Tennis: the effects of grip firmness on ball velocity after impact.

The effects of grip firmness on the ball velocity after impact has been investigated in tennis. The average horizontal velocity of the ball prior to contact and after completion of contact was determined by a motion-picture camera. A tennis ball was fired from a machine to impact with a tennis racket, which was fixed in several different positions. No significant difference was found between the velocity of the ball after impact with a racket which was horizontally clamped and with a racket in a balanced, upright position. The velocity ratio (post-impact vs pre-impact velocity) was an inverse function of the velocity of impact.