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Jpn J Biomechanics Sports Exercise 10(1):2-13, 2006

Effects of the height of hitting point on joint angular kinematics in baseball batting

Takahito TAGO1), Michiyoshi AE2), Norihisa FUJII2)
Sekiya KOIKE2), Keizo TAKAHASHI1), Takashi KAWAMURA2)

1)University of Tsukuba, Graduate School of Comprehensive Human Sciences,
2)University of Tsukuba, Institute of Health and Sport Sciences

Abstract

The purpose of this study was to investigate kinematic changes in the baseball batting motion for high, middle and low hitting points. Subjects were ten right?]handed male skilled batters of a varsity baseball club. Nine hitting points were set according to the baseball rules:three heights(high, middle, low)times three courses(inside, center, outside)based on the subject's height and the width of a home plate. The subjects were requested to hit a ball on a batting tee randomly assigned one of nine hitting points at each trial. Angular kinematic data were collected at 120Hz with a Vicon 612 system.
In case of the high hitting point, the right shoulder flexion and left shoulder horizontal?]adduction at the instant of Left upper arm perpendicular to the hitting direction(LUP), and the left shoulder flexion at the Impact(IMP)were smaller than those of the middle height. In case of the low hitting point, the right hip flexion at the Toe?]on, and the right shoulder flexion, extension of both elbows, and flexion of both hips at the LUP were greater than those of the middle height. The left elbow extension, left shoulder flexion, adduction and flexion of both hips were greater at the IMP than those of the middle height.
These results indicated that to hit a ball at high and low points appropriately a batter first adjusted flexion?]extension and abduction?]adduction of the hip joints, and then swing the bat adjusting both arms, especially the left arm just before the impact.

Key Words: three dimensional motion analysis, joint angle, trunk rotation

Submittted for Publication : Oct. 24, 2004,

Accepted for Publication : Jan. 22, 2006

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