乒乓球运动状态变化的动力学特征及其在搓球和反拉中的应用研究

Study on Dynamic Characteristics of Ball Motion State Change in Table Tennis and Its Application in Chop and Loop Redrive

正确理解乒乓球运动状态变化的动力学特征是提高技术运用合理性的重要前提。结合乒乓球项目特征,运用力学理论对乒乓球运动状态变化的动力学特征进行分析,阐述了击球过程中球体平动量与转动量的转化规律,并对其在搓球和反拉技术中的运用进行了探讨。结论:球体在空中飞行过程中的转速持续减小;碰撞时球与拍的碰撞点沿球面切线方向的相对速度越大,球受到拍面的摩擦力相对越大;碰撞点沿球心方向的相对速度越大,球受到拍面的正碰力越大;摩擦力的大小决定着球体沿摩擦力方向的法向平动速度变化的大小和球面旋转速度变化的大小,而正碰力的大小则决定着球体沿拍面垂直方向反弹速度变化的大小;下降期回搓下旋来球,需增大球拍的后仰幅度,否则容易搓球下网;上升期回搓下旋来球,可在不降低搓球旋转的同时将球搓得更短;上升期以大幅前倾拍面的形式反拉高吊弧圈球相对能更好地兼顾击球的“质量”和“命中率”。本研究旨为乒乓球的技术创新和科学化训练提供理论参考。

Correct understanding of the dynamic characteristics of table tennis motion state change is an important premise to improve the rationality of technology application.Combined with the characteristics of table tennis,the dynamic characteristics of ball motion state change are analyzed with the theory of mechanics,and expounded the law of the transformation of the ball′s horizontal momentum and rotational momentum of hitting,discussed its application in the technique of chop and loop redrive.Conclusion:The rotational speed of the ball decreases continuously during the flight.When the ball collides with the bat,the greater the relative velocity along the tangential direction of the sphere,the greater the friction force of the ball against the bat surface.The greater the relative velocity of the collision point along the center of the ball,the greater the forward impact force of the ball against the bat surface.The magnitude of friction determines the change of normal translation velocity and rotation velocity of the sphere along the direction of friction,while the magnitude of forward impact force determines the change of rebound velocity along the vertical direction of the bat surface.Chop the backspin ball during descent period,it is necessary to increase the backswing of the bat,or it is easy to chop the ball under the net;Chop the backspin ball during rising period,it can keep the spin of the ball and let the ball flying shorter at the same time.During rising period,loop redrive with a large forward tilt can effective balance the“quality”and“hit rate”of the shot.The purpose of this study is to provide theoretical reference for technological innovation and scientific training of table tennis.