[[alternative]]The analysis of swimming start and reaction time of relay in relay competition

[[abstract]]The purpose of this study was to analyze the difference of the grab start and swing start. Using the swing start, the suggested way of the research result to make the practice of relay to find out the reaction time of relay practice. Eleven elite male swimmers participated in this study. One Redlake high speed camera and a Kistler force plate were positioned perpendicularly to the movement direction to collect the kinematics and kinetics data. The data were calculated with SAS statistics software and Pearson Product moment correlation and get the difference of the two starts by T-test. The conclusion of this study were as below： 1. Comparing with the data of the two start, we found the following items with significant difference: vertical velocity, takeoff angle, flight time, enter distance and 10 meters time. 2. Significant correlations (P<.05) between grab start and swing start are as following : takeoff horizontal velocity and takeoff velocity/10 meters time, vertical velocity and takeoff angle/flight time and enter distance, takeoff angle and flight time and enter distance, flight time and enter distance. 3. The reaction time of relay of all the swimmers were improved 0.25sec after the 4 weeks training. Key words: