Naito Kozo, Takagi Tokio, Kubota Hideaki, Maruyama Takeo
Faculty of Education, Soka University, Hachioji, Japan.
Department of Sports Sciences, Japan Institute of Sports Sciences, Tokyo, Japan.
Hum Mov Sci. 2017 Aug;54:363-376. doi: 10.1016/j.humov.2017.05.013. Epub 2017 Jul 7.
The purpose of this study was to identify the detailed mechanism how the maximum throwing arm endpoint velocity is determined by the muscular torques and non-muscular interactive torques from the perspective of the dynamic coupling among the trunk, thorax and throwing and non-throwing arm segments. The pitching movements of ten male collegiate baseball pitchers were measured by a three-dimensional motion capture system. Using the induced-segmental velocity analysis (IVA) developed in this study, the maximum fingertip velocity of the throwing arm (MFV) was decomposed into each contribution of the muscular torques, passive motion-dependent torques due to gyroscopic moment, Coriolis force and centrifugal force, and other interactive torque components. The results showed that MFV (31.6±1.7m/s) was mainly attributed to two different mechanisms. The first is the passive motion-dependent effect on increasing the angular velocities of three joints (thorax rotation, elbow extension and wrist flexion). The second is the muscular torque effect of the shoulder internal rotation (IR) torque on generating IR angular velocity. In particular, the centrifugal force-induced elbow extension motion, which was the greatest contributor among individual joint contributions, was caused primarily by the angular velocity-dependent forces associated with the humerus, thorax, and trunk rotations. Our study also found that a compensatory mechanism was achieved by the negative and positive contributions of the muscular torque components. The current IVA is helpful to understand how the rapid throwing arm movement is determined by the dynamic coupling mechanism.
本研究的目的是从躯干、胸廓以及投掷臂和非投掷臂各节段之间的动态耦合角度，确定最大投掷臂端点速度是如何由肌肉扭矩和非肌肉相互作用扭矩决定的详细机制。通过三维运动捕捉系统测量了10名男性大学棒球投手的投球动作。使用本研究开发的诱导节段速度分析（IVA），将投掷臂的最大指尖速度（MFV）分解为肌肉扭矩、由陀螺力矩、科里奥利力和离心力引起的被动运动相关扭矩以及其他相互作用扭矩分量的各自贡献。结果表明，MFV（31.6±1.7m/s）主要归因于两种不同机制。第一种是对增加三个关节（胸廓旋转、肘部伸展和腕部屈曲）角速度的被动运动相关效应。第二种是肩部内旋（IR）扭矩对产生IR角速度的肌肉扭矩效应。特别是，离心力引起的肘部伸展运动是各个关节贡献中最大的因素，主要是由与肱骨、胸廓和躯干旋转相关的角速度相关力引起的。我们的研究还发现，肌肉扭矩分量的正负贡献实现了一种补偿机制。当前的IVA有助于理解快速投掷臂运动是如何由动态耦合机制决定的。
