Arm Coordination, Active Drag and Propelling Efficiency in Front Crawl

Amsterdam University of Applied Sciences

Arm Coordination, Active Drag and Propelling Efficiency in Front Crawl

Seifert, L.; Schnitzler, C.; Alberty, M.; Chollet, D.; Toussaint, H.M.

Publication date 2010

Document Version Final published version Published in

Biomechanics and Medicine in Swimming XI

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Citation for published version (APA):

Seifert, L., Schnitzler, C., Alberty, M., Chollet, D., & Toussaint, H. M. (2010). Arm

Coordination, Active Drag and Propelling Efficiency in Front Crawl. In P-L. Kjendlie, R. Keig Stallman, & J. Cabri (Eds.), Biomechanics and Medicine in Swimming XI (pp. 115-117).

Norwegian School of Sport Sciences.

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Chapter 1. Invited Lectures Chapter 2. Biomechanics

Chapter 3. Physiology and Bioenergetics Chapter 4. Training and Performance

Chapter 5. Education, Advice and Biofeedback Chapter 6. Medicine and Water Safety

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B io me ch anics and M edici ne i n Swi mmi n g XI

Biomechanics and Medicine in Swimming XI

Per-Ludvik Kjendlie, Robert Keig Stallman, Jan Cabri (eds)

OSLO 2010

NORWAY

XI

Biomechanics and Medicine in Swimming XI

Per-Ludvik Kjendlie, Robert Keig Stallman, Jan Cabri (eds)

Biomechanics and Medicine in Swimming XI

Per-Ludvik Kjendlie, Robert Keig Stallman, Jan Cabri (eds)

Bibliographic information:

Biomechanics and Medicine in Swimming XI.

Proceedings of the XIth International Symposium for Biomechanics and Medicine in Swimming, Oslo, 16th -19th June 2010

Per-Ludvik Kjendlie, Robert Keig Stallman and Jan Cabri (Eds) Published by the Norwegian School of Sport Science, Oslo, 2010 ISBN 978-82-502-0438-6 (printed)

ISBN 978-82-502-0439-3 (electronic / pdf version) Printed by Nordbergtrykk as

Front cover photos © by Per Eide / Innovation Norway and Per-Ludvik Kjendlie

Front Cover Graphics by Beta Grafisk AS



Scientific Committee

Kjendlie, Per-Ludvik, NOR, (Chair) Stallman, Robert, NOR, (Chair) Cabri, Jan, NOR, (Chair) Alves, Fransisco (POR) Arellano, Raul (ESP) Aspenes, Stian (NOR) Barbosa, Tiago (POR) Castro, Flavio (BRA) Chatard, Jean Claude (FRA) Chollet, Didier (FRA) Clarys, Jan Pieter (BEL) Costill, David (USA) da Silva, Antonio (POR) Daly, Dan (BEL) Dekerle, Jeanne (FRA) Dopsaj, Milivoj (SRB) Esser-Noethlics, Marc (NOR) Fernandes, Ricardo (POR) Hollander, Peter (HOL) Issurin, Vladimir (ISR) Jürimäe, Toivo (EST) Keskinen, Kari (FIN) Langendorfer, Steven (USA) Lemyre, Nicolas (NOR) Mason, Bruce (AUS) Millet, Gregoire (SUI) Moran, Kevin (NZL) Nomura , Teruo(JPN) Ogita, Futoshi (JPN) Onodera, Sho (JPN) Payton, Carl (GBR) Pendergast, David (USA) Prins, Jan (USA) Psychariakis, Stelios (GBR) Pyne, David (AUS) Rejman, Marek (POL) Rodrigues, Ferran (ESP) Sanders, Ross (GBR) Seifert, Ludovic (FRA) Stager, Joel (USA) Swaine, Ian (GBR) Toussaint, Huub (HOL) Ungerechts, Bodo (GER) Vikander, Nils (NOR) Vilas-Boas, João Paulo (POR) Wakayoshi, Kohji (JPN) Zamparo, Paola (ITA)

BMS International Steering Group

Kari Keskinen, Finland (Chair) Jan Pieter Clarys, Belgium Bodo Ungerechts, Germany João Paulo Vilas-Boas, Portugal

Local Organizing Committee

Robert Stallman (Chair) Per-Ludvik Kjendlie (Chair) Cabri, Jan (Chair)

Bakke, Tom Atle Caspersen, Cecilie Dahl, Dagmar

Keskinen, Kari (intn. advisor) Midtun, Ingvild Riise Olstad, Bjørn Harald Steinbekken, Karoline

Vilas-Boas, João Paulo (intn. advisor)

Sponsors

The publishing of this book was supported by:

World Commission for Sport Sciences The Norwegian School of Sport Sciences Department of Physical Performance

Norwegian Research Centre for Training and Performance Norwegian Swimming Federation

Norwegian Life Saving Society Norwegian Rheumatism Association AP Lab

Coaches Infoservices Cortex Biophysik GmbH Hector Engineering Inc.

Ide AS Klubben AS Nespresso Pahlen Norge Sensorize Srl Sport-Thieme GmbH Tine AS

VitaVoss Water

BiomechanicsandmedicineinswimmingXi

4

Preface

Biomechancis and Medicine in Swimming.

40 Years of Swimming Science.

The local organizing committee for BMS2010 is proud to welcome the delegates of the XI International Symposium for Biomechanics and Medicine in Swimming. It is an honor for us, for the Norwegian School of Sport Sciences, and for Norway, to host this unique con- ference and to present this Book of Proceedings. We feel that BMS XI is a reference work which covers the central advances in aquatic science since BMS 2006 in Porto and of which you will have considerable pleasure.

The International Symposium for Biomechanics and Medicine in Swimming remains the most prestigious of all aquatic oriented scientific congresses in the world. It has also retained its’ high ideal of the classic peer review process, so essential to scientific progress.

Every submission has had the benefit of expert creative critique. Eleven times now, we have presented cutting edge research in a variety of aquatic activities and sports. Each time the challenge has been to present the best possible overview of the most important develop- ments in the four year period since the previous BMS symposium.

The first symposium was held in Brussels in 1970 and it has now been held in ten differ- ent countries and on both sides of the Atlantic. Today, BMS has a unique place and a proud tradition. The series of eleven published BMS Proceedings has formed the backbone of lit- erature in aquatic research for four decades. They are a collection of peer reviewed scientific papers commanding considerable respect and serving as a valuable resource for all who are interested in keeping up to date with aquatic research. Perhaps we should more properly be called a gathering of experts in aquatic human movement. Since the laws of nature are completely democratic, advances applied to one activity can also be applied to others. While the majority of papers lie within biomechanics, physiology and training, others are grow- ing in popularity; sociology, education, psychology, anthropometry, epidemiology, drowning prevention, special needs swimming, learn to swim, life saving, etc. - all are represented.

