2016 Volume 23 Pages 141-150
A standard baseball pitch is a process that involves a set of complex, whole-body movements that enable kinetic energy to be effectively transmitted from the body-center to the upper limbs, in what we refer to as "the kinetic chain". In this respect, the trunk functions as a relay point. One of the terms used in coaching is “the stretching of the chest”, which is also considered to be related to the kinetic chain. In order to analyze this motion quantitatively, we developed a novel parameter denoted as S, in earlier work. Here, we applied parameter S to the analysis of pitching motion and studied the kinetic chain from the lower trunk to the upper limb, from the perspectives of kinematics and energy transmittance. Experiments using 18 healthy volunteer pitchers revealed that the kinetic chain was clearly evident, between the stretching of the chest and the internal rotation of the shoulder, and was more or less the same, for all subjects.
