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Jpn J Biomechanics Sports Exercise 8(1):12-26, 2004

The mechanical energy flows between body segments during baseball pitching

Kazushi SHIMADA1), Michiyoshi AE2), Norihisa FUJII2), Takashi KAWAMURA2), Keizo TAKAHASHI3)

1) Department of Physical Therapy, School of Health Sciences, Ibaraki Prefectural University of Health Sciences,
2) Institute of Health and Sport Sciences, University of Tsukuba
3) Doctoral Program in Health and Sport Sciences, University of Tsukuba

Abstract

    The purpose of this study was to analyze the mechanical energy during baseball pitching for 22 varsity baseball players by using three‐dimensional motion analysis technique with two force platforms. Joint torque powers, joint force powers, and segment torque powers of the joints were computed using an inverse dynamics approach.
    In the energy increasing phase of upper torso, a great deal of mechanical energy flowed into the torso. The mechanical energy transferred to the upper torso due to the segment torque power significantly related to the ball velocity at the release (r = 0.480, p < 0.05). In the late cocking and accelerating phase, great mechanical energy flowed into the distal segment and the ball due to the joint force power were observed at the throwing arm joints. There were significant relationships between the ball velocity at the release and mechanical energy flows due to the elbow and the wrist joint force powers (r = 0.775, p < 0.001 and r = 0.827, p < 0.001). These results suggested that the mechanical energy flows to the upper torso in the energy increasing phase of upper torso and to the throwing arm and ball in the late cocking phase are important to increase the ball release velocity.

Key Words: pitching, mechanical energy flow, three-dimensional motion analysis technique, joint force power, joint torque power

Submittted for Publication : September 15, 2003,

Accepted for Publication : January 9, 2004

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