一、高质量的发球我们知道发球主要决定于击球力量和击球部位，球拍对球产生作用力和作用力通过击球的部位决定球的旋转（如下表）。判断一个发球质量的好坏，其质量要素取决于速度、旋转、落点。笔者通过实际训练发现只有从发球旋转变化、球的落点、球的速度上下功夫，才... First, the high-quality service We know that the main service depends on the ball and hit the ball site, the racket on the ball to produce force and force through the ball hit the site determines the rotation of the ball (the following table). Judge the quality of a service is good or bad, the quality factor depends on the speed, rotation, landing. The author through practical training found that only from the rotation rotation changes, the ball’s landing point, the speed of the ball work hard, just ...