Its’ said that life begins at forty. We can thus expect the next forty years to be as brilliant as the last forty. The first edition of the proceedings (1971) gathered an intellectually rich mixture of the early pioneers, the established researchers and young, aspiring investigators.

It read like the Who’s Who of aquatic research, including the pioneers T.K. Cureton Jr. who already in 1930 had published a biomechanical analysis of the crawl kick and Dr. Ernst Jokl. It also included established researchers of the day such as Dr. James “Doc” Counsil- man who introduced us to Bernoulli’s principle as a possible explanation for propulsion in swimming and Dr. Per-Olof Åstrand who introduced the first swimming mill or flume. Dr.

Leon Lewillie and Dr. Barthels and Dr. Adrian introduced underwater electromyography.

Dr. Mitsumasa Miyashita and Dr. Richard Nelson presented, at that time, sophisticated analyses of the crawl.

A systematic attempt to broaden the base of BMS characterized the Oslo meeting. Ar- eas previously less well represented are present in larger numbers than ever before. This was extremely satisfying to us and we hope that the BMS family will continue this tradi- tion. There are really three principles here which are important. Firstly, the quality of the research is what counts, not the activity to which it is applied. Secondly, by including more academic disciplines and aquatic activities, a far greater degree of cross-fertilization of ideas is possible. To give an obvious example, the biomechanical techniques applied to analyze competitive swimming can also be used to analyze recreational swimming, learn to swim, water polo and life saving. And thirdly, multi-disciplinary research will grow. We know that this is where reality is best mirrored.

The BMS Symposium 2010 includes 127 poster presentations, 125 oral presentations, three workshops and four poolside demonstrations. Also, nine keynote speakers presented outstanding lectures to the audience. The keynote speakers Dr. Stephen Langendorfer, Dr.

Preface

5 Nicolas Lemyre, Dr. Bruce Mason, Dr. Katszuo Matsuuchi, Dr. Jan Prins, Dr. Ferran Ro-

driguez, Dr. Annie Rouard, Dr. Ludovic Seifert and Dr. João Paulo Vilas-Boas are honored especially for their contribution. These contributions ensure that the essence of our confer- ence series is passed on, and these backbone presentations present the current research in their respective fields. In honor of the BMS community’s 40th anniversary, the first paper in this book is from the hand of Dr. Vilas-Boas and is entitled “Past, Present and Future of Swimming Science”.

The 147 papers in this book are organized into 6 different chapters, reflecting each pa- per’s scientific discipline. We take also this opportunity to thank all of the authors who contributed to these papers. Their contribution often represents months of work, sometimes years. It builds on a lifetime of experience and collegial exchange of ideas, often these days, across international borders.

The BMS Symposium 2010 would not have been possible without our partners, ex- hibitors and sponsors. We thank The Norwegian School of Sport Sciences, The Norwe- gian Swimming Federation, The Norwegian Lifesaving Association and the Norwegian Rheumatism Association. This kind of contact between BMS and practitioners ensures that aquatic science adapts to, and studies real life, applied situations. We would also like to thank our sponsors and exhibitors for their contribution to making BMS 2010 happen;

All of the volunteers are thanked for making BMS a memorable conference. We hope you, in the midst of your hard work, gained valuable experience as well as enjoyable mo- ments. The Scientific and Organizing committees provided laudable effort in preparing for this conference. We thank you deeply for your contribution. We thank also the International Steering Group of BMS for providing expert advice and for providing the continuity which has made 40 years of BMS possible. Finally we wish to honor The Norwegian School of Sport Science and its Rector, Prof. Sigmund Loland, for making BMS in Oslo possible. In difficult financial times all over the world, the support of The Norwegian School of Sport Sciences ensured the conference by providing the venue, pool, personnel and specifically sponsoring the banquet. Finally this book would not have been a reality without the edito- rial assistance of Bjørn Harald Olstad and Ingvild Riise Midtun.

We hope you will enjoy reading the contributions of this fine congress!

Per-Ludvik Kjendlie Robert Keig Stallman Jan Cabri Oslo, June 16^th 2010

BiomechanicsandmedicineinswimmingXi

6

Table of Contents

Preface

Biomechancis and Medicine in Swimming.; 40 Years of Swimming

Science. 4

Chapter 1. Invited Lectures

Langendorfer, S.J. 20

The Psycho-Physiology of Overtraining and Athlete Burnout in

Swimming - Lemyre, P.-N. 22

Biomechanical Services and Research for Top Level Swimming: the Australian Institute of Sport Model - Mason, B.R. 25 Aquatic Training in Rehabilitation and Preventive Medicine - Prins, J.

28

Training at Real and Simulated Altitude in Swimming: Too High

Expectations? - Rodríguez, F.A. 30

Muscle Fatigue in Swimming - Rouard, A.H. 33 Inter-Limb Coordination in Swimming - Seifert, L. 35

Chapter 2. Biomechanics

Comparison of Manikin Carry Performance by Lifeguards and Life- savers When Using Barefoot, Flexible and Fiber Fins - Abraldes, J.A., Soares, S.2, Lima, A.B., Fernandes, R.J. Vilas-Boas, J.P. 42 Effect of Stroke Drills on Intra-cycle Hip Velocity in Front Crawl -

Arellano R., Domínguez-Castells R., Perez-Infantes E., Sánchez E. 45 The Usefulness of the Fully Tethered Swimming for 50-m Breaststroke

Performance Prediction - Barbosa A.C. Milivoj Dopsaj M.2, Okicic T.

Andries Júnior O. 47

Joint Torque Request for Different Fin Uses - Gouvernet, G., Rao, G., Barla, C. 1, Baly, L., Grélot, L., Berton, E. 50 3D Computational Fluid-structure Interaction Model for the Estima-

tion of Propulsive Forces of a Flexible Monofin Bideau, N. , Razafimahery, F. , Monier, L. , Mahiou, B. ,

Nicolas, G. , Bideau, B. , Rakotomanana, L. 52 Do Fastskin Swimsuits Influence Coordination in Front Crawl Swim- ming and Glide? - Chollet, D., Chavallard, F., Seifert, L., Lemaître, F.

