FEW VARIABLES ASSOCIATED WITH BREAK-OUT VELOCITY FOLLOWING A FREESTYLE TURN
Tanaka, T., Yoshimura, Y., Yasukaws, M., & Oishi, K. (2012). Skill differences for elite sprint freestyle competitive swimmers. Presentation 2980 at the 59th Annual Meeting of the American College of Sports Medicine, San Francisco, California; May 29-June 2, 2012.
This study analyzed the skills of streamlining and dolphin kicking during the break-out phase of a freestyle turn and provided quantitative evidence of effects. Elite Japanese sprint freestyle competitive swimmers (N = 6) were members of the winning team at the 2011 Japan Intercollegiate Swimming Championship. A speed meter that measured forward velocity by pulling a fine wire over a generator was used. The meter recorded intracyclic velocity changes during a 15-m maximum-effort freestyle swim following a freestyle turn. The swim included an underwater dolphin kicking phase of approximately five meters. An underwater video analysis system was also to check streamlining, kicking, and stroking techniques. The length of the kicking cycle and the rate of rise were recorded. The rate of rise was determined as the velocity divided by the maximum water depth which was then multiplied by the dolphin kicking time. Both the rate of rise and the distance per kick (DPK) were measured for each S.
There was a significant relationship between the time required to cover 15 m after the turn and distance per kick for all swimmers. There was also a significant relationship between the time to 15 m and the rate of rise. When the distance per kick and rate of rise were greater, the time to 15 m was faster.
Implication. Improvements in distance per kick and the rate of rise during dolphin kicking may be important factors for improving swimming times to 15 m following turns. [However, there is an optimal amount of rise beyond which more resistance is created than propulsion developed.]
Return to Table of Contents for Biomechanics of Swimming.