Inter-limb coordination and energy cost in swimming.
OBJECTIVE
This study investigated the relationship between inter-arm coordination and the energy cost of locomotion in front crawl and breaststroke and explored swimmers' flexibility in adapting their motor organization away from their preferred movement pattern.


METHODS
Nine front-crawlers performed three 300-m in front crawl and 8 breaststrokers performed three 200-m in breaststroke at constant submaximal intensity and with 5-min rests. Each trial was performed randomly in a different coordination pattern: freely chosen, 'maximal glide' and 'minimal glide'. Two underwater cameras videotaped frontal and side views to analyze speed, stroke rate, stroke length and inter-limb coordination.


METHODS
In front crawl, inter-arm coordination was quantified by the index of coordination (IdC) and the leg beat kicks were counted. In breaststroke, four time gaps quantified the arm to leg coordination (i.e., time between leg and arm propulsions; time between beginning, 90° flexion and end of arm and leg recoveries). The energy cost of locomotion was calculated from gas exchanges and blood lactate concentration.


RESULTS
In both front crawl and breaststroke, the freely chosen coordination corresponded to glide pattern and showed the lowest energy cost (12.8 and 17.1Jkg(-1)m(-1), respectively). Both front-crawlers and breaststrokers were able to reach 'maximal glide' condition (respectively, +35% and +28%) but not 'minimal glide' condition for front crawl.


CONCLUSIONS
The freely chosen pattern appeared more economic because more trained. When coordination was constrained, the swimmers had higher coordination flexibility in breaststroke than in front crawl, suggesting that breaststroke coordination was easier to regulate by changing glide time.
Centre d'Etude des Transformations des Activités Physiques et Sportives (CETAPS) - EA 3832, University of Rouen, Faculty of Sports Sciences, France. Electronic address: udovic.seifert@univ-rouen.fr.
L
L
Seifert
Centre d'Etude des Transformations des Activités Physiques et Sportives (CETAPS) - EA 3832, University of Rouen, Faculty of Sports Sciences, France.
J
J
Komar
ISSUL Institute of Sport Sciences, Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Switzerland.
F
F
Crettenand
Laboratory of Movement Analysis and Measurement, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland.
F
F
Dadashi
Laboratory of Movement Analysis and Measurement, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland.
K
K
Aminian
ISSUL Institute of Sport Sciences, Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Switzerland.
G P
GP
Millet
D000293:Adolescent; D001132:Arm / Q000502:physiology; D001696:Biomechanical Phenomena / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000502:physiology; D009048:Motor Skills / Q000502:physiology*; D013550:Swimming / Q000502:physiology*; D055815:Young Adult
Biomechanics; Coordination; Economy; Motor control; Swimming