas on the court from where players hit their winners and errors, and the shots used. Armed with this information the coach can then analyse any technical deﬁciencies of their players when playing in these particular areas of the court or when playing a certain shot. This in turn will inform the player of tactical considerations of shot sequences. This can be done live in training, or with use of video feedback. Seeing technical faults in the past has been quite diﬃcult on video due to the low frame rates. However, with introduction of high-speed cameras for feedback purposes, technical analyses of the racket swings and individual player movement can now be scrutinized in detail.

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Movement analysis Hughes et al. (1989) designed a tracking system for squash. The tracking system was designed to be used post-match from video at match speed. A ‘Power pad’ was used to gather the positional data along with the time base (Hughes, 1998). Accurate tracking was enabled by training a video camera on the ‘Power pad’ and mixing the image from the camera with the footage of the match and transferring it to a single VDU screen. The image of the representation of the playing area on the ‘Power pad’ was aligned to exactly meet the dimensions of the court on screen. This allowed the operator to be able to focus upon where they were tracking and where the player was moving at the same time. This was shown to be an accurate and reliable method of gathering information regarding player velocities and accelerations. This system was utilized by Hughes and Franks (1994) in a study comparing the motions of squash players of diﬀering standards. They recorded the distances moved, the average velocities and the accelerations during rallies of four diﬀerent standards of players ranging from club level to elite internationals. The mean distance travelled by recreational and regular club players was only 12 m, which raised some questions about the type and speciﬁcity of the training that these players were performing. The study also showed that the then number one player in the world, Jahangir Khan, had a physiological advantage over the other top players in the world. It was found that when the data for Jahangir Khan were compared to that of the top six players, his acceleration during a rally was 50 per cent greater than that of his opponents. O’Donoghue and Liddle (1998) investigated rally and rest times for each discipline of badminton (apart from mixed doubles) and found mean rest durations to be longer than mean rally durations for all forms of the game. In men’s singles, mean rally duration was found to be 9.15 ± 0.43 s, whilst the mean rest time was 13.84 ± 1.16 s. However, the study by was limited in that only four of each men’s and ladies’ singles, ﬁve men’s doubles and four ladies doubles matches were notated. This meant that a restricted study size was examined for each discipline. Conclusions drawn from the research were that training should be speciﬁc to the discipline in which performers participate. This is reinforced by the fact that the Badminton Association of England have appointed specialist singles and doubles coaches in recent times. Pereira et al. (2001) indicated the importance of movement within the game of squash, a concept that is reiterated by many tennis professionals, even given the diﬀerences in reported rally time, intensity and rest ratios between the two sports. The principle aim of the research undertaken by Pereira et al. (2001) was to link movement patterns form diﬀerent areas of the court, to establish a normative movement proﬁle. Such proﬁles of movement are not currently available in the ﬁeld of tennis, and if a reliable and valid measure for these movements in tennis could be produced, it would serve as a valuable resource for both coaches and players alike.

Computerized notational analysis and performance 191 Movement analysis in racket sports has enabled a better understanding of the physical demands of the sports and, as a result, the creation of speciﬁc training drills to better prepare the players for match-play. This information can also be used to help strengthen junior players who are currently ﬁnding the transition from the junior game to the senior (professional) sport diﬃcult due to the greater physicality of the senior game (Pearson, 1999). Databases and modelling Mathematical modelling can be used to describe sport and can be applied to racket sports to expose strategic patterns of play. Using the mathematical theory of probability, Alexander et al. (1988) analysed and modelled the game of squash. They ﬁrst suggested that the actions in squash a series of discrete events with each event having an associated probability function. However, this model cannot take into account the human factors of the game such as form and tiredness. They then took these factors into account and were able to make recommendations for players on how to ‘set’ the game at 8–8 depending on fatigue and technical ability. McGarry and Franks (1994) created a stochastic model of championship squash match-play which inferred prospective results from previous performance through forecasting shot response and associated outcome from the preceding shot. Their results were limited however by the fact that players used the same playing patterns against the same opponents but diﬀerent playing patterns against diﬀerent opponents. This was in contrast to the work of Sanderson (1983) who found that squash players did not alter their patterns of play against diﬀerent opponents whether they were winning or losing. These discrepancies could be the result of diﬀering levels of detail in terms of measuring the responses of the players, McGarry and Franks used a very detailed analysis structure, but they do remain a contradiction to the more generally accepted view of the stabilization of playing patterns. To try to promote a more attacking style of play in squash, ‘point-per-rally’ scoring was introduced to all PSA tournaments in 1990 along with the tin being lowered from 19 inches to 17 inches. It was thought that with points on oﬀer when receiving serve as well as being able to play shots lower on the front wall, players would hit more oﬀensive shots, rallies would become shorter and squash would become more spectator friendly. To analyse the diﬀerences in the game when using point-per-rally scoring compared to the traditional English scoring method, Hughes and Knight (1995) designed a computerized notational analysis system that utilized a graphical user interface. Surprisingly rallies were found to be marginally, but not signiﬁcantly longer, when playing using the point-per-rally scoring. There was an increase in winners but no increase in errors, which was attributed to the lower tin. Further analysis of the scoring systems in squash was conducted by Hughes (1995), when he investigated the scoring structures in tennis and squash. Key terms ‘activity cycles’ and ‘critical points’ were described by Hughes as the

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crucial events that lead up to exciting points in the games. In tennis the activity cycles leading up to a ‘game point’ were about three mins in duration, whereas in squash (and in badminton at that time) it took 15–20 mins to reach a critical point, i.e. game-ball. Hughes realized that in order to make the game more attractive the activity cycles preceding critical points in the games needed to be shortened to make the game more appealing, more exciting. So, Hughes recommended playing more, shorter games in squash thereby increasing the number of critical points and, it was hoped, crowd excitement. A time analysis of badminton was performed of both the 1999 Welsh Open in the three games to 15 points format, and the 2000 Welsh Open in the ﬁve games to seven points format. Post-event analysis (Pritchard et al., 2001) allowed repeated viewings to enable the collection of extra data. Performance indicators such as rally length and duration, rest times and game lengths were recorded by hand on computer printed record sheets. The experimental scoring system under trial in 2001 by the International Badminton Federation seems to have the desired eﬀect on elite men’s singles. This research enabled the following conclusions to be made.

• • • • • • • • •

Mean, mode and median rally lengths showed no signiﬁcant change and were comparable to those found by O’Donoghue and Liddle (1998), and Liddle et al. (1996); A signiﬁcant diﬀerence (P = 0.025) was found in the lengths of games under the new scoring system. The average duration dropped from 19:24 min under the old system, to 8:53 min under the new one; Match length decreased signiﬁcantly (P = 0.025) when deﬁned by the number of rallies played; A tight match in 3 × 15 format may last up to an hour. This decreased to 45 minutes in 5 × 7 format; Work-to-rest ratios were identical under both forms of scoring; Critical Points occurred 4.05 times per game under the new scoring compared to 1.76 per game under the traditional format; Shorter games containing more Critical Points making badminton more exciting and better suited to television; There were more breaks in play as there were more games of a shorter length. This gives time for expert analysis on television coverage; Spectators are likely to better understand the new scoring format as all ties are the best of ﬁve games to seven points, irrespective of which discipline of the game is being played.

The professional men’s squash association has recently introduced a new scoring system, with the aim of making the game more appealing to television audiences. It is so far unclear as to whether this change has achieved its aim. The aim of a study by Hughes et al. (2007) was to analyse any changes in the game structure or diﬀerences in the patterns of play occurring amongst the elite of men’s squash whilst playing in competition under the old (point

Computerized notational analysis and performance 193 per rally to 15) and new (point per rally to 11) scoring systems. Overall the study determined that matches were shorter and more ‘critical points’ were created through the new scoring system, hence making it more attractive to the television media. McGarry (2006) examined the space–time patterns of squash players as they move around the squash court in the context of a dynamical system. The phase relations that describe the squash dyad (i.e. where one player is in relation to the other player) demonstrated a strong tendency towards an antiphase (180°) relation, as expected. These new and exciting ways of examining racket sports provide innovative ways of modelling these sports and point the way toward an ongoing series of modelling developments.

Performance proﬁling Recent applied research has made the deﬁnition of proﬁles much less a matter of guesswork in terms of how accurately a particular proﬁle really represented the way a player or a team performed in general. The use of performance proﬁling (Hughes et al., 2001) has created a sound empirical method of ensuring the stability of the data proﬁles. Further, the work of James et al. (2004) has introduced the ideas of using conﬁdence intervals, that enable the use of any number of matches for a proﬁle with some quantitative statement about the quality of the data.

Reliability It is vital that any data gathering system used within research has been proven to be reliable and in a manner that is compatible with the intended analyses of the data (Hughes et al., 2002a). The data gathered must be tested in the same way and to the same depth in which it will be processed in the subsequent analyses. Hughes et al. (2002b) went on to demonstrate how insensitive the non-parametric tests of comparison, such as chi-square, Mann-Whitney and Kruskal-Wallis, are to diﬀerences between sets of data – no signiﬁcant diﬀerence between sets of data more than 25 per cent apart. They pointed out that this creates diﬃculties for analysts, and researchers, working with sets of data taken from elite performances, where the diﬀerences between winning and losing are as small as 1 or 2 per cent. At elite levels of sport, diﬀerences as large as 10 per cent between winning and losing performances are rare, so perhaps diﬀerent types of test need to be deﬁned with these sorts of data sets.

Current areas of research and support Most of the support that is currently being oﬀered to England Squash is based upon the work of Murray and Hughes (2001). During their research they oﬀered England Squash various types of feedback from information

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gathered using simple winner and error analysis and ‘the full analyses’ systems. Analyses ranging from simple winner and error ratios to complex rally ending patterns were produced from the computerized systems. Murray and Hughes (2001) also introduced the concept of momentum analysis in racket sports – this has been further extended by Hughes et al. (2007). The use and further recent developments in feedback both for competition and training and coaching were presented by Murray and Hughes (2006) – an applied demonstration of the strengths and uses of the Focus, Quintic, Dartﬁsh and SiliconCoach software, together with digital video, high-speed video and the best available VDU’s for feedback.

Future research Momentum analysis is a new way of extending performance analysis and its signiﬁcance is not yet fully explored. It does seem apparent, however, that the results of the analysis combined with the work of sport psychologists can be of great beneﬁt to players in their attempts to maintain focus during matchplay. Further research needs to be carried out as to why the peaks of the top players in the world are longer and steeper than those of the lesser players. The research into neural networking and fuzzy logic (Perl, 2001) has huge potential for modelling purposes. If models for elite racket sports players can be created, using the theories that he is applying to other aspects of sports science, this could have huge potential for analysts and coaches. The ideal would be to have models created via neural networking that could be used to predict future performance of players taking into account factors such as fatigue, temperature, and crowd support. These types of applications of fuzzy logic, together with artiﬁcial intelligence shells should make ideal models for analysing the coaching process – a ‘nettle’ few coaching science experts have grasped so far.

References Alexander, D., McClements, K. and Simmons, J. (1988). Calculating to win. New Scientist, 10 December, 30–33. Brown, D. and Hughes, M.D. (1995). The eﬀectiveness of quantitative and qualitative feedback on performance in squash. In Science and Racket Sports (edited by T. Reilly, M. Hughes and A. Lees), London: E.&F.N. Spon, pp. 232–236. Cort, M. (2006). Voice recognition software for soccer analysis. In Performance Analysis of Sport VII (edited by M. Hughes and H. Dancs), Cardiﬀ: CPA, UWIC. Downey, J.C. (1973) The Singles Game. London: E.P. Publications, London. Hughes, M.D. (1985). A comparison of patterns of play in squash. In International Ergonomics (edited by I.D. Brown, R. Goldsmith, K. Coombes and M.A. Sinclair), London: Taylor and Francis, pp. 139–141. Hughes, M.D. (1994). A time-based model of the activity cycles in squash, with diﬀerent scoring systems, and tennis, on diﬀerent surfaces. Journal of Sports Science, 13, 85.

Computerized notational analysis and performance 195 Hughes, M.D. (1995). Using notational analysis to create a more exciting scoring system for squash. In Sport, Leisure and Ergonomics (edited by G. Atkinson and T. Reilly), London: E.&F.N. Spon, pp. 243–247. Hughes, M.D. (1998). The application of notational analysis to racket sports. In Science and Racket Sports II (edited by T. Reilly, M.D. Hughes, A. Lees and I. Maynard), London: E.&F.N. Spon, pp. 211–220 Hughes, M. and Clarke, S. (1995) Surface eﬀect on patterns of play of elite tennis players. In Science and Racket Sports (edited by T. Reilly, M Hughes and A Lees), London: E.&F.N. Spon, pp. 272–278. Hughes, M.D. and Franks, I.M. (1994). A time–motion analysis of squash players using a mixed-image video tracking system. Ergonomics, 37, 23–29 Hughes, M.D. and Knight, P. (1995). A comparison of playing patterns of elite squash players, using English scoring to point-per-rally scoring. In Science and Racket Sports (edited by T. Reilly, M Hughes and A Lees), London: E.&F.N. Spon, pp. 257–259. Hughes, M.D. and McGarry, T. (1989). Computerised notational analysis of squash. In Science in Squash (edited by M.D. Hughes), Liverpool: Liverpool Polytechnic. Hughes, M.D. and Robertson, C. (1998). Using computerised notational analysis to create a template for elite squash and its subsequent use in designing hand notation systems for player development. In Science and Racket Sports II (edited by T. Reilly, M.D. Hughes, A. Lees and I. Maynard), London: E.&F.N. Spon, pp. 227–234. Hughes, M.D., Franks, I.M. and Nagelkerke, P. (1989). A video system for the quantitative motion analysis of athletes in competetive sport. Journal of Human Movement Studies, 17, 212–227. Hughes, M.D., Evans, S. and Wells, J. (2001). Establishing normative proﬁles in performance analysis. International Journal of Performance Analysis in Sport, 1, 4–27. Hughes, M., Cooper, S-M. and Neville, A. (2002a). Analysis procedures for nonparametric data from performance analysis. eIJPAS, 2, 6–20. Hughes, M., Ponting, R., Murray, S and James, N (2002b). Some examples of computerised systems for feedback in performance analysis. UKSI Website: www.uksi.com, October. Hughes, M.D., Howells, M. and Hughes, M.T. (2006). Using perturbations in elite men’s squash to generate performance proﬁles. Culture, Science and Sport, 2(4) Supplement, 30. James, N., Mellalieu, S.D. and Jones, N.M.P. (2004). The development of positionspeciﬁc performance indicators in professional rugby union. Journal of Sports Sciences, 23, 63–72. Liddle, S.D., Murphy, M.H. and Bleakley, E.W. (1996). A comparison of the demands of singles and doubles badminton among elite male players: a heart rate and time/ motion analysis, Journal of Human Movement Studies, 29(4), 159–176. Liddle, S.D. and O’Donoghue, P.G. (1998). Notational analysis of rallies in European circuit badminton, In Science and Racket Sports II (edited by A. Lees, I.W. Maynard, M.D. Hughes and T. Reilly), London: E&FN Spon, pp. 275–282. McGarry, T. (2006). Identifying patterns in squash contests using dynamical analysis and human perception. In Performance Analysis of Sport VII (edited by M. Hughes and H. Dancs), Cardiﬀ: CPA, UWIC, pp. 619–630. McGarry, T. and Franks, I.M. (1994). A stochastic approach to predicting competition squash match-play. Journal of Sports Sciences, 12, 573–584.

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Murray, S. and Hughes, M. (2001). Tactical performance proﬁling in elite level senior squash. In pass.com (edited by M. Hughes and I.M. Franks), Cardiﬀ: CPA, UWIC, pp. 185–194. Murray, S. and Hughes, M.T. (2006). The working performance analyst. First International Workshop of Performance Analysis, International Society of Performance Analysis of Sport (ISPAS), Cardiﬀ, January. O’Donoghue, P. and Liddle, D. (1998) A notational analysis of time factors of elite men’s and ladies’ singles tennis on clay and grass surfaces. In Science and Racket Sports II (edited by A. Lees, I.W. Maynard, M.D. Hughes and T. Reilly), London: E.&F.N. Spon, pp. 241–246. Pearson, D. (1999). Movement is the key. http://uksquash.hypermart.net/ movement.htm Pereira, A., Wells, J. and Hughes, M. (2001) Notational analysis of elite women’s movement patterns in squash. In pass.com (edited by M. Hughes and I.M. Franks), Cardiﬀ: CPA, UWIC, pp. 223–238. Perl, J. (2001). Artiﬁcial Neural Networks in Sport: Concepts and Approaches. International Journal of Performance Analysis in Sport, 1, 56–64. Pritchard, S., Hughes, M. and Evans, S. (2001) Rule changes in elite badminton. In pass.com (edited by M. Hughes and I.M. Franks), Cardiﬀ: CPA, UWIC, pp. 213–225. Sanderson, F.H. (1983). A notation system for analysing squash. Physical Education Review, 6, 19–23. Sanderson, F.H. and Way K.I.M. (1977). The development of an objective method of game analysis in squash rackets. British Journal of Sports Medicine, 11, 188. Taylor, S. and Hughes, M.D. (1988) Computerised notational analysis: a voice interactive system. Journal of Sport Sciences, 6, 255.

27 Playing patterns of world elite male and Austrian top male single’s badminton players E. Oswald

Introduction The purpose of this study is to highlight the technical components of badminton games using a speciﬁc computer program for data analysis. Diﬀerences between international top players and Austrian top players are established in order to ﬁnd the areas in which the Austrian top players should improve in their technical and tactical training. The author wants to establish a proﬁle of the world’s top players and their Austrian counterparts and to contrast the two groups. The following questions are investigated:

• •

What diﬀerences between the two groups of players can be observed? What are strong and weak points of the Austrian players compared to the international top 20?

Some results shall be compared with the data of earlier studies (e.g. Bochow, 1989 or Hong and Tong, 2000). In this way the technical development of badminton in more recent years can be shown.

Methods The author videotaped matches of the Austrian top players (players in the Austrian top 20 ranking for male single badminton as recorded in May 2006) in the year 2005 and 2006. These matches and videos of international players (top 20 world ranking as recorded in May 2006) from the year 2005 and 2006 were analysed. Twenty games of international top players and the same number of games of Austrian top players were evaluated. This added up to approximately 20,000 shots by the elite international players and 13,000 by Austrian players. Data were analysed with a speciﬁc computer program based on MS Access®. The program used is capable of analysing most kinds of ball games and was adapted to be applicable in badminton. The following attributes were selected:

198

•

• • • •

E. Oswald the position of the player: the centre line, short service line and the long service line divide the court in six areas. Thus a total of six diﬀerent areas were available for recording the moves of the players. The six areas are: right forecourt, left forecourt, right mid-court, left mid-court, right rear-court and left rear-court; type of stroke: backhand, forehand, drop, smash, drive, clear, swipe; direction of stroke: long-line, diagonal; eﬀectiveness: neutral shots, eﬀective shots, ineﬀective shots and lucky shots; height where the ball was hit: underhand, side-hand, overhand.

Also recorded was whether a stroke was a service, and if it resulted in a fault or a point. In addition, the number of each stroke, the name of the playing person, sets and points, playing time and the ranking of the players were collected. In order to investigate the objectivity of the model, ﬁve people were taught how to work with the computer program. Each of them had to analyse three sets of a game. The collected data were tested for reliability by calculating Cohen’s kappa. The mean value of Cohen’s kappa over the several attributes was 0.896 with a range from 0.754 to 1.00. This shows that the model has a high degree of objectivity (Lames, 1990, p. 103).

Results All the games in this study were counted in the English scoring system. Table 27.1 shows basic statistics for the forty games. The main diﬀerences between international top players and Austrian top players are that the latter had fewer rallies per game and fewer strokes per rally on average. Consequently they had fewer total strokes and shorter playing time. More than 52 per cent of the rallies of the Austrian players lasted only one to four strokes. International top players perform longer rallies. A total of 35.6 per cent of the rallies had more than nine strokes. At the time of the

Table 27.1 Basic statistics of the investigation

analysed games total strokes mean playing time eﬀective playing time maximum rally length rallies per game strokes per rally

International top players

Austrian top players

20 games 19,965 strokes 53 minutes 27 minutes 43 strokes 104.6 rallies 8.0 strokes

20 games 13,072 strokes 34 minutes 16 minutes 43 strokes 97.8 rallies 5.9 strokes

Playing patterns of elite male badminton players

199

Table 27.2 Strokes per rally Strokes per rally

International top players

Austrian top players

International top players (Bochow, 1989)

1 to 4 5 to 8 9 to 12 13 to 16 over 16 mean

39.0% 25.5% 15.2% 9.0% 11.4% 8.0 strokes per rally

52.3% 25.3% 11.6% 5.7% 5.1% 5.9 strokes per rally

39.1% 29.7% 14.3% 7.4% 9.6% 8.2 strokes per rally

study of Bochow (1989, p. 57) the international top players had 31.3 per cent rallies which lasted more than nine strokes. The service Diﬀerences of the service strokes between the two analysed groups are shown in Figure 27.1. Nearly 80 per cent of the services of international top players were backhand or forehand drops. The Austrian top players used just 40 per cent drops and tended to forehand clears in more than 50 per cent of the services. Compared to a study by Hong and Tong (2000, p. 190) the international top players played more short services.

Figure 27.1 Type of service strokes.

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The return International top players returned 53 per cent of the long services with a smash. Austrian top players reacted in the same situation with 35 per cent smashes only. They played 35 per cent attack clears whereas the international top players used only 11 per cent. This shows the oﬀensive playing pattern of the world class. Looking at the returns of short services there were a few main diﬀerences between the two groups. A total of 51 per cent of the returns of short services in the international top players’ group were drops and 39 per cent were swipes. The Austrian top players used the drop in only 43 per cent and the swipe in 50 per cent of the shots. Analysing the faults and points during the return (Figure 27.2) international top players made most of their points hitting smashes and faults hitting underhand drops. The Austrian top players made most of their faults with the underhand drop and most of their points by hitting smashes.

Figure 27.2 Faults and points during the return.

Playing patterns of elite male badminton players

201

The rally shots International top players used more underhand clear, underhand drop, drive, smash and swipe shots compared to the Austrian top players (Figure 27.3). The Austrian athletes preferred overhand clear, overhand drop and attack clear shots. The most dominant shot in both groups was the underhand drop followed by overhand drop, smash and swipe shots. Figure 27.4 gives an overview of the height of the strokes depending on the court position of the players. It is obvious that the international top players

Figure 27.3 Type of strokes during the rally.

Figure 27.4 Shot frequencies in diﬀerent areas.

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performed more shots in the net area hitting underhand shots. The Austrian top players hit more strokes in the middle overhand area. It is assumed that the Austrians did so because they often play long shots too short (Figure 27.5). By deﬁnition, long shots should be played in the rear-court to have optimal length. Too-short shots are returned in the mid-court. Figure 27.5 shows that the Austrian top players did not use optimal length shots as often as the international players and second that they played tooshort shots more often. In the situation of attack clear and swipe the Austrian top players mostly use too-short strokes. This shows that under training conditions the Austrians should exercise optimal long strokes. An interesting aspect is the frequency of the kinds of stroke before the point (Figure 27.6). The most frequent kind of stroke in both groups was an underhand drop. The most noticeable diﬀerences are in the use of drive, swipe and attack clear before point.

Discussion and conclusion The main goal of the given investigation was to highlight the structural differences in the playing patterns between the world’s top male players and the Austrian top male players in single badminton. As a central point, it could be shown that international games had more rallies and more strokes per game than the Austrians. The world class players also performed more oﬀensive strokes. Noticeable diﬀerences in making

Figure 27.5 Distribution of too-short and optimal long strokes.

Playing patterns of elite male badminton players

203

Figure 27.6 Distribution of diﬀerent kinds of strokes before point.

points, respectively faults concerning aspects such as type of stroke, height of stroke and area of stroke could be observed. Because of the longer rallies in international top level badminton compared to the Austrian, more importance should be attached to rally shots when coaching the Austrian athletes.

References Bochow, W. (1989). Badminton optimiere [Optimal badminton]. Ahrensburg bei Hamburg: Czwalina. Hong, Y. and Tong, Y.M. (2000). The playing pattern of the world’s top single badminton players in competition: a notation analysis. Journal of Human Movement Studies, 38, 185–200. Lames, M. (1990). Leistungsdiagnostik durch Computersimulation [Game diagnostics through computer simulation]. Frankfurt am Main: Harri Deutsch.

28 Comparison of the average game playing time in diﬀerent scoring systems in badminton L. Petrinovic´-Zekan, Zˇ . Pedisˇic´, D. Ciliga and M. Kondricˇ

Introduction There are a few sports, and badminton is one of them, that are interesting to watch and play but are nevertheless underrated in worldwide TV coverage. Despite the well known popularity of badminton, it is very rarely on TV channels. One of the reasons was that long games with many rallies would be interesting to an expert but not to an ordinary TV audience. Furthermore, long playing time, without many breaks, is challanging for the players and also very unpopular for sponsors who would like their commercials to be seen between games. The duration of the games is not easily predictable and live telecasts are notoriously hard to schedule. Therefore, the International Badminton Federation (IBF) has tried to make the game more interesting for spectators and sponsors by introducing in 2002 a worldwide experimental change in the scoring system from a conventional three games to 15 (3×15) to ﬁve games to seven (5×7). Research showed signiﬁcant decrease in total match playing time (Pearce, 2002) for the new system. However, the experiment was not well accepted and IBF decided to return to the old scoring system. A new experiment which involved all tournaments approved by IBF started in May 2005. The conventional format of three games to 15 points (3×15) with counting points on change service was changed to a three games to 21 points (3×21) format, with every rally counting for a point. There was some controversy in badminton circles, but also positive reactions and so the IBF decided in May 2006 to oﬃcially adopt the new scoring system (http://www.internationalbadminton.org). This change will deﬁnitely aﬀect many aspects of the badminton game. The players and coaches will have to adjust to the new ways of playing and coaching the game. It remains to be seen who will beneﬁt from the new system the most, but there is a general opinion that something in tactics has to be changed. Whether the training should be changed as well, and in which part, also remains to be seen. The aim of this study was to compare average playing time in the old scoring system and in the new one.

Comparison of the average game playing time

205

Methods In order to establish diﬀerences in average game playing time in the two systems, a total 271 games were analysed. Only the matches from the quarter ﬁnals, semi ﬁnals and the ﬁnals were included. In all, 152 games (36 men’s singles, 40 women’s singles, 37 men’s doubles and 39 women’s doubles games) from the Olympic Games in 2004 were used to represent the old scoring system. A total of 119 games (34 men’s singles, 49 women’s singles, 23 men’s doubles and 13 women’s doubles games) from the Thomas and Uber Cup in 2006 were used to represent the new scoring system. All data were collected from the oﬃcial web pages of the above-mentioned events. To make comparisons across sub-scales of the games, descriptive parameters (mean, standard deviation, minimum, maximum and range) and 99 per cent conﬁdence intervals for the mean for each sub-scale were calculated. Normality of distribution for each variable was tested using KolmogorovSmirnov test. Diﬀerences between average game playing time in the old and new scoring systems were evaluated by t-test. Normality of distributions and diﬀerences between average game playing time were tested at signiﬁcance level of P<0.05. All analysis were done with Statistica, version 7.1.

Results Results of the Kolmogorov-Smirnov test showed that all game playing time data sets were normally distributed. Results of the t-test showed a statistically signiﬁcant decrease in the average game playing time in men’s singles (22.9 vs. 18.4 min) and women’s doubles (22.9 vs. 16.4 min). For men’s doubles there was no signiﬁcant decrease in average duration of the game (20.7 vs. 18.0 min). For women’s singles, a statistically signiﬁcant increase of the average game playing time (14.3 vs. 18.2 min) was found.