55

The Effect of Wearing a Synthetic Rubber Suit on Hydrostatic Lift and Lung Volume - Cortesi, M. , Zamparo, P. , Tam, E., Da Boit, M.,

Gatta, G. 57

The Development of a Component Based Approach for Swim Start Analysis - Cossor, J.M., Slawson, S.E.², Justham, L.M., Conway, P.P.²,

West, A.A. 59

Hydrodynamic Characterization of the First and Second Glide Posi- tions of the Underwater Stroke Technique in Breaststroke - Costa, L.; Ribeiro, J.; Figueiredo, P.; Fernandes, R.J.; Marinho, D.; Silva, A.J.,4; Rouboa, A.,4; Vilas-Boas, J.P.1; Machado, L. 62

Biomechanical Characterization of the Backstroke Start in Immerged and Emerged Feet Conditions - De Jesus, K., De Jesus, K., Figueiredo, P., Gonçalves, P., Pereira, S.M., Vilas-Boas, J.P. Fernandes, R.J. 64 Tethered Force Production in Standard and Contra-standard Scull-

ing in Synchronized Swimming - Diogo, V., Soares, S., Tourino, C., Abraldes, J.A., Ferragut, C., Morouço, P., Figueiredo, P., Vilas-Boas, J.P.,

Fernandes, R.J. 67

Pulling Force Characteristics of 10 s Maximal Tethered Eggbeater Kick in Elite Water Polo Players: A Pilot Study - Dopsaj, M. 69 Motor Coordination During the Underwater Undulatory Swimming

Phase of the Start for High Level Swimmers - Elipot, M. , 2, Houel,

N. 2, Hellard, P. 2, Dietrich, G. 72

Relationship between Arm Coordination and Energy Cost in Front Crawl Swimming - Fernandes, R.J., Morais, P., Keskinen, K.L., Seif-

ert, L., Chollet, D., Vilas-Boas, J.P. 74

Evaluation of the Validity of Radar for Measuring Throwing Velocities in Water Polo - Ferragut, C., Alcaraz, P.E.1, Vila, H., Abraldes, J.A.,

Rodriguez, N. 77

Biophysical Analysis of the 200m Front Crawl Swimming: a Case Study - Figueiredo, P., Sousa, A.1; Gonçalves, P., Pereira, S.M., Soares,

S., Vilas-Boas, J.P., Fernandes, R.J. 79

Measuring Active Drag within the Different Phases of Front Crawl Swimming - Formosa, D. P., Mason, B.R. & Burkett, B. J. 82 The Mechanical Power Output in Water Polo Game: a Case Report -

Gatta, G., Fantozzi, S., Cortesi, M., Patti, F., Bonifazi, M. 84 Comparison of Combinations of Vectors to define the Plane of the

Hand in order to calculate the Attack Angle during the Sculling Mo- tion - Gomes, L.E.1, Melo, M.O.1, La Torre, M. 1, Loss, J.F. 86 The Acute Effect of Front Crawl Sprint-resisted Swimming on the

Direction of the Resultant Force of the Hand - Gourgoulis, V., Ag- geloussis, N., Mavridis, G., Boli, A., Toubekis, A.G., Kasimatis, P., Vezos,

N., Mavrommatis, G. 89

Relationship between Eggbeater Kick and Support Scull Skills, and

Isokinetic Peak Torque - Homma, M. 91

A Biomechanical Comparison of Elite Swimmers Start Performance Using the Traditional Track Start and the New Kick Start - Honda, K.E., Sinclair, P.J., Mason, B.R. & Pease, D.L. 94 Kinematic Analysis of Undulatory Underwater Swimming during

a Grab Start of National Level Swimmers - Houel N., Elipot M.,

Andrée F., Hellard H. 97

Comparison of Front Crawl Swimming Drag between Elite and Non- Elite Swimmers Using Pressure Measurement and Motion Analysis - Ichikawa, H., Miwa, T., Takeda, T., Takagi, H., Tsubakimoto, S.

100

Whole Body Observation and Visualized Motion Analysis of Swim-

ming - Ito, S., Okuno, K. 102

A Full Body Computational Fluid Dynamic Analysis of the Freestyle Stroke of a Previous Sprint Freestyle World Record Holder - Keys, M.1; Lyttle, A.2; Blanksby, B.A.1 & Cheng, L. 105 An Analysis of an Underwater Turn for Butterfly and Breaststroke -

Kishimoto, T.,Takeda, T.,Sugimoto, S., Tsubakimoto, S.2 and Takagi, H.

108

Mechanical and Propulsive Efficiency of Swimmers in Different Zones of Energy Supply - Kolmogorov, S.V., Vorontsov, A.R., Rumyantseva,

O.A., Kochergin, A.B. 110

Preface

7

Prediction of Propulsive Force Exerted by the Hand in Swimming -

Kudo, S. and Lee, M.K. 112

Arm Coordination, Active Drag and Propelling Efficiency in Front Crawl - Seifert, L., Schnitzler, C., Alberty, M., Chollet, D. 1, Toussaint,

H.M. 115

Modelling Arm Coordination in Front Crawl - Seifert, L., Chollet, D.

117

Different Frequential Acceleration Spectrums in Front Crawl - Made- ra, J., González, L.M., García Massó, X., Benavent, J., Colado, J.C.,

Tella, V. 119

The Gliding Phase in Swimming: The Effect of Water Depth - Marin- ho, D.A., Barbosa, T.M., Mantripragada, N., Vilas-Boas, J.P., Rouard, A.H., Mantha, V.R., Rouboa, A.I., Silva, A.J. 122 A Method to Estimate Active Drag over a Range of Swimming Ve-

locities which may be used to Evaluate the Stroke Mechanics of the Swimmer - Mason, B.R., Formosa, D.P., Toussaint, H.M. 124 50m Race Components Times Analysis Based on a Regression Analy- sis Model Applied to Age-Group Swimmers - Morales, E. , Arellano, R. , Femia, P. , Mercade, J. , Haljand R. 127 Regression Analysis Model Applied to Age-Group Swimmers: Study

of Stroke Rate, Stroke Length and Stroke Index - Morales, E., Arel-

lano, R., Femia, P., Mercade, J. 130

Advanced Biomechanical Simulations in Swimming Enabled by Exten- sions of Swimming Human Simulation Model “SWUM” - Nakashima, M., Kiuchi, H., Maeda, S., Kamiya, S., Nakajima, K.,

Takagi, H. 132

Influences of the Back Plate on Competitive Swimming Starting Mo- tion in Particular Projection Skill; Kinematical Characterisation of a Basic Head-out Aquatic Exercise during an Incremental Protocol - Oliveira, C., Teixeira, G., Costa, M.J., Marinho, D.A., Silva, A.J.,

Barbosa, T.M. , 137

Influence of Swimming Speed on the Affected- and Unaffected-Arm Stroke Phases of Competitive Unilateral Arm Amputee Front Crawl Swimmers - Osborough, C.D., Payton, C.J., Daly, D.J. 140 Co-ordination Changes during a Maximal Effort 100 m Short Course Breaststroke Swim - Oxford, S., James, R., Price, M., Payton, C.

