Orthopaedic Basic Science Journal Scan

Do Qualitative Changes in Inter-limb Coordination Lead to Effectiveness of Aquatic Locomotion Rather than Efficiency?

J Appl Biomech. 2013 Jul 22;

Authors: Komar J, Sanders RH, Chollet D, Seifert L

Abstract
This study compared inter-limb coordination and indicators of swim efficiency and effectiveness between expert and recreational breaststroke swimmers. Arm-leg coordination of 8 expert and 10 recreational swimmers at two different paces, slow and sprint, were compared using relative phase between elbow and knee. For each participant, knee and elbow angles were assessed using a 3-D video analysis system with four below and two above cameras. During each phase of the cycle, indicators of swim efficiency (intra-cyclic velocity variations) and effectiveness (horizontal distance, velocity peaks, acceleration peaks) were calculated. Two coordination patterns emerged between expert and recreational swimmers, with significant differences in the relative phase at the beginning of a cycle (-172.4° for experts and -106.6° for recreational swimmers) and the maximum value of relative phase (9.1° for experts and 45.9° for recreational swimmers) (all P<.05). Experts' coordination was associated with higher swim effectiveness (higher acceleration peak: 2.4m.s-2 for experts and 1.6m.s-2 for recreational swimmers) and higher distance covered by the center of mass during each phase of the cycle (all P<.05). This study emphasized how experts coordinate arms and legs to achieve effective behaviour, therefore exhibiting flexibility, mainly in the timing of the glide phase, to adapt to different speed.