Discusion and conclusion The purpose of the study was to compare the old and new scoring systems in badminton based on average game playing time in the Olympic Games in 2004 and the World Team Championships in 2006 for men (Thomas Cup) and for women (Uber Cup). The matches from the quarter ﬁnals to the ﬁnals in both tournaments were chosen because the level of play in the closing stage of both tournaments was similar. A decrease in average playing time in men’s singles was expected and since it is the most popular event the authors believed that the change would be the most prominent. Player concentration was expected to be high in every rally and it was thought to be psychologically more demanding than before. In the old scoring system, women’s singles was the only event that was played to 11 points per game, while the other events were played to 15 points per game, so a statistically signiﬁcant increase of average game playing time

40

37

39

34

49

23

13

OW

OMD

OWD

TCM

UCW

TCMD

UCWD

16.4

18.0

18.2

18.4

22.9

20.7

14.3

22.9

Mean

12.9

14.8

16.5

16.5

19.3

17.8

12.2

19.9

Conﬁdence −99%

19.9

21.3

20.0

20.4

26.5

23.7

16.4

26.0

Conﬁdence +99%

9

11

10

11

10

11

5

9

Minimum

26

37

33

28

46

36

23

34

Maximum

17

26

23

17

36

25

18

25

Range

4.2

5.5

4.6

4.2

8.3

6.6

4.9

6.7

Std.Dev.

Notes: OM = Olympic Games – men; OW = Olympic Games – women; OMD = Olympic Games – men’s doubles; OWD = Olympic Games – women’s doubles; TCM = Thomas Cup – men; UCW = Uber Cup – women; TCMD = Thomas Cup – men’s doubles; UCWD = Uber Cup – women’s doubles

36

OM

Valid N

Table 28.1 Descriptive parameters and conﬁdence intervals for mean playing time (min)

Comparison of the average game playing time

207

Table 28.2 Diﬀerences between mean playing time (min)

OM vs. TCM OW vs. UCW OMD vs. TCMD OWD vs. UCWD

Mean OSS

Mean NSS

Std.Dev. Std.Dev. t-value OSS NSS

df

p

22.9 14.3 20.7 22.9

18.4 18.2 18.0 16.4

6.7 4.9 6.6 8.3

68 87 58 50

0.00 0.00 0.11 0.01

4.2 4.6 5.5 4.2

3.3 −3.9 1.6 2.7

Notes: OSS = old scoring system; NSS = new scoring system

was not unexpected. In this event, players and coaches faced diﬀerent challenges. Since the game is longer the philosophy of the game is diﬀerent, with a stress on players’ stamina. Men’s doubles showed no signiﬁcant decrease in average duration of the game but this could be biased with a small sample of matches that were analysed. This should be examined further on a bigger sample. Unfortunately, the World Team Championship was not an ideal competition for the analysis of doubles because in many team matches the tie would be already decided in single matches and therefore the doubles would not be played at all. Women’s doubles showed a decrease in average duration of the game. This result is very encouraging for the event that was notorious for long durations of play resulting in it being less popular than other events. All events in the new system are of almost equal length, compared to the old system in which some events lasted much longer than the others. This will certainly help the organization of the tournaments and possibly improve live TV coverage of badminton. The growth of sports science and the commercialization of racket sports in recent years have focused attention on improved performance and this has led to a more detailed study and understanding of all aspects of racket sports. Changes in the average game playing time, as shown in this study, should point to changes that will aﬀect physiological, psychological and tactical approaches to training and competition of every event. The authors hope that the changes that were made will help badminton to become more popular without losing its attractiveness for the players worldwide.

References Lees, A. (2003). Science and the major racket sports: a review. Journal of Sports Science, 21, 707–732. Pearce, A.J. (2002). A physiological and notational comparison of the conventional and new scoring system in badminton. Journal of Human Movement Studies, 43, 49–67. www.internationalbadminton.org (last accessed 3 April 2008).

29 Feedback systems in table tennis A. Baca and P. Kornfeind

Introduction According to Farfel’s principle (Farfel, 1977), eﬀective feedback systems applied in training should provide feedback information rapidly and objectively. Powerful information and communication technology simplify the development of sports speciﬁc feedback systems of that kind. Special focus must be put on the acquisition and presentation of performance relevant parameters. In the case of table tennis, factors aﬀecting the quality of the ball played are the spin, the position, where the ball hits the table and the time left for the opponent to react properly (Baca et al., 2004; Hohmann et al., 2004). Systems that give immediate feedback on these performance parameters may assist training. The purpose of this paper is to describe two types of feedback systems which have been built and their applications. The ﬁrst variant is based on the detection of impact positions of the ball on the table, the second on the acquisition of ball impact intervals. Both systems shall direct and condition the technique and, moreover, have a motivational eﬀect in training.

Methods Impact position detection A schematic of the setup is presented in Figure 29.1. A detailed description can be found in Baca and Kornfeind (2004). Four accelerometers (Kistler 8632C10; four-channel ampliﬁer 5134A1; Kistler, Winterthur, Switzerland) are ﬁxed on the underside of one half of the table and connected to an ampliﬁer, which itself is connected to a DAQ-system consisting of a notebook computer and a data acquisition card (NI-6062E, National Instruments, Austin, USA). Vibration signals produced by the ball hitting the table are registered by the four sensors. A trigger impulse, generated from an electronic circuit, starts the recording of a speciﬁed number of samples repeatedly after every ball impact (1000 Samples at 125 kHz). A threshold algorithm

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determines the four instants of time, when the vibration signal arrives at the sensors. Software (LabVIEW®, National Instruments, Austin, USA) has been programmed for this purpose. A triangulation algorithm, which is also implemented in this software, calculates the impact position from the four instants of time. To determine the coordinates of the impact position, xT and yT, only three instants of time are required. The fourth, redundant sensor is used to increase accuracy. A least square method has been selected to determine the impact point coordinates. xT and yT are calculated, which minimize

冱冢冪(x − x )

2

i

i, j

T

2

冣

− (yi − yT)2 + z2i − 冪(xj − xT)2 − (yj − yT)2 + z2j − (ti − tj)v

(i = 1 . . . 4; j = 1 . . . 4; i ≠ j) where xi , yi and zi are the coordinates of the i-th sensor with regard to the table coordinate system, ti, the instants of times, the vibration signal arrives at sensor i (i = 1, . . ., 4), and v is the velocity of signal propagation, which depends on material properties of the table. If metallic parts are coupled to the table top, as is the case for the type of tables used by Baca and Kornfeind (2004), vibration damping material has to be used for a mechanical decoupling of the table top and the metallic parts. Thus, faster signal propagation towards the sensors through the metal resulting in noise signals can be prevented. The program developed displays the reconstructed impact points immediately after the impact. A circle representing the ball is drawn onto the

Figure 29.1 Setup for detection of ball impact positions. S1–S4 denote the positions of the accelerometers ﬁxed on the underside of one half of the table.

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calculated position into a graphic presentation of the table half. In addition, the numerical values of the coordinates are shown (Figure 29.2). An average error of 0.020 ± 0.011 m was obtained by Baca and Kornfeind (2004) within the area of the table at least 0.25 m away from the net. Impact time interval detection A low cost system has been developed to determine time intervals between ball impacts after the serve in table tennis. In the case of long serves the time interval between ﬁrst (own side) and second (opponent’s side) impact is determined. In the case of short serves, the ball bounces on the opponent’s side twice resulting in a second time interval to be calculated. Two microphones are used for recording the acoustic signals caused by the ball impact on the table. Both are ﬁxed in metallic boxes. The boxes are put onto both halves of the table. The signals from the microphones are preprocessed electronically and then fed to a microcontroller (PIC16F628; Microchip, USA), which is also connected to the serial port of a PC, notebook or PDA (Figure 29.3). A LabVIEW® application program acquires the data from the serial port and displays the results on the computer screen. In addition to a numerical presentation of the time intervals a speedometer informs on the player’s performance graphically (Right area – good; Left area – bad; Figure 29.4). The overall system is not bound to a speciﬁc table tennis table and can easily be transported to the environment (table, hall, etc.), where it is used. The system operation is self-controlled. Because of an automated system reset into a ‘wait state’ after a short period without acoustic impact signal, no user intervention is required between successive serves. If connected to two monitors, the system may be used by two players standing on both sides of the table, who serve alternately.

Figure 29.2 Computer screen presenting a series of ball impact positions.

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Figure 29.3 Left: Schematic presentation of the system for calculating impact time intervals. Right: Complete system without PC/PDA.

Figure 29.4 Presentation of impact time intervals. Time 1: First to second impact, Time 2: Second to third impact (short serves only).

Results and discussion Both types of systems have successfully been applied to give feedback in youth training. Usability and system stability were considered satisfactory by the users. Feedback based on impact position detection The feedback system neither disturbs the players nor does environmental noise inﬂuence the system. Feedback on the accuracy of the placement when performing certain tasks may be given. In addition, a series of trials may be evaluated and summary feedback may be given. In a typical application of the system in training a table tennis robot serves the ball in short intervals. The player has to return each ball into a marked area or to return one ball cross and the following into the marked area

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alternately. After each series of trials the player gets visual feedback on the ball impact positions (Figures 29.2 and 29.5). The system may also be used to give feedback on impact positions and impact time intervals in serve training. Players are thereby able to study the variability of diﬀerent serve techniques. Feedback based on impact interval detection Typical exercises performed by the players include the task to minimize the impact intervals in order to decrease the time of the opponent to react properly. Obviously the time interval is strongly aﬀected by the degree of spin of the serviced ball. Youth players utilizing the system in serve training enjoyed this kind of aid and were highly motivated. A kind of competition situation can be observed. A ﬁrst study showed tendencies that training with the system might be useful in shortening the impact time intervals of short services (i.e. Time 2 in Figure 29.4).

Conclusion Rapid feedback systems utilizing powerful sensor and information technology provide innovative and eﬀective support to coaches and athletes. Mighty IT-tools facilitate the development of user-friendly systems, which are specifically oriented towards their needs. In the development of the systems used to give feedback in table tennis special care has been taken to measure and/or calculate the characteristics of interest accurately and to present the results to the users (coaches and athletes) fast and comprehensive. Graphic visualization forms have therefore been implemented in both cases in addition to the presentation of the numerical values (Figures 29.2 and 29.4). It is expected that novel and rapid performance measurement and feedback tools based on modern information technology will become more and more pervasive in daily table tennis training.

Figure 29.5 Feedback training using impact position detecting system.

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References Baca, A. and Kornfeind, P. (2004). Real time detection of impact positions in table tennis. In The Engineering of Sport 5, Vol. 1 (edited by M. Hubbard, R.D. Mehta and J.M. Pallis), Sheﬃeld: ISEA, pp. 508–514. Baca, A., Baron, R., Leser, R. and Kain, H. (2004). A process oriented approach for match analysis in table tennis. In Science and Racket Sports III (edited by A. Lees, J.-F. Kahn and I. Maynard), London: Routledge, pp. 214–219. Farfel, W.S. (1977). Control over Movement in Sport [In German: Bewegungssteuerung im Sport]. Berlin: Sportverlag. Hohmann, A., Zhang, H. and Koth, A. (2004). Performance diagnosis by mathematical simulation in table tennis in left and right handed shakehand and penholder players. In Science and Racket Sports III (edited by A. Lees, J.-F. Kahn, I. Maynard), London: Routledge, pp. 220–226.

30 Practice oriented match analyses in table tennis as a coaching aid R. Leser and A. Baca

Introduction Baca et al. (2004) introduced a process oriented approach to analyse and improve the behaviour of table tennis players. Through reducing the game characterizing parameters of the data collection system to the very essential ones for the coaching process this method was adapted for the implementation in practice. The paper gives an overview of the modiﬁed system and exempliﬁes one possible scenario for using this system to support coaches and athletes in preparing for a competitive opponent (e.g. whilst in a tournament). The basic ideas of the method have also been used to realize a table tennis speciﬁc game analysis software. Some screenshots and explanations describing this tool illustrate how the analysis concept is used in practice. In today’s world of sports, computer-aided video and game analysis programmes have become standard tools for preparing and analysing competitions, and for training use. Lames and Hansen (2001) discuss the methodical way of day-to-day use of such systems for game sports in general, while Dufour (2000) and Leser (2006) give concrete examples of how these systems can be used in soccer and handball. Depending on the approach chosen, the analysis processes focus on diﬀerent criteria. All these concepts share, however, some fundamental elements. The aim of this paper is to illustrate a method for game analysis in table tennis where these fundamental elements are integrated in a proven and tested workﬂow.

Method Figure 30.1 illustrates the procedure for analysing table tennis matches by the method presented in this paper. Matches are recorded on video and, if possible, observed on location. In shooting the video a standard perspective from the long side of the table including an adequate view of the players’ action areas is recommended (see coverage angle in Figure 30.2 from the video window).

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Figure 30.1 Flowchart of applied match analysis in table tennis.

The completed game video is used for quantitative data collection whose results, together with the impressions of the match observer, are proper used in the analysis. Finally the results are translated into a training plan during a video-aided meeting with the player.

Data collection Figure 30.2 shows the data collection screen comprising three areas: form for point information, form for stroke information and video window. Special attention was given to the usability of the system – e.g. using graphical input assistances for some parameters instead of having to write long attribute lists. Only few of the game and performance parameters, which are necessary to describe a table tennis match, have to be gathered manually by mouse action or alternatively by keyboard-shortcut:

• • • •

type of stroke (forehand/backhand, topspin, counter, block, defence, etc.) impact position of the ball on the table instant of service and moment when the point is ﬁnished type of error (out, net, etc.).

All other parameters that are required for the analysis are added automatically after entering some initial information at the beginning of the match respectively from the parameters entered manually (e.g. by marking the type of error on the correct side of the interactive table the system ‘knows’ which team made the point):

216

• • • • • • • •

R. Leser and A. Baca number of set number of point current score number of stroke server receiver length and direction of the stroke (short/long, left/right) winner of the point.

Video capturing and entering the information into the point form may be done during the game. Consequently, video feedback (selective access to all rallies/points) and elementary statistics (regarding to point information) are available immediately after the game. Further analyses (regarding to stroke information) require entering the parameters characterizing each stroke. Since this process is very time consuming it can only be done oﬄine (after the match, using the digital game-video). Depending on the duration of the game this procedure lasts between one and two working hours.

Figure 30.2 Data collection screen.

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Analysis process In the next step, a standard evaluation of the collected data is presented in a clear manner (ﬁgures, tables, diagrams, etc.) that is easily comprehensible for the user. Evaluations relate primarily to some structural features of the match (e.g. distribution of stroke types used) and success and failure-related statistics (e.g. type and number of faults, type and number of scoring strokes, etc.). A comparison of results against reference values allows to ﬁlter diﬀering results automatically and to be studied in greater detail. The diagram in Figure 30.3, for instance, contains the success rate of an athlete (player A) showing that he scored a point in 90 per cent of all rallies he had started with a long service. Assisted by the video feedback tool a qualitative analysis to access the playing pattern of the player/players of interest is performed. Simultaneously, conclusions from the quantitative evaluations are drawn. Figure 30.4, for instance, shows that for this purpose the sequences, relevant for the facts described above (Figure 30.3), were ﬁltered from all rallies (‘Player A serving’ and ‘Player A scoring’) to examine the possible causes of this signiﬁcant result. In addition, attention is paid to any of the on location observer’s assumptions about speciﬁc player actions, and the video is studied intensively to ﬁnd other signiﬁcant scenes. When this process is completed, the subjective discoveries are worded as hypotheses, e.g. ‘The player returns fast topspin strokes to the side very well but he has problems when they are placed in the centre.’ The software tool used for video analysis provides selective access to all

Figure 30.3 Success and failure of player A when starting a rally with his own service.

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Figure 30.4 Video feedback screen.

scenes of interest and has the beneﬁt of saving about two thirds of total video time by replaying only the net playing time as the start and end points of each rally can be accessed directly. This economic aspect is most beneﬁcial when the system is used in situations where little time is available for analysis (e.g. between two rounds of a tournament).

Practical training The ﬁrst step in practical training is a video-aided meeting of the coach with the athlete. Again, the video feedback tool with the above-mentioned beneﬁts can be extremely helpful. However, in order to save time and because intensive study of video content quickly causes fatigue of the central nervous system, the trainer should not use all the video sequences used for the preliminary analysis but rather selected sequences with comments by the trainer (refer to Figure 30.4 for the comment function provided by the software). For didactic reasons, the trainer and player should jointly work out the analysis that is part of the second step and the consequent strategy (e.g. for the match against the next opponent). Concrete instructions that might result from the analysis of the examples given earlier might be, ‘Respond to long services of your opponent as passively as you can because he usually scores on active returns! Then try to place topspin strokes right in the centre!’ If there is enough time between completing the entire match analysis and the next competition, the competition strategy and concrete tactical instructions for the various game situations may be appropriately drilled with practice and playing exercises during the training sessions.

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Summary and outlook The described workﬂow for match analysis can be seen as practice-proven way to support table tennis players with helpful information about game competitions. At the end of this process the results of the analysis are implemented into the training, e.g. positioning fast topspin strokes rather to the middle of the table than to the side. It is expected that the method introduced here combining expert knowledge with a quick and feasible quantitative analyses by using an integrated and eﬃcient game and video analyses tool is very helpful to develop promising competition strategies – future use will show if this process turns out to be useful.

References Baca, A., Baron, R., Leser, R. and Kain, H. (2004). A process oriented approach for match analysis in table tennis. In Science and Racket Sports III (edited by A. Lees, J. Kahn and I. Maynard), London: Routledge, pp. 214–219. Dufour, W. (2000). Computer assisted scouting in soccer. In Science and Football 3 (edited by T. Reilly, J. Bangsbo and M. Hughes), London: E&FN Spon, pp. 160–166. Lames, M. and Hansen, G. (2001). Designing observational systems to support top-level teams in game sports. International Journal of Performance Analysis, 1, 85–91. Leser, R. (2006). Zum Einsatz eines computergestützten Spielbeobachtungssystems im Leistungs-Faustball [The application of computer-generated observations of elite ﬁstball]. Sporttechnologie zwischen Theorie und Praxis IV (edited by K. Witte, J. Edelmann-Nusser, A. Sabo and E. Moritz), Aachen: Shaker, pp. 209–214.

31 Quantitative analysis of playing eﬃciency in squash G. Vucˇ kovic´, B. Dezˇ man, S. Kovacˇ icˇ and J. Persˇ

Introduction A high-level performance in squash depends on many factors or elements of the game, among which appropriate playing tactics are clearly of great importance. It manifests itself in a variety of strokes executed by the player or group of players in a match. Given the great number of diﬀerent strokes and their execution in various parts of the court, a player may select and use diﬀerent strokes in identical or similar circumstances or the same strokes in diﬀerent circumstances. The proper choice of stroke depends on the player’s tactical assessment that leads to the choice of the most eﬃcient stroke in the given circumstances. The scientiﬁc literature abounds with studies dealing with playing tactics in squash. These studies have applied various data collection methodologies based on the notation of diﬀerent tactical indicators obtained by analyses of video recordings. Hong et al. (1996a) and Hughes and Robertson (1998) analysed the structure of strokes in the court divided into a small number of equivalent segments. Similarly, Hong et al. (1996b) and Hughes (1985, 1986) analysed the diﬀerences in patterns of play between players at diﬀerent competitive levels. A more detailed analysis of playing tactics used in squash was provided by McGarry and Franks (1994). They used a stochastic Markov model as a descriptor of empirical athletic behaviour and predictor of future sport performance. McGarry and Franks (1995) used a slightly modiﬁed stochastic model in their subsequent studies. They found that the player’s tactics do not change in a match against the same opponent, which is not true when playing against diﬀerent opponents. The authors reported similar ﬁndings even after they had changed their stroke tracking methodology by taking into consideration the player’s previous stroke besides the stroke of the opponent and by observing the backhand and forehand of each stroke separately (McGarry and Franks, 1996a, 1996b). In spite of the large number of investigated tactical indicators, such studies bring up the question of how accurate is the determination of the stroke location. Most often the problem concerning the accuracy of the result has been resolved by establishing reliability (Wells et al., 2004) and the validity of

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the measurement procedure (repeated determination of the stroke location) which, however, should not be interpreted as measurement accuracy. Moreover, the division of the court has failed to correspond to the playing conditions and the ensuing bouncing of the ball oﬀ all court walls. To avoid the above-mentioned deﬁciencies, our study took into consideration speciﬁc playing conditions (bouncing of the ball oﬀ all walls), which is why the court was divided into 29 segments. The eﬃciency of individual playing tactics was established on the basis of the positioning of all strokes in a two-dimensional space. Therefore, the aim of this study was to establish stroke distribution and, consequently, stroke eﬃciency as well as to investigate diﬀerences in the percentage of strokes executed in speciﬁc segments of the court by two groups of players of diﬀerent quality.

Methods Data was collected during two competitions, the World Team Championship (Vienna, 2003) and the Slovenian National Championship (Ljubljana, 2003). Eleven matches were recorded in both competitions, and the players played until they won their third game. In total, 42 games at the World Team Championship and 44 at the Slovenian National Championship were recorded. As an individual game is in itself a separate part of the match and not related to other games in terms of time or result, all variables were examined at the level of a game and the results of both players (the winner and the loser) were considered. The sample of variables included the number and percentage of strokes in individual segments of the court. Sixteen of the world’s top squash players played in the world championship and 14 top Slovenian squash players in the national championship. All matches were recorded with a ﬁxed SVHS video camera (JBL, UTC – A6000H, Korea) with the frequency of capturing input pictures of 25 Hz. The camera was mounted on the ceiling in the centre of the squash court and its wide-angle lens (JBL, SCV 2982D, Korea) covered the entire court. The wide-angle lens did not aﬀect the measurements (Persˇ et al., 2002). The videorecordings were digitized using the Video DC30+ video digitizer hardware (Miro, Germany) with a resolution of 384 × 576 pixels at a data rate of 2 MB.s−1, while the processing was carried out at a resolution of 384 × 288 pixels. The second camera (Sony, DCR-TRV17E, Japan) was positioned outside the court, a few metres behind the back (glass) wall of the court. It was used to measure the height of individual strokes (the distance between the ﬂoor and the point of striking). The data obtained were entered manually in the Sagit/Squash software. The Sagit/squash tracking system (Vucˇ kovic´ et al., 2004) was used to divide the court into 29 segments (Figure 31.1) to determine the positions of the strokes. Each segment represents one variable. The size of the segments corresponds to speciﬁc playing conditions (bouncing of the ball oﬀ the front,

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Figure 31.1 The court divided into 29 segments.

side and back walls of the court). Canonical discriminant analysis and a oneway analysis of variance with the level of signiﬁcance of P < 0.05 were applied to establish diﬀerences between the groups of players of diﬀerent quality in terms of the percentage of strokes made in an individual segment.

Results Table 31.1 shows the percentage of strokes executed by both groups of players by segment. To allow for better transparency, only those variables were taken into account whose resulting values are normally distributed. All strokes were taken into consideration, less the serves. With the initial stroke, the point of striking is often in the central part of the court and therefore recording these points (strokes) would certainly aﬀect the results and/or the number and percentage of strokes in those segments of the court which are considered disputable from the point of view of playing quality and point to playing imprecision. The world’s top players executed the majority of strokes in segment 26, followed by 27, 25, 4, 2, 3 and 28. In these segments the percentage of strokes exceeded 4 percent. The top Slovenian players also executed the highest percentage of strokes in segment 26. More than 4 percent of all strokes were executed in segments 27, 25, 19 and 28. In both groups of players, the highest number of strokes was recorded in the back area of the court (segments 22, 24, 25, 26, 27, 28 and 29), namely top world players 52.7 per cent and top national players 52.3 per cent of the total. The values of the correlation coeﬃcients show the highest discriminant

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Table 31.1 Percentage of strokes executed by top world (W) players and top Slovenian (N) players by court segment Segment

mean-W

mean-N

F (170)

P (≤ 0.05)

1 2 3 4 9 12 14 16 19 22 24 25 26 27 28 29

3.05 4.68 4.48 5.02 2.36 1.71 3.12 2.90 3.45 1.40 2.71 5.95 25.20 11.12 4.02 2.26

2.40 3.59 2.87 2.94 2.35 2.12 3.05 2.42 5.31 3.29 3.84 7.26 19.42 10.10 4.91 3.46

5.854 7.379 29.572 37.269 0.001 4.289 0.052 4.103 26.622 52.331 19.915 11.490 36.192 2.392 6.571 17.736

0.017 0.007 0.000 0.000 0.971 0.040 0.820 0.044 0.000 0.000 0.000 0.001 0.000 0.124 0.011 0.000

Table 31.2 Results of discriminant analysis in terms of the percentage of strokes executed by both groups of players in various segments of the court Function 1 canonical correlation coeﬃcient % of explained variance Wilks’ lambda Chi-square Degrees of freedom Degree of signiﬁcance

0.756 100.0 0.429 137.114 16 < 0.001

power with the function of segments 3, 4, 19, 22, 24 and 26, while the negative values seen in the variables 19, 22 and 24 show that the nationally ranked players probably executed a higher percentage of strokes in the above segments of the court. The results of the analysis of variance (Tables 31.2 and 31.3) conﬁrm this.

Discussion Despite the fact that players from both groups executed the highest and an almost identical percentage of strokes in the back area of the court, a detailed analysis of the strokes in this part of the court reveals statistically signiﬁcant diﬀerences. The percentage of strokes executed by the world ranked players was statistically signiﬁcantly higher in segment 26 (P < 0.001) and that of the Slovenian players in segments 22, 24, 25, 28 and 29 (P < 0.05, see Table 31.1).

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SCC

1 2 3 4 9 12 14 16 19 22 24 25 26 27 28 29

0.161 0.181 0.361 0.406 0.002 −0.138 0.015 0.135 −0.343 −0.481 −0.297 −0.225 0.400 0.103 −0.170 −0.280

In terms of squash playing tactics, the strokes in the back area of the court consist of the basic tactical principles of defensive play (McKenzie, 1994) which could also be named basic play. In this part of the court the player has the least possibilities of hitting a winning return. It is evident that both groups of players are well aware of this fact, nevertheless, the world ranked players play much more precisely and eﬃciently. Similar results were found when reviewing patterns of play at diﬀerent competitive levels (Hughes, 1986) Such conclusions are underpinned by the statistically signiﬁcant diﬀerence (p < 0.05, see Table 31.1) between the strokes executed in segments 1, 3, 4 and 16 by both groups. Irrespective of the playing tactics the ball has to be hit as closely as possible to the side wall to prevent the opponent from delivering a simple return or even starting an oﬀensive action. Moreover, these segments (3, 4 and 16) are located in that part of the court where the players often execute volleys. The higher percentage of strokes seen in these segments with top players could thus indicate more oﬀensive tactics. In the said (central) part of the court, the nationally ranked players executed the highest percentage of strokes in segment 19. It constitutes a strategic position (T-position) which the player wishes to take at the time the opponent strikes the ball, which is very important from the point of view of playing performance (Vucˇ kovic´ et al., 2004). This group of players recorded a statistically signiﬁcantly higher percentage of strokes in segment 12 (P = 0.040), located in the direct proximity of the abovementioned segment. All this manifests the very ineﬃcient employment of playing tactics by the nationally ranked players. The more aggressive tactics of the top players is manifested in the values for segment 2, which is located in the outermost front left part of the court. The strokes in this segment are correlated with oﬀensive strokes whose

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purpose is either to deliver a winning return or force the opponent to make a mistake. Clearly the higher percentage of strokes of world ranked players (P <0.001) indicates their more oﬀensive playing tactics, which is probably due to their more precise and thus more eﬃcient basic play.

Conclusions It may be concluded from the results that the playing tactics of players of diﬀerent quality are quite similar. Both groups executed the highest percentage of those strokes whose aim was to hit the ball to the back area of the court. Consequently, the highest percentage of strokes was executed in segments located in the back of the court. This points to the fact that players from both groups are aware of the signiﬁcance of the fundamental tactical principles for achieving a high performance, namely that the ball has to be hit as close as possible to the side wall and back corner of the court. Apparently the precision of strokes and related application of individual tactical principles and tactics are the main factors distinguishing the groups of players.

