著者

Naoki Tanaka Yasutomo Sakai Yosuke Maruyama Tetsuro Hirayama Wataru Iwamoto Koji Wagatsuma

出版者

The Society of Physical Therapy Science

雑誌

Journal of Physical Therapy Science (ISSN:09155287)

巻号頁・発行日

vol.34, no.1, pp.22-25, 2022 (Released:2022-01-12)

参考文献数

17

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[Purpose] The purpose of this study was to investigate changes in the shoulder and elbow joint angles, upper limb angular velocities, and elbow varus torque when throwing balls of two different sizes. [Participants and Methods] The pitching motion of 26 junior baseball players was analyzed using an optical motion capture system. The balls used were a standard baseball and a small ball of equal weight. Shoulder external rotation/abduction and elbow flexion were measured. The maximum values of shoulder joint internal rotation, elbow joint extension, wrist flexion angular velocity, and elbow joint varus torque were also evaluated. The ball velocity was determined as an index of pitching performance. [Results] The shoulder external rotation and elbow flexion angles were higher when pitching with a small ball. The joint angular velocity was also significantly higher when pitching with a small ball for all items examined. The ball speed was significantly higher with the small ball. The maximum varus torque of the elbow joint divided by the ball velocity was significantly lower for the small ball. [Conclusion] For a junior baseball player with a small hand length, using a small ball enables pitching with low stress on the elbow joint.