Tanaka, T., Yoshimura, Y., Yasukawa, M., & Oishi, K. (2009). Skill differences of freestyle competitive swimmers detected by means of a speed meter. A paper presented at the 14th Annual Congress of the European College of Sport Science, Oslo, Norway, June 24-27.

A speed meter that measures a S’s moving velocity by pulling a fine wire over a generator for a distance of 25 m has been used with competitive swimmers (N = 4). In this study, the speed meter and an underwater video analysis system were used to determine the skill differences between short-distance freestyle competitive swimmers of national and collegiate swimmers. The speed meter recorded intra-cyclic velocity changes during a 25 m maximum effort freestyle swim. The underwater video analysis system also was used to check underwater stroke techniques during the maximum efforts.

Based on the video data, the crawl stroke cycle was divided into three phases: 1) downsweep, 2) insweep, and 3) upsweep. Average velocities during each phase, based on the speed meter data, were compared individually among the four Ss. There were no differences between Ss for the insweep and upsweep phases. However, the mean velocities of the national swimmers showed significantly higher values for the downsweep phase.

Implication. It was suggested that improvements in freestyle swimming are dependent mostly upon improving the downsweep phase. [However, there is more research published that justifies the assertion that the end of the underwater propulsive phase is the most important phase of crawl stroke swimming. The small number of Ss in this study warrant its conclusions being considered carefully.]

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