References Hong, Y., Robinson, P.D., Chan, W.K., Clark, C.R. and Choi, T. (1996a). National analysis on game strategy used by the world’s top male squash players in international competition. The Australian Journal of Science and Medicine in Sport, 28, 18–23. Hong, Y., Chang, T.C. and Chan, D.W. (1996b). A comparison of the game strategies employed by national and international squash players in competitive situation by notational analysis. Journal of Human Movement Studies, 31, 89–104. Hughes, M. (1985). A comparison of the patterns of play of squash. In International Ergonomics (edited by I.D. Brown, R. Goldsmith, K. Coombes and M.A. Sinclair), London: Taylor and Francis, pp.139–141. Hughes, M. (1986). A review of patterns of play in squash at diﬀerent competitive levels. In Sport Science (edited by J. Watkins, T. Reilly and L. Burwitz), London: E.&F.N. Spon, pp. 363–368. Hughes, M. and Robertson, C. (1998). Using computerised notational analysis to create a template for elite squash and its subsequent use in designing hand notation systems for player development. In Science and Racket Sports II (edited by A. Lees, I. Maynard, M. Hughes and T. Reilly), London: E.&F.N. Spon, pp. 227–234. McGarry, T. and Franks, I.M. (1994). A stochastic approach to predicting competition squash match-play. Journal of Sports Sciences, 12, 573–584. McGarry, T. and Franks, I.M. (1995). Modelling competitive squash performance from quantitative analysis. Human Performance, 8, 113–129. McGarry, T. and Franks, I.M. (1996a). In search of invariant athletic behaviour in sport: an example from championship squash match-play. Journal of Sports Sciences, 14, 445–456. McGarry, T. and Franks, I.M. (1996b). Development, application and limitation of a stochastic Markov Model in explaining championship squash performance. Research Quarterly for Exercise and Sport, 67, 406–415.

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McKenzie, J. (1994). Beyond the Basics: Excelling at Squash. London, Sydney, Auckland: Hodder and Stoughton. Persˇ, J., Bon, M., Kovacˇ icˇ , S., Sˇ ibila, M. and Dezˇ man, B. (2002). Observation and analysis of large-scale human motion. Human Movement Science, 21, 295–311. Vucˇ kovic´, G., Dezˇ man, B., Ercˇ ulj, F., Kovacˇ icˇ , S. and Persˇ, J. (2004). Monitoring the time and frequency of players staying on the basic T-position in squash. In Science and Racket Sports III (edited by A. Lees, J.-F. Khan and I. Maynard), London: Routledge, pp. 208–213. Vucˇ kovic´, G., Dezˇ man, B., Ercˇ ulj, F., Kovacˇ icˇ , S. and Persˇ, J. (2005). Position error analysis of Sagit/squash system in manual stroke annotation. In Proceedings of the 10th Annual Congress of the European College of Sport Science, Belgrade, Serbia, pp. 265. Wells, J., Robertson, C., Hughes, M. and Howe, D. (2004). Performance proﬁles of elite men’s squash doubles match-play. In Science and Racket Sports III (edited by A. Lees, J.-F. Khan and I. Maynard), London: Routledge, pp. 196–201.

32 A comparison of whole match and individual set data in order to identify valid performance indicators for real-time feedback in men’s single tennis matches H. J. Choi, P.G. O’Donoghue and M.D. Hughes Introduction Within performance analysis of sport, discriminations between winning and losing teams have been used to identify the key performance indicators in particular sports such as football (Choi et al., 2006a), badminton (Blomqvist et al., 1998; Hong and Tong, 2000) and basketball (Tina, 1998; Evangelos et al., 2005; Tavares and Gomes, 2003). The selection of the most valid performance indicators is also important when performance analysis is used within coaching contexts. Performance indicators in the ﬁeld of performance analysis of sport (Hughes and Bartlett, 2002) are valid elements that explain the performances of successful performers within matches. Outcome indicators (Hughes and Bartlett, 2002) are rationally useful for coaches to evaluate performances and to plan and conduct further training for athletes. In recent years, performance indicators have been selected and utilized in the analysis of sports performances in order to enhance the performance of individuals and teams (Hughes and Franks, 2004). Performance indicators have traditionally been derived from the data for whole matches, which include periods of matches where successful teams may have been performing worse than unsuccessful teams (Choi et al., 2006b). The fact that winners do not perform better than losers in all subsections of matches means that some valid performance indicators will not be recognized when using whole match data to determine the factors distinguishing between winning and losing performances. In tennis, in particular, performance within the whole match would not always be reﬂected within each set of the match. Therefore, the consideration of valid performance indicators needs to use smaller separated time scales, such as sets in tennis, in order to discriminate winning and losing performances. The identiﬁcation of valid performance indictors within the valid sets of data is an important step in establishing the construct validity of performance indicators. The purpose of this study was to determine use both whole match data as well as match section data to

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establish the performance indicators that most discriminated between winning and losing performers.

Methods The results of tennis matches in the men’s singles event of the 2005 Wimbledon Tennis championship were used within the current investigation. There were 127 matches in total, but the data included in this study was from 126 matches because one match was missing from the oﬃcial web site of Wimbledon Tennis championship (IBM Corp., 2005). Two data sets were produced from the statistics reported on the oﬃcial tournament website; one based on whole match performances and the other based on individual set performances. SPSS version 12.0 was used to perform statistical tests on the data. The following performance indicators were recorded for winning and losing performers within each match and within each set of the 126 matches included in the current investigation. 1 Total numbers of participations within the Wimbledon tennis championship 2 World ranking 3 per cent of 1st serves that were in 4 Number of aces 5 Number of double faults 6 Number of unforced errors 7 per cent of points won when 1st serve was in 8 per cent of points won when relying on a 2nd serve 9 Number of winners played 10 Number of points played when receiving serve 11 Number of break points played 12 per cent of points where the net was approached. A series of Wilcoxon Signed Ranks tests were used to compare winning and losing performers within the matches of the whole match data and within the sets of the individual set data.

Results Within the 126 matches, there were 446 individual sets of tennis. Table 32.1 summarizes the performances of the match winners within each data set. There were a considerable number of individual sets in which the match winners were not successful. All of the performance indicators were signiﬁcantly diﬀerent between the winning and losing performances in both data sets except for the per cent of successful ﬁrst serves within the whole match data set (z = −0.568, P > 0.05). The level of signiﬁcance of the diﬀerences found between winning and

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Table 32.1 Summary of the winning and losing performances Whole match data Winning performances

Individual set data Losing performances

Winning performances

Losing performances

Won

126

0

288

158

Lost

0

126

158

288

Total

126

126

446

446

Table 32.2 The results of the Wilcoxon Signed Ranks test Whole data

Total numbers of participations World ranks of players % of 1st serves in Aces Double faults Unforced errors %won on 1st serve %won on 2nd serve Winners Received points Break points % of net approaches

Individual Data

Z value

P

Z value

P

−1.67906a −4.88121a −0.56816 −5.38446a −2.18558a −4.37713a −8.5329a −7.38885a −6.73284a −9.39056a −6.0432a −5.52837a

0.09 <0.01 0.57 <0.01 0.03 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

−2.18722a −5.76249a −2.77023a −7.818a −4.33034a −8.21245a −14.1653a −12.0444a −11.1387a −16.4804a −12.6664a −7.45767a

0.03 <0.01 0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Note: a Signiﬁcant diﬀerence found

losing performers was greater in the individual set data than in the whole match data for all performance indicators.

Discussion Signiﬁcant diﬀerences between the winning and losing performances revealed by the Wilcoxon Signed Ranks tests have often been used in order to determine the key performance indicators to be used (Choi, 2004; Choi et al., 2006b; Choi et al., 2006c; O’Donoghue, 1998). The current investigation has used the same approach except with individual set data. Although most of the performance indicators signiﬁcantly distinguish winning and losing performances, it is not possible to collect all performance indicators during real time match analysis. Therefore, it is important to recognize the subset of key performance indicators (Tina, 1998; Hughes and Bartlett, 2002). The use of individual set data provides a diﬀerent priority order of the performance

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indicators than if whole match data was used; for instance the most discriminating indicator in the individual set data was the percentage of points won on second serve which was diﬀerent to break points which was the third most important indicator according to the whole match data. This shows that using whole match data can provide a distorted picture of the relative importance of performance indicators. It has been suggested that statistical analysis can prioritize performance indicators when only a few can be incorporated into a real-time system (Choi et al., 2006b; Choi et al., 2006c). It is recommended that such decisions are not based on whole match data that conceal winning performances within match sub-sections. The approach recommended in the current research should be used along with other approaches to improving the quality of performance indicators. Such an approach is the dimensionalizing of performance indicators; for example the productivity of possessions of diﬀerent numbers of passes in soccer is best determined by relating the number of opportunities for each type of possession to the total number those possessions that occur. The current research used broad sub-sections of tennis matches (sets), but further research should look at ﬁner sequences of play in order to be fully representative of successful passages of play. The selection of key performance indicators (Choi et al., 2006b), in addition, has already emphasized the application of those key performance indicators within real-time analysis (Choi et al., 2006b). This supports real-time feedback within a match due to the feasibility of gathering data for a small but highly valid subset of performance indicators.

Conclusions The individual set data reveals a greater discrimination between winning and losing performances for each performance indicator than the whole match data. The order of importance of the performance indicators is also diﬀerent when using individual set data meaning that diﬀerent decisions will be made about the most valid performance indicators when using individual set data.

References Blomqvist, M., Luhtanen, P. and Laakso, L. (1998). Validation of a notational analysis system in badminton. Journal of Human Movement Studies, 35, 137–150. Choi, H.J. (2004). A study of formations and roles of gender between winning and losing team in an international level of mixed double badmintons. MSc. Dissertation, Cardiﬀ: University of Wales Institute. Choi, H.J., Kim, J.H. and Lee, W.H. (2004). The analysing system of broadcasting in real time. In Performance Analysis of Sport VI (edited by P. O’Donoghue and M.D. Hughes), Cardiﬀ: Centre for Performance Analysis, UWIC, pp. 245–252. Choi, H.J., Kim, J.H., Kim, J.H., Hong, S.J. and Hughes, M. (2006a). A study of valid contents for an evaluation of team performance in Soccer. In Performance Analysis of Sport 7 (edited by H. Dancs, M. Hughes, and P.G. O’Donoghue), Cardiﬀ: CPA, UWIC, pp. 90–97

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Choi, H.J., O’Donoghue, P. and Hughes, M. (2006b). A study of team performance indicators by separated time scale using a real-time analysis techniques within English national basketball league. In Performance Analysis of Sport 7 (edited by H. Dancs, M. Hughes, and P.G. O’Donoghue), Cardiﬀ: CPA, UWIC, pp. 125–128. Choi, H.J., Reed, D., O’Donoghue, P. and Hughes, M. (2006c). The valid numbers of performance indicators for real-time analysis using prediction models within men singles in 2005 Wimbledon Tennis Championship. In Performance Analysis of Sport 7 (edited by H. Dancs, M. Hughes, and P.G. O’Donoghue), Cardiﬀ: CPA, UWIC, pp. 207–213. Evangelos, T., Alexandros, K. and Nikolaos, A. (2005). Analysis of fast breaks in basketball. eIJPAS, 5, 17–22. Hong, Y. and Tong, Y. M. (2000). The playing pattern of the world’s top single badminton players in competition: a notation analysis. Journal of Human Movement Studies, 38, 185–200. Hughes, M. and Bartlett, R. (2002). The use of performance indicators in performance analysis. Journal of Sports Sciences, 20, 739–754. Hughes, M. and Franks, I. M. (2004). Notational Analysis of Sport (2nd edn). London: Routledge. IBM Corp. (2005). The Championship, Wimbledon 2005 – Grand Slam Tennis – Oﬃcial site by IBM. http://www.wimbledon.org (last accessed 4 April 2008). O’Donoghue, P. (1998). Notational analysis of rallies in European club championship badminton. In Notational Analysis of Sport IV (edited by M. Hughes and F. Tavares), Portugal: Centre for Team Sports Studies, University of Porto, pp. 225–228. Tavares, F. and Gomes, N. (2003). The oﬀensive process in basketball: a study in high performance junior teams. eIJPAS, 3, 34–39. Tina, P. (1998). Performance indicators of basketball: a study of their impact for winnings. In Notational Analysis of Sport IV (edited by M. Hughes and F. Tavares), Portugal: University of Porto, pp. 123–126.

33 Variability in men’s singles tennis strategy at the US Open P.G. O’Donoghue

Introduction Variables used in performance analysis have some key diﬀerences to those used in other sports science disciplines. In kinanthropometry for example, variables such as height, body mass and even ﬁtness test performances are relatively stable with changes occurring only over long-term periods. Variables used in performance analysis, on the other hand can vary considerably from match to match as well as within the same match (O’Donoghue, 2004). The main source of variability in performance is opposition eﬀects (McGarry and Franks, 1994), with other sources of variability in performance including scoreline eﬀects within games (Shaw and O’Donoghue, 2004) and match venue (Devlin et al., 2004). Further evidence of match to match variability was provided by an exercise that compared independent samples of tennis players from diﬀerent regions (Wells et al., 2004). When each player’s performance was represented by a single match, there was much greater within sample variance than when two, three, four or ﬁve matches were used to derive a typical performance for each player. It is worth considering the diﬀerences between performance indicators (Hughes and Bartlett, 2002) in sports performance and variables. All performance indicators are variables but not all variables are performance indicators. In other disciplines such as computer science, performance indicators are individual raw measurements or metrics derived from combinations of raw measurements (Jain, 1991) that have the following metric properties (Bevan et al., 1991): 1 2 3

There is an objective measurement procedure. The measure is a valid of the aspect of performance of interest. There must be a means of interpreting the values made using the measurement.

These properties, together with reliability, are essential for a sports performance variable to be considered a performance indicator. Even when performance indicators possess these properties, values are often unrepresentative

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of typical player or team performances. Sometimes this is not an issue as the purpose of a performance analysis exercise might be to report on an individual performance. However, for scientiﬁc purposes unrepresentative data can eﬀect the conclusion of a study (Wells et al., 2004). The purpose of the current paper is to explore the nature of variability in sports performance. The example performance indicator used is the percentage of points where a player goes to the net. The scope of the paper will be restricted to men’s singles tennis at the US Open between 2002 and 2005 inclusive.

Methods Matches The percentage of points where a player went to the net was used as an indicator of strategy within the current study. Data from 319 US Open men’s singles matches played between 2002 and 2005 inclusive were gathered from the match statistics pages of the oﬃcial tournament website (www.usopen.org, accessed on 9/9/2002, 8/9/2003, 13/9/2004, 12/9/2005) allowing the percentage of points that each player went to the net within each match included to be determined. Matches were included if they were completed without players withdrawing or being disqualiﬁed and if the number of net points was included in the match statistics provided on the oﬃcial tournament website. This provided a total of 638 values for 171 diﬀerent players. Reliability The 2002 US Open men’s singles ﬁnal between Pete Sampras and Andre Agassi was observed by the author with points being recorded as net points where a player crossed the service box line and there was at least one more shot played during the rally. The author’s totals of 105 net points for Pete Sampras and 13 for Andre Agassi agreed with the totals reported for in the match statistics on the oﬃcial tournament internet site. There was also agreement that the match contained 277 points. Data processing The frequency of net points played by the winning and losing players and the total number of points played in the match was recorded for each match allowing the percentage of net points to be determined for the winning and losing players within the match. These 638 values from the 319 matches did not come from 638 diﬀerent players but from 171 individuals. Therefore, the values recorded were arranged into sets for the 171 individual players. A record summarizing the percentage of net points was produced for each player. This record consisted of the player name, the number of matches he

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played in within the data set, the mean percentage of net points played and the standard deviation of net points played. Analysis of variability Intra-player variability was evaluated using the sets of values for the four players who played more than 15 matches within the data set. Table 33.1 shows that in each case the player’s values were normally distributed (−1.96 < zSkew < +1.96; −1.96 < zKurt < +1.96). The mean and standard deviation for the percentage of points where each player went to the net was determined for these players. Inter-player variability was evaluated using the mean values recorded for each of the 171 players in the data set. The distribution of the player mean for percentage of net points was positively skewed (zSkew = +7.31) and lepokurtic (zKurt = +3.91). However, the distribution of the player mean for the natural logarithm of the percentage of net points was normal (zSkew = +0.64, zKurt = +0.38). Pearson’s r was used to explore if there was any association between various derivatives of the mean and standard deviation for players’ percentage net points. This was done using the data for those 42 players who had played ﬁve or more matches within the data set. The coeﬃcient of determination, r2, indicated the proportion of the standard deviation that was explained by any derivative of the mean. Regression analysis was then done to model the standard deviation in terms of the mean.

Results The mean value for percentage net points for the 171 players was determined and was found to be positively skewed (15.95±9.17 per cent, zSkew = +7.31, zKurt = +3.91). Figure 33.1 illustrates the leptokurtic nature of the variable as well as the positive skew that exists. However, the natural logarithm of player mean values was found to be normally distributed (2.62±0.54, zSkew = +0.64, zKurt = +0.38). The mean and standard deviation (SD) of the percentage of points a player went to the net was determined for the 42 players who were involved in Table 33.1 Skewness and kurtosis of percentage net points for the four players who played in more than 15 matches Player

Matches

zSkew

zKurt

Andre Agassi Roger Federrer Leyton Hewitt Andy Roddick

24 19 23 18

+0.05 +0.23 +0.73 +0.72

+0.17 −1.74 −0.59 −0.19

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Figure 33.1 Distribution of percentage net points for diﬀerent players.

Figure 33.2 Relationship between the mean and SD for percentage net points.

ﬁve or more matches within the data set. A relationship was found between the natural logarithm of the mean and the standard deviation (SD = −3.93 + 3.50 ln(Mean), r2 = 0.487) with no relationship between ln(Mean) and residual values (r = 0.000) and the residuals being normally distributed (0.00±1.66, zSkew = +1.25, zKurt = −0.30). Figure 33.2 shows the relationship between the mean and SD. Thirty nine of these 42 players had a lower intraplayer SD than the inter-player SD of 9.17 per cent. The data for the four players who played 15 or more matches of the data set is summarized in Table 33.2.

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236

Table 33.2 Percentage of points where four players went to the net during a series of men’s singles matches at the US Open between 2002 and 2005 inclusive Player

Matches

Mean

Standard Deviation

Andre Agassi Roger Federrer Leyton Hewitt Andy Roddick

24 19 23 18

6.87 18.89 11.53 11.45

2.36 6.42 4.78 4.48

Discussion and conclusion The current investigation has provided evidence that there is less intra-player variability for the percentage of net points in men’s singles tennis at the US Open players than inter-player variability. This is not the case for all performance indicators in all sports, as O’Donoghue (2004) provided examples of one soccer player (David Beckham) whose work rate varied between matches more than that of the player means between diﬀerent midﬁelders and another soccer player (Michael Owen) whose variability in work rate within the same match was comparable with the variability in player mean work rate between diﬀerent players. However, the inter- and intra-player variability for this indicator of player strategy is distributed in fundamentally diﬀerent ways. Match to match variability within individual players is normally distributed in contrast to the skewed distribution between diﬀerent players. This information should be taken into account when evaluating player performances from individual matches. Knowledge of inter-player and intra-player distributions for the values of performance indicators allow realistic synthetic data to be produced. There are legitimate purposes of synthesizing data, especially where investigations are testing proﬁling techniques (O’Donoghue and Ponting, 2005). Such investigations purposely and openly use synthetic data because the volume of data required cannot feasibly be collected though observational techniques or even from internet sources. A performance indicator may require over 30 matches to stabilize (Hughes et al., 2001) but a tennis player will play a maximum of seven singles matches at a given Grand Slam tournament each year. The analysis undertaken of inter-player and intra-player variability in percentage net points has allowed a procedure for synthesizing realistic data to be devised. The steps of the procedure are described as follows: 1

2

Randomly determine the natural logarithm for the player’s mean value. This is done by ﬁrst generating a random probability (between 0 and 1) and looking up the associated z-score from the standard normal distribution. Second, the ln(mean value) value is calculated as being 2.62 + 0.54 z. The exponential of ln(mean value) will be the player’s mean value for

Variability in men’s singles tennis strategy

3 4

5

237

percentage net points. The ﬁrst two steps need to be repeated if a value of less than 0 per cent or greater than 100 per cent is produced. The expected SD for the player’s value will be determined from the regression equation; SD = −3.93 + 3.50 ln(mean value). The actual SD for the player will be synthesized by determining a random residual value and adding this to the expected SD. First, a random probability (between 0 and 1) is produced and the associated z-score is looked up from the standard normal distribution. Second, the residual is determined as being 1.66 z. Third, the actual SD will be the sum of the expected SD and the residual. This step needs to be repeated if a SD of less than 0 per cent is produced. A random value for percentage net points can now be synthesized for an individual match for the synthetic player. First, a random probability (between 0 and 1) is produced and then the associated z-score from the standard normal distribution is used; individual performance value = player’s mean value + z × player’s SD. This step needs to be repeated if a value of less than 0 per cent or greater than 100 per cent is produced.

There are a number of diﬀerent studies that can be undertaken using data that can be synthesized using the kind of procedure described here. First, the eﬀect of limited reliability on the results of investigations can be determined. Reliability is a critically important issue in performance analysis (Hughes et al., 2004). This is not only the case in scientiﬁc research but also in coaching contexts where player, coach and team decisions need to be supported by reliable data (O’Donoghue and Longville, 2004). The additional variability due to measurement error may mean that a signiﬁcant diﬀerence is produced. Therefore, any signiﬁcant result found in the presence of measurement error is one in which there can be conﬁdence. Synthetic data can be used to represent true values for athletes as well as measured values that synthesize the eﬀect of measurement error. The results of inferential statistical procedures can be compared when applied to synthesized true and synthesized measured values. Future investigations should analyse the impact of measurement error in independent sample comparisons, related sample comparisons and correlation studies. A second area for future research is the eﬀect of using unrepresentative data. Wells et al. (2004) used real performance data to show the impact of using individual and multiple match data to derive values for players within a study. Using synthetic data would allow greater investigation of this problem. For diﬀerent types of performance indicator it would be useful to understand how many matches are required to produce a typical proﬁle for a player. The combined eﬀects of limited reliability of measurement and unrepresentative data can also be investigated using synthetic data. In conclusion, player strategy in tennis can be indicated by the percentage of points where they go to the net. The value for this performance indicator is inﬂuenced by the player’s typical strategy but also by individual match eﬀects especially opposition eﬀects. The amount of between-player variability is

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greater than within-player variability for most players. The distribution of this performance indicator is normal for an individual player’s performances but is not normal between diﬀerent players.

References Bevan, N., Kirakowski, J. and Maissel, J. (1991). What is usability? In Human Aspects in Computing: Design and use of Interactive Systems with Terminals (edited by H.-J. Bullinger), Amsterdam: Elsevier, pp. 651–654. Devlin, G., Brennan, D.A. and O’Donoghue, P.G. (2004). Time–motion analysis of work-rate during home and away matches in collegiate basketball. In Performance Analysis of Sport 6 (edited by P.G. O’Donoghue and M.D. Hughes), Cardiﬀ: CPA, UWIC, pp. 174–178. Hughes, M. and Bartlett, R. (2002). The use of performance indicators in performance analysis. Journal of Sports Sciences, 20, 739–754. Hughes, M., Evans, S. and Wells, J. (2001). Establishing normative proﬁles in performance analysis. International Journal of Performance Analysis of Sport (e), 1, 4–27. Hughes, M., Cooper, S.M. and Nevill, A. (2004). Analysis of notation data: reliability. In Notational Analysis of sport, 2nd edn (edited by M. Hughes and I.M. Franks), London: Routledge, pp. 189–204. Jain, R. (1991). The Art of Computer Systems Performance Analysis: Techniques for Experimental Design, Measurement, Simulation and Modelling, New York: Wiley. McGarry and Franks, I.M. (1994). A stochastic approach to predicting competition squash match-play. Journal of Sports Sciences, 12, 573–584. O’Donoghue, P.G. (2004). Sources of variability in time–motion data; measurement error and within player variability in work-rate. International Journal of Performance Analysis of Sport(e), 4(2), 42–49. O’Donoghue, P.G. and Longville, J. (2004). Reliability testing and the use of statistics in performance analysis support: a case study from an international netball tournament. In Performance Analysis of Sport 6 (edited by P.G. O’Donoghue and M.D. Hughes), Cardiﬀ: CPA, UWIC, pp. 1–7. O’Donoghue, P.G. and Ponting, R. (2005). Equations for the number of matches required for stable performance proﬁles. International Journal of Computer Science in Sport(e), 4(2), 48–55. Shaw, J. and O’Donoghue, P.G. (2004). The eﬀects of scoreline on work-rate in amateur soccer. In Performance Analysis of Sport 6 (edited by P.G. O’Donoghue and M.D. Hughes), Cardiﬀ: CPA, UWIC, pp. 84–91. Wells, J., O’Donoghue, P.G. and Hughes, M.D. (2004). The need to use representative player data from multiple matches in performance analysis. In Performance Analysis of Sport 6 (edited by P.G. O’Donoghue and M.D. Hughes), Cardiﬀ: CPA, UWIC, pp. 241–244.

34 Time analysis of three decades of men’s singles at Wimbledon H. Takahashi, T. Wada, A. Maeda, M. Kodama, H. Nishizono and H. Kurata

Introduction Tactics are an important factor in racket sports. The main characteristics of racket sports are continuous play and changing situations. Match analysis contributes to tactical coaching. Hughes (1994) outlined one of the purposes of notation as ‘tactical evaluation’. Franks et al. (1983) also showed that a computerized system can be used for the purpose of gaining immediate feedback and the development of a database. A computerized system provides beneﬁts for tactical coaching. Although computerized systems have been developed by some researchers (Kudo, 1995; O’Donoghue and Ingram, 2001), these systems are not in common use. The authors developed a new computerized scorebook for tennis. The characteristic of the scorebook was in getting a time factor immediately. The scorebook can analyse not only the frequency of shots and classiﬁcations of results but also time duration of playing, time duration of out-of-play and the time duration of each shot. Historical comparison of match analysis is important on tactical coaching. There is some research about match analysis. The tactical diﬀerence among court surfaces were reported by O’Donoghue and Ingram (2001) and O’Donoghue and Liddle (1998). These are not historical researches. A historical comparison of physical factor was reported by Kovacs (2004). The purpose of this study was to clarify the historical characteristics of playing time in tennis using a computerized scorebook for tennis.

Methods Data collection Data were collected from Wimbledon ﬁnals held in 1980, 1981, 1993, 1994, 2004 and 2005. All of the players were ranked number one or two in world ranking at that time. Those matches were deﬁned as a group of 80s (1980 and 1981), 90s (1993 and 1994) and 00s (2004 and 2005). The number of points of all matches was 1,593.

240 H. Takahashi, et al. Computerized scorebook for tennis The computerized scorebook for tennis was developed by the authors. It records a time factor using the internal computer clock in 1/100s intervals. The scorebook records time data when the scorer clicks a shot button at the same time as a player contacts the ball. Time data can clarify the timing of tennis such as time duration per point, time duration of shots and time duration between points. The accuracy of time duration of shots was veriﬁed by Takahashi et al. (2006). The error between the data from the scorebook and the data from the recording of high-speed video was veriﬁed by a onesample t-test. The null hypothesis was rejected at the 95 per cent limits of agreement. The average error was 0.003 ± 0.05 s. In order to record the data accurately the scorer needs to be well trained in its operation and to be able to see the match clearly. Data analysis The scorebook was used for data collection. The scorer recruited for this study was a member of the developing team of the scorebook and adequately trained on scorebook operation. The matches were recorded broadcasts. The scorer could see the matches clearly. Timing data were obtained from the scorebook: time duration per point, rally numbers per point, time duration of service, time duration of ground stroke and time between points. Time duration per point was deﬁned as the time between the impact of service and the impact of the last shot. Rally numbers per point were deﬁned as shot numbers from the service to last shot of point. Service aces were deﬁned as rallies of one shot. The faults of service were deﬁned as rallies of zero shots and was excluded from the analysis. Time duration of service was deﬁned as the diﬀerence between the clock time of return of service and the time of service. Time duration of ground strokes was deﬁned as the diﬀerence between the time of shot by one player and another. This was only calculated when both players played ground strokes. Time between points was deﬁned as the diﬀerence between the time of ﬁrst service and the time of last shot of previous point. The time of changing ends was excluded from the analysis. Timing data were compared by groups of the matches. An ANOVA test was used to compare those timing data between groups of the matches, and Tukey’s HSD test was used for pair-wise comparisons. The limitation of this study was that the data came from three groups of two matches. It was not independent as required by the ANOVA test.

Time analysis of three decades of men’s singles 241

Results Time duration per point A comparison of time duration per point among match groups is shown in Figure 34.1. The numbers shown in the columns are the point numbers (or shot numbers) of the groups. This applies to all the ﬁgures. Signiﬁcant diﬀerences existed between 00s and other groups. Time duration per point was longest in the 00s.

