它作用是增加作功距离所以所作的功会越大如此得藉以提高力量使用而且这挥摆动作是快速的不是动作大的挥摆
Its function is to increase the distance of work done, so the work done will be greater. Thus, it can enhance the use of force. Moreover, this swing action is fast, not a large swing
以上为机器翻译结果，长、整句建议使用 人工翻译 。