142

The Effect of Angle of Attack and Depth on Passive Drag - Pease, D.L.

1, Vennell, R. 145

Graphic Removal of Water Wave Impact in the Pool Wall during the Flip Turn - Pereira, S.M., Gonçalves, P., Fernandes, R.J., Machado, L.,

Roesler, H., Vilas-Boas, J.P. 148

Extending the Critical Force Model to Approach Critical Power in Tethered Swimming, and its Relationship to the Indices at Maximal Lactate Steady-State - Pessôa Filho, D.M., Denadai, B.S. 151 Preliminary Results of a “Multi-2D” Kinematic Analysis of “Straight- vs. Bent-arm” Freestyle Swimming, Using High-Speed Videogra- phy. - Prins, J.H., Murata, N.M., & Allen, J. S. III. 154 Biomechanical Factors Influencing Tumble Turn Performance of Elite Female Swimmers - Puel, F., Morlier, J., Cid, M., Chollet, D., Hellard,

P. 155

Front Crawl and Backstroke Arm Coordination in Swimmers with Down Syndrome - Querido, A., Marques-Aleixo, I., Figueiredo, P., Seifert, L., Chollet, D., Vilas-Boas, J.P., Daly, D.J., Corredeira, R.,

Fernandes, R.J. 157

Identifying Determinant Movement Sequences in Monofin Swim- ming Technique - Rejman, M. & Staszkiewicz, A. 160 Evaluation of the Gliding Capacity of a Swimmer - Roig, A. 163 Effects of a BlueseventyTM Bodysuit on Spatial-temporal and

Coordinative Parameters During an All-out 50-m Front Crawl - Silveira, R.P., Kanefuku, J.Y., Moré, F.C., Castro, F.A.S.

165

Fatigue Analysis of 100 Meters All-Out Front Crawl Using Surface EMG - Stirn, I. Jarm, T., Kapus, V., Strojnik, V. 168 Comparison Among Three Types of Relay Starts in Competitive

Swimming - Takeda, T., Takagi, H., Tsubakimoto, S. 170 A Study About the 3D Acceleration in Front Crawl and its Relation

With Performance - Tella, V., Madera, J., Colado, J.C., Mateu, J.,

García Massó, X., González, L.M. 173

Aquatic Space Activities – Practice Needs Theory - Ungerechts, B.,

Klauck, J². 175

Analysis of Swim Turning, Underwater Gliding and Stroke Resump- tion Phases in Top Division Swimmers using a Wearable Inertial Sensor Device - Vannozzi, G., Donati, M., Gatta G. & Cappozzo, A.

178

Influence of Swimming Start Styles on Biomechanics and Angular Momentum - Vantorre, J., Seifert, L., Bideau, B., Nicolas, G., Fer- nandes, R.J., Vilas-Boas, J.P., Chollet, D. 180 The Validity and Reliability of a Procedure for Competition Analysis

in Swimming Based on Individual Distance Measurements - Veiga, S., Cala, A., González Frutos, P., Navarro, E. 182 An Analysis of the Underwater Gliding Motion in Collegiate Com-

petitive Swimmers - Wada, T., Sato, T., Ohishi, K., Tago, T., Izumi, T., Matsumoto, T., Yamamoto, N., Isaka, T., Shimoyama, Y. 185 Head Out Swimming in Water Polo: a Comparison with Front Crawl in Young Female Players - Zamparo, P., Falco, S. 187

Chapter 3. Physiology and Bioenergetics

Polo Players - Dopsaj, M. 192

Critical Velocity and the Velocity at Maximal Lactate Steady State in

Swimming - Espada, M.A., Alves, F.B. 194

Modelling the VO₂ Slow Component in Elite Long Distance Swim- mers at the Velocity Associated with Lactate Threshold - Hellard, P. , Dekerle, J., Nesi, X., Toussaint, J.F., Houel, N., Hausswirth, C. 196 The Impact of Tension in Abdominal and Lumbar Musculature in

Swimmers on Ventilatory and Cardiovascular Functions - Henrich,

T.W., Pankey, R.B. Soukup, G.J. 199

Relationship between Propelling Efficiency and Swimming Perfor- mance in Elite Swimmers. - Huang, Z., Kurobe, K., Nishiwaki, M., Ozawa, G., Tanaka, T., Taguchi, N., Ogita, F. 201 Effect of Increasing Energy Cost on Arm Coordination at Different

Exercise Intensities in Elite Sprint Swimmers - Komar, J.1, Leprêtre, P.M.2, Alberty, M.3, Vantorre, J.1, Fernandes, R.J.4, Hellard, P.,6,

Chollet, D.1, Seifert, L. 204

Swimming and Respiratory Muscle Endurance Training: A Case Study - Lemaître, F., Chavallard, F., Chollet, D. 206

BiomechanicsandmedicineinswimmingXi

8

Heart Rate Responses During Gradually Increasing and Decreasing Exercise in Water - Nishimura, K., Nose, Y., Yoshioka, A., Kawano, H.,

Onodera, S., Takamoto, N. 208

Effects of Recently Developed Swimwear on Drag During Front Crawl Swimming; - Ogita, F., Huang, Z., Kurobe, K., Ozawa, G.,

Taguchi,T., Tanaka, T. 211

Relationship between Heart Rate and Water Depth in the Stand- ing Position - Onodera, S., Yoshioka, A., Matsumoto, N., Takahara, T., Nose, Y. 1, Hirao, M., Seki, K., Nishimura, K., Baik, W., Hara, H.,

Murakawa, T. 213

Oxygen Uptake Kinetics Around the Respiratory Compensation Point in Swimming - Pessôa Filho, D.M., Reis, J.F., Alves, F.B., Denadai,

B.S. 215

Hormonal, Immune, Autonomic and Mood State Variation in the Initial Preparation Phase of a Winter Season, in Portuguese Male Swimmers - Rama, L., Alves, F., Teixeira, A. 217 Oxygen Uptake Kinetics and Performance in Swimming - Reis, J.F.,

Alves, F.B. 220

Maximum Blood Lactate Concentration after two Different Specific Tests in Freestyle Swimming - Rozi, G., Thanopoulos, V., Dopsaj, M.

222

Can Blood Glucose Threshold be Determined in Swimmers Early in the Swimming Season? - Sengoku, Y., Nakamura, K., Takeda, T. ,

Nabekura, Y., Tsubakimoto, S. 224

The Effects of Rubber Swimsuits on Swimmers Using a Lactic Acid Curve Test - Shiraki, T., Wakayoshi, K., Hata, H., Yamamoto, T., Tomi-

kawa, M. 226

Some Factors Limiting Energy Supply in 200m Front Crawl Swim- ming - Strumbelj, B., Usaj, A., Kapus, J., Bednarik, J. 228 Lactate Comparison Between 100m Freestyle and Tethered Swim-

ming of Equal Duration - Thanopoulos, V., Rozi, G., Platanou, T.

