ABSTRACT

Given the speed of the games in tennis, the duration of the tournaments and the length of the matches, the outcome of competitions is increasingly determined by the degree of physical fitness, due to the similar abilities of most professional tennis players (Konig et al., 2001). It appears that explosive strength is becoming an important aspect in tennis performance (Roetert et al., 1996). During a tennis match, the players carry out highspeed movements executed within very short periods of time. The time available to execute each hit depends not only on the velocity of the ball, but also on the resistance or the load that the player has to overcome (the racket and the body weight), as well as on the distribution of the movement acceleration. These aspects determine the characteristics of force production in tennis: low resistance high-speed movements. Thus, tennis is an intermittent sport, in which there is a requirement to move quickly in varied directions, to stop and start with an explosive first step (Bergeron and Keul, 2002). It has been estimated that during a tennis match, 300-500 high-speed movements are performed (Deutsch et al., 1988). The mean displacement of a tennis player is 3 m per shot and 8-12 m per point in a mean time period of 3-8 s each rally (Ferrauti et al., 200 la). Modern tennis also demands high power generation in every tennis stroke. Moreover, in professional tennis players, a close correlation between the velocity of the ball and performance has been recently reported (Vergauwen et al., 1998).