The effect on human body at the impact of tennis racket and balls from the viewpoints of mechanical characteristics of the grip

实验清楚地表明，当球和球拍撞击时发生振动时，存在两种频率，一种是130 Hz左右的高频，另一种是10 - 50 Hz左右的低频。这些结果使我们得出结论，球拍作为一个振动体，另一个是一个刚性物体的影响。当球只撞击在拍面中心时，这种高频振动消失，低频仍保留在球拍上。这种低频振动传递到手和前臂。在偏心冲击时，当将握把的刚性从紧变为松时，发现高频难以传递到手，但低频通过握把。米山、S.（2003）等研究报道，撞击后的振动可能导致“网球肘”。实验结果表明，不仅高频振动，而且低频振动也是一个重要的振动源。 ...更多信息 实验结果表明，球拍作为一个物体，在撞击时具有两种性质，一种是振动体，另一种是刚体。从这个角度出发，我们将球拍作为一个刚体进行撞击，球拍通过具有粘弹性的握杆与手相连。利用该模型研究了抓地力的特性。通过比较球与球拍接触的持续时间、球的恢复系数、振动的阻尼特性、振动的频率和峰值等实验数据，对模型进行了辨识。根据模型的模拟，可以推断，根据抓握的紧密度，抓握的粘性系数在1.0至5.5 N/m/s之间变化，弹性系数在50至500 N/m之间变化。握杆松紧度的变化对腕关节的粘弹性系数也有影响。少

Experiments reveal clearly that when the vibration occurred at the impact of a ball and a racket, there are two kinds of frequency, one is high frequency around 130 Hz and another one is low frequency around 10 to 50 Hz. These results lead us to the conclusion that the racket acts as one is a vibration body and another one is a rigid object at the impact. This high frequency vibration disappeared when a ball impacts only just on the center of racket face, and low frequency remains on the racket. This law frequency vibration transmits to a hand and a forearm though. At the off center impact, when changing the rigidity of the grip from tight to loose, it was found that the high frequency was hard to transmit to a hand, but low frequency passed through the grip. Yoneyama, S. (2003) and other studies reported that the vibration after the impact may causes the "tennis elbow". The results of this experiment reveal that not only the vibration of high frequency but also the low frequency origi … More nates in the tennis elbow, when the racket is regarded as a rigid body.Findings from the experimental results show that the racket acts as a body with two types of properties, one is a vibration body and another one is a rigid object at the impact. From this point of view, we made a model of impact as a rigid body, and the racket links to a hand through a grip that has the characteristics of visco-elasticity. By means of this model, the characteristics of grip are investigated. The model was identified by comparing the experiment data such as the duration time of contact with the ball and racket, the coefficient of restitution of ball, the characteristics of damping of vibration, the frequency and the peak value of vibration. From the simulation of the model, it is inferred that the coefficient of viscosity of grip changes 1.0 to 5.5 N/m/s and the coefficient of elasticity changes from 50 to 500 N/m, according to the tightness of grip. As the tightness of the grip changes, the visco-elasticity coefficients of wrist joint are also influenced. Less