230

Blood Lactate Concentration and Clearance in Elite Swimmers Dur- ing Competition - Vescovi, J.D., Falenchuk, O., Wells G.D. 233 Determination and Validity of Critical Velocity in Front Crawl, Arm

Stroke and Leg Kick as an Index of Endurance Performance in Competitive Swimmers - Wakayoshi, K., Shiraki, T., Ogita, F., Kita-

jima, M. 236

Differences In Methods Determining The Anaerobic Threshold Of Triathletes In The Water - Zoretić, D., Wertheimer, V., Leko, G. 238

Chapter 4. Training and Performance

Continuous Swimming and 4x50m ‘’Broken Swimming’’ with Dif- ferent Rest Intervals - Beidaris, N., Botonis, P. and Platanou, T. 242 General Indexes of Crawl Swimming Velocity of Junior Water Polo

Players in a Match - Bratusa, F.Z., Perisic, S.M., Dopsaj, J.M. 245 Bench Press and Leg Press Strength and its Relationship with In-

Water Force and Swimming Performance when Measured in-season in Male and Female Age-group Swimmers - Carl, D.L., Leslie, N., Dickerson, T., Griffin, B., Marksteiner, A. 247 Effect of Start Time Feedback on Swimming Start Performance. - de

la Fuente, B. and Arellano, R. 249

Predictors of Performance in Pre-Pubertal and Pubertal Male and Female Swimmers - Douda, H.T., Toubekis, A.G., Georgiou, Ch.,

Gourgoulis, V. and Tokmakidis, S.P. 252

Changes of Competitive Performance, Training Load and Tethered Force During Tapering in Young Swimmers - Drosou, E., Toubekis, A.G., Gourgoulis, V., Thomaidis, S., Douda, H., Tokmakidis, S.P. 254 Perceived Exertion at Different Percents of The Critical Velocity in

Front Crawl - Franken, M., Diefenthaeler, F., de Souza Castro, F.A.

257

Ventilatory and Biomechanical Responses in Short vs. Long Interval Training in Elite Long Distance Swimmers. - Hellard, P., Dekerle, J., Nesi, X., Toussaint, J.F., Houel, N.1, Hausswirth, C. 259 Talent Prognosis in Young Swimmers - Hohmann, A.1, Seidel, I. 262 Determination of Lactate Threshold with Four Different Analysis

Techniques for Pool Testing in Swimmers; Competitive Systemati- zation in Age-group Swimming: An Evaluation of Performances, Maturational Considerations, and International Paradigms - Kojima,

K. and Stager, J.M. 267

Effects of Reduced Knee-bend on 100 Butterfly Performance: A Case Study Using the Men’s Asian and Japanese Record Holder - Ide, T., Yoshimura, Y., Kawamoto, K., Takise, S., Kawakami, T. 270 Stability and Prediction of 100-m Breaststroke Performance During

The Careers of Elite Swimmers - Costa, M.J.; Marinho, D.A., Reis, V.M., Silva, A.J., Bragada, J.A., Barbosa, T.M.,4 272 Effect of Subjective Effort on Stroke Timing in Breaststroke Swim-

ming - Ohba, M., Sato, S., Shimoyama, Y., Sato, D. 274 Models for Assessing General Horizontal Swimming Abilities of

Junior Water Polo Players According to Playing Position - Özkol, Z., Dopsaj, M., Thanopoulos, V., Bratusa, Z. 276 A Markov Chain Model of Elite Water Polo Competition - Pfeiffer,

M., Hohmann, A., Siegel, A., Böhnlein, S. 278

Throwing Accuracy of Water Polo Players of Different Training Age and Fitness Levels in a Static Position and after Previous Swim-

ming - Platanou, T. and Botonis, P. 281

The Effect of Cognition-Based Technique Training on Stroke Length in Age-Group Swimmers - Schmidt, A.C., Ungerechts, B.E., Buss, W.1

& Schack, T. 283

Assessing Mental Workload at Maximal Intensity in Swimming Using the NASA-TLX Questionnaire - Schnitzler, C., Seifert, L., Chollet,

D. 286

Does the Y-Intercept of a Regression Line in the Critical Velocity Concept Represent the Index for Evaluating Anaerobic Capacity? - Shimoyama, Y., Okita, K., Baba,Y., Sato, D. 288 Evaluation of Force Production and Fatigue using an Anaerobic Test

Performed by Differently Matured Swimmers - Soares, S., Silva, R., Aleixo, I., Machado, L., Fernandes, R.J., Maia, J., Vilas-Boas, J.P. 291 Identification of a Bias in the Natural Progression of Swim Perfor-

mance - Stager, J.M., Brammer, C.L., Tanner, D.A. 294 Tethered Swimming as an Evaluation Tool of Single Arm-Stroke

Force - Toubekis, A.G., Gourgoulis, V., Tokmakidis, S.P. 296 Blood Lactate Responses During Interval Training Corresponding

to Critical Velocity in Age-Group Female Swimmers - Tsalis, G., Toubekis, A.G., Michailidou, D., Gourgoulis, V., Douda, H., Tokmakidis,

S.P. 299

Preface

9

Monitoring Swim Training Based on Mean Intensity Strain and Individual Stress Reaction of an Elite Swimmer - Ungerechts, B.E.,

Steffen, R., and Vogel, K. 302

Accelerometry as a Means of Quantifying Training Distance and Speed in Competitive Swimmers. - Wright, B.V. , Hinman, M.G. ,

Stager, J.M. 305

Critical Swimming Speed Obtained by the 200-400 Meters Model in Young Swimmers - Zacca, R., Castro, F.A.S. 307

Chapter 5. Education, Advice and Biofeedback

the “Biomechanics and Medicine in Swimming” Proceedings Books from 1971 to 2006 - Barbosa, T.M., Pinto, E., Cruz, A.M., Marinho, D.A.,, Silva, A.J., Reis, V.M., Costa, M.J., Queirós ,T.M. 312 Quantitative Data Supplements Qualitative Evaluations of Butterfly

Swimming - Becker, T.J., Havriluk, R. 314

The Effect of Restricting the Visual Perceptual Task in the Temporal Organization of Crawl Swimming: Surface Characteristics - Brito,

