Abstract
In the kick-start, swimmers put their right or left foot on the front edge of the starting block and the other foot on the back plate. This study investigated the effect of the position of the leg with greater power on the kick-start performance of competitive swimmers. The participants were eight male collegiate swimmers who preferred foot combinations with the leg with greater power in front. All participants practiced kick starts with non-preferred foot combinations in the front and rear foot positions for 10 days （10 min/day） and swam a 15-m front crawl with maximum effort kick-starts using both the preferred and non-preferred foot combinations in the front and rear foot positions. A high-speed camera （100 fps） was used to analyze the reaction time from the start signal to take-off from the starting block, and to calculate the kinematic variables at take-off; a second camera （60 fps） was used to analyze the elapsed time from the start signal to 15 m. Single leg jumps were used to determine which leg had greater power. The start parameters （reaction time, 15 m time, take-off velocity and take-off angle） were analyzed. The resultant and horizontal take-off velocities did not differ significantly between the foot combinations, while the take-off angle was significantly larger, and 15 m time significantly faster, with the leg with greater power on the front edge. Therefore, although there were no differences in the resultant and horizontal take-off velocities, regardless of foot combination, putting the leg with greater power in front improved kick-start performance.
