Identification of the roles of wrist snap in baseball pitching

一些研究报道了前臂和手腕的运动有几个滚动来完成棒球投球。然而，其动力机制尚不清楚。作为理解棒球投球中前臂和手的滚动的一步，我们研究了每个环节的非肌肉力是如何产生、吸收和传递机械能以产生最大速度的。手的机械能是由前臂的离心力控制的非肌肉力提供的。然而，手腕的肌肉扭矩吸收了手的机械能。结论是，只有手腕不能产生高球速。因此，手腕配备了自卫机制，并为外部手指控制提供了相对稳定的基础。也有人认为，手腕关节有一个滚适用旋转球。手腕关节可能对球的旋转速度有贡献，而不是对球的平移速度有贡献。

Some studies have reported that movements of forearm and wrist has several rolls to perform a baseball pitching. However dynamical mechanism are still unclear. As a step toward understanding the rolls of forearm and hand in baseball pitching, we investigated how non-muscular forces of the each link generates, absorbs, and transfers mechanical energy in order to produce maximum velocity. The mechanical energy of the hand was supplied the non-muscular force, which is governed by the centrifugal force of the forearm. However, the muscle torque of the wrist absorbs the mechanical energy of the hand. It is concluded that only the wrist cannot generate a high ball velocity. The wrist, therefore, is equipped with a self-defense mechanism and provides a relatively stable base for extrinsic finger control. It is also thought that the wrist joint have a roll to apply spin a ball. The wrist joint may contribute to the rotational velocity and not the translational velocity of a ball.