Figure 34.1 A comparison of time duration per point among match groups. Note: **p<0.01

Figure 34.2 A comparison of rally length per point among match groups. Note: **p<0.01

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Rally length per point A comparison of rally length per point among match groups is shown in Figure 34.2. Signiﬁcant diﬀerences existed among all match groups. Rally length per point was longest in the 00s and shortest in the 90s. Time duration of service A comparison of time duration of ﬁrst service among match groups is shown in Figure 34.3. Signiﬁcant diﬀerences existed between the 80s and other groups. Time duration of ﬁrst service was longest in the 80s. A comparison of time duration of second service among match groups is shown in Figure 34.4. Signiﬁcant diﬀerences existed among all match groups. Time duration of second service was longest in the 80s and shortest in the 90s. Time duration of ground strokes A comparison of time duration of ground strokes among match groups is shown in Figure 34.5. Signiﬁcant diﬀerences existed between the 00s and other groups. Time duration of ground stroke was shortest in the 00s. Time between points A comparison of time between points among match groups is shown in Figure 34.6. Signiﬁcant diﬀerences existed between all match groups. Time between points was longest in the 90s and shortest in the 00s.

Figure 34.3 A comparison of time duration of ﬁrst service among match groups. Note: **p<0.01

Time analysis of three decades of men’s singles 243

Figure 34.4 A comparison of time duration of second service among match groups. Note: **p<0.01

Figure 34.5 A comparison of time duration of ground stroke among match groups. Note: **p<0.01

Discussion Time duration and rally numbers per point Time duration and rally numbers per point was longest in the 00s. Rally numbers became longer, time duration per point became longer. Several reports showed time duration per point at Wimbledon. O’Donoghue and Liddle (1998) reported that time duration per point was 3.69 ± 2.54 s in the 1996 tournament. O’Donoghue and Ingram (2001) reported that time duration per point was 4.3 ± 1.6 s in the 1997 and 1998 tournaments. In this

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Figure 34.6 A comparison of time between points among match groups. Note: **p<0.01

study, it was 2.70 ± 3.22 s in the 90s and 3.99 ± 4.00 s in the 00s. Time duration per point became longer from the middle of the 1990s. Time duration and rally numbers per point on grass courts were shorter than other court surfaces (O’Donoghue and Ingram, 2001). However, these indicators became longer in the 00s. The rule about the ball was changed by International Tennis Federation (ITF) in 2002. It regulated that the type 3 ball, high bouncing and slower, was used on grass courts. It inﬂuenced the results of time duration and rally numbers per point in the 00s. Time duration of service and ground stroke Time duration of the ﬁrst service was shorter in the 90s and the 00s than in the 80s. Time duration of the second service was shortest in the 90s and longest in the 80s. It is aﬀected by the innovation of rackets and also changing ball regulations. In the matches of the 90s, the rate of service winner was 16.5 per cent and rally numbers per point was shorter than in the 80s. It conﬁrmed players selected ‘serve-and-volley’ in the 90s. Players needed a strong service for ‘serve-and-volley’. On the other hand, time duration of the ﬁrst service was not signiﬁcantly diﬀerent between the 90s and the 00s. However, the rate of service winner was decreased in the 00s (9.3 per cent). It is considered that the players’ ability of service return was improved in the 00s. This inﬂuenced the decrease of ‘serve-and-volley’ in the 00s. Time duration of ground stroke was shortest in the 00s. Rally numbers per point were also highest in the 00s. Players needed eﬀective baseline-play in the 00s. It is considered that ball speed of ground stroke became faster and players played ground strokes inside the baseline in the 00s. These are aﬀecting both point-winning and time duration.

Time analysis of three decades of men’s singles 245 Time duration of shot was inﬂuenced by the ball speed, direction of shots and hitting position. So, time duration of shot evaluates the tactical validation of each shot. It is considered a new approach for evaluating player’s performance. Time between points Time between points was shortest in the 00s. The rule about continuous play had changed several times. It was determined in 1991 that the time between points should not at any time exceed 25 s. Furthermore, it was changed to 20 s in 1994. Results showed that players obeyed the rule about time between points. In the matches of 00s, time duration and rally numbers per point were longest and time between points was shortest. This indicates that players’ physical load becomes higher. Players used the maximum time interval between points. It is considered that players attempt to recover physical strength during interval time. In the 00s, results showed that many points took intervals over 20 s. This was inﬂuenced by the deﬁnition of time between points. In this study, time between points was deﬁned as the diﬀerence between the time of ﬁrst service and the time of last shot of previous point. On the other hand, the rules of tennis deﬁne that the ball is in play from the moment the server hits the ball and until the point is decided. The diﬀerence between these deﬁnitions aﬀected the results of this study.

Conclusions Over the years, time factors changed historically in the Wimbledon ﬁnals. From 80s to 00s, time duration per point became longer, time duration of shot became shorter and time between points became shorter. Players have needed increased physical strength in recent years. A computerized scorebook for tennis is useful for analysing time factors. In particular, the time duration of shots evaluates the tactical importance of each shot. This is considered a new approach for evaluating player’s performance.

References Franks, I. M., Goodman, D. and Miller, G. (1983). Analysis of performance: qualitative or quantitative. Science Periodical on Research and Technology in Sport, March, 1–8. Hughes, M. (1994). Computerised notation of racket sports. In Science and Racket Sports (edited by T. Reilly, M. Hughes, and A. Lees), London: E&FN Spon, pp. 249–256. Kovacs, M. (2004). A comparison of work/rest intervals in men’s professional tennis. Medicine and Science in Tennis, 9, 10–11.

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Kudo, T. (1995). Development of score system for singles match: Tean.exe (Tennis analyzer for singles). In Proceedings of the First Asian Congress of Tennis Science, pp. 7. O’Donoghue, P. and Ingram, B. (2001). A notational analysis of elite tennis strategy. Journal of Sports Sciences, 19, 107–115. O’Donoghue, P. and Liddle, D. (1998). A notational analysis of time factors of elite men’s and ladies’ singles tennis on clay and grass surfaces. In Science and Racket Sports II (edited by A. Lees, I. Maynard, M. Hughes and T. Reilly), London: E&FN Spon, pp. 241–246. Takahashi, H., Wada, T., Maeda, A., Kodama, M., Nishizono, H. and Kurata, H. (2006) The relationship between court surface and tactics in tennis using a computerized scorebook for tennis. In Proceedings of World Congress of Performance Analysis, pp. 595–603.

Part 5

Pedagogy, sociology and coach education in racket sports

35 New perspectives and research applications in tennis M. Crespo

Introduction Tennis is a sport played by more than 60 million people worldwide in more than 200 countries. It is one of the top individual sports and racket sports and has a long tradition as international and Olympic sport (ITF, 2006). Sport science based research focusing on tennis has been discussed previously (Crespo, 2004) and it has stated that research in tennis is an indispensable element in the quest to link tennis and sport sciences. The main goal of this research process is clear: to increase our scientiﬁc knowledge and to consequently increase the number of people playing tennis and the standard of tennis players. Below are some of the more signiﬁcant areas of tennis research made during recent years that have attempted to achieve this. In tennis medicine they are: overuse injuries; injury pathology at Grand Slams and in the men’s and women’s professional tennis circuits; ACL treatments; medical issues of junior tennis players; speciﬁc medical issues of female tennis players; physical conditioning and its role in injury prevention; isokinetic proﬁle testing; shoulder rotator cuﬀ issues; tennis elbow; injuries related to surfaces and equipment; stress fractures in tennis. In tennis physiology they are: energetic characteristics of singles tennis; physiological and kineanthropometric indicators of junior performance; ﬂuid ingestion; physiology of on-court drills; physiological adaptations and energy metabolism during tennis play; bone content, growth and recovery in tennis players; speciﬁc ﬁtness testing for tennis players. In tennis biomechanics they are: techniques and footwork in all strokes; correctional methods; observational patterns; muscular activity during play; kinematic variability during diﬀerent strokes, kinematic characteristics of players with and without tennis elbow; forces in the hand at impact; factors aﬀecting the physical load of strokes; power development in strokes; wrist kinematics in beginners and advanced players; kinematic adaptations in the coordination of diﬀerent strokes. In tennis psychology they are: personality; goal-setting, visualization, routines, anxiety and self-conﬁdence; pychological training programmes, selfeﬃcacy, self-talk; psychological implications for retired players; coach-player

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compatibility, psychological momentum during match-play; leadership; tennis parents; players’ and coaches’ ‘burn out’. In tennis motor control and learning they are: diﬀerences between beginner and advanced players; visual search strategies; expertise; vision training; cognitive strategies; information processing in tennis; eﬀect of practice organization. In tennis equipment they are: vibration and rebound characteristics of conventional and oversized rackets; racket ﬂexibility and string tension and its inﬂuence on ball bounce characteristics; selection criteria of tennis rackets, optimal racket performance; eﬀects of grip models in impact precision; eﬀect of oversized ball on serve performance; tennis surfaces and shoe characteristics. The purpose of this paper is to evaluate the role of tennis research to the game of tennis and to provide some perspectives of where future research should be directed in order to best support tennis at all levels.

Why perform tennis research? Several reasons have been given to justify the need for performing sport science research in tennis. The need for a better understanding of the game that will beneﬁt players and the image of tennis by the application of the most updated research methods and technologies is at the forefront (Woods, 1995). The importance of having sport science at the core of the programmes and policies of tennis organizations by eﬀectively creating links between tennis and science to further motivate research and stimulate researchers has been stressed. Facilitating access to the most up-to-date information on sport sciences and tennis to all those involved is also considered important (Crespo, 2004). Crespo et al. (2000) commented on how scientiﬁc research can result in new and eﬀective plans, models and training systems that contribute to increased performance, improved injury prevention and safe practice of the game. They suggested that prevention and avoidance of drop-out and burn-out through the facilitation of fun, enjoyable and lifetime experiences will help the overall improvement of the game.

Some research perspectives in tennis Future research perspectives in tennis will face a series of important challenges such as the study of key topics of interest for all those involved in the game and the viability of its application to daily practice and training in competitive, developmental methodological and other contexts of the game (Woods, 1995). Research in tennis should apply the most modern scientiﬁc methods and technologies to study the game with the aim of gathering a broader

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understanding of the diﬀerent processes and phenomena that deﬁne our sport. Tennis research and development are, thus, closely related (Elliott et al., 2003). A crucial aspect in the progress of our game is the use of the scientiﬁc knowledge acquired through research. This can be used to propose the use and application of evidence based models, plans and training systems that will help player and coach development at all stages of the game. It would also be able to guide the policies and programmes of all tennis organizations worldwide (Reid et al., 2003). Facilitating access to the most up-to-date information on sport sciences applied to tennis for all those involved in tennis coaching and teaching is an all-important aspect of coaches’ education and research practice. It helps to share best practice and motivate tennis research and application in the diﬀerent areas of sport sciences applied to the game (Crespo et al., 2001). After a comprehensive analysis of the diﬀerent research conducted in tennis it is possible to identify several important areas in which eﬀorts should be focused to increase our understanding of the characteristics and needs of the game. Table 35.1 summarizes some of the sport science areas and the speciﬁc issues in each of them that would be relevant to tennis.

Table 35.1 Research areas suggested for scientiﬁc research in tennis Sport Science

Advancements, trends and research areas to study

Medicine

• • • • • • • • • • • • • • • • • • • •

Biomechanics

Injury prevention Role and training of vision in tennis Improvements in speeding up the rehabilitation process Less invasive surgery methods Application of scientiﬁc knowledge to clinical knowledge Increased relevance of preventive techniques Concern on developmental processes and overuse injuries in juniors New diagnostics, treatments, injury prevention and recovery procedures (i.e. Injury Tracker) Guidelines for speciﬁc treatments Growth, development and health care of players (overtraining) Nutritional needs Reasons for disordered eating habits Female athlete triad Weight and body image concerns Biomechanical models for beginner players Study of ‘new’ technical solutions for tennis strokes Optophotogrammetry Performance models Comparison of mechanical determinants of junior and pro players Biomechanical interventions Continued

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Table 35.1 Continued. Sport Science

Advancements, trends and research areas to study

Psychology

• • • • • •

On-court psychological training Behaviours of players, coaches, relationships Burn-out, drop-out Psychological routines Parents’ role in tennis: working with the parents of tennis players Practical intervention models oﬀ-, and most importantly, oncourt

Physiology

• • •

The female athlete triad Physiological control of training

Training theory

• • Physical conditioning Motor control/ learning

Technology and materials

Multidisciplinary

Sociology Doping Statistics

• • • • • • • • •

• • • • • • • • • • • • • • •

Planning of the tennis training at the diﬀerent levels of the game: periodization: No. matches/year/age Adequate training intensity/volume Competition schedule Quantiﬁcation of long-term player development (contents and loads)

• •

Dynamic warm-up Importance of core stability for tennis Strength training with young players Discovery vs. prescriptive Game based approach (tactics) Load of typical on-court drills Methodology of error diagnosis and improvement Tactical decision process Increasing demands of modern competitive tennis: Speed of perception and execution Time pressure Observation strategies Vision in tennis

• • • •

Computer aided line-calling ‘Hawk Eye’ Evaluation of new materials (surfaces, clothing, shoes) Rules of tennis Quality control, performance, equipment safety Protecting the nature of the game Adapted equipment (balls, rackets) Burn-out Long-term player development and long-term coach development Competency based coach education Talent ID / selection vs. talent development Prevention of drop-out ‘Marketing’ strategies for tennis Player, coach and entourage education Applications of notational analysis to tactics Data interpretation in matches

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Importance of applied research One relevant issue that has been stressed previously (Crespo, 2004) is the need for applied studies that could be meaningful to researchers but also to players, coaches and oﬃcials of the game. This will help tennis practice to be scientiﬁc-based, safe, modern and more comprehensive. To this end the role of coach educators is fundamental since their main duty is to be ‘translators’ of the research ﬁndings with the aim of building communication bridges between the scientiﬁc and the applied world. Coaches need to be able to understand the beneﬁt of the studies on sport sciences and make all possible eﬀorts to apply the research results in their daily practice with players. On the other hand, researchers should get closer to the real needs of the game to investigate issues that will substantially aﬀect the practical implications of tennis practice. A two-way eﬀort is needed by both parties with a great degree of open-mindedness (Crespo and Reid, 2002). Research grants oﬀered by institutions such as the International Tennis Federation or the United States Tennis Association show the interest of some tennis organizations in co-operating with researchers in this quest to increase the scientiﬁc knowledge of the game. Experience and evidence have shown that these grants are uncommon at Federation level since immediate results are expected and funds are always less than what is needed. In this scenario, the ITF’s role is to act as a catalyst of research initiatives covering not only the direction in which studies are heading but, sometimes more importantly, the process of disseminating and ensuring that the information reaches all those interested and the application of research ﬁndings to the daily practice of tennis play. Hopefully the future will see an increase in the number of institutions undertaking tennis research (federations, universities, private companies) as well as in the amount of funding dedicated to these studies for the beneﬁt of the players and the game (Wood, 2006).

Conclusions Crespo and Reid (2002) noted that sport sciences have greatly contributed to the increase in tennis knowledge during recent times. Despite the eﬀorts of the International Tennis Federation, some National Associations as well as academic and private institutions, it has become apparent that more investment in tennis research is required. The application of sport science to health, training and development of tennis players at all levels of the game has, in our opinion, a promising future but it should be seen as a joint venture between the applied world and the research institutions. We are immersed in a challenge of knowledge and practical application of research ﬁndings that will contribute to the general improvement of the game (Crespo et al., 2000). Even though in this paper the considerable and gradual increase in tennis

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research has been highlighted, also noted has been the research ﬁelds in which more eﬀort and focus is needed to improve our scientiﬁc knowledge. The main challenge of all those involved in research and teaching remains, however, in the ‘transformation’ of scientiﬁc ﬁndings into knowledge, tools, methods and systems that can be eﬀectively used in daily practice at all levels of the game. The application of scientiﬁc knowledge will help more people worldwide beneﬁt from a healthy involvement in a sport for a lifetime; tennis.

Acknowledgement The author would like to thank the assistance of Mr Patrick McInerney in the preparation of this paper.

References Crespo, M. (2004). Panorama mundial de la investigación en el tenis. Congreso Nacional de Ciencias Aplicadas al Tenis [Research in tennis: a worldwide overview. National Congress on Sport Sciences Applied to Tennis]. Murcia: Universidad Católica de Murcia Crespo, M. and Reid, M. (2002). ITF involvement in tennis medicine and science. In Tennis (edited by P.A.F. Renstrom), Oxford: Blackwell Publishing, pp. 291–295. Crespo, M., Miley, D. and Cooke, K. (2000). Modern day tennis coaching: the impact of the Sport Sciences. In Tennis Science and Technology (edited by S.J. Haake ad A.O. Coe), Oxford: Blackwell Science, pp. 361–375. Crespo, M., Pluim, B. and Reid, M. (2001). Tennis Medicine for Tennis Coaches. London: ITF Ltd. Elliott, B., Pluim, B. and Kibler, B. (2003). Science and medicine in tennis: an integral part of player development. Journal of Science and Medicine in Sport, 6, 1, 1–3. ITF (2006). The ITF Year. Roehampton, London: ITF Ltd. Reid, M., Quinn, A. and Crespo, M. (2003). ITF Strength and Conditioning for Tennis. Roehampton, London: ITF Ltd. Wood, T. (2006). Medical care of tennis players by country. British Journal of Sports Medicine, 40, 5, 379–381. Woods, R.B. (1995). The future. In Clinics in Sports Medicine: Racquet Sports (edited by R. Lehman), Philadelphia: Saunders, pp. 277–281.

36 Sport identity of Polish badminton players in the context of other selected sport disciplines M. Lenartowicz and P. Rymarczyk

Aims and theoretical premises of the research The main theme of this paper is the notion of sport identity and identity reinforcement of top Polish badminton players in comparison to representatives of other sport disciplines at various levels of social recognition and popularity in Poland. The desire of recognition from one’s own social setting constitutes undoubtedly one of the most important human psychological needs. The aforementioned desire can be explained by the fact that social recognition is the main factor enabling a person to achieve a feeling that his or her life is meaningful and valuable. A person obtains such recognition of his/her activities when they are consistent with the scenarios of the social roles he/she is expected to play. Thus, the feelings of meaningfulness and valuableness of someone’s own life appear when a person plays the social roles he/she is demanded to play, and that is without any doubt the basic reason why people internalize their social roles, which means that they identify themselves with them and make them elements of their identity. The assumption that the need of social recognition exerts a decisive inﬂuence on the formation of human identity is probably the most important of the assumptions we formulated before doing our research on sport identity in contemporary Poland. We carried it out following the example of Weiss, who used the above-mentioned assumption as a basis for his research on sport identity, which he carried out in Austria (Weiss, 1999). However, this was not the only assumption we made. According to the second of our assumptions, people tend to increase the feeling of meaningfulness of their lives by carrying out a peculiar psychological hierarchization of the social roles which they play – a person increases above the average level his or her identiﬁcation with the roles which are the source of relatively large social recognition and he/she distances himself/herself from the rest of his/her roles, perceiving them as such aspects of his/her life which do not express his/her ‘real self’. While particularizing this assumption, we put forward a supposition that a person displays inclinations to identify him/herself with those of his/her

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social roles, which are perceived by his/her social setting as more valuable and which are played by this person more successfully. Thus, individual inclinations to identify oneself with a given social role would be directly proportional to the product of two factors: individual abilities to play it successfully and social recognition, which is enjoyed by a given sphere of activity. Inspiration for the second of our assumptions was also provided by Weiss, who undoubtedly assumed it implicitly while carrying out the abovementioned research. We were also inspired by the theoretical conceptions of Turner, R.H. (1978) and Homans (1961). The ﬁrst maintained that an individual builds his/her identity by identifying him/herself with some of his/her roles and distancing him/herself from others. Thus, he assumed that ‘individuals tend to merge positively evaluated roles with their persons’ and ‘to locate their persons in the roles they enact most adequately’ (Turner, R.H., 1978, p. 14). The latter perceived man as a rational and calculating being and hence he presupposed that human behaviour (which, in our case, means: human auto-deﬁning) is ‘a function of its pay-oﬀ’ (Homans, 1961, p. 13), so that ‘in choosing between alternative actions, a person will choose that one for which, as perceived by him at the time, the value of the result multiplied by the probability of getting the result is greater’ (Turner, J.H., 1978, p. 228). The third of our assumptions regarded relations between the investment of time and eﬀort and the strength of identity. Inspired by one of Turner’s propositions (Turner, R. H., 1978, p. 15), we assumed that the greater the investment in some form of activity, the stronger the identiﬁcation with a suitable social role. The fourth of our assumptions regarded factors determining inclinations of one’s own social setting to identify a given person with particular social roles this person plays. We assumed that the high social prestige of a role and its successful performance are factors which cause not only that an actor is inclined to identify himself (or herself ) with it, but also that such inclinations appear in his (or her) social setting, which treats prestigious and well-played roles as more important – and, in this sense, more ‘real’ – than low prestige roles that are played badly. Formulating this assumption we also followed the traces of R. H. Turner, who maintained ‘roles that are quite positively evaluated and those that are quite negatively evaluated attract more attention than neutral roles. Because appearances are more striking, inferences about the person are likely to be stronger’ (Turner, R.H., 1978, p. 8). The above-mentioned assumptions served as a basis to formulate our working hypotheses. Namely, we presumed that sports identity should be expected to be stronger in the case of persons who achieve successes in sports and whose sporting activities meet the recognition of their settings. On the other hand, it should be expected to be weaker in the case of persons whose level of sports performance is not high and whose sporting activities do not meet their settings’ recognition.

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Research approach We assumed that persons who spend a relatively large amount of time on their sporting activities should have stronger sport identity than persons who spend relatively little time on them. We also assumed that persons who perform their sporting activities at relatively high levels and achieve successes in sports will be more often and to a greater extent perceived by their social settings as athletes than those who perform sports at relatively low levels and without successes. The sporting successes of our respondents were measured by us based on answers for question 7 from part I of the applied questionnaire (Curry and Weiss, 1989), in which the responding persons characterized the level of their sporting activities. The measurement of social recognition experienced by the respondents because of their sporting activities was made by us on the basis of their answers for questions included in part III of the questionnaire, where the respondents assessed, inter alia, whether their sport commitment is important for their friends and families. It seems probable that ﬁnancial rewards received by athletes through their sporting activities are also perceived by them as a form of recognition of their sporting activities. Thus, we formulated a hypothesis that the strength of sport identity is positively correlated with the receiving of ﬁnancial gratiﬁcation for sport participation and that the higher percent of the respondent’s income coming from this source, the stronger the sport personality should be expected to be. We measured the investment of time and eﬀort in sporting activities with the help of question 6, part I: ‘How much time do you spend every week on the practising of your sports discipline?’ We measured the strength of sports identity with the help of the question which appears in part II of the applied questionnaire. It asks the respondent to rate on a scale of zero to one hundred the importance of diﬀerent aspects of his/her life, sporting activities being mentioned here as one of these aspects. Our respondents made the evaluation of the importance of sporting activities in their own life also by answering questions from part IV of the applied questionnaire. Our respondents were asked there, for example, if they usually organized their day in connection with their sporting activities and if they often dreamed of sporting successes. Finally, some questions included in part III of the questionnaire – where the respondents were asked, for example, whether they were perceived by many people mainly as athletes – were used to measure to what extent our respondents were identiﬁed with their sport roles by their social settings.

Methods A total 238 athletes from diﬀerent sport disciplines were investigated. The sample included 33 top Polish badminton players. They were asked to ﬁll in a standard questionnaire on sport identity developed by Curry and Weiss (1989). A pilot study was carried out in order to check the validity of the research tool. There were 80.7 per cent men and 19.3 per cent women in the

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sample. The mean age was 22.58, while 82 per cent of respondents were between 18–29 years of age. The sample included both national team players (e.g. in badminton) and amateur athletes, whose sport involvement might be deﬁned as recreational. They represented 19 sport disciplines. The majority of respondents practiced football (20.1 per cent), basketball (20.8 per cent), followed by badminton (14 per cent), handball (9.7 per cent) and swimming (5.5 per cent). Other disciplines’ representatives groups did not exceed 10 persons. In our sample we have included team and individual, indoor and outdoor, very popular and less recognized sports in Poland. The popularity level of investigated sport disciplines in Poland was estimated based on Charzewski (1997) and GUS (2000) research on sport disciplines most often practised by the Poles. From his point of view the most popular would be swimming, basketball and football, while relatively unpopular sports represented also in our research would be weightlifting, pentathlon, triathlon, rugby and badminton, although the latter according to GUS (2000) is well recognized as a recreational activity. On the other hand, there is also marketing research evidence for the social recognition of certain sports with regard to sport sponsorship. For example, ARC Rynek i Opinia company annual reports on sport sponsorship market and the marketing value of certain disciplines, reported low recognition of badminton as a sport discipline in Polish society. It was assumed in the research that sport skills and involvement level would diﬀerentiate research results on the strength of sport identity of respondents. Almost half of the sample (43.7 per cent) included athletes representing the national ﬁrst division level. The second biggest group was amateur athletes playing sport at a local competition level. Swimmers, pentathletes and part of the badminton group, represented the highest sport level (national team). Female basketball, handball and badminton players also presented a high sport level (1st division). The lowest competition level included mainly the representatives of team games: football and male basketball players. Signiﬁcant diﬀerences in sport competition level and the character of speciﬁc sport disciplines diﬀerentiated sport involvement of respondents with regard to the number of training sessions and hours per week. Half of the respondents devoted to sport training over 10 hours per week. The mean number of hours per week spent on sport training for the whole sample was 11.2 hours, while the mean number of training sessions per week was 6.2. The highest number of training hours was reported by swimming, pentathlon, female basketball and badminton players, who declared 25 to 35 hours of training per week (up to 21 training sessions per week in the case of pentathlon). Low competitive level football players and male basketball players indicated the lowest amount of sport training time. Our sample was also heterogeneous with regard to receiving ﬁnancial support or remuneration because of their sport involvement. Over half of them reported they do receive some form of ﬁnancial support, while 45.1 per cent reported no ﬁnancial support of any kind. It was clear that ﬁnancial rewards

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from playing sports would be closely related to sport competition level: the higher was the sport level, the more frequently respondents reported receiving them (correlation of 0.328, P=0.01). Yet, it should be noticed that over 26 per cent of local leagues players also declared receiving ﬁnancial beneﬁts through sport. This may be related to the fact, that in this group of athletes, more commercialized sports such as football and basketball were represented. In the case of badminton, three quarters of players reported receiving ﬁnancial beneﬁts, which is most likely the result of their high sport competition level (national team and ﬁrst division).

