INFLUENCES OF BODY CONFIGURATION ON THE BIOMECHANICAL PROPERTIES

Abstract

The purpose of this study was to investigate the influences of body configuration on the biomechanical properties of leg extensor muscles in squat jump (SJ) performances. Ground reaction force data were collected during four different SJ tests of SJ70, SJ90, SJ110, and SJ130 (numbers denoted the knee angles) for maximum jump execution of 22 subjects. The results showed that the forces measured on a force platform, and other variables calculated from the force-time data, were strongly associated with the body configuration at push-off. Peak and average forces were greater in wider knee angle conditions, however, optimum power output and jumping height appeared in SJ90. From the data obtained in this study, it seemed that the force production measured with SJ test could not be used simply to assess the level of active state and muscular strength of leg extensors. The reaction force measured on a platform was the vertical component of the muscular strength generated by extensors, which was determined not only by the strength level, but also the joint angles at push-off position.