C.A.F., Belvis, W.C., Oliveira, M. 2 317

Analyses of Instruction for Breath Control While Swimming the Breaststroke - Hara, H., Yoshioka, A., Matsumoto, N., Nose, Y., Wata-

nabe, R., Shibata, Y., Onodera, S. 319

Performance Level Differences in Swimming: Relative Contributions of Strength and Technique - Havriluk, R. 321 Evaluation of Kinaesthetic Differentiation Abilities in Male and Fe-

male Swimmers - Invernizzi, P.L., Longo, S., Scurati, R., Michielon,

G. 324

Swimming in Eyesight Deprivation: Relationships with Sensory- Perception, Coordination and laterality - Invernizzi, P.L., Longo, S.,

Tadini, F., Scurati, R. 326

Progression in Teaching Beginning Swimming: Rank Order by Degree of Difficulty - Junge, M., Blixt, T., Stallman, R.K, , 329 The Construct Validity of a Traditional 25m Test of Swimming Com-

petence - Junge, M., Blixt, T., Stallman, R.K., 331 Using a Scalogram to Identify an Appropriate Instructional Order for Swimming Items - Langendorfer, S.J., Chaya, J.A. 333 Imagery Training in Young Swimmers: Effects on the Flow State and

on Performance - Scurati, R., Michielon, G., Longo, S., Invernizzi,

P.L. 336

Shallow or Deep Water for Adjustment? A Study in Children Aged 3 to 6 Years - Scurati, R., Michielon, G., Longo, S., Invernizzi, P.L.

339

The Effect of a Target Sound Made by a Model Swimmer’s Dolphin Kick Movement on Another Swimmer’s Dolphin Kick Performance - Shimojo, H., Ichikawa, H., Tsubakimoto, S., Takagi, H. 341 Tendencies in Natural Selection of High Level Young Swimmers -

TimakovaT.S., Klyuchnikova M.V. 343

The Cognitive Interplay Between Sensory and Biomechanical Features While Executing Flip Turns Wearing Different Swim Suits - Vieluf, S., Ungerechts, B.E., Toussaint, H.M., Lex, H. 1, Schack, T. 346 The Role of Verbal Information about Sensory Experience from

Movement Apparatus in the Process of Swimming Economization

- Zatoń, K. 349

Chapter 6. Medicine and Water Safety

Teaching Applications - Avramidis, S., McKenna, J., Long, J., But-

terly, R., Llewellyn, J.D. 354

Swimming, Cycling, Running and Cardiovascular Health - Bagheri, A.B., Mohebbi, H.D., Azizi, M.H., Saiiari, A.R. 357 Analysis of Aerobic/Anaerobic Performance in Functionally Disabled

Swimmers: Low Classes vs High Classes - De Aymerich, J., Bena- vent, J., Tella, V., Colado, J.C., González, L.M., García-Massó, X. 2,

Madera, J. 359

Athletic Rehabilitation of a Platform Diver for Return to Competition after a Shoulder Dislocation - Fujinawa, O., Kondo, Y., Tachikawa,

K., Jigami, H., Hirose, K., Matsunaga, H. 362

Comparisons of Water- and Land-based Physical Activity Interven- tions in Japanese Subjects with Metabolic Syndrome - Hanai, A. and

Yamatsu, K. 364

Estimation Method for Energy Expenditure by Acceleration of Hu- man Head during Water Walking - Kaneda, K., Ohgi, Y., Tanaka, C.

366

Real and Perceived Swimming Competency, Risk Estimation, and Preventing Drowning among New Zealand Youth - Moran, K.

368

Keeping the Safety Messages Simple: The International Task Force on Open-Water Recreational Drowning Prevention - Quan, L., Ben-

nett, E., Moran, K. (co-chairs) 371

Immune Status Changes and URTI Incidence in the Initial 7 Weeks of a Winter Training Season in Portuguese Swimmers - Rama, L., Alves, F.B., Rosado, F., Azevedo, S., Matos, A., Henriques, A., Paiva, A.

3, Teixeira, AM. 374

Swimming Ability, Perceived Competence and Perceived Risk among Young Adults - Stallman, R.K., Dahl D.1, Moran, K., Kjendlie, P.L., 377

Movement Economy in Breaststroke Swimming: A Survival Perspec- tive - Stallman R.K., Major J., Hemmer S., Haavaag G. 379 Post-exercise Hypotension and Blood Lipoprotein Changes follow-

ing Swimming Exercise - Tanaka, H., Sommerlad, S.M., Renzi, C.P.,

Barnes, J.N., and Nualnim, N. 381

A Conceptual Paper on the Benefits of a Non-Governmental Search and Rescue Organization - Wengelin, M., de Wet, T. 384

Author Index

chaPter2.Biomechanics

115

Arm Coordination, Active Drag and Propelling

Efficiency in Front Crawl

seifert, l. ¹, schnitzler, c. ^1,2, Alberty, M. ³, chollet, d. ¹, tous- saint, h.M. ⁴

1 CETAPS EA 3832, Faculty of Sports Sciences, University of Rouen, France

2 Faculty of Sports Sciences, Strasbourg Marc Bloch University, France

3 LEMH EA 3608, Faculty of Sports Sciences, University of Lille, France

4 Move Institute, Vrije University, Amsterdam, The Netherlands

Active drag, regularity and Index of Coordination (IdC) all increase with speed in front crawl swimming, but the link between those pa- rameters remains unclear. The aim of this study was thus to examine the relationships between the index of coordination (IdC) and propel- ling efficiency (e_p) and the active drag (D). Thirteen national level male swimmers completed two incremental speed tests swimming front crawl with arms only in free condition and using a Measurement of Active Drag (MAD) system. The results showed that inter-arm coordination was linked to active drag and not propelling efficiency.

Key words: Biomechanics, motor control, efficiency IntroductIon

Swimming speed results from the interaction of propulsive and resistive forces. However, as the swimmer’s hand lacks a fixed push of point to propel the body forward, mechanical power applied by the hand in the water is wasted in kinetic energy imparted to the water (P_k). Thus the total mechanical power out-put (P_o) is the sum of the kinetic power (P_k) and power delivered to overcome drag force (P_d). Toussaint et al. (2006) defined the propelling efficiency (e_p) as the ratio between P_d and P_o. The question remains how the inter-arm coordination in front crawl can be organised to have the highest e_p? For example, does superposition mode of coordination, in comparison to catch-up mode, relates to a higher e_p? Indeed, in superposition mode the total propelling force is shared by the two hands (for a brief moment in time) and it looks like force is generated with a double hand-surface. Previously, Toussaint et al. (1991) demonstrated that using paddles e_p increases by 7.8%.