Results and discussion Investigated players were quite positive about their sporting achievements: 7.3 per cent of them estimated their results as very good, almost half of them reported that they have good sporting results. It was interesting to see that the correlation between declared sport competition level and assessment of own sport achievements was very weak: 0.244 at p=0.01. Among 33 investigated badminton players (including 10 national team members and 19 ﬁrst division players) evaluated their sport achievements as good, and 15.2 per cent as very good, which is twice as much as the sample average. Among the spheres of life (categories) presented to respondents, the highest valued was family (mean value of 93.78 points with 100 points as a maximum) and sport (87.34 points). The third most valued spheres were friends and education (almost 80 points each). Less important were religion and Church, arts and music and ethnic or national membership (all categories of more than 50 points). The least important in the view of investigated players was politics. The high position of family is in no way surprising. It complies with general research of the Polish society. It is interesting to see that, regardless of the 36 per cent representation of lowest competition level, sport was valued almost as high as family. This result supports the notion that sport identity and importance of sport in one’s life is (surprisingly) not dependent on sport competition level. It seems strange, but somehow consistent with other results of our research on sport identity. Our research does not support the hypothesis on signiﬁcant diﬀerences in identifying with a role of an athlete and importance of sport in life in the case of a sample which is highly diﬀerentiated with regard to sport competition level, receiving ﬁnancial rewards through sport and the type of sport discipline represented. This concerns both response to the questions regarding selfevaluation of sport in the respondents’ life (part IV of the questionnaire) and perceived social recognition of respondents’ sport involvement (part III of the questionnaire). In both groups of questions, no signiﬁcant correlations between answers category and sport discipline and sport level variables were recorded. However, that does not mean that there were no correlations and patterns with regard to sport level and self-evaluated importance of sport involvement and perceived social recognition. Players representing higher

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sport levels more often declared that sport is an important part of their personality. In spite of this no signiﬁcant correlations were recorded here. All national team members gave a positive answer (75 per cent ‘agree’ and 25 per cent ‘rather agree’). With representatives of lower sport levels, answers varied more, but even at local league competition level over 75 per cent of respondents declared that being an athlete is an important part of their personality. High-level athletes more often declared that they organized their daily time schedule around sport (over 80 per cent of national team members and only 20 per cent of local league players). Being a good sportsman and permanent improvement of sport skills were very important for over 90 per cent of respondents. Over 60 per cent considered themselves mainly as athletes and over 90 per cent dreamt of sport success. Badminton players more often than average declared perceiving themselves as athletes (almost 70 per cent), and all of them reported dreaming of sport success and that sport is an important part of their lives. With regard to this group of questions, there were no other diﬀerences between badminton and other sport disciplines. National team members and representatives of the lowest sport competition level see in the same way how their social environment perceives them. Again, there was no correlation between sport level and answers to this group of questions. Respondents (76 per cent) declared they are mainly perceived as athletes, while 70 per cent claimed their sport involvement is important to their friends and acquaintances. Over 86 per cent of the sample reported, that people think sport is very important in their life. In the case of badminton, players more often (in comparison to general results) declared that they are perceived mainly as athletes (84.8 per cent). Analysis of respondents’ motives for playing sports show that for the whole sample the most important motivation was improving ﬁtness and health (almost 90 per cent of answers) and emotions related to sport competition (87.6 per cent). Yet, at the same time, almost half of the sample declared that because of injuries, sport is more harmful than beneﬁcial to their health. Answers to these questions are quite inconsistent. Competitiveness as an important motive for playing sports was reported by 77.5 per cent of respondents. Badminton players were less focused on competitiveness (67.7 per cent) and paid less attention to the teamwork aspect of sports. The latter is most likely the result of the individual character of badminton competitions. Half of the sample expressed their willingness to continue in or to move to a professional sport career (45 per cent in case of badminton players).

Conclusions Diﬀerent sport level, diﬀerent popularity of certain sports in Poland and receiving ﬁnancial beneﬁts from involvement in sport did not signiﬁcantly inﬂuence the strength of identiﬁcation with a role of a sportsman and perceived importance of sport in respondents’ lives. The research concerned

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both the importance of sport in the life of respondents, and social recognition of the role of athletes from the social environment. It showed that the declared strength of sport identity of low sport level athletes was unexpectedly high and this group of respondents was also very positive about their sport achievements. It mainly concerned team games athletes and may be closely related to the high popularity of football and basketball in Poland. We may therefore consider that Weiss’ (1999, p. 366) conclusions on stronger sport identity of athletes representing the most popular sport disciplines and higher sport level and social prestige are somehow (but not deﬁnitively) conﬁrmed in our research. This may be the result of a limited number of respondents, general problems with deﬁning the most popular sport disciplines or the general low interest of Polish society in active sport involvement. Regardless of the relatively low popularity of badminton in Poland, investigated players represented the sample’s higher average sport identity level. Relatively high sport identity self-assessment in comparison to overall sample may be the result of high sport level represented by badminton players, which weakened the impact of discipline popularity.

References Charzewski, J. (1997). Aktywnosc Sportowa Polakow [Physical Activity of the Poles]. COS Physical Culture Training Methods Center, Warsaw: Estrella. Curry, T.J. and Weiss, O. (1989). Sport identity and motivation for sport participation: a comparison between American college athletes and Austrian student sport club members. Sociology of Sport Journal, 6, 257–268. Homans, G.C. (1961). Human Behaviour: Its Elementary Forms. New York: Harcourt, Brace and World. GUS (2000). Uczestnictwo Polaków w sporcie i rekreacji ruchowej (w okresie 1.X. 1998 r. – 30.IX.1999 [Sport and Physical Recreation Participation of the Poles (between Oct. 1, 1998 and Sept. 30, 1999)]. Warsaw: Main Statistical Oﬃce (GUS). Turner, J.H. (1978). The Structure of Sociological Theory. Homewood, IL: The Dorsey Press. Turner, R.H. (1978). The Role and the Person. American Journal of Sociology, 84, 1–23. Weiss, O. (1999). Identity and Motivation in Competitive Sport. Wychowanie Fizyczne i Sport [Physical Education and Sport], vol. 43 (Suppl.), 364–368.

37 Coach education Models, characteristics and views of Greek tennis coaches N. Grivas and K. Mantis

Introduction Coach education is one of the keys for improvement of the training process and for the achievement of best possible levels of performance. As a result of rapid progress in sport in the last decades, the training and educational needs of coaches will continue to grow. The coaches’ education programmes must be thoroughly evaluated to take into account the ﬁndings of all areas of applied sport research, as well as the personal characteristics, backgrounds and opinions of coaches in the particular sport. Most modern coaching programmes consist of three key areas: a) modules of study in sport science, b) the components related to the skills, techniques and strategies of the sport and c) practical experience. The balance of these aspects and the relative importance placed on each depends on the particular needs of the sport and the level at which the coach operates (Campbell, 1993). Nowadays, many sport organizations develop diﬀerent theories or sportspeciﬁc modules for coaches from diﬀerent backgrounds (Haslam, 1990; Douge and Hastie, 1993). In coaching, in most cases, more emphasis should be placed on skill development, both physical and social, than the competition result. Because coaches play such a crucial role in the educational and motivational process, they should be encouraged to attend seminars and to gather the latest scientiﬁc knowledge in various ways, as self-improvement is a key to increase coach eﬀectiveness (Gratto, 1983; Pﬂug, 1980). Also, these actions should be emphasized and a positive approach to coaching developed. The purpose of this study is to present the Greek model for coach education, as well as characteristics and views of participant coaches. This will provide further information to the improvement and development of coach education.

Models of tennis coaches education programmes in Greece The national systems of coach education are determined mainly by culture, policy, tradition and the athletic structures of each country. Although some of the most established tennis nations have started their coaches’ education

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programmes in the early part of the twentieth century (Crespo et al., 2005), in Greece this procedure was only put into practice systematically after the 1980s. The situation is similar to the great majority of sports in the country. The main reason for beginning coach education programmes was the decision of the state (1983) to declare the Sport Academy to have University Sport Department status and to provide coaching diplomas in particular sports. Until then coach education was based around full-time university training (four-year degree programmes). The development of Physical Education as an academic discipline, together with an ongoing demand for an increase in the knowledge base of that discipline, has certainly served to improve the quality of teaching in sport. According to the Greek Athletic Law, there are two ways of receiving a coaching diploma in Greece – through the full-time four-year studying in the (ﬁve) Universities Sport Departments simultaneously with a Physical Education teacher degree or through courses organized by the Governmental Secretariat of Sport in conjunction with the National Federations. The graduates of University Sport Departments receive directly an A level (higher) diploma in a particular sport. In the second way, mainly focused on explayers and ‘unoﬃcial’ trainers, volunteers are a small minority, every course is organized for a particular level, starting from the level C (initial) and ending with the level A diploma. From the above it is clear that the vast majority of tennis coaches in Greece are professionals and are employed on a full-time or part-time basis mainly by community sport clubs. The Hellenic Tennis Federation, as well as almost all National Sport Federations, has no speciﬁc formal coach education programme in place which leads to a diploma. Instead, it participates in the organization of periodic courses in conjunction with the Governmental Secretariat of Sport. This participation consists of proposals about the level, the year and the organization place of coach education programmes, as well as proposals about playing level of participants. Also, the Hellenic Tennis Federation can propose two out of ﬁve members of the Management Committee and the Course Director. The last one is responsible for the course content. The Governmental Secretariat of Sport course structure consists of three levels and the names of the courses are C (initial), B and A (higher). The minimum time between diﬀerent level courses is two years coaching experience after completion of a lower level training. The pre-requisite criteria for participation in courses are: age, playing level and education level. From these pre-requisites, age and education level are ﬁxed (at least 22 years old and a secondary education diploma). The playing level for every course could be changed, based on the National Federation proposal. For the two tennis courses carried out in 2002 (Athens, Thessalonica) the pre-requisites for playing level were eight years player’s licence. There are no fees for the participants, while the cost is ﬁnanced completely by the Governmental Secretariat of Sport. Thirty-one men and seven women took part in the Athens 2002 level C

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tennis coaches’ course. The course duration was three consecutive weeks (16 days and 150 academic hours). The course subjects were focused on different general modules of sport science and in practical sport skills. The programme included diverse theoretical and practical assessments. The subjects of the course were focused on diﬀerent modules of sport science (65 per cent of the total hours), such as biomechanics, psychology, injuries treatments, sport history, sport law, sport management, communication, nutrition, coaching, planning, methodology, didactics. Fewer hours (35 per cent) were allocated to the skills, techniques and strategies of the sport, because of the satisfying playing level of the participants and their experience, acquired in advance. On-court training was the subject that required the higher number of teaching hours. Among assessment procedures a project/thesis in a free choice sport topic with a minimum of 2500 words was required. The classiﬁcation of participants’ papers in thematic areas was the following: Technique 9, Coaching 8, Nutrition 5, Mini-tennis 4, Physical Condition 3, Psychology 3, The Coach 2, Tactics 2, other 2.

Method The sample consisted of 31 men and seven women. Their age was 32.8 (SD = 8.9, min = 22 max = 54) years old. A questionnaire was used for the collection of data, which included closed questions, with a scale of evaluation from 1 (lower) to 7 (higher), and open ones (AHTC, 2000). For the analysis the statistical programme SPSS was used, as well as to provide descriptive statistics. Chi-square was used to test for signiﬁcant diﬀerences when appropriate at a signiﬁcance level of P < 0.05.

Results The majority of the participants were men, four and a half times more than women (81.6 per cent and 18.4 per cent correspondingly). Their region of origin was province (51.4 per cent) and Athens (48.6 per cent), but more of them lived in Athens (73 per cent) than in a province (27 per cent). Regarding the educational level of participants, 60.5 per cent had a secondary education diploma, 21.1 per cent had a tertiary education degree (not Sport University), 10.5 per cent had a sport university degree (or were students) and other 7.9 per cent. Of the coaches, 86.8 per cent were right-handed and 13.2 per cent were left-handed. Among the participants 81.6 per cent were full-time coaches, 10.5 per cent were part time, while 7.9 per cent were current players. Concerning their working place (n = 26) 38.5 per cent of them worked in Athens private and high-level (community sport) clubs, 38.5 per cent in the province and 23 per cent in Athens suburban (community sport) clubs. A total of 42.9 per cent of coaches (n = 35) worked more than 30 hours weekly, 34.3 per cent 21–30 hours, 20 per cent 11–20 hours and 22.9 per cent less than ten hours.

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Of those that worked more than 30 hours weekly, 80 per cent worked in private and high-level clubs in Athens with 50 per cent in the suburban clubs, while those working 20–30 hours, 70 per cent worked in the provincial clubs (statistically signiﬁcant diﬀerence, P < 0.05). Of the coaches who worked in the Athens private and high-level clubs, 58.3 per cent were of Athenian origin, while only 21.4 per cent were of provincial origin (statistically signiﬁcant diﬀerence, P < 0.05). The tennis coaches (n = 35) generally considered their salary as poor (11.4 per cent), satisfactory (57.1 per cent), good (25.7 per cent) and very good (5.7 per cent). The coaches who worked 30+ hours were more satisﬁed with their salaries. The percentage that considered their salary as good was 40 per cent, and as satisfactory 53.3 per cent. The 25 per cent of coaches born in the province considered their salary as poor, in comparison to none of the coaches born in Athens (statistically signiﬁcant diﬀerence, P < 0.5). The 30 per cent of coaches residing in the province considered their salary as poor (in comparison to the 10 per cent of those of Athens residence) (P < 0.05). On the contrary, 50 per cent of Athenian private and high-level clubs coaches estimated their salary as good and 40 per cent as satisfactory. The great majority of women claim satisfactory salary (66.6 per cent), while on the contrary, in the men’s ﬁeld there was a wider variety of answers. The 34.5 per cent of men considered their salary as good and very good in comparison to 16.6 per cent of women. The diﬀerence was not statistically important, because of the small sample of women (n = 6). Also, it is interesting to note that 80 per cent of left-handed coaches stated their salary to be good in comparison to 53.3 per cent of right-handed. The coaches estimated that they personally have a high level of information regarding tennis issues (M = 5.2). The estimation was independent of the coaches’ working place. Nevertheless, the estimation from those working in Athens high-level private clubs was a little higher (M = 5.25) in comparison to those working in Athens suburban clubs (M = 5.1) or in the provinces (M = 5.05). On the contrary, they generally evaluated the capability of Greek tennis coaches with a lower mark (M = 4.4) than their own. Generally, the evaluation of Athens high-level private clubs coaches was higher (M = 4.8) than the provincial club coaches (M = 4.3) and Athens suburban club coaches (M = 4). The way of informing players on scientiﬁc topics applicable to tennis is through magazines (81.6 per cent), books (63.2 per cent), a followup of seminars and meetings (55.3 per cent) and only 36.2 per cent through the internet. Another more ‘unoﬃcial’ way was through the follow-up of matches and discussions with other coaches (18.4 per cent). Access to a personal computer was available to 78.9 per cent of the coaches. Those who had access to the internet amounted to 73.7 per cent, but only 60.5 per cent of these had a PC at home. From the latter, 56.5 per cent stated that they used PCs for gathering tennis information and for the preparation of training, while 43.5 per cent used PCs for other activities. The percentage which have an email account (57.1 per cent) was lower. The

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coaches had a ﬁrst-hand experience with computers during elementary education (2.7 per cent), secondary education (21.6 per cent), and tertiary education (10.8 per cent), in private courses and seminars (13.5 per cent) and ‘by themselves’ (51.4 per cent) The main reasons for not having access to PCs and the internet were: the lack of relative knowledge, the low estimation and the high cost. Finally, the number of coaches (n = 35) who speak foreign languages (92.1 per cent) is particularly high. Among them 60 per cent speak one, 28.6 per cent speak two and 11.5 per cent speak more than three foreign languages.

Discussion Two basic proposals could be made in order to improve the Governmental Secretariat of Sport courses content. First, the introduction of new subjects, and mainly the use of a computer. The aim is to help the coaches in the acquisition of new knowledge and the recording of the training process. Other proposed subjects are ﬁrst aid treatment, equipment analysis and notation. Second, it is very important to increase the duration of courses without increasing the total hours, so as to provide a bigger period of practical work under real conditions with diﬀerent levels and ages players. In this way, it could be seen at which level coaches put into practice what they have learnt from the coaches’ education programmes, a fact which seems to be a diﬃculty in the development of coaching courses (Douge and Hastie, 1993). In comparison with similar courses in other countries (Crespo et al., 2005) the total amount of time for the level C course (150 academic hours) is very high and it resembles a B Level for them. The organization of Governmental Secretariat of Sport programmes should be repeated after a certain period of time (e.g. 3–4 years for C level courses) with a more permanent staﬀ and contents. Moreover, the operation of B and A levels courses is essential. Particularly important is the contribution from the National Federation, Coaches Union and University’s Sport Departments in planning and managing of modern coaches’ education programmes. It has been proposed that Universities Sport Departments, or another body, take on the responsibility of the management of Governmental Secretariat of Sport courses and that their duration be extended to eight months. Finally, there is a need for harmonization with the EC guidelines regarding coaches’ education, as well as the establishing equivalence between existing coaches’ education programmes. Although the structure and the content of coach education in University Sport Departments diﬀers from one University to another, two general proposals could be made in order to improve the quality of University coach education programmes. First, there is a need for stricter choice of students who are candidates as tennis coaches based on their playing ability. Second, ensuring a wider environment for students’ practice and future work by enhancing the relations among Universities Sport Departments and the sport clubs.

Coach education of Greek tennis coaches 267 Particularly worrying is the low rate of attendance by women in the Governmental Secretariat of Sport course. This percentage should be increased to promote equal integration of women in society and for the attraction of a higher percentage of girls into the sport. It is very satisfactory, in fact, that among the University Sport Departments alumnus the percentage of women is much higher than among the programmes of Governmental Secretariat of Sport. At certain times it exceeded 50 per cent of total graduates. This does not mean that all women alumnus succeed in ﬁnding or keeping a coaching job. The role of the Hellenic Tennis Federation in coach education should become more energetic. The creation of a Coach Education Department according to the standards of leading National Federations is an essential step. Its aim is to gather, develop and disseminate the latest knowledge to all coaches’ education programmes providers and coaches all over the country. This eﬀort will include the creation of educational materials, as well as conducting seminars and workshops for all coaches. The application of the latest scientiﬁc knowledge has been a contributing factor in the increase of worldclass tennis European players (Saviano, 2000). Also, this Department could be responsible for the lifelong education of players, parents and oﬃcials. According to this study, coaches working in the most prestigious clubs, which are the private and high-level clubs in Athens, more are of Athenian than provincial origin. This is due ﬁrst, to Athens-born coaches having been players of some of these clubs and members of their family who have been involved as members in these clubs, too. Second, they are living and playing tennis in the capital at the same time, which gives them more experience and challenges, and greater access to private and high-level clubs – factors which lead to higher salaries. The ﬁndings show also that most coaches are satisﬁed with their salaries and verify that generally a tennis coach is a well-paid job in Greek society. However, the fact that the majority of coaches are at a relatively young age, probably without family responsibilities may contribute to the acceptance that salaries are satisfying. The coaches who work more hours are more satisﬁed with their salaries. It is common in every job to ﬁnd more men than women getting a higher level of salary. This is true generally in coaching, plus the fact that in Greece the role of a tennis coach as sparring player is emphasized, a role in which men are considered more eﬃcient. The Athens private and high-level clubs coaches have a higher estimation regarding their level of information concerning tennis issues. This may be attributed to the fact that they work in an advanced working area where they have more experience and sources of information. The percentage of coaches who participate and gather information from seminars is low and may be the result of the small number of seminars which are organized in Greece. The percentage of people using the internet systematically for information purposes regarding tennis issues is lower. The number (36.2 per cent) is even lower than the number of those who have access to the internet (73.7 per cent) or have a PC at home (60.5 per cent). It is worth

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noting that although the percentage of Greek tennis coaches using PCs and the internet is relatively low, it signiﬁcantly outnumbers the proportion of the Greek population who use PCs and the internet, which is 45 per cent and 32 per cent respectively. In combination with the high percentages of coaches speaking foreign languages (92 per cent), training in the use of PCs and the internet could provide an advantage to Greek tennis coaches in gathering up-to-date information.

Conclusion From the ﬁndings of this study, the improvement and the re-designing of a national coach education system in Greece becomes a necessity. Any coach education strategy must be built around the sporting structures and traditions that already exist in the country. Some basic proposals have been made regarding the need to ensure the provision of update scientiﬁc knowledge by University Sport departments and the Governmental Secretariat of Sport Tennis Coach Education Programmes, as well as the role of the Hellenic Tennis Federation. This research eﬀort should be considered as a step in planning the most suitable programmes for Greek tennis coaches.

References Association of Hellenic Tennis Coaches (AHTC) (2000). Questionnaire of AHTC. Unpublished document. Campbell, S. (1993). Coaching Education Around the World. Sport Science Review, 2, 62–74. Crespo, M., Reid, M. and Miley, D. (2005). Tennis coaches education: a worldwide perspective. ITF Coaching and Sport Science Review, 35, 11–13. Douge, B. and Hastie, P. (1993). Coach eﬀectiveness. Sport Science Review, 2, 14–29. Gratto, J. (1983). Competencies used to evaluate high school coaches. Journal of Physical Education, Recreation and Dance, 54, 59–60. Haslam, I.R. (1990). Expert assessment of the National Coaching Certiﬁcation Programme (NCCP) theory component. Canadian Journal of Sport Sciences, 15, 201–212. Pﬂug, J. (1980). Evaluating high school coaches: a description of the programme used at the Beaverton (Oregon) School District. Journal of Physical Education and Recreation, 51, 76–77. Saviano, N. (2000). Meeting the worldwide challenges for coaching education. USTA High-Performance Coaching, 2, (1), 1–2.

38 Modern teaching methods for tennis What do they have in common? P. Unierzyski and M. Crespo

Introduction Tennis has been changing, but for many decades teaching methods have been behind the general development of the game. It started to lose the battle to other, especially ‘new’ or more ‘elite’, sports and other leisure activities. One of the reasons was that the traditional methods of teaching used in tennis were based on a technique and stroke production (Crespo, 1999) without understanding the real character of the game. This approach has not changed for many years. Results of studies undertaken by the International Tennis Federation (ITF) showed that in some, especially more matured tennis countries, tennis appeared ‘not to be a fun game to learn and play for the vast majority of youngsters interviewed’ (ITF, 1998). Children, parents and coaches acknowledged that ‘games and game-like situations were more fun than technically oriented drills’ (Stean and Holt, 2000). ‘Having fun’ is the most important motivator for children’s involvement in sport (Wankel and Kreisel, 1985; Scanlan et al., 1993) and a need for an alternative, more attractive way of practising was widely identiﬁed. Findings of researches (e.g. Bunker and Thorpe, 1982; Thorpe et al., 1986; Thorpe and Dent, 1999), observations of the careers of many top tennis players and experience of the most successful coaches have given a basis for a new teaching and training philosophy. Many national federations have formed their own systems and have used their own names, but modern training methods follow a similar philosophy and have many commonalities. The aim of this paper is to describe these commonalities and ﬁnd the characteristic points of the ‘new’ teaching philosophy in tennis.

Common characteristics of modern teaching methods Adaptation to specify to the game of tennis: game based, tactical approach to coaching Despite the fact that diﬀerent nations use diﬀerent terms (e.g. Action Method, Game-Based Coaching, Tactical Approach, GAG) the commonality is that

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teaching process takes into consideration the speciﬁc character of the game. A major shift in teaching methodology has been the catalyst of structuring the teaching and coaching process with the idea of adapting it to the match situation – game based, and thus emphasizing the role of strategy and tactics already in the initial stages of the game (a tactical approach to coaching). While the ability to perform a skill eﬀectively is critical to performance, appropriate decisions concerning what to do in the game situation are equally important. Therefore the aim of the Tactical Approach to coaching tennis is to improve the overall game performance of the player combining tactical awareness and skill execution (Crespo and Cooke, 1999). Research (McPherson, 1991; McPherson and French, 1991; Turner, 2003) has conﬁrmed that because of tactical (and game-based) approaches tennis players demonstrate better game performance (shot precision and decision making) and have higher levels of speciﬁc knowledge than players coached according to the traditional approach. It is very important to use modiﬁed games (Wright et al., 2005), which engage pupils cognitively, stimulate pupil interest, allow for more game play and provide pupils with the opportunity to transfer concepts from one game to another. This methodology may be used with players of diﬀerent skills, from beginners to professionals. Level of technical skills is not a barrier (Thorpe, 1992) because it is possible to have a good game even with poor technique. Because the criteria of success in practice are ‘wider’ (traditionally, success = the drill was well performed) it is easier to create a positive motivational climate. In the game of tennis the methodology is based on the assumption that at any given moment the player must be in one of ﬁve game situations (serving, receiving, playing at the back of their own court with the opponent at the back of their court, approaching or at the net, playing at the back of the court with the opponent approaching or at the net). In each of these situations players perform certain tactics: e.g. keep the ball in play, try to move the opponent around, or use own strengths (Tennant, 2004). Therefore the goal of the coaching process in all modern methods around the world is to teach players how ‘to deal’ with these ﬁve situations. The priority for the players is to understand the game, develop a game sense and learn practical competences, e.g. how to attack the net, not just how to hit ‘nice’ shots. It is important that students rally and, at the same time learn how to solve diﬀerent tactical problems. Coaches working according to this method ﬁrst try to develop cognitive skills and later, if necessary, they use technique in closed drills. In this approach to coaching, the classical analytic methods become less important. The priority of tactics over technique does not mean that coaches must not work on shots. Technique taught globally, in a certain tactical context and with the use of an adapted size of the court, cannot be only more attractive but also more eﬃcient.

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Holistic approach to coaching Modern tennis training takes into account the importance of tennis as a whole, a holistic approach to coaching, and the principle of integration vs. isolation. The relevance of a holistic view of tennis coaching is gaining more and more recognition worldwide and is promoted by major tennis associations. Terms like ‘integrated’, ‘total’ or ‘complex’ tennis training are very close to each other and are increasingly common among coaches of all levels. These terms refer to a global vision of tennis training in which all components are integrated and are put into practice using a ‘complex’ training approach. The concept of integrated training for tennis states that the traditional distinction between technique, tactics, conditioning and mentality is more artiﬁcial than real. It is practically applied following the principle that when working on technical aspects, players are also working on tactics, conditioning and mentality, and vice versa, since there is an interrelation and interdependence between all of them. That is why a lesson should have a versatile character; its goals should concern more that just tactics and technique. A good coach will address motor and mental development in almost every lesson (Crespo, 1999; Schönborn, 1999). Player-centred coaching, goal (skills)-oriented learning Modern coaching fully recognizes the player as the centre of the coaching process and all eﬀorts should be made to provide the best assistance possible to help the player achieve his goals. The coach is educating a person as a whole, teaching not just techniques but also skills and the ability to solve problems. Winning in children/junior categories is not as important as reaching planned goals step by step, and the general development of a player. Therefore, the role of a coach in modern sport is diﬀerent. A coach should be more a guide, who creates a positive motivational climate, rather than being an authoritarian. Players are taught to be more independent; they often ﬁnd their ‘own way’ and learn from their success. A Swedish study (Thorpe and Dent, 1999) reported that Swedish players who made it to the top as adults, had childhoods that were typiﬁed by play and practice in a supportive atmosphere, rather than intensive coaching. Use of sports science and technology, injury prevention Modern coaching is sport science coaching. It is impossible to understand the coaching process at any level of tennis without a sound sport science basis, which implies the use of the sport science fundamentals in daily coaching. Sport science provides tennis coaching with a much better understanding of almost all aspects of the game since major scientiﬁc contributions have helped to develop coaching theories and education. The progressive developments in sports medicine, tennis technology, psychology, training theory

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and other major sport sciences are having a major impact in the delivery of injury-free training programmes for players of all ages and playing levels. This is the reason why sport science has become a major part of coach education programmes worldwide. Development of coordination as a base of technique and the main motor ability to be improved As far as coordination is concerned tennis is one of the most demanding sports. Because every incoming ball is diﬀerent, reaching it on time and hitting it back eﬀectively requires well developed coordination skills. That is why it is a base for developing technical skill and optimal use of other motor abilities as speed and strength. Learning ‘ﬁnal’ technique (Schönborn, 1999) must be preceded by the development of general, speciﬁc coordination and the gaining of skills similar to tennis (like catching or throwing). Another important matter is that all major methods aim to teach both reception (ability to judge correctly the ﬂight of the ball and move to the position to play a particular shot) and projection (ability to develop the techniques) skills. If development of coordination is missed during the mini-tennis stage it is very diﬃcult to ‘catch up’ (Pankhurst, 2003). Because of its importance, all federations emphasize the need to work on diﬀerent aspects of coordination not only in every lesson, and not only during the warm-up. Functional and biomechanical approach to movements Adopting ‘the new methodology’ does not mean that the role of biomechanics and technique in players’ development is less important than before. Eﬀective implementation of strategy and tactics requires tennis-speciﬁc (technical) skills (Thorpe and Bunker, 1997; Crespo and Reid, 2003). In today’s tennis, technique (the action) is seen as a function of the correct biomechanical principles and as a means to implement tactics more eﬃciently. Each movement should be treated as a tool useful to solve a tactical problem. Consequently, the perfect (model) stroke does not exist; ‘strict imposition of certain grips, stances, backswings and follow-through is not recommended’ (Crespo and Reid, 2003). The goal of technical development is to structure an individualized model of performance and every player has a right to execute strokes in an individual way although with respect to biomechanical principles. Looking from this perspective success in teaching means respecting individuality, the laws of the game and the principles of science (e.g. biomechanics). Adapting the equipment, facilities and rules to the pupils The beginner has to deal and become familiar with new equipment – a racket and a ball. Using the right equipment supports the learning process; low

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compression tennis balls, reduced-size rackets and courts makes the game easier to play from the ﬁrst lesson, develops an all-court, all-stroke game, promotes the use of the correct techniques and reduces risk of injury. The need to scale down sports equipment, ﬁeld dimensions and rules was raised many years ago and has been widely used in many countries. What is relatively new is the importance placed on coordinating methodology with the equipment and facilities. The methodology uses the natural feature of the human being, which is the ability to adjust to new situations. Creating certain situations, coaches support the training goal(s). Therefore the learning process is usually divided into stages. The names are diﬀerent, e.g. mini-tennis (red/orange/green levels) or micro/mini/midi/maxi tennis but the purpose is the same: making the game more accessible for beginners. Because, at the beginning, children start to play from a small distance and slowly, step by step they form their own strokes. Generally there is a tendency to postpone the moment of playing on regular court. The majority of federations use midi tennis programmes (where the court is 18 m long) as a transition between mini-tennis (in the UK mini-tennis red) and playing on a regular court. Generally it is agreed that only an extremely gifted player may start to play regularly on a full court before the age of ten.

