A new technique for assessing ball speed and impact force in volleyball

This paper presents a description of a simple ballistic pendulum used for assessing ball speed and forces in volleyball. A seven-meter long pendulum with a wooden block of mass 10 kg was constructed and then used in conjunction with a specially designed timer with a precision of 10(-3)s to measure ball speed, pendulum speed and forces exerted to the ball and to the hand. Twelve volleyball players, ranging in ability from beginners to elite (National team) level were used as subjects, and separated into three groups; beginners, university and elite. All subjects performed five services of each kind. Subjects were instructed to jump to the height where the ball and pendulum were hung and hit it against the pendulum as hard as possible. A video camera, Panasonic M9000, was also used for the deviation angle measurement of pendulum. The results showed that highly skilled players receive larger forces and produce higher ball speeds than lower-level athletes.