著者

宮西 智久 藤井 範久 阿江 通良 功力 靖雄 岡田 守彦

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.41, no.1, pp.23-37, 1996-05-10 (Released:2017-09-27)

被引用文献数

7

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We investigated the contribution of the motions in the upper torso and the throwing arm joints to the ball velocity during the baseball throw. The ball velocities caused by the anatomical rotations at the upper torso, shoulder, elbow, wrist and metacarpophalangeal joints were calculated as the vector products between the anatomical angular velocity vectors of joints and the respective relative displacement vectors from the joint centers to the center of ball, by using a mathematical model reported by Sprigings et al. (1994). Horizontal throws of twenty-four male university baseball players were filmed using a three-dimensional DLT method. In order to verify the ball velocities obtained from the anatomical joint rotations from the instant of the stride foot contact to the ball release, the velocity of ball measured directly from video recording was compared with that calculated by the mathematical model. A good agreement was acquired between the velocity of ball measured and that calculated. The velocities obtained from the left-rotation, flexion at the upper torso joint and the horizontal flexion at the shoulder joint contributed to the ball velocity in the early phase where the increase of ball velocity was slow. The velocities obtained from the internal-rotation at the shoulder joint, extension at the elbow joint, palmar-flexion at the wrist joint, and left-rotation/flexion at the upper torso joint contributed in the late phase where the increase of ball velocity was rapid. At the ball release, the contribution of each joint, which is the ratio of the positive ball velocity obtained from the anatomical joint rotations to the summation of individual positive ball velocities was as follows; 34.1% by the internal-rotation at the shoulder, 17.7% by the palmar-flexion at the wrist, 15.2% by the extension at the elbow, and 9.6% by the left-rotation at the upper torso joint.