Chollet et al. (2000) proposed the Index of Coordination (IdC) to quantify the lag time, continuity or superposition between the propul- sive actions of the two arms. These authors observed that IdC changed from catch-up (IdC<0%) to superposition (IdC>0%) mode when the swimmers increased their speed from the 800-m race pace to 100-m race pace. Examining eight race paces (from 1500-m to maximal speed), Seifert et al. (2007b) noted that above a critical value of speed (1.8 m·s^-1) and stroke rate (50 stroke·minute^-1), only the superposition coordina- tion mode occurred in elite sprinters. Thus, it seemed that swimming at higher speeds requires an increase in IdC. In fact, Alberty et al. (2009), Seifert et al. (2007a) respectively showed that through a 400-m and a 100-m, some swimmers increased their IdC from the first to the last lap but at the same time, decreased their swimming speed and their stroke length due to fatigue. In this case, the increase in propulsive continuity between the two arms (i.e. higher IdC) seemed an effective way to deal with fatigue, i.e. a reduction in ability to deliver work per stroke. Because of the above, the first aim of this study was to explore whether inter- arm coordination was linked to propelling efficiency when swimming at maximal speed on 25-m.

Secondly, considering that active drag (D) increases with speed square, and that IdC also increases with speed following a quadratic re- gression (Seifert & Chollet, 2009), the relationship between active drag and inter-arm coordination was investigated, also. This was carried out to examine to what extent overcoming the aquatic resistances is related to the increase of the propulsive forces and to the minimization of the

kinetic power or to the increase of the propulsive continuity between the two arms. In other words, there exists a challenge to explore inter-arm coordination changes as a function of active drag, and to the question wether these changes relate to propelling efficiency.

Methods

Thirteen national male front crawl swimmers (mean age: 21.5±3.9yr, mean height: 185.5±5.2cm, mean weight: 80.5±7.8kg, time on 100-m front crawl: 53.4±3.2, years of practice: 11.8±3.5) performed two in- termittent graded speed tests in randomised order, using an arms-only front crawl stroke (using a pull-buoy): one on the MAD-system (10 bouts of 25-m) and one in the free swimming condition (8 bouts of 25-m), from slow (~60%) to 100% of maximal speed (with an absolute increment of 0.05 m·s^-1, which corresponded to a relative increment of 5% of maximal speed). The bout was self-paced to avoid the speed varia- tions that can arise when the swimmer follows a target. To be sure that the normalized v (expressed in % of maximal speed) on the MAD- system and in free swimming condition were close for each bout, two more bouts were allowed on the MAD-system as this condition was uncommon for the swimmers. Four minutes of rest were given before the next bout was swum.

For the MAD-system condition, the swimmers swum by pushing off from fixed pads with each stroke. These push-off pads were attached to a 22-m rod and the distance between them was 1.35 m. The rod was mounted 0.8 m below the water surface and was connected to a force transducer, enabling direct measurement of push-off forces for each stroke. Assuming a constant mean swimming speed, the mean propel- ling force equals the mean drag force (D in N). Hence, swimming one bout on the system yields one data-point for the speed-drag curve. Fol- lowing the equation D = K • vⁿ, the relationship between drag force and speed was established for each swimmer and thus the individual K factor and n coefficient were determined. According to Toussaint et al. (2006), while swimmers swim on the MAD-system, propulsion is generated without wasting kinetic energy (P_k=0) and consequently all P_o of can be used to overcome drag. Thus, P_o equals P_d. Knowing that, P_d = D • v², P_d = K • v³. If assumed that during all-out 25-m sprints, P_o was maximal and, equal on the MAD-system and in the free condition, propelling efficiency (e_p) could be calculated as: e_p= P_d / P_o = K • v³_free/K • v³_MAD

For the free swimming condition, two underwater video cameras filmed from frontal and side views at 50Hz. They were connected to a double-entry audio-visual mixer, a video timer, a video recorder and a monitoring screen to mix and genlock the frontal and lateral views on the same screen, from which the mean stroke rate was calculated. A third camera, mixed with the side view for time synchronisation, filmed all trials with a profile view from above the pool. This camera measured the time over the 12.5-m distance (from 10-m to 22.5-m) to obtain the velocity. Stroke length was calculated from the mean speed and stroke rate values. From the video device, three operators analysed the key points of each arm phase with a blind technique, i.e. without knowing the analyses of the other two operators. Each arm stroke was broken into four phases: entry and catch of the hand in the water, pull, push and recovery. The duration of the propulsive phases was the sum of pull and push phases and that of the non-propulsive phases was the sum of entry and recovery phases. Arm coordination was quantified using the index of coordination (IdC) as defined by Chollet et al. (2000). The IdC represented the lag time between the propulsive phases of each arm.

The mean IdC, which was calculated from three complete strokes, was expressed as a percentage of the mean stroke duration. When there was a lag time between the propulsive phases of each arm, the stroke coor- dination was in “catch-up” (IdC<0%). IdC=0% indicated that the arms were in “opposition” and IdC>0% corresponded to the “superposition”

of the propulsive phases of both arms. According to Seifert and Chollet (2009) quadratic regression was calculated to model the relationships between IdC and speed.

BiomechanicsandmedicineinswimmingXi

116

Assuming that during all-out 25-m sprints, P_o was maximal and equal in the MAD- system and in the free condition, e_p for each swim- mer was calculated. Pearson correlation was assessed between e_p and IdC for the maximal swimming condition. An ANOVA analysed the effect of bouts of 25-m on IdC and D. Quadratic regression between IdC and v in the free condition and a power regression between D and v in the MAD-system condition were established for each swimmer; then, the average equation for the whole sample of swimmers were calculated. If assumed that during all-out 25-m sprints, P_o was maximal and equal both on the MAD-system and in the free condition, it was also assumed that the effort was equal when swimming bout 1 at 60% of maximal speed on the MAD-system and bout 1 at 60% of maximal speed in the free condition (and so on for bout 2 at 65% of maximal speed, then bout 3 at 70% of maximal speed). Regressions between IdC and D were established for each swimmer, after which the average equation for the whole sample of swimmers was calculated. For all tests, the level of sig- nificance was set at 95% (p<0.05).

results

The average value of e_p was 0.55±0.11 and ranged between 0.34 and 0.79, while average IdC is -0.9±2.8% that corresponded to an opposi- tion coordination mode (Table 1); IdC values ranged between -5.1% to 3.6%, supporting that swimmers used various modes of arm coordina- tion when they swim at maximal speed. There was no significant correla- tion between IdC and e_p, IdC and v while e_p was positively correlated to v (r=0.68; p<.05).

Table 1. v values on MAD-system and in free condition, e_p and IdC during maximal speed on 25-m sprint for the thirteen swimmers.

