A speed meter that measures a subject`s moving velocity by pulling a fine wire over a generator (Maglischo, 2003) for a distance of 25m was developed for use with competitive swimmers. In our previous study, the authors used the speed meter to check for skill differences between competitive swimmers of international achievement and collegiate breaststroke swimmers. The results showed that this method was useful for identifying skill differences among a group of swimmers as well as reasons for improvement for each swimmer. In the present study, the authors used the speed meter and an underwater video analysis system to determine the skill differences between short distance freestyle competitive swimmers of national achievement and collegiate swimmers. The speed meter recorded their intracyclic velocity changes during a 25m maximum effort freestyle swimming. The underwater video analysis system was also used to check their stroke techniques during these maximum efforts. Based on the video data, the authors divided the stroke cycle into three phases, i.e., 1) downsweep phase, 2) insweep phase, and 3) upsweep phase. Average velocities during each phase, based on the speed meter data, were compared individually among four swimmers. In consequence, no statistical differences were observed among all swimmers for the insweep phase (Test of contrasts, p=0.0628) and upsweep phase (p=0.8707). However, the mean velocities of national achievement swimmer showed significantly higher value for the downsweep phase (p=0.0287). It was suggested that improvements in freestyle swimming were dependent mostly upon improving downsweep phase.
© Copyright 2009 14th annual Congress of the European College of Sport Science, Oslo/Norway, June 24-27, 2009, Book of Abstracts. Published by The Norwegian School of Sport Sciences. All rights reserved.