标题：A study of leg recovery motion and sprint speed in male elementary school students: which motion should be learned, forward swing of the thigh or flexion of the knee in the recovery leg
出版社：Japan Society of Physical Education, Health and Sport Sciences
摘要：Although sprint running has been studied by many investigators, the running techniques taught by a coach have not been researched in detail. The purpose of the present study was to clarify how sprint running is taught to male elementary school students by a coach, focusing on how the motion of the recovery leg affects that of the support leg and running velocity, and whether the forward swing of the thigh or flexion of the knee joint of the recovery leg is most important. Thirty-four 5th and 6th grade elementary school children performed 50-m sprints, and their motions were recorded using a video camera (60 fps). The step length, step frequency, running velocity, relative velocity of the center of mass, and the angles and angular velocity of the thigh, leg and knee were calculated. The main results were as follows: 1. We found a significant positive correlation between running velocity and the relative velocity of the recovery leg around the support phase. 2. Sabsequently to maximize the angular velocity of thigh recovery, a minimum angle of the recovery knee was obtained. These variables showed a significant positive correlation. 3. The time instant to reach the maximal forward swing velocity of the recovery leg was similar to the time instant to reach the maximal backward swing velocity of the support leg. When recovery leg and support leg velocity reached maximal, both leg were intersected. These results suggest that a coach should teach sprinters to swing the recovery leg forward prior to flexion of the recovery knee.
关键词：elementary school children ; joint force ; sprint motion
