Effects of the Lower Half of the Body on Batting

Abstract

The purpose of this study was to clarify the effects of the lower half of the body on batting performance with a comparative analysis among three different kinds of tee-batting. Those tee-battings were performed 1) with no restraints of movements on the lower half of the body (standing posture), 2) with a restraint of movements on the lower half of the body by sitting on a non-swivel chair (fixed posture), 3) with a restraint of movements on the lower half of the body by sitting on a swivel chair (turn posture).The subject in the experiment was an intermidiate-skilled baseball player, who was right-handed. The batting performances were recorded with EMG and a videocamera, and analyzed from a biomechanical viewpoint.The main results obtained were as follows:1) By comparison with the distance of a batted-ball at the standing posture, the percent-age of that at the fixed posture showed only 56.4%and58.7%was shown at the turn posture.2) Muscle activity of the upper half of the body at the fixed posture was different from that at the turn posture.3) It tended that the inclinations to the forward of right shoulder, right elbow and right wrist at the fixed and the turn posture were quicker than those at the standing posture.4) Horizontal movement of head at the fixed and the turn posture were larger than that at the standing posture. It seemed that the movement had an effect on the accuracy of batting.5) It was clear that the bat swing speed at the standing posture was quicker than that at the fixed and the turn posture.From the results above metioned, it was concluded that the lower half of the body was very important to the effective and speedy batting performance, so it was essential to make a careful consideration for a training load, coordination enhancement and a training period in order to provide a training program for the lower half of the body.