Subject v_MAD (m·s^-1) v_free (m·s^-1) e_p IdC

BJ 1.89 1.53 0.53 -0.9

BS 2.05 1.43 0.34 -2.9

BS 1.90 1.55 0.54 -5.1

CVD 1.72 1.53 0.70 -0.3

JFJ 1.88 1.53 0.54 -0.6

JG 1.95 1.56 0.51 -1.1

MT 1.69 1.43 0.61 -4.0

MN 1.72 1.41 0.55 3.6

MA 1.78 1.39 0.47 2.7

MB 1.88 1.56 0.58 -0.1

MK 1.93 1.54 0.51 -2.9

TK 1.91 1.49 0.48 -3.1

SJ 1.95 1.80 0.79 3.3

Mean 1.87 1.52 0.55 -0.9

SD 0.11 0.10 0.11 2.8

The ANOVA indicated significant changes of D and IdC with bouts of 25-m. Significant quadratic regression between IdC and v (0.91<R²<0.99), power regression between D and v (0.93<R²<0.98) and linear regression between IdC and D (0.64<R²<0.98) were established for each swimmer; the average equations of each regression were respec- tively presented in Figures 1, 2 and 3.

Biomechanics and Medicine in Swimming XI Chapter 2 Biomechanics b 13

MN 1.72 1.41 0.55 3.6

MA 1.78 1.39 0.47 2.7

MB 1.88 1.56 0.58 -0.1

MK 1.93 1.54 0.51 -2.9

TK 1.91 1.49 0.48 -3.1

SJ 1.95 1.80 0.79 3.3

Mean 1.87 1.52 0.55 -0.9

SD 0.11 0.10 0.11 2.8

The ANOVA indicated significant changes of D and IdC with bouts of 25-m.

Significant quadratic regression between IdC and v (0.91<R²<0.99), power regression between D and v (0.93<R²<0.98) and linear regression between IdC and D (0.64<R²<0.98) were established for each swimmer; the average equations of each regression were respectively presented in Figures 1, 2 and 3.

Fig. 1. Quadratic regression between the Index of Coordination (IdC) and speed (v) averaged for the 13 swimmers.

Fig. 2. Power regression between active drag (D) and speed (v) averaged for the 13 swimmers.

IdC = 36v²- 57.6v +4.8

-20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0

0,80 0,90 1,00 1,10 1,20 1,30 1,40 1,50 1,60

Index of Coordination (%)

Speed (m.s^-1)

D = 28.2v^2.12

40 50 60 70 80 90 100 110

0,80 1,00 1,20 1,40 1,60 1,80 2,00

Active Drag (N)

Speed (m.s^-1)

Biomechanics and Medicine in Swimming XI Chapter 2 Biomechanics b 14

Fig. 3. Linear regression between the IndexIdC and active drag (D) averaged for the 13 swimmers.

Fit may be observed from Figures 1 and 3 that, the average speed and the average active drag at which the sample of the 13 swimmers switched from catch-up (IdC<0%) to superposition (IdC>0%) coordination mode were respectively ~1.5 m·s^-1 and ~105 N.

DISCUSSION

The main finding of this study was that for national level swimmers, swimming front crawl with arms only, the inter-arm coordination was not linked to ep but related to active drag. Therefore, a high IdC does not automatically guarantee fast speed because the efficiency of the propulsion can be very low. Indeed, Alberty et al. (2009) suggested that a high IdC at the end of a race could be the consequence of fatigued swimmers having the propulsive phases of the hands overlap because the fatigue prohibited enough force generation by a single limb to overcome total drag. Hence, the change in IdC seemed an effective change in coordination to deal with fatigue in the limbs that was related to the balance propulsive and resistive forces. During 4 × 50 m at maximal intensity, Alberty et al. (2005) reported an increase of IdC from -6.5 to -3.3 %, while for a 100 m race, Seifert et al. (2007a) observed that the swimmer with the lowest performances had an increase of IdC from a relative opposition (-1.2 %) to superposition coordination mode (2.8 %) between the third and last 25 m lap. These changes of arm coordination may be related to lower average hand speed. Toussaint et al. (2006) showed that with fatigue occurring during 100 m at maximal intensity, swimmers decreased their swimming speed by 12.4 %, their power by 23.5 %, their hand speed from 2.14 m·s^-1 at first lap to 1.91 m·s^-1 at last lap. Thus, in the study where ep was assessed during swimming 25-m all out, some swimmers were not able to apply great power and great impulse, showing high IdC without high ep. Conversely, other swimmers used lower IdC that may be coupled to great impulse and power generation, and may favour high ep. According to Toussaint (1990), who showed differences of ep

of triathletes with those of competitive swimmers, high IdC seemed only interesting if it coupled with high ep.

On the other hand, the results showed that the whole sample of the 13 swimmers increased their IdC and active drag when speed increased. The inter-arm coordination switched from catch-up to superposition mode at a lower speed value than observed by Seifert et al. (2007b) because in the study, the swimmers swam arms only. The positive

IdC = 0.27D -28.28 -20-18

-16-14 -12-10-8-6-4-20

40 50 60 70 80 90 100 110

Index of Coordination (%)

Active Drag (N)

Fit may be observed from Figures 1 and 3 that, the average speed and the average active drag at which the sample of the 13 swimmers switched from catch-up (IdC<0%) to superposition (IdC>0%) coordi- nation mode were respectively ~1.5 m·s^-1 and ~105 N.

dIscussIon

The main finding of this study was that for national level swimmers, swimming front crawl with arms only, the inter-arm coordination was not linked to e_p but related to active drag. Therefore, a high IdC does not automatically guarantee fast speed because the efficiency of the propul- sion can be very low. Indeed, Alberty et al. (2009) suggested that a high IdC at the end of a race could be the consequence of fatigued swimmers having the propulsive phases of the hands overlap because the fatigue prohibited enough force generation by a single limb to overcome total drag. Hence, the change in IdC seemed an effective change in coordi- nation to deal with fatigue in the limbs that was related to the balance propulsive and resistive forces. During 4 × 50 m at maximal intensity, Alberty et al. (2005) reported an increase of IdC from -6.5 to -3.3 %, while for a 100 m race, Seifert et al. (2007a) observed that the swimmer with the lowest performances had an increase of IdC from a relative op- position (-1.2 %) to superposition coordination mode (2.8 %) between the third and last 25 m lap. These changes of arm coordination may be related to lower average hand speed. Toussaint et al. (2006) showed that with fatigue occurring during 100 m at maximal intensity, swimmers decreased their swimming speed by 12.4 %, their power by 23.5 %, their hand speed from 2.14 m·s^-1 at first lap to 1.91 m·s^-1 at last lap. Thus, in the study where e_p was assessed during swimming 25-m all out, some swimmers were not able to apply great power and great impulse, show- ing high IdC without high e_p. Conversely, other swimmers used lower IdC that may be coupled to great impulse and power generation, and may favour high e_p. According to Toussaint (1990), who showed differ- ences of e_p of triathletes with those of competitive swimmers, high IdC seemed only interesting if it coupled with high e_p.