Conclusions Despite obvious national diﬀerences, teaching methodologies of leading countries follow a similar philosophy, which makes the game attractive, especially to the younger generation. New ideas have come very fast and already after two to three positive results, the attraction to the game can be noticed. Because of dynamic action taken by the ITF and leading tennis nations, the crisis of the game in developed tennis nations has been overcome. We believe that this is a good moment to increase promotional activities and advance modern teaching methodology around the racket sport world.

References Bunker, D.J. and Thorpe, R.D. (1982). A model for the teaching of games in Secondary Schools. Bulletin of Physical Education, 18(1), 5–8. Crespo, M. (1999). Teaching methodology for tennis. ITF Coaches Review, 19, 3–4. Crespo, M. and Cooke, K. (1999). The tactical approach to coaching tennis. ITF Coaches Review, 19, 7–8. Crespo, M. and Reid, M. (2002). Modern tactics: an introduction. ITF Coaching and Sport Science Review, 27, 2. Crespo, M. and Reid, M. (2003). Biomechanics and teaching methodology. In ITF Biomechanics of Advanced Tennis (edited by B. Elliott, M. Reid and M. Crespo), London: International Tennis Federation. International Tennis Federation (ITF) (1998). Tennis towards 2000. London: ITF Ltd. McPherson, S.L. (1991). Changes in knowledge content and structure in adult beginner

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tennis: a longitudinal study. Paper presented at the annual meeting of the NASPSPA, Pittsburg USA. McPherson, S.L. and French, K.E. (1991). Changes in cognitive strategies and motor skill in tennis. Journal of Sport and Exercise Psychology, 13, 26–41. Pankhurst, A. (2003). Presentation from Polish Coaches Symposium, 24 April 2003. Scanlan, T.K., Carpenter, P.J., Lobel, M. and Simons, J.P. (1993). Sources of enjoyment of youth sport athletes. Journal of Pediatric Exercise Science, 5, 275–285. Schönborn, R. (1999). Advanced techniques for competitive tennis. Aachen, Germany: Mayer and Mayer. Stean, W.B. and Holt, N.L. (2000). Players’, coaches, and parents’ perceptions of fun in youth sport. Avante, 6, 84–98. Tennant, M. (2004). The ﬁve game situations in mini-tennis. ITF Coaching and Sport Science Review, 32, 7–9. Thorpe, R.D. (1992). The psychological factors underpinning the ‘teaching for understanding games’ movement. In Sport and Physical Activity: Moving Toward Excellence. Proceedings of the AIESEP World Convention (edited by T. Williams, L. Almond, and A. Sparkes), London: E&FN Spon, pp. 209–218. Thorpe, R.D. and Bunker, D.J. (1997). A changing focus in games teaching. In Physical Education in Schools (edited by L. Almond), London: Kogan Page, pp. 52–80. Thorpe, R.D. and Dent, P. (1999). Developing a more player oriented approach to coaching tennis. ITF Coaches Review, 19, 5–7. Thorpe, R.D., Bunker, D.J. and Almond, L. (1986). A change in the focus of teaching games. In Sport Pegagogy: Olympic Scientiﬁc Congress Proceedings, Volume 6, (edited by M. Pieron and G. Graham), Champaign, IL: Human Kinetics, pp. 163–169. Turner, A. (2003). A comparative analysis of two approaches for teaching tennis: game based approach versus technique approach. Presented at the second ITF Tennis Science and Technology Congress. London. Wankel, L.M. and Kreisel, P.S.J. (1985). Factors underlying enjoyment of youth sport. Journal of Sport Psychology, 7, 51–64. Wright, S., McNeill, M., Fry, J. and Wang, J. (2005). Teaching teachers to play and teach games. Physical Education and Sport Pedagogy, 10(1), 61–82.

39 Season-of-birth eﬀects on elite junior tennis players’ world rankings P.G. O’Donoghue

Introduction Skewed month-of-birth distributions have been discovered in many sports including Ice hockey (Barnsley et al., 1985; Boucher and Mutimer, 1994), soccer (Brewer et al., 1995) and basketball (Thompson et al., 1991). A skewed month-of-birth distribution will typically have more players who were born in one quarter of the year than any other and there will be a decreasing number of players who were born in the successive quarters. There is a skewed monthof-birth distribution of tennis players participating in the singles events of Grand Slam tournaments with more players than expected being born in the ﬁrst half of the calendar year (Edgar and O’Donoghue, 2005). It is thought that the International Tennis Federation (ITF) cut-oﬀ date of 1 January is responsible for this skewed month-of-birth distribution. Indeed, there is considerable evidence that the skewed month-of-birth distributions observed in soccer participants result from the cut-oﬀ date for the junior competition year (Brewer et al., 1995; Musch and Hay, 1999). Simmons and Paul (2001) noted that the England schoolboy soccer international squad and players from the English Football Association youth squad had diﬀerent skewed month-of-birth distributions that were associated with the two diﬀerent cutoﬀ dates that applied. Musch and Hay (1999) found that month-of-birth distributions for top league soccer players reﬂected the cut-oﬀ date for junior competition in Australia, Brazil, Germany and Japan unaﬀected by the different hemispheres, climates and cultures of those countries. Furthermore, when the start date of the junior competition year in Australia changed, it eventually produced a corresponding shift in the distribution of month-ofbirth of participants. Previous research into season-of-birth eﬀects on tennis participation has been based on cross-sectional studies (Dudink, 1994; Baxter-Jones, 1995; Edgar and O’Donoghue, 2005) rather than tracing the participation of players over time. Therefore, a longitudinal programme of research has commenced to track the participation of players over the course of their careers. This will allow changes in participation levels and success of players born in diﬀerent parts of the year to be compared. Speciﬁcally two groups will be compared; those born in H1 (from 1 January to 30 June

276

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inclusive) and those born in H2 (from 1 July to 31 December inclusive). The scope of the research will be restricted to players born in 1987 or 1988. The purpose of the current paper is to report on the ﬁrst three years of the longitudinal study.

Methods The junior world rankings of 1987- and 1988-born players competing in the ITF junior circuit were traced over a three-year period from 2003 to 2005 inclusive. The name, nationality, date of birth and world ranking of all 3071 tennis players born in 1987 or 1988 who achieved any junior ranking points in 2003, 2004 or 2005 were obtained from the end of year ITF junior rankings (www.itfjunior.com, accessed 31/12/03, 31/12/04 and 31/12/05). It was necessary to sort the details of the players with ranking points in each of the three years into gender, then nationality, then birth date, then name order so as to match each player’s record from diﬀerent years within a single data sheet of 3071 players. There were some female players who had changed their names due to marriage and some players whose names had been expressed in diﬀerent ways between 2003 and 2005. There were some other players who had changed their nationality over the three-year period. Table 39.1 summarizes the number of male and female players born in each half of the year who had achieved ITF junior tour ranking points in the diﬀerent years for which data was recorded. A minority of 615 of the 3071 players were ranked in all three years from 2003 to 2005. Chi square goodness-of-ﬁt tests were used to compare the proportion of diﬀerent sub-groups of players with theoretically expected proportions assuming equal number of births on each day of the calendar year. Therefore, a fraction of 181¼/365¼ of a group would be expected to be born in H1 and 184/365¼ of the group would be expected to be born in H2. Chi square tests of independence were used to compare the proportion of players born in Table 39.1 Number of 1987- and 1988-born tennis players achieving ITF junior ranking points in diﬀerent years Years

Female

Male

Born in H1

Born in H2

Born in H1

Born in H2

2003 only 2004 only 2005 only 2003 and 2004 2003 and 2005 2004 and 2005 2003, 2004 and 2005

94 123 96 139 11 109 170

71 108 111 94 9 106 120

63 125 243 77 26 217 196

38 85 250 34 11 216 129

Total

742

619

947

763

Season-of-birth eﬀects on world rankings

277

each half of the year who entered or exited the rankings in particular years and to compare the proportion of players born in each half of the year who rose in the rankings over a one- or two-year period. The change in median world ranking of players was compared between players born in each half of the year using Mann Whitney U tests. For each of the inferential procedures used in the study, a P value of less than 0.05 indicated a signiﬁcant diﬀerence or association.

Results Table 39.2 shows that in each year from 2003 to 2005, there were signiﬁcantly more male junior players achieving ranking points who had been born in H1 than H2. There were signiﬁcantly more female junior players achieving ranking points who had been born in H1 than in H2 in 2003 and 2004 but not in 2005. In both the male and female players, the chi square value and hence the level of signiﬁcance decreased steadily from 2003 and 2005. The total number of 1987- and 1988-born male players who were ranked increased from 2003 to 2005 as older players gradually moved into senior tennis. However, the total number of 1987- and 1988-born female players who were ranked in the ITF junior rankings decreased from 2004 to 2005, possibly due to some of these players participating in senior competition before the age of 18. Table 39.3 summarizes changes in the set of players who were ranked in 2003 and 2004 and Table 39.4 summarizes changes in the set of players who were ranked in 2004 and 2005. These tables categorize the players into three groups; those ranked in both of the two years of interest, those leaving the rankings in the second of the two years and those appearing in the rankings in the second year having not been ranked in the ﬁrst year. There were no signiﬁcant diﬀerences in the proportions of the three types of players between the female players born in H1 and H2 from 2003 to 2004 (χ22 = 4.9, P = 0.085) or from 2004 to 2005 (χ22 = 5.7, P = 0.057). However, half-year of birth did have a signiﬁcant inﬂuence on the proportions of male players entering and Table 39.2 Half year of birth of 1987- and 1988-born players with junior ranking points in each year Gender

Half year of birth

Total

χ21

P

Year

H1

H2

2003 2004 2005

414 541 386

294 428 346

708 969 732

22.0 14.8 2.8

< 0.001 < 0.001 0.096

2003 2004 2005

362 615 682

212 464 606

574 1079 1288

41.3 23.2 5.6

< 0.001 < 0.001 0.018

Female

Male

278

P.G. O’Donoghue

Table 39.3 Changes in the set of 1987- and 1988-born players achieving ranking points in 2003 and 2004 Female

Male

H1

H2

Total

H1

H2

Total

Ranked in 2003 but not in 2004 Ranked in 2003 and 2004 Appearing in 2004

105

80

185

89

49

138

309

214

523

273

163

436

232

214

446

342

301

643

Total

646

508

1154

704

513

1217

Table 39.4 Changes in the set of 1987- and 1988-born players achieving ranking points in 2004 and 2005 Female

Male

H1

H2

Total

H1

H2

Total

Ranked in 2004 but not in 2005 Ranked in 2004 and 2005 Appearing in 2005

262

202

464

202

119

321

279

226

505

413

345

758

107

120

227

269

261

530

Total

648

548

1196

884

725

1609

exiting the rankings from 2003 to 2004 (χ22 = 12.3, P = 0.002) and from 2004 to 2005 (χ22 = 12.1, P = 0.002). Between 2003 and 2004 the ratio of new arriving male players to leavers was 3.8:1 for players born in H1 and 6.1:1 for players born in H2. Between 2004 and 2005 the ratio of arriving players to leavers was 1.3:1 for the male players born in the H1 and 2.2:1 for the male players born in H2. The 291 H1 born male players dropping of the rankings between 2004 and 2005 is 73 per cent higher than the 168 H2 born male players who dropped out over the same period. As well as analysing participation levels of 1987 and 1988 born players in the ITF junior circuit, it was desirable to monitor and compare their world rankings over the three-year period. Table 39.5 summarizes the end of year ITF junior rankings of the 290 female and 325 male players who had achieved ranking points in all three years. The female players’ rankings improved from 2003 before declining in 2005. The male players’ rankings improved considerably from 2003 to 2004, but there were diﬀerent fortunes experienced by the H1- and H2-born players between 2004 and 2005. The H1 born players dropped 10 ranking points on average between 2004 and 2005 in comparison to the 79 places dropped by the H2 born players. A Mann

Season-of-birth eﬀects on world rankings

279

Table 39.5 World rankings of male and female players born in the ﬁrst and second halves of the year who had achieved ranking points in all three years (2003, 2004 and 2005) Born in ﬁrst half of year

Born in second half of year

2003

2004

2005

2003

2004

2005

Female L. Quartile Median U. Quartile

260.5 545 955

173 380.5 629.8

183 521 914

239.25 539 1027

135.75 314.5 758.5

210 539.5 997.75

Male L. Quartile Median U. Quartile

428.25 667 1079

168.75 350.5 598.75

132.75 360.5 770.25

410 701 993.5

140.5 353 729.5

156.5 432 917.5

Whitney U test did not ﬁnd a signiﬁcantly greater improvement in world ranking between the female players born in H1 and H2 from 2003 to 2004 (z = −0.327, P = 0.744) or from 2003 to 2005 (z = −0.938, P = 0.348) or between the male players born in H1 and H2 from 2003 to 2004 (z = −0.517, P = 0.129). However, the improvement in the median world ranking of the H1 born male players from 667th to 360.5th between 2003 and 2005 was signiﬁcantly greater than the improvement from 701st to 432nd for the male players born in H2.

Discussion and conclusion This study has tracked the participation of the 3071 players born in 1987 or 1988 who appeared in the ITF junior world rankings in 2003, 2004 or 2005. Despite only covering the ﬁrst three years of a longitudinal study, some interesting patterns have already been observed. First, while the number of 1987- and 1988-born male players achieving ranking points rose steadily from 2003 to 2005, the number of 1987- and 1988-born females decreased after 2004. An explanation of the fall in the number of 1987- and 1988-born female players in the ITF junior rankings in 2006 is that some had already commenced their senior careers. Indeed, there were 61 of these female players who were already ranked in the top 500 senior female players in the world at the end of 2005 (WTA rankings) compared with 11 of the 1987- or 1988-born male players who were ranked in the top 500 senior male players (ATP rankings). The earlier maturation in females than males (Malina, 1990) may explain the ability of larger numbers of female players to compete in the senior tour before the age of 18. There may also be a greater strength of depth in the men’s senior game than in the women’s senior game as it is more diﬃcult for 17- and 18-year-old male players to achieve top 500 rankings in the world senior rankings. Evidence of the greater strength in depth in the

280

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men’s game also comes from the 2006 French Open where four unseeded male players reached round four and two reached the quarter ﬁnals. There were no unseeded players in the same rounds of the women’s singles. O’Donoghue (2004) also found that there were fewer matches where players were defeated by lower ranked opponents in women’s singles than in men’s singles. The current results agree with previous investigations into tennis that there is a skewed season of birth distribution (Dudink, 1994; Baxter-Jones, 1995; Edgar and O’Donoghue, 2005) with more H1-born players participating in the ITF junior tour. However, the proportion of players born in H1 was not as high as the 85 per cent reported by Baxter-Jones (1995) for elite junior players. This study has discovered that the proportion of players achieving ranking points who were born in 1987 or 1988 declined in both male and female groups to the extent that in 2005, the season of birth distribution was no longer signiﬁcantly diﬀerent to a theoretically expected distribution for the female players. The changes in the numbers of H1- and H2-born players between 2003 and 2005 shown in Table 39.2 result from the balance of players entering the rankings and players leaving the rankings as shown in Tables 39.3 and 39.4. The larger number of H1-born players who leave the rankings may be explained by some of these players not being as talented as their H2-born counterparts. Such player may have been able to achieve ranking points up to the ages of 15 and 16 as a result of their relative age advantage over H2-born players. This relative age advantage will decrease as the players mature. The relative age advantage enjoyed by the H1 players before the age of 16 may be largely physical, which would agree with the views expressed by Edwards (1994) that there are physical eﬀects as well as psychological eﬀects of relative age advantage. As these players become older, the physical advantage over H2-born players reduces which may lead to some H1-born players becoming discouraged when they are not able to compete as eﬀectively as when they were younger. The psychological eﬀects associated with such experiences may lead some to drop out of the sport. There are limitations in the methods used in the current investigation that must be recognized. First, where players do not appear in the rankings, it may not be due to injury or competing at senior level but being ranked outside the world’s top 500 senior players. Some players’ junior rankings decline because they have partially competed in the ITF junior tour but concentrated on senior tournaments. An example is Andrew Murray of Scotland who was the ninth ranked junior at the end of 2003 and the eighth ranked junior at the end of 2004. At the end of 2005, he was ranked 301st in the ITF junior rankings but 64th in the ATP senior rankings. This research will continue, following the careers of these 1987- and 1988-born players comparing the progress of those born in H1 and H2. There are many research questions that will be addressed by this longitudinal study. If the level of participation in senior Grand Slam tournaments changes in diﬀerent ways for the players born in the diﬀerent halves of the year, it will provide evidence of psychological

Season-of-birth eﬀects on world rankings

281

factors associated with the relative age eﬀect. It is possible that some H1-born players may not have as much genuine talent and will fall in the senior world rankings and drop out of the sport. The H2-born players may rise though the rankings, thus feeling encouraged to prolong their careers. Alternatively, if the H1 players have been misidentiﬁed as talented, they may improve as a result of the opportunities of higher levels of coaching and competition (Rejewski et al., 1979). In conclusion, this research has applied a more dynamic approach to investigating season-of-birth eﬀects in sport by following participation levels of a set of players over a period of three years. There was a skewed month-ofbirth distribution in the 1987- and 1988-born players in 2003 to 2005, with a more pronounced skewed distribution in the male players. However, between 2003 and 2005 the proportion of players who had been born in H1 reduced in both male and female players.

References Barnsley, R.H., Thompson, A.H. and Barnsley, P.E. (1985). Hockey success and birthdate: the relative age eﬀect. Canadian Association for Health, Physical Education and Recreation, 51, 23–28. Baxter-Jones, A.D.G. (1995). Growth and development of young athletes: should competition be age related? Sports Medicine, 20, 59–64. Brewer, J., Balsom, P.D. and Davis, J.A. (1995). Season of birth distribution amongst European soccer players. Sports, Exercise and Injury, 1, 154–157. Boucher, J.L. and Mutimer, B.T.P. (1994). The relative age phenomenon in sport: replication and extension with ice-hockey players. Research Quarterly for Exercise and Sport, 65, 377–381. Dudink, A. (1994). Birth date and sporting success. Nature, 368, 592. Edgar, S. and O’Donoghue, P.G. (2005). Season of birth distribution of elite tennis players. Journal of Sports Sciences, 23, 1013–1020. Edwards, S. (1994) Born too late to win? Nature, 370, 186. Malina, R.M. (1990). Growth, exercise, ﬁtness and later outcomes. In Exercise, Fitness and Health: A Consensus of Current Knowledge (edited by C. Bouchard and R.M. Malina), Champaign, IL: Human Kinetics, pp. 637–653. Musch, J. and Hay, R. (1999). The relative age eﬀect in soccer: cross-cultural evidence for a systematic discrimination against children born late in the competition year. Sociology of Sport Journal, 16, 54–64. O’Donoghue, P.G. (2004). The advantage of playing less sets than the opponent in the previous two rounds of Grand Slam tennis tournaments. In Science and Racket Sports III (edited by A. Lees, J-F. Khan and I.W. Maynard), London: Routledge, pp. 175–178. Rejewski, W., Darracott, C. and Hutstar, S. (1979). Pygmalion in youth sport: a ﬁeld study. Journal of Sport Psychology, 1, 311–319. Simmons, C. and Paul, G.C. (2001). Season-of-birth bias in association football. Journal of Sports Sciences, 19, 677–686. Thompson, A., Barnsley, R. and Stebelsky, G. (1991). Born to play ball: the relative age eﬀect and major league baseball. Sociology of Sport Journal, 8, 146–151.

40 Health-related habits of tennis coaches B. R. Matkovic´, B. Matkovic´ and L. Ruzˇ ic´

Introduction Sports in general, as well as other professions that are in close relation with sport are usually presumed to be in connection with life quality, in particular regarding health. Most people would conclude that those involved professionally in sport lead a healthy way of life, take care about their dietary habits and avoid most of the habits that would endanger health. Sports coaches would be a typical example of a professional who should be well aware of the basis of healthy living, although this has never been scientiﬁcally proven and there is a lack of published work dealing with this issue. The World Health Organization has already established the main factors inﬂuencing health, being socio-economic factors, way of life and physical environment (WHO, 2003). The risk factors in relation to the way of life are nutrition, physical inactivity, smoking, alcohol consumption and use of drugs. The main purpose of sport coaches is to teach the athletes the basic and advanced skills and knowledge that is needed to compete in sports competitions. Coaches lead the team through training whose principal goals are improvement of physical ﬁtness, sports technique and skills, knowledge about the sport and tactical assignments in order to improve performance during competition. Apart from that the coaches are responsible for team spirit, selection, leadership of the player or team during competition and they are frequently involved in solving problems that are not always related to sport. All that leads to extreme working hours, irregular schedules, many hours of evening work and of course many weekends spent working, often much more than the regular 40 hours a week. Good results are a must and poor results often lead to loss of employment. Taking that into account we must presume that coaching is deﬁnitely a profession that has a high amount of stress involved and that surely has an impact on health. Though these are well-known facts, this profession has never been of major interest to scientists working in the ﬁeld of occupational medicine. Sometimes the only information related to the health of coaches is the notice in a sports

Health-related habits of tennis coaches

283

magazine announcing the death of a coach caused by myocardial infarction or similar, and usually everybody assumes that as the profession of a coach is related to sport that they also lead a healthy life, full of physical activity with no unhealthy habits. The aim of this research is to determine the health-related habits of tennis coaches regarding nutrition, smoking and alcohol consumption.

Methods The sample comprises 49 male tennis coaches from Croatia, for whom dietary habits, alcohol consumption and smoking habits were determined. A new questionnaire was constructed based on previous national and international studies (Paugh, 2005; Matkovic´ et al., 2006). The questionnaires were completed anonymously on a voluntary basis. Smoking habits were detected with simple questions with Yes or No answers, the number and type of cigarettes were determined. Questions about alcohol consumption were connected with the type of drink, daily amounts, heavy drinking and drinking in front of athletes. Dietary habits of the subjects were determined by items regarding the number of meals per day, skipping meals, intake of particular food subgroups based on the food pyramid, liquid intake and vitamin and mineral supplement intake, especially those used usually in sports. The data were analysed by standard statistical procedures, with the statistical software package STATISTICA for Windows. The correlations between nutritional knowledge and dietary habits were tested by Pearson correlation coeﬃcient. The level for signiﬁcance was set at P < 0.05.

Results and discussion With regard to alcohol consumption, the results of our study (Table 40.1) indicate that all 61 per cent of coaches are light-to-moderate drinkers and most of them are drinking one to two glasses of wine with their main meals. It seems that coaches are not engaged in occasional heavy drinking and, the most important thing, they are not used to drinking in front of their players. It is well established that large amounts of alcohol have detrimental eﬀect on health inﬂuencing most of the organs (Kasper et al., 2004). The scientiﬁc Table 40.1 Alcohol consumption of tennis coaches Alcohol

Beer

Wine

Spirits

0.3 l/day

0.2 l/day

0.03 l/day

Yes

No

1–2

3–5

>5

1–2

3–5

>5

1–2

3–5

>5

30

19

15

2

0

27

3

0

11

0

0

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B. R. Matkovic´, B. Matkovic´ and L. Ruzˇ ic´

investigations established a J-shaped relationship between alcohol use and health with the lowest mortality and morbidity risk occurring among light and moderate drinkers (Gunzerath et al., 2004). Light-to-moderate drinking is deﬁned as no more than two drinks per day for healthy men (U.S. Department of Health and Human Services and U.S. Department of Agriculture, 2000). Lighter drinking carries lower total mortality risk largely because of lower coronary disease risk. The investigators connect this ﬁndings with antioxidant and antithrombotic substances present in wine, mostly in red wine, which are potentially beneﬁcial against atherothrombotic disease and cancer (Booyse and Park, 2001; Paschall and Lipton, 2005). From Klatsky et al.’s (2003) prospective study of over 12,000 Californians, light-to-moderate wine drinking was associated with the lowest risk for all-cause and coronary disease mortality. They also reported that light-to-moderate beer and spirits drinkers had also lower mortality risk relative to lifetime abstainers. So the light-to-moderate habit of wine or beer drinking in the tennis coaches in this study may have beneﬁcial long-term health eﬀects. Smoking is unfortunately widely accepted and though the campaign against smoking is going on in Croatia, as in many countries worldwide, the real results are still not apparent, and the number of deaths caused by trachea, bronchial and lung cancer is still very high (Prabhat and Chaloupka, 1999; Samet and Yang, 2001; Samet and Yoon, 2001). The results of our study for smoking habits (Table 40.2) found that 27.3 per cent of tennis coaches are smokers. This is under the estimated average ratio in the Croatian population which in the male population is 34.1 per cent (data from Croatian Ministry of Health – School of Public Health ‘Andrija Sˇ tampar’ – www.snz.hr, 2006). The good thing in this ﬁnding is that most of the smokers are smoking between ﬁve and ten cigarettes per day. Interestingly, there are no pipe or cigar smokers. Among the non-smokers there are also those who previously were smokers. The dietary habits questionnaire consisted of 18 questions (Table 40.3, Paugh, 2005). According to the results it was obvious that the dietary habits of the coaches were not adequate. In particular, there was a problem with skipping meals and eating fast food. Probably this was in connection with their busy schedule due to closely following one or more tennis players. Coaches are rarely dieting and they do not seek nutrition information nor are they recording what they eat. The lack of interest in recent ﬁndings in the area of nutrition, not only sports nutrition, can be devastating for coaches because today there are Table 40.2 Smoking habits of tennis coaches Smoking

Per day

Yes

No

If ever

5–10

11–20

> 20

13

36

10

9

3

1

Health-related habits of tennis coaches

285

Table 40.3 Nutrition habits questionnaire (Paugh, 2005) 1 How often do you eat breakfast in the morning? 2 Based on three meals per day, how often do you skip at least one meal per day? 3 How often do you take vitamin supplements? 4 How often do you take mineral supplements? 5 How often do you eat three base meals per day? 6 How often do you record what you eat? 7 How often do you drink water? 8 How often do you drink carbonated beverages? 9 How often are you on a ‘diet’? 10 How often do you eat breads, cereals, pasta, potatoes, or rice? 11 How often do you eat fruits, such as apples, bananas, or oranges? 12 How often do you eat vegetables, such as broccoli, tomatoes, carrots, or salad? 13 How often do you eat dairy products such as milk, yogurt, or cheese? 14 How often do you eat berry jams, cookies, candies, or other sweets? 15 How often do you snack on foods like potato chips, cakes, candies, donuts, or soda? 16 How often do you snack on foods like bagels, yogurt, popcorn, pretzels, or fruits? 17 How often do you eat fast food? 18 How often do you seek out nutrition information?

scientiﬁc proofs that good dietary habits inﬂuence to a large extent a person’s health. This conﬂicts with the notion that coaches are most of the time educators for their players, and this lack of knowledge can aﬀect players’ performance.

Conclusion Tennis coaches are part of the population that have their own life style characteristics and because of their connection to athletes, especially young ones, their way of life deserves to be researched. As sports have a very important role in many nations worldwide, coaches are of great importance. Their education in all ﬁelds would surely contribute to the improvement of an athlete’s performance.

References Booyse, F.M. and Parks, D.A. (2001). Moderate wine and alcohol consumption: beneﬁcial eﬀects on cardiovascular disease. Thrombosis and Haemostasis, 86: 517–528.

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Croatian Ministry of Health (2006) www.snz.hr/nepusenje/site/Itemspage.php? strana_id=13& (last accessed 18.6.2006). Gunzerath, L., Faden, V., Zakhari, S. and Warren, K. (2004). National Institute on Alcochol Abuse and Alcocholism report on moderate drinking. Alcocholism: Clinical and Experimental Research, 28, 829–847. Kasper, D.L., Braunwald, E., Fauci, A.S. et al. (2004). Harrison’s Principles of Internal Medicine. New York: McGraw Hill Book Company. Klatsky, A.L., Friedman, G.D., Armstrong, M.A. and Kipp, H. (2003). Wine, liquor, beer, and mortality. American Journal of Epidemiology, 158, 585–595. Matkovic´, B., Knjaz, D. and Cigrovski, V. (2006). Znanje trenera o sportskoj prehrani [Sport nutrition knowledge of coaches]. Hrvatski sˇportsko medicinski vjesnik, 21(1), 3–8. Paschall, M. and Lipton, R.I. (2005). Wine preference and related health determinants in a U.S. national sample of young adults. Drug and Alcohol Dependence, 78, 339–344. Paugh, S.L. (2005). Dietary habits and nutritional knowledge of college athletes. Unpublished PhD thesis. University of Pennsylvania, USA. Prabhat, Jha. and Chaloupka, F.J. (1999). Curbing the epidemic: governments and the economics of tobacco control. Washington, DC: World Bank. Samet, J.M. and Yoon, S-Y. (2001). Women and the Tobacco Epidemic: Challenges for the 21st century. Geneva: World Health Association. Samet, J.M. and Yang, G. (2001). Passive smoking, women and children. In Women and the Tobacco Epidemic: Challenges for the 21st Century (edited by J.M. Samet and S.-Y. Yoon), Geneva: World Health Organization, pp. 17–45. U.S. Department of Health and Human Services and U.S. Department of Agriculture (2000). Nutrition and Your Health: Dietary Guidelines for Americans, 5th edn. Home and Garden Bulletin 2000; Nr. 23, U.S. Department of Agriculture, Washington, DC. World Health Organization (WHO) (2003). Shaping the Future. www.who.int/whr/ 2003/en/

41 Integrated functional evaluation A speciﬁc proposal for badminton C. Blasco, A. Ruiz and R.P. Garrido

Introduction Coaches know the importance of a constant assessment of all the elements of the training programme, particularly those concerning physical ﬁtness. As a result, the so-called functional evaluation has become more and more important. Over the last few years, a number of assessment units have been established, with their appropriate medical equipment and technology, so as to take constant measurements that allow us to speed up and make the best of the performance optimization processes. The purpose of a good functional evaluation is to provide signiﬁcant data that will regard and view athletes as entire beings, as a whole dynamic system subjected to constant ﬂuctuations. Since we obviously support the proposals of integrated training (Seirul-lo Vargas, 2003), it is timely to highlight the necessity of a similarly integrated functional evaluation. After a few years of non-speciﬁc and doubtful usefulness of batteries of tests that provided very interesting data on the functional abilities of our players but little information on the level of their speciﬁc abilities, we considered that the prospect of integration would be of great importance in order to validate the results of any assessment and use them to guide the training process. The following text presents a model of integral functional evaluation in which the results of all the elements assessed are regarded as interrelated. Likewise, we think that it is very important that the opinion of all the professionals involved in the assessment goes on record in order for the evaluation to be integral. Before giving a direct explanation of the work done, we present a summary (see Box 41.1) in which we have tried to show the main objectives of an integrated functional evaluation, as well as a quotation that, from our point of view, reasserts the necessity of assessing the individual in a dynamic, speciﬁc and integral fashion: ‘The chance of ﬁnding the most appropriate exercise for each ideal technical model seems to be much smaller than if we changed the exercises

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C. Blasco, A. Ruiz and R.P. Garrido constantly, so that the subject would go through so many situations that he would be able to solve, in the most appropriate fashion, the problems that might come up, in accordance with his/her own characteristics, those of his/her adversary (in case of competitive sports) and the game situation.’ (Tous, 1999)

Box 41.1 Objectives of functional evaluation (based on Blázquez, 1990)

•

PRIMARY OBJECTIVES * Gather and arrange data concerning the functional condition of the athlete: Identify and diagnose the level of the athlete’s performance: a) Generic diagnosis: anthropometric assessment, somatic characteristics and general physical level. b) Speciﬁc diagnosis: level of technical–tactical execution in accordance with the speciﬁc demands of the category, in contexts of maximum physiological condition. c) Emotional diagnosis: level of motivation and interest in the sport practiced within the above-mentioned contexts. d) Diagnosis of weak points. Foretell and predict possible improvements and/or achievements of both the athlete and the group. *

•

Gather and arrange data concerning the training process: Direct and re-adjust the training process at all its levels, both individually and as a group. Group together according to levels and adjust the new objectives for each group/level. Inform trainers and athletes about the objectives/progresses of the training process.

SECONDARY OBJECTIVES

Motivate and encourage both athletes and coaches. Assess the eﬀectiveness of the training system. Research into the training process itself. Research into the evaluation itself.

Apart from explaining the individual physiology, our functional evaluation must analyse the interdependent behaviour of our player with regard to the requirements of the game. If we evaluate the fatigue or motivation, among other elements, because they are considered to inﬂuence the technical – tactical behaviour, we think that it is necessary to place the stress on that behaviour by monitoring, analysing and assessing it in accordance with the

Integrated functional evaluation

289

information provided by the evaluation as a whole (anthropometries, blood lactate levels, and so on). Methods We designed several speciﬁc prototypes for the integral functional evaluation for badminton players at the Centro de Tecniﬁcación (Technical Centre) of Alicante where we train a group of 14 ﬁrst national-level players. These players belong to the Techniﬁcation team of the Superior Council of Sports of the Autonomous Region of Valencia, which allows us easy access to functional assessments, medical care, and so on. Over the last three years, we have gone from the traditional evaluation of measurements of oxygen consumption using a treadmill (evaluation that we kept making at the beginning of the season to obtain the initial data) to more aspiring proposals of integrated evaluation. In this article, we will present the latest proposal on which we have been working. As we shall now explain, the test gathers together a signiﬁcant amount of data which makes the participation of diﬀerent professionals necessary. Therefore, and in view of the complexity of the data to be analysed, we have chosen to present only one case study, so that we will be able to explain properly the way in which our proposal must be undertaken. The athlete analysed plays in the club league and has a medium-high sports level. He moved to Alicante a year ago and is in the process of adaptation to our systems of training. We could describe him as the classical athlete with very high functional abilities, but with many technical and speciﬁc deﬁciencies. This test is based on the technical response of the athlete in situations of maximum fatigue, so we have called it Integral Test of Fatigue in Badminton. The test is passed when the player is able to tolerate maximum levels of fatigue after a certain training period. Professionals involved and their roles

• • • •

Doctor and Registered Nurse: they collect data on reactive force from the Bosco test, saturation and blood lactate levels. Coach: who feeds multi-shuttlecocks in training and provides motivation and general monitoring of the player. Physical Trainer: who is in general control of the test, with special attention to the measurement of times. Second Coach: who records the test results and controls the full collection of data for each player.

Materials used and its organization A video camera (Sony DCR-HC 18E) was placed ﬁve metres from the back line of the court, behind the player executing the test, and in line

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with the centre line. The mat for the Bosco test (Ergo jump from Globus) was situated in front of the camera, between it and the court. Both the Staturimeter (portable pulseoxymeter, TuﬀSat, Datex-Ohmeda), and the rest of the materials for the blood lactate levels were placed on a table in line with the mat, although slightly to one side to prevent them from hindering the player’s view. The player wore a heart rate meter (Polar S610i) throughout the test. Format and development of the test After an appropriate warm-up of about 15 minutes, the test starts with all the professionals ready at their working places. The physical trainer marks the performance times of the groups. As over 80 per cent of play lasts less than 10-s this duration was used for the Bosco test (Cabello and González-Badillo, 2003). The numbering in Box 41.2 refers to the order in which all the performances take place.

Box 41.2 Integral test of fatigue in badminton 1 2

Capture of basal lactate and heart rate (HR) pre-test. Bosco Test of reactivity for 10-s (data on mean strength; mean height in cm and number of jumps). 30-s of pre-game break (the player gets ready on court)

3

Game series: Blocks of speciﬁc work of four exercises. Multishuttlecocks with a 20-s pause between exercises. The ﬁrst and third series of game are developed counting the number of shuttles. The second series take place according to time, not the number of shuttles. 20 shuttlecocks – movements from behind striking with order 20 shuttlecocks – movements forwards/backwards with order 30 shuttlecocks – 4 points (two forwards and two sideways) with no order 30 shuttlecocks – no order on court

4 5 6

7 8

20-s 20-s 30-s 30-s

HR0 or HR post-test (immediately after the end of the game). Bosco test of reactivity for 10-s post-test. Lactate 1 and HR1 (after a minute’s recovery); the athlete is asked about his assessment of the eﬀort perceived according to the Borg’s scale (EP). Lactate 3 and HR3 (after three minutes’ recovery). HR5, end of the recovery stage and pre-test (after ﬁve minutes and before block 2).

Integrated functional evaluation

291

Once the test has been performed, its analysis presents four well-distinguished stages: 1

2

3

4

Stage of data collection in the List of data record (Figure 41.1). The following day, all the professionals enter their data on the athletes’ individual list using Excel. Stage of analysis. The analysis is made through the joint viewing of the video; the physical trainer monitors and completes the List of data record (Figure 41.1) with (1) the times and number of shuttlecocks of each sequence in order to ﬁll in the data concerning the execution speed or actions per second (number of shuttlecocks executed/time of execution of the sequence). With this value we measure the rate or intensity of the sequences and (2) the technical quality of the jumps in Bosco and jumps and movements on court, etc. At the same time we also evaluate feelings of fatigue/athlete’s freshness, eﬀort motivation. All these elements are gathered in the observation section. The coach monitors and writes down the diﬀerent items relating to technique execution, errors, etc, on the List of qualitative evaluation (Table 41.1). In this stage, every sequence is viewed as many times as considered necessary, both the joint assessment and communication between both professionals being of great importance. Stage of report completion. At the end of this stage in which both technicians must have worked jointly, getting the information and signiﬁcance of medical data, the two lists of which the ﬁnal report consists must be ﬁnished: the list of quantitative evaluation (Figure 41.1) is thus completed with the List of qualitative evaluation (Table 41.1). This list is directed to the conditional assessment that justiﬁes and explains the reason why the technical-tactical behaviour is analysed. Stage of communication with the athlete and viewing / analysis of the test.

Results Quantitatively, it is necessary to highlight problems of foot support and balance after the shots and in movements. The Bosco test conﬁrmed the lack of reactive strength. Technical defects become very pronounced with fatigue. However, conditionally the lactate values are good, appropriate to the eﬀort, with high lactacide tolerance and heart rate, which do not prevent him from being in high spirits and showing good tolerance to fatigue. These elements, along with the qualitative observation, are very clear in his assessment of the perceived eﬀort, with low values for the physiological fatigue pointed out by the rest of the data. His saturation values remain high until the third series, which show his good physical ﬁtness and recovery.

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Figure 41.1 Quantitative evaluation. At the top, the record of the partial times of eﬀort and rest can be found, as well as the totals for each exercise and series; the number of executed shuttles and execution speed. At the bottom, on the right side, chart of mean speed for each exercise and series (in columns) and heart rate (in lines).

Discussion and conclusions At the psychological-emotional and metabolic level, the subject is within the normal range. At the neuromuscular level it is necessary to put the stress on technique and strength. The fatigue aﬀects the errors even more, so we will have to work hard on this aspect. As for the design of the test, it is not necessary to collect unforced errors in future analyses, for it is a fatigue test where he exerts himself in practically all the shots. The sequences still seem to be too long, thus we will have to review the suggested structure of the eﬀort in the test, in order for it to more resemble a competition.

He does not jump in the rectiﬁed He does not turn the side, nor does he turn his body body when striking in the right side

Wrong position of feet towards the right side

He does not strike the shuttle up Between the shots and He holds the racket when striking in the net down after striking the he holds the racket down shuttle

He does not look in the direction where he wants to send the shuttle. Lack of accuracy in all the exercises. For future evaluations, it will not be necesary to gather unforced errors since it is a fatigue test and he exerts himself in practically all the shots.

FOOT POSITION

RACKET POSITION

OBSERVATIONS

He drags his left foot forwards

6 shuttles

He does not get back into position quickly

He does not use his left arm to compensate

He holds the racket down after striking the shuttle

He puts too much pressure on the sole of his foot when moving

He does not use his left arm to compensate

6 shuttles

5 shuttles

3 shuttles

10 shuttles

BODY POSITION

6 shuttles

UNFORCED ERRORS

The whole court with no order

2 shuttles

Four points forwards/ sideways

FORCED ERRORS

Movement forwards/ backwards

Movement from behind

SERIES 1

Table 41.1 List of qualitative evaluation

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References Blasco, C. (2003). The functional evaluation in individual sports. Fifth Conference on the Improvement of Sports Performance. Alicante: DGD, Generalitat. Blázquez, D. (1990). Evaluation in Physical Education. Barcelona: Inde. Cabello, D. and González-Badillo, J.J. (2003). An analysis of the characteristics of competitive badminton. British Journal of Sport Medicine, 37, 18–25 Seirul-lo Vargas, F. (2003). Dynamic Systems and performance in team sports. First Meeting of Complex System and Sport. Barcelona: INEF. Tous, J. (1999). New Tendencies Towards Strength and Muscle-building. Barcelona: Fajardo.

42 The social structure of racket sports practice in Spain R. Llopis Goig and D. Llopis Goig

Introduction Tennis was ﬁrst played in Spain towards the end of the nineteenth century at the Universal Exhibition of Barcelona in 1888. A year later, the Royal Tennis Club of Barcelona was founded, now the oldest tennis club still working in Spain. In 1902 the Recreation Club of San Sebastian and the English Club of Madrid were founded. By 1909 the basis of the Royal Tennis Federation of Spain, as it is now known, was fully working and four years later became a member of the Lawn Tennis Association, which in those days established the rules for worldwide tennis playing. Even as late as 1969 the Spanish Tennis Federation only had seven thousand members while at present there are 97,309 members. This means that, according to memberships given out by Spanish Sports Federations, tennis is the eighth most popular sport played in Spain. Referring to popular sports played in Spain the latest survey on sports habits show that 8.9 per cent of the sport-playing population prefer tennis, putting this in ninth place behind swimming, football, cycling, ﬁtness, mountain sports, aerobics, jogging and basketball (García Ferrando, 2006). In Spain, tennis is a sport with a strong social impact, the proof of which is shown not only through the above-mentioned facts but also through the numerous international achievements dating from the 1960s. There have been many successful tennis players: M. Santana, A. Gimeno, M. Orantes, J. Higueras, Sánchez Vicario brother and sister, S. Bruguera, C. Costa, A. Berasátegui, A. Corretja, C. Martínez, S. Casal, J. Arrese, C. Moyá, J.C. Ferrero and R. Nadal. However, in spite of this, neither historians nor sociologists have paid much attention to tennis (Adrio, 2005). Thus, contrary to what has happened in other countries (Saeki, 1990; McKay, 1983; Vanreusel et al., 2002; Defrance and Pociello, 1993; Földesi et al., 1994) in Spain we know little about this issue. This study describes the social structure of the practice of racket sports in Spain, namely tennis, table tennis, pelota (that is to say: ‘frontón’, ‘trinquete’ and ‘frontenis’, local varieties of racket sports), paddle, squash and badminton. The study, which is a social analysis, aims to advance the scientiﬁc knowledge of these sports in the context of a more general analysis of

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Spanish sports habits (García Ferrando, 2001, 2006). The ﬁrst aim is to show the relevance of racket sports in as far as the number of people playing them, the historical evolution of the games and the nature of the playing. The second aim is to analyse the social structure and stratiﬁcations patterns of these sports practices (Bourdieu, 1991; Sugden and Tomlinson, 2000; Scheerder and Breedveld, 2004)

Methods The data analysed was gathered from the Survey on the Sports Habits of the Spanish carried out by Consejo Superior de Deportes (CSD) and Centro de Investigaciones Sociológicas (CIS) during the months of March and April 2005. During the survey 8,170 people of both sexes between the ages of 15 and 75 were interviewed. The area covered was national, including the islands, Ceuta and Melilla. The survey was carried out in 389 towns of 52 provinces. A multi-stage sample with stratiﬁed clusters and primary sampling units (municipalities) and secondary sampling units (sections) in a proportional and aleatory way, was chosen. The ﬁnal units (individuals) were found according to random assignment and sex and age quotas. The ﬁeldwork was carried out from 18 March to 25 April 2005. The sampling error for a conﬁdence level of 95.5 per cent (two sigma), a p = q, and according for a simple random sample was ± 1.11. This study needed individual samples of those playing tennis, table tennis, pelota, paddle, squash and badminton. These were included in the abovementioned Survey on the Sports Habits of the Spanish 2005. These individual samples included 440 cases, representing the Spanish population aged between 15 and 75.

Results Racket sports practice in Spain An estimated 5.4 per cent of the Spanish population aged between 15 and 74 and 14.4 per cent of the total population play some of the six racket sports available. The estimated numbers participating in each sport are given in Table 42.1. The information obtained in the available surveys on the sports habits of the Spanish allows us to trace back the evolution of racket sports over the last decade. The information contained in Table 42.2 suggests a trend towards a fall in the practice of tennis, pelota and table tennis. In the last ten years the number of those playing the ﬁrst two forms has come down to half. The other three racket sports were not included in the 1995 survey, but they were included in the 2000 survey. In the survey carried out in 2005 the trend towards a growth in the number of players stopped, at least in the case of squash and badminton.

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Table 42.1 Racket sports participation in Spain Game type

% between 15 and 75

% of total population who play sports

Estimation of number of players

Tennis Pelota Paddle Table tennis Squash Badminton

3.4 1.0 0.9 0.7 0.5 0.2

8.9 2.7 2.4 1.8 1.3 0.5

1,136,052 334,133 300,720 233,893 167,066 66,827

Total of racket sports

5.4

14.4

1,804,317

Source: Table compiled by the authors using data from Survey E-2599, CIS, April 2005.

Table 42.2 Change in participation (% of population) in racket sports in Spain Historical evolution

1995

2000

2005

Tennis Pelota Paddle Table tennis Squash Badminton

18.0 5.0 6.0 – – –

13.0 3.8 3.9 1.4 1.9 0.8

8.9 1.8 2.7 2.4 1.3 0.5

Source: Table compiled by the authors using data from Survey E-2599, CIS, April 2005. 1995 and 2000 data from Ferrando (2002).

Table 42.3 Motivation for racket sports practice Competes . . .

Tennis Table tennis Pelota

In national leagues 5.1 In local or provincial 16.4 leagues Just for fun with friends 23.3 Plays sports without 52.7 competing Refused 2.5

Paddle Squash Badminton

10.5 26.3

2.4 16.9

2.7 30.1

– 25.6

– 6.3

15.8 47.4

26.5 50.6

17.8 46.6

23.1 41.0

37.5 56.3

–

3.6

2.7

10.3

–

Source: Table compiled by the authors using data from Survey E-2599, CIS, April 2005.

In all six sports the highest percentage of those interviewed said that they play sport without worrying about competing (Table 42.3). For players of badminton, pelota or tennis, the second reason for playing is to amuse themselves with friends. Among those who play paddle, table tennis and squash there was a higher degree of participation in local or provincial leagues, but lower for pelota and tennis, and much lower among those who play badminton. Finally, participation in national leagues is 10.5 per cent for table tennis

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players and 5.1 per cent for tennis players. In the case of paddle and pelota it is 2.7 per cent and 2.4 per cent, whereas those who play squash and badminton do not participate in national leagues. Social structure of racket sports practice in Spain In this section we analyse the main social and demographic variables and their incidence on the practice of racket sports. The ﬁrst variable examined refers to sex. Table 42.4 shows that there are more men than women playing racket sports which is reﬂected in tennis. For the rest, with the exception of badminton which is the sport which shows similar proportions of male and female players, about eight in ten players are men. Table 42.4 Racket sports practice according to sex Sex

Tennis

Table tennis

Pelota

Paddle

Squash

Badminton

Total

Male Female

76.1 23.9

83.2 16.8

88.0 12.0

82.7 17.3

89.7 10.3

62.5 37.5

76.5 23.5

Source: Table compiled by the authors using data from Survey E-2599, CIS, April 2005.

Table 42.5 Racket sports practice according to age Age

Tennis

15–24 35.2 25–34 32.9 35–44 17.4 45–54 8.6 55–64 4.3 65 and more 1.7

Table tennis Pelota

Paddle

Squash

Badminton

Total

49.1 25.3 19.6 2.5 3.6 –

24.3 41.9 27.0 6.8 – –

23.1 35.9 30.8 10.3 – –

56.3 37.5 6.2 – – –

36.1 31.7 18.2 8.0 4.4 1.5

24.1 33.7 30.1 7.2 1.2 3.6

Source: Table compiled by the authors using data from Survey E-2599, CIS, April 2005.

Table 42.6 Racket sports practice according to the highest education attainment Education

Tennis Table tennis Pelota

Paddle Squash Badminton Total

Primary School Secondary School Trade qualiﬁcation A-levels University Refused/do not know

4.8 21.5

9.9 23.6

8.5 31.7

1.4 6.8

– 13.2

20.0 33.3

5.6 20.4

17.2

16.6

21.9

17.6

15.8

–

18.6

21.7 34.2 0.5

26.5 23.5 –

11.0 25.5 1.2

20.3 54.1 –

18.4 52.8 –

6.7 40.0 –

21.7 33.2 0.5

Source: Table compiled by the authors using data from Survey E-2599, CIS, April 2005.

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The second variable examined is age (Table 42.5). Two thirds of players are below 34 years. The sport with the youngest proﬁle is badminton, with 93.8 per cent of its players younger than 34 years, followed by table tennis, tennis and paddle. Pelota and squash are the sports whose players are the oldest. The third variable examined is educational attainment. Generally, 33.2 per cent of the people who practise some racket sport have a university degree (Table 42.6) but it is more than a half for those who play paddle and squash. In the case of tennis the diﬀerent educational levels are much more evenly distributed. Although those with university degrees are the most represented group (34.3 per cent), as far as table tennis players are concerned, the most common qualiﬁcation is A-levels (26.5 per cent), followed closely by those with secondary school completion (23.6 per cent) and University graduates (23.5 per cent). The other two sports, pelota and badminton have more players with secondary school and University education. The fourth variable examined is employment status (see Table 42.7). Most players are in the labour force with 63.5 per cent stated to be working. A total of 82.5 per cent of squash players worked, followed by paddle and pelota. However, we must point out that 26.5 per cent and 35.1 per cent of players of tennis and table tennis were students. Finally, among badminton players there is a clear majority of students (75 per cent).

Conclusions Racket sports are practised by an estimated 1,804,317 people in Spain. This amounts to 5.4 per cent of the Spanish population aged between 15 and 74 and 14.4 per cent of the Spanish who practise some sport. Tennis is the most played racket sport with 8.9 per cent for those who practise some sport; followed by pelota, paddle, table tennis, squash and badminton. In the last ten years, tennis, pelota and table tennis have reduced in the number of players. Squash and badminton ﬁgures have stopped growing and have reduced their growth since 2000. The social structure of these sports suggests that most Table 42.7 Racket sports practice according to employment status Employment status

Tennis Table tennis Pelota

Paddle Squash Badminton

Total

Currently working Retired/ Pensionist Unemployed Student Domestic work Others

64.5

48.9

69.0

74.0

82.5

25.0

63.5

2.4

–

7.1

–

–

–

2.2

4.6 26.5 2.0 –

12.6 35.1 1.1 2.3

4.8 15.5 2.4 1.2

4.1 19.2 1.4 1.4

7.5 10.0 – –

– 75.0 – –

5.6 26.4 1.9 0.4

Source: Table compiled by the authors using data from Survey E-2599, CIS, April 2005.

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players are male between 15 and 34 years of age, with a University degree and are in the labour force.

References Adrio, M. (2005). 1880–1936. De una Historia Gloriosa I [A Glorious History 1]. In Ciento Veinticinco Años de Tenis en España. Madrid: MA Editor. Bourdieu, P. (1991). Sport and social class. In Contemporary Perspectives in Cultural Studies: Rethinking Popular Culture (edited by C. Mukerji and M. Schudson), Berkeley: University of California Press, pp. 357–373. Defrance, J. and Pociello, C. (1993). Structure and evolution of the ﬁeld of sports in France, 1960–1990. International Review for Sociology of Sport, 28, 1–21. Földesi, G.S., Irlinger, P., Louveau, C. and Metoudi, M. (1994). East–West: the practice of sports as revealing aspects of French and Hungarian societies International Review for the Sociology of Sport, 29, 149–167. García Ferrando, M. (2001). Los Españoles y el Deporte: Prácticas y Comportamientos en la Última Década del Siglo XX [Spanish Population and Sport: Performance and Practice during the Last Decade of the twentyith Century]. Madrid: CSD. García Ferrando, M. (2002). Estructura social de la práctica deportiva [Social Structure of Sport], in Sociologia del Deporte [Sociology of Sport] (edited by M. García Ferrando, N. Pug and F. Lagardera), Madrid, Alianza Editorial, pp. 43–68. García Ferrando, M. (2006). Postmodernidad y Deporte: Entre la Individualización y la Masiﬁcación [Postmodernity and Sport: Between Innovation and Overcrowding]. Madrid: CIS/CSD. Mckay, J. (1983). The Democratization of Australian Sport. International Review for the Sociology of Sport, 18, 91–111. Saeki, T. (1990). The characteristics of sociological research on sport organization in Japan. International Review for the Sociology of Sport, 25, 109–123. Scheerder, J. and Breedveld, K. (2004). Incomplete democratisation and signs of individualisation. European Journal of Sport and Society, 1, 115–134. Sugden, J. and Tomlinson, A. (2000). Theorizing sport, social class and status. In Handbook of Sports Studies (edited by J. Coakley and E. Dunning), London: Sage, pp. 309–321. Vanreusel, B., Taks, M. and Renson, R. (2002). Belgium-Flanders. Origins, development and trends of Sport for All. In Worldwide Experiences and Trends in Sport for All (edited by L.P. DaCosta and A. Miragaya), Aachen: Meyer and Meyer Sport, pp. 379–400.

