Effect of increasing energy cost on arm coordination in elite sprint swimmers J. Komar a , P.M. Leprêtre b , M. Alberty c , J. Vantorre a , R.J. Fernandes d , P. Hellard e,f , D. Chollet a , L. Seifert a,⇑ a Centre d’Etudes des Transformations des Activités Physiques et Sportives, EA-3832, Faculté des Sciences du Sport, Université de Rouen, France b Laboratoire de Recherche Adaptations Physiologiques à l’Exercice et Réadaptation à l’Effort, EA-3300, Faculté des Sciences du Sport, Université de Picardie Jules Verne, Amiens, France c Laboratoire d’Etude de Motricité Humaine, EA-3608, Faculté des Sciences du Sport, Université de Lille, France d Center of Research, Educational, Innovation and Intervention in Sport, Faculty of Sports, University of Porto, Portugal e Département d’Etudes et Recherches, Fédération Française de Natation, Paris, France f Laboratoire Vie Sportive, Tradition, Innovation et Intervention, EA-498, Faculté des Sciences du Sport de Bordeaux 2, France article info Article history: Available online xxxx PsycINFO classification: 2330 3720 Keywords: Coordination Biomechanics Motor control Energy cost Swimming efficiency abstract The purpose of this study was to analyze the changes in stroke parameters, motor organization and swimming efficiency with increasing energy cost in aquatic locomotion. Seven elite sprint swimmers performed a 6 Â 300-m incremental swimming test. Stroke parameters (speed, stroke rate and stroke length), motor organization (arm stroke phases and arm coordination index), swimming efficiency (swimming speed squared and hand speed squared) and stroke index were calculated from aerial and under- water side-view cameras. The energy cost of locomotion was assessed by measuring oxygen consumption and blood lactate. Results showed that the increase in energy cost of locomotion was correlated to an increase in the index of coordination and stroke rate, and a decrease in stroke length (p < .05). Furthermore, indicators of swimming efficiency and stroke index did not change significantly with the speed increments (p < .05), indicating that swimmers did not decrease their efficiency despite the increase in energy cost. In parallel, an increase in the index of coordination IdC and stroke rate were observed, along with a decrease in stroke length, stroke index and hand speed squared with each increment, revealing an adaptation to the fatigue within the 300 m. Ó 2011 Elsevier B.V. All rights reserved. 0167-9457/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.humov.2011.07.011 ⇑ Corresponding author. Address: Centre d’Etudes des Transformations des Activités Physiques et Sportives, EA-3832, Faculté des Sciences du Sport, Boulevard Siegfried, Université de Rouen, 76821 Mont-Saint-Aignan, France. Tel.: +33 232107784. E-mail address: ludovic.seifert@univ-rouen.fr (L. Seifert). Human Movement Science xxx (2011) xxx–xxx Contents lists available at SciVerse ScienceDirect Human Movement Science journal homepage: www.elsevier.com/locate/humov Please cite this article in press as: Komar, J., et al. Effect of increasing energy cost on arm coordination in elite sprint swimmers. Human Movement Science (2011), doi:10.1016/j.humov.2011.07.011