This study aimed to investigate the acute effects of sprint training on sprint motions evaluated
by the observational motion assessment method and sprint velocity in elementary- and middleschool students. 38 elementary- and middle- school students performed 50m sprint tests before and after the 30-min training intervention, consisting of the mini-hurdle sprinting and the rebound jump exercises. The sprint velocity from 20m to 40m was measured as the mean sprint velocity. The sprint motion was captured by video cameras, and it was qualified using the observational motion assessment method. No significant change was found in the mean sprint velocity between pre and post sprint tests（P＝0.567, d＝0.020）. Meanwhile, the scores of the motions, such as the direction of arm swinging（P＝0.001, d＝0.405）, the range of motion of the legs（P＝0.031, d＝0.191）and the timing of the scissors motion（P＝0.029, d＝0.304）were significantly improved in the post test. Therefore, our results suggested that acute sprint training did not improve the sprint velocity, but sprint motions.