Index

Note: italic page numbers denote references to Figures/Tables. Abernethy, B. 157 acceleration 190 aces 228, 229, 240 action-perception link 150, 154–61 advance cue utilization 146, 151, 155 aerobic performance: badminton 7, 9–10, 11, 70; squash 67; table tennis 162; tennis 29–35, 36–43 Agassi, Andre 233, 234, 236 age: badminton injuries 136–7; body mass 28; cardiovascular events 121, 122; impact on anaerobic performance 22, 24, 25–7, 26, 28; relative age advantage 280–1; Spanish racket sports 298, 299 agility tests 9, 70, 72, 73–5, 73, 74, 76 alactacid energy production 9–10, 11, 22 Alain, C. 148 Alcaraz, P.E. 83–90 alcohol consumption 282, 283–4, 283 Alexander, D. 191 Álvarez, M.F. 139–42 Alvero Cruz, J.R. 64–9 amino acids 59 anaerobic performance: table tennis 162; tennis 22–8 anaerobic threshold: badminton 8, 9, 10; squash 64; tennis 30–4 ankle injuries 116, 119, 136 anthropometric proﬁles: badminton 91–5; comparative study 83–90; functional evaluation 288 anticipation 145–53, 173; ball-ﬂight 169, 172, 177, 178, 180, 181, 182; movement organization 167; perception-action perspective

154–61; sequential ball-hitting movements 177–8 anticipatory locomotion movements 169, 170, 171–2, 175, 177–8, 179–80, 181–3 arm perimeter 84, 87, 88 arousal 169, 170 assessment: integrated functional evaluation 287–94; junior badminton players 70–6 attack clear shot 200, 201, 201, 202, 202, 203 attention concentration 169, 170, 173 attitudes after injury 128 Australian Open 188 Australian tennis players 124–31 Austrian badminton players 197–203 Azarbal, M. 115 Baca, A. 208–13, 214–19 backhand stroke: badminton service 199, 199; muscle contraction 46 badminton: anthropometric proﬁles and body composition 83–90, 91–5; anticipation skill 145, 146, 147, 154, 157, 158; eﬀective playing time 6; endurance and speed testing 7–9; energy expenditure 77–82; forehand smash 102; game duration 192, 204–7; ground-foot interface 103–4; injuries 112–17; integrated functional evaluation 289–93; jump smash 100; junior players 70–6, 91–5; match characteristics 5–6; movement analysis 190; perception-action coupling 157; performance analysis 188; physiological testing 5–13; plantar supports 132–8; playing patterns

302

Index

197–203; rally times 5–6; scoring systems 192, 204–7; Spain 295, 296, 297, 297, 298, 298, 299, 299; sport identity of players 255–61; stroke frequency 6 Badminton England 70 Bahamonde, R.E. 103 ball-hitting: impact point of ball 139; psychomotor eﬃciency 169, 171; sequential ball-hitting movements 177–84 ball type 244 Barrera Expósito, J. 64–9 Baxter-Jones, A.D.G. 88, 280 Beckham, David 236 Behan, H. 187–96 Bergeron, M.F. 29 Bernales, O. 44–50 Bernstein, N.A. 158 Billat, V. 68 biomechanics 99–105; centre of gravity 139; lower extremities 132, 134; research areas 249, 251; teaching methods 272 Blasco, C. 287–94 blood glucose 52, 53, 54–5, 55 blood lactate concentrations: badminton 6, 7, 10–11; integrated functional evaluation 290, 291; squash 65–6, 66, 67–8; tennis 29, 30, 32, 33, 38, 52, 53 BMC see bone mineral content BMD see bone mineral density body composition: comparative studies 83–4, 86, 88; impact on anaerobic performance 22, 23, 24, 25, 27–8; junior badminton players 72, 73, 73, 74, 91–5, 93; see also somatotype body mass: comparative studies 84, 84, 88; hydration status 16–17, 18, 20; impact on anaerobic performance 22, 23, 24–5, 25, 27–8; junior badminton players 73, 73, 74, 92, 93–4, 93; overweight 93–4; squash 65, 67; weight loss 59–61 bone mineral content (BMC) 48 bone mineral density (BMD) 48 Bopf, G. 70, 74 Bosco test 290, 291 break points 228, 229, 230 burn-out 250, 252 Cabello, D. 7, 64–9, 132–8 caﬀeine 51–7

Calbet, J.A.L. 44–50 calcium (Ca) 80, 81 Canda, A. 92 carbohydrates 61, 80, 81 carbon dioxide production (VCO2) 38, 39, 40, 41, 42 cardiovascular events 118, 119, 120, 121, 122 Carrasco, L. 83–90 Carroll, D. 124 Carter, J.E.L. 92 catecholamine 6, 121 centre of gravity (COG) 139–42 Charland, T. 118–23 Charzewski, J. 258 Chase, M.A. 124 Chevalier, R. 36–43 children: anthropometric proﬁles and body composition 91–5; injuries 136; tennis teaching methods 269, 273; see also junior players Chin, M.K. 8, 9, 67 Choi, H.J. 227–31 Christmass, M.A. 34 Ciliga, D. 112–17, 204–7 CK see creatine kinase Clarke, S. 188 Clauser, C.E. 107 coaches: analysis of coaching process 194; assessment of athletes 287; education for 131, 253, 262–8, 285; game based teaching methods 270; health-related habits 282–6; holistic approach to coaching 271; information-movement coupling 159; integrated functional evaluation 289, 291; nutrition knowledge and habits 58–63; player-centred coaching 271; singles/doubles 190; technical evaluation 189; tennis research 251 Coen, B. 8, 9 COG see centre of gravity competition level 258, 259 competitiveness 170, 172–3, 175, 180, 182, 260 complexity 162, 167 computer technology: coaches’ use of 265–6, 267–8; ‘Hawk Eye’ 252; speciﬁc incremental test for tennis 38; table tennis match analysis 214, 215–18; tactical evaluation 239; see also simulators computerized notational analysis 187–8, 191, 193–4, 239

Index computerized scorebook 239, 240, 245 conditioning: integrated training 271; ITF physical conditioning programme 22; maintaining 128; research areas 252; see also endurance; ﬁtness coordination 272 core temperature (Tc) 14–21, 19, 52, 53, 54–5, 55 Coyle, E.F. 29 creatine kinase (CK) 52, 54–5, 55, 56 Crespo, M. 249–54, 269–74 critical points 192, 193 Croatia 283, 284 Cross, R. 139 cue utilization 146, 151, 155 Curry, T.J. 257 Dal Monte, A. 6 Damsgaard, R. 88 Dansou, P. 29 Dapena, J. 102, 103 data collection: performance analysis 193; table tennis match analysis 215–16 Davey, P.R. 29 Dawson, B. 14, 20 De Hoyo, M. 91–5 De Leva, P. 107 De Rose, E.H. 84, 92 dehydration 14, 20, 61 depression 124 Devonport, T.J. 125 Dezˇ man, B. 220–6 dietary habits 58–63 dietary intake: badminton players 78–9, 80, 81; coaches 283, 284–5, 285; veteran players 122 digitization pads 187 discovery learning 151 displacement 42, 177, 179 Dixon, S.J. 104 DLW see doubly-labelled water method Docherty, D. 6 dominant arm 44, 45–6, 47–8 doping 252 Dorado, C. 44–50 doubles 190, 207 doubly-labelled water (DLW) method 77, 78–9 Downey, J.C. 187 drive shot 200, 201 drop-out 250, 252 drop shot 199, 199, 200, 200, 201, 203

303

Drury, D.G. 20 Dufour, W. 214 Durand, M. 162 ecological approach 155 education: appropriate levels of training 131; coaches 253, 262–8, 285 educational attainment 298, 299, 300 Edwards, S. 280 eﬀective playing time (EPT) 6 eﬃciency: index of psychomotor 170, 173, 174, 175, 180–1; squash 220–6; table tennis 162–8; tennis 169–76, 180–1 Eklund, R.C. 125, 130 Elliott, B.C. 101, 102, 103, 106, 109 employment status 299, 299, 300 endurance: badminton 7–9, 10, 11; speed 180; tennis 29; see also conditioning; ﬁtness energy: range of motion 100–1; tennis serve 109 energy expenditure: badminton 77–82; table tennis 163, 166, 167; tennis 27 England Squash 193–4 EPT see eﬀective playing time equipment 250, 252, 272–3 errors: functional evaluation 292, 293; performance indicators for tennis 228, 229; table tennis match analysis 215 Esparza, F. 92 expertise: anticipation skill 154–5; locomotion behaviour 157 explicit instruction 151 Faccini, P. 6 facilitative environment 159–60 Farfel, W.S. 208 Farrow, D. 51–7 fast overhead shot 100, 102 fatigue: caﬀeine impact on 51–7; injuries due to 136–7; Integral Test of Fatigue in Badminton 289–93; time to exhaustion 33–4, 39 Faude, O. 5–13 faults 200, 228, 229 Fayt, V. 162–8 Federer, Roger 234, 236 feedback: computerized notational analysis 188–93, 239; table tennis 208–13 Ferrauti, A. 6 ﬁbrosis 137

304

Index

ﬁeld-based training 149, 150 ﬁeld testing (FT) 36, 37–43 ﬁlm-based simulation training 148–9, 150, 151 ﬁnancial rewards 257, 258–9 ﬁtness: badminton 9, 10, 70, 75; functional evaluation 287; maintaining 128; squash 67; tennis 29–35, 36–43; see also conditioning; endurance Fleck, S.J. 88 Fleisig, G. 106, 107, 109, 110 ﬂuids 61 foot injuries 116, 132–8 ‘foot work’ 169, 173, 175 footwear 116, 132 forehand smash 102, 200, 200, 201, 203 forehand stroke: anticipation of 147, 157; badminton service 199, 199; muscle contraction 46, 47; peak torques 103; table tennis 162–8; velocity 53, 55 Fox, E.L. 27 fractures 119, 120, 121 Franks, I.M. 190, 191, 220, 239 freeing 158–9 freezing 158–9 French Open 280 Fries, M. 5–13 FT see ﬁeld testing fun 269 functional evaluation 287–94; objectives of 288; qualitative 291, 293; quantitative 291, 292 Furjan-Mandic´, G. 112–17 fuzzy logic 194 Gabbett, T. 9 gait 132, 133, 134 game based teaching methods 269–70 game duration 192, 204–7 Garcin, M. 68 Garrido, R.P. 287–94 Garsztka, T. 22–8 gaze 146–7, 157 gender diﬀerences: body mass 94; cardiovascular events 121; coaches 265; energy expenditure 78, 79, 80–1; grip strength 88; junior badminton players 74, 75, 92–3, 94; junior rankings in tennis 276, 277–80, 277, 278, 279, 281; rally times 190; Spanish racket sports 298, 298, 299–300 Gijón Noguerón, G.A. 132–8 Gijón Noguerón, M. 132–8

Girard, O. 36–43, 67 goal-oriented learning 271 goal setting 126, 131 Gómez, J.R. 94 Gómez Píris, P.T. 139–42 Gonzalez-Badillo, J.J. 7 Gordon, B.J. 102, 103 Gosh, A.K. 10 Grand Slam tournaments 14, 275, 280 grass courts 188, 244 Greece 262–8 Green, J.M. 68 grip strength: comparative studies 83, 84–7, 87, 88; muscle contraction 47 Grivas, N. 262–8 ground strokes 240, 242, 243, 244–5 Guadalupe-Grau, A. 44–50 Guerra, S. 44–50 guided discovery 151 Guimaraes, A.C. 84, 92 Haake, S. 106 Hansen, G. 214 ‘Hawk Eye’ 252 Hay, R. 275 heart rate (HR): badminton 6–7, 77; cardiovascular events 121; energy expenditure 77; integrated functional evaluation 290, 291; squash 64, 65, 66, 67, 68; table tennis 163, 164, 165–6; tennis 30–1, 32–3, 34, 38–40, 41, 52, 53, 54–5, 55 heat 14, 15, 16, 20 Hellenic Tennis Federation 263, 267, 268 Hewitt, Leyton 234, 236 holistic approach to coaching 271 Homans, G.C. 256 Hong, Y. 220 Horiuchi, S. 77–82 Hornery, D.J. 51–7 HR see heart rate Hughes, M.D. 187–96, 220, 227–31, 239 Hughes, M.G. 31, 70–6 Hughes, M.T. 187–96 Hurley, C. 103–4 hydration 14–21, 122 IAT see individual anaerobic threshold IBF see International Badminton Federation identity 255–61 Igawa, S. 77–82 imagery 131

Index impact position detection 208–10, 211–12, 212 impact time interval detection 210, 211, 212 individual anaerobic threshold (IAT): badminton 8, 9, 10; squash 64; tennis 30–4 information and communication technology 208, 212; see also computer technology information-movement coupling 158–9, 160 information processing: anticipation skill 145, 146, 147–8, 155; motivation impact on 183 Ingram, B. 239, 243–4 injury: centre of gravity of paddle rackets 139, 141–2; joint torques 103; minor 125–6, 126, 127, 130; plantar supports 132, 133, 134; prevention 112–13, 118–23, 250, 251; research areas 251; return from 124–31; severe/ chronic 126–8, 128, 129, 130; table tennis and badminton players 112–17; tennis serve 109; treatment 126, 127, 128, 129 instruction: modern teaching methods for tennis 269–74; perceptual-cognitive skills 150–1; see also training Integral Test of Fatigue in Badminton 289–93 integrated functional evaluation 287–94; objectives of 288; qualitative 291, 293; quantitative 291, 292 integrated training 271, 287 International Badminton Federation (IBF) 192, 204 International Tennis Federation (ITF): ball type 244; energy expenditure 27; hot conditions 14, 15; junior world rankings and month-of-birth distributions 275, 276, 279, 280; physical conditioning programme 22; research grants 253; teaching methods 269, 273 iron 80, 81 ITF see International Tennis Federation James, N. 193 Japan Institute for Sports Sciences (JISS) 77 Johnston, L.H. 124 joint ﬂexibility 100, 101

305

joint injuries 103, 114, 115, 119, 120, 121 joint torques 103 Jørgensen, U. 112, 115 Jospin, L. 162–8 jump smash 100 jump test 70, 71, 73–5, 73, 74, 76 junior players: anthropometric proﬁles and body composition 83–90; badminton 70–6, 91–5; injuries 136, 137, 251; movement analysis 191; psychomotor predispositions 174, 174; season-of-birth eﬀects 275–81; table tennis 212; teaching methods 269 Kahn, J.-F. 118–23 Keele, S.W. 183 Khan, Jahangir 190 kinanthropometric proﬁles 83–90, 91–5, 232 Kindermann, W. 5–13 kinematics: 3D analyses 99, 101–3, 104; tennis serve 54, 56 kinetics 99, 103, 104, 106, 109 Klatsky, A.L. 284 Knight, P. 191 Knudson, D. 103 Kodama, M. 239–46 Kondricˇ , M. 112–17, 204–7 König, D. 40 Kornfeind, P. 208–13 Kovacˇ icˇ , S. 220–6 Kovacs, M. 27, 239 Kroner, K. 136 Kurata, H. 239–46 lactate concentrations: badminton 6, 7, 10–11; integrated functional evaluation 290, 291; squash 65–6, 66, 67–8; tennis 29, 30, 32, 33, 38, 52, 53 Lames, M. 214 Lapszo, J. 169–76, 177–84 LAT see Live Adaptation Technique Lazzari, S. 162–8 learning: anticipatory schema 172; equipment 272–3; goal-oriented 271; perception-action coupling 157, 158–9; stages of 273; table tennis eﬃciency 167 Lees, A. 99–105 Lenartowicz, M. 255–61 Leone, M. 88 Leser, R. 214–19 Leveque, F. 36–43

306

Index

Liddle, S.D. 5, 188, 190, 192, 239, 243 lipids 79, 80, 81 Live Adaptation Technique (LAT) 133 Llopis Goig, D. 295–300 Llopis Goig, R. 295–300 locomotor movements: psychomotor predispositions 169–76; sequential ball-hitting 177, 178; visual search behaviour 156–7 long shot 202 López de Subijana, C. 106–11 lower limbs 103–4, 132, 134; see also foot injuries Lundin, A. 162 Maeda, A. 239–46 Majumdar, P. 6, 10–11 Mantis, K. 262–8 Marfell-Jones, M. 92 Marshall, R.N. 101 Martínez, E. 83–90 match analysis 239–46 match length 192, 193, 204 mathematical modelling 191–3 Matkovic´, B. 58–63, 282–6 Matkovic´, B.R. 58–63, 282–6 Matthews, D.K. 27 McGarry, T. 188, 191, 193, 220 medical check-ups 122 medicine 249, 251 Meeusen, H.J. 183 memory 148, 169, 178 mentality 271 Mesa Alonso, A. 64–9 Meyer, T. 5–13 Meyers, R.W. 29–35 Micallef, J.P. 36–43 Millet, G.P. 36–43 mineral supplements 59 minute ventilation (VE) 38, 39, 41 Miyazaki, M. 77–82 modelling 191–3, 194 momentum analysis 194 month-of-birth distributions 275–81 motion analysis technology 99–100 motivation 169, 170, 173, 183, 260; functional evaluation 288; positive motivational climate 271; Spanish racket sports 297 motor control 250, 252 motor skill organization 162, 167 movement analysis 190–1 movement principles 100–1

Mujika, I. 51–7 Murray, Andrew 280 Murray, S. 189, 193–4 Musch, J. 275 muscle injuries 114, 115; feet 136, 137; veteran players 119, 120–1 muscles 44–50; adapted muscular recruitment 167; comparative study 87; grip strength 84–7, 88; motor speed capability 182; speciﬁc incremental ﬁtness test for tennis 42; stretchshorten cycle 101 Navarro, E. 106–11 net points 233–8 neural networking 194 Nishizono, H. 239–46 non-dominant arm 44, 45–6 ‘non optimal solicitation’ 162, 166 notational analysis 187–8, 191, 193–4, 252 nutrition 58–63, 128; coaches 282, 283, 284–5, 285; research areas 251 occlusion technique 146, 149, 154–5, 156, 157 O’Donoghue, P. 188, 190, 192, 227–31, 232–8, 239, 243–4, 275–81 oﬀensive strokes 224–5 Olmedillas, H. 44–50 Orfeuil, F. 162 orientation locomotion movements 169, 170, 171–2, 175, 177, 179–80, 181–3 orthopodiatry 132 orthotic compensator elements 133, 134 Oswald, E. 197–203 overhand shot 200, 201, 201, 202, 202, 203 overhead smash 100, 101 overtraining 127, 130, 251 overuse injuries 112, 115, 116, 251 Owen, Michael 236 oxygen uptake (VO2): badminton 6–8, 10, 11; integrated functional evaluation 289; squash 64, 67; tennis 29, 33–4, 36, 38–9, 40, 41, 42 paddle 295, 296, 297, 297, 298, 298, 299, 299 paddle rackets 139–42 Pain, M.D. 124–31 París, F. 91–5 pattern recognition 147, 151

Index Paul, G.C. 275 PCr see phosphocreatine Pearce, A.J. 14–21, 124–31 Pedisˇic´, Zˇ . 204–7 pelota 295, 296, 297, 297, 298, 298, 299, 299 perception-action link 150, 154–61 perceptual-cognitive skills 145–8, 150–1 perceptual degrees of freedom 158–9 perceptual skill 54, 56–7, 154 Pereira, A. 190 performance analysis 187–96; badminton 197–203; modelling 191–3, 194; movement analysis 190–1; proﬁling 193; reliability 193, 237; research and support 193–4; table tennis 214–19; tactical evaluation 188–9, 239, 245; technical evaluation 189; tennis 227–31, 232–8, 239–46; time analysis of Wimbledon ﬁnals 239–46; valid performance indicators 227–31; variability 232–8 performance indicators: valid 227–31; variability 232–8 performance proﬁling 193 Persˇ, J. 220–6 Petrinovic´-Zekan, L. 112–17, 204–7 phosphocreatine (PCr) 10, 27 physiological testing: badminton 5–13; squash 64–9; tennis 29–35, 36–43 physiology: functional evaluation 288; research areas 249, 252 plantar supports 132–8 player-centred coaching 271 playing patterns 197–203 Podlog, L. 125, 130 ‘point-per-rally’ scoring 191–2, 204 points analysis 200 points won 228, 229 Poland 255–61 power: junior badminton players 70, 75; tennis 27, 29 ‘Power Pads’ 187, 190 practice 159 Pradas, F. 83–90 projection skills 272 prolactin (PRL) 52, 55, 56 Proteau, L. 148 proteins 59, 61, 80, 81 proximal-to-distal sequence 101 psychology: relative age advantage 280–1; research areas 249–50, 252; skills promotion 131; social

307

recognition 255; sport psychologists 126, 127, 128, 129, 130 psychomotor eﬃciency 169–76, 180–2, 183 questionnaires: return after injury 125–9; sport identity 257–60; Survey on the Sports Habits of the Spanish 296–9 rackets: centre of gravity 139–42; teaching methods 272–3 rally shots 201–2, 203, 240 rally times: analysis of 188, 190, 240, 241, 242, 243–4; badminton 5–6, 198–9, 203; energy expenditure 27; scoring systems 191, 192 range of motion 100–1 ratings of perceived exertion (RPE): Integral Test of Fatigue in Badminton 290; squash 65, 66, 67, 68; tennis 38, 39, 42, 53, 54–5; velocity 56 RCP see respiratory compensation point reaction time 145, 173 reception skills 272 recognition 255, 256, 257, 259, 261 recovery: from injury 130; nutrition role 61 rehabilitation 112, 251 rehydration 61 Reid, M. 253 RER see respiratory exchange ratio research: functional evaluation 288; tennis 249–54 resistance to disturbances 169, 170 respiratory compensation point (RCP) 36, 39, 40, 64 respiratory exchange ratio (RER) 38, 39, 40, 41, 42 rest 122, 128, 192 retirement, premature 124 return stroke 200 risk 118 Rivas, F. 154–61 Robertson, C. 188, 220 Roddick, Andy 106, 234, 236 rotation analysis 100, 102–3, 109–10 RPE see ratings of perceived exertion Ruiz, A. 287–94 Russell, D.G. 157 Ruzˇ ic´, L. 282–6 Rymarczyk, P. 255–61 salaries, coaches 265, 267 Sampras, Pete 233 Sanchís-Moysi, J. 44–50

308

Index

Sanderson, F.H. 187, 191 Sañudo, B. 91–5 Sato, T. 77–82 Savelsbergh, G.J.P. 154–61 Schmidt, R.A. 178 scientiﬁc knowledge 251, 251, 254, 262, 267, 268 scientiﬁc methods 250–1 scoring systems 191–3, 204–7 season-of-birth eﬀects 275–81 second serve 228, 229, 230, 242, 243, 244 Seki, K. 77–82 self-talk 126, 131 self-treatment 126, 127, 128, 129 serve: angular velocity 106–11; badminton playing patterns 199, 200; kinematics 54, 56; muscle strength 46–7; peak torques 103; performance indicators 228, 229; proximal-to-distal sequence 101; return 200; second 228, 229, 230, 242, 243, 244; table tennis 210, 212, 215, 217; time analysis 240, 242, 242, 244; velocity 53, 55, 56, 56, 106–11; video observation 100 SF see stroke frequency Sharp, N.C.C. 88 Sheppard, J.M. 9 Shida, Y. 115 Simmons, C. 275 Simpson, K.J. 104 simulation training 148–9, 150, 151 simulators: psychomotor eﬃciency 170, 171, 174, 175; sequential ball-hitting movements 177–83 singles 190, 205–7 situational probabilities 147–8, 151 skinfolds: comparative studies 83–4, 85, 88; junior badminton players 72, 91–2, 93 Slaughter, M.H. 92 Slovenia 112–17, 221–5 smash shot 100, 101, 102, 200, 200, 201, 203 Smeeton, N.J. 151 Smekal, G. 6, 42 Smith, A.M. 124 smoking 282, 283, 284, 284 soccer: endurance capacity 7, 8; monthof-birth distributions 275; variability in player performance 236; visual search and locomotion behaviour 156–7 social recognition 255, 256, 257, 259, 261

social roles 255–6 social structure 295–300 sociology 252 somatotype: comparative study 83, 84, 87, 88; functional evaluation 288; junior badminton players 91–5, 93; squash players 65–6, 66, 67; see also body composition Spain 295–300 speed: badminton 8–9, 11, 70, 71–2, 73–5, 73, 74, 76; sequential ball-hitting movements 177–83; tennis 32, 33, 34, 177–83 spine injuries 116 split-step 177, 179 sponsorship 258 sport identity 255–61 sport psychologists 126, 127, 128, 129, 130 sport science 249, 250–1, 251–2, 253, 271–2 Sprigings, E. 102 sprinting 8 squash: anticipation skill 145, 146, 154; grip strength 88; modelling 191; movement analysis 190; notational analysis 187, 193–4; physiological responses 64–9; plantar supports 132–8; playing eﬃciency 220–6; rally times 5; scoring systems 191–3; Spain 295, 296, 297, 297, 298, 298, 299, 299; tactical evaluation 188–9; ventilatory breakpoints 40–2 statistics 252 Stiles, V.H. 104 strategies: eﬀective implementation of 272; game based teaching methods 270; table tennis match analysis 218, 219; variability 232–8 strength 47, 83; training 128, 252; see also grip strength stress: cardiovascular events 121; coaches 282 stretch-shorten cycle 101 stroke analysis: badminton 198, 199, 200, 201–2, 203; table tennis 215 stroke execution 220, 221, 222–5, 272 stroke frequency (SF) 6, 202 Stuempﬂe, K.J. 20 Survey on the Sports Habits of the Spanish 296–9 swipe shot 199, 200, 201, 201, 202, 202, 203 synthetic courts 188

Index TA see Tennis Australia table tennis: anthropometric proﬁles and body composition 83–90; eﬃciency 162–8; feedback systems 208–13; injuries 112–17, 118–23; practice oriented match analysis 214–19; psychomotor eﬃciency 169, 174; Spain 295, 296, 297–8, 297, 298, 299, 299; veteran players 118–23 tactical evaluation 188–9, 239, 245 tactics: eﬀective implementation of 272; game based teaching methods 270; integrated training 271; squash 220, 224, 225 Takahashi, H. 239–46 Tang, H.P. 102 task diﬃculty 163, 165, 166–7 teaching methods 269–74 technical evaluation 189 technical-tactical execution 288, 291 technique 270, 271, 272 technology 252 temporal occlusion paradigm 146, 149, 154–5, 156, 157 tendon injuries 114, 115, 119, 120–1, 120 tennis: aerobic ﬁtness 29–35, 36–43; anaerobic performance 22–8; anthropometric proﬁles and body composition 83–90; anticipation skill 145, 146, 147, 154; caﬀeine impact on fatigue 51–7; coach education 262–8; core temperature and hydration status 14–21; eﬀective playing time 6; ﬁlmbased simulation training 148; groundfoot interface 103, 104; health-related habits of coaches 282–6; kinematics 101–2; kinetics 103; muscle plasticity 44–50; net points 233–8; nutrition knowledge of coaches 58–63; observation of technique 100; oxygen uptake 6, 7; performance analysis 188; performance indicators 227–31, 233–8; psychomotor eﬃciency 169–76, 180–2; racket centre of gravity 139; rally times 5; research 249–54; return from injury 124–31; scoring systems 191–2; season-of-birth eﬀects 275–81; sequential ball-hitting movements 177–84; serve velocity 53, 55, 56, 56, 106–11; Spain 295, 296, 297–8, 297, 298, 299, 299; speciﬁc incremental test 36–43; stroke frequency 6; teaching methods 269–74; time analysis 188, 239–46

309

Tennis Australia (TA) 15, 124, 125, 130 ‘tennis leg’ 119, 120 thermal sensation 53, 54–5, 55 Therminarias, A. 20 thirst 61 3D analyses 99, 101–2, 103, 104, 107 time analysis 188, 239–46 time between points 240, 242, 244, 245 time duration per point 240, 241, 241, 243–4 time to exhaustion 33–4, 39 Tomlin, D.L. 10 Tous, J. 287–8 tracking systems 190 training: anaerobic performance 27, 28; anticipation skill 148–9, 151; badminton 9–11, 75; children 91; coach’s role 282; education about 131; feedback systems 208, 212; ﬁtness components 22; functional evaluation 288; holistic approach to coaching 271; impact on body mass 28; informationmovement coupling 159; injury during 115; injury prevention 122; integrated 271, 287; modern teaching methods for tennis 269–74; movement analysis 191; overtraining 127, 130; research areas 252; simulation 148–9, 150, 151; speciﬁc incremental ﬁtness test for tennis 42–3; squash 68; table tennis eﬃciency 163, 165, 166–7; table tennis match analysis 218; weekly sessions 258 treadmill testing (TT) 36, 37, 38–42; integrated functional evaluation 289; on-court testing comparison 30–1, 32–4; squash 64 triceps brachialis 44, 45–6, 47, 48 TT see treadmill testing Tudor-Barbaros, P. 58–63 Turner, R.H. 256 underhand shot 200, 201, 201, 202, 202, 203 Unierzyski, P. 269–74 United States Tennis Association 253 University Sport Departments 263, 266, 267, 268 US Open 233–6 Van der Kamp, J. 154–61 Van Gheluwe, B. 102 variability in performance 232–8

310

Index

VCO2 see carbon dioxide production VE see minute ventilation velocity lever 101 ventilatory threshold 8, 36, 39, 40, 41, 64 veteran players 118–23 video analysis 188, 197; squash 221; table tennis 214–15, 216, 217–18; technical evaluation 189 video simulation training 148–9, 150, 151 visual search behaviour 146–7, 147, 151, 154, 155, 156–7 vitamins 59, 80, 81 VO2 see oxygen uptake volleys 46 Vucˇ kovic´, G. 220–6 Wada, T. 239–46 warm-up 115, 252 Watanabe, E. 77–82

Way, K.I.M. 187 weight loss 59–61 Weiler, B. 6, 8, 10 Weiss, O. 255, 256, 257, 261 Wells, J. 237 Wenger, H.A. 10 whole match performance 227–30 Williams, A.M. 145–53 Wimbledon 188, 228, 239–46 Wingate test 23, 27 Winge, S. 112, 115 women: badminton game duration 205–7; coaches 264, 265, 267; see also gender diﬀerences working hours 282 world rankings 275–81 Young, J.A. 124–31 Young, W.B. 9, 51–7 Ziemann, E. 22–8