Settings Adjustment for String Tension and Mass of a Tennis Racket Depending on the Ball Characteristics: Laboratory and Field Testing

The sensations of power for a tennis racket may change drastically when used with different balls. The aim of this work was to determine the optimal string tension and mass distribution of a tennis racket, based on its initial configuration and the type of ball used. This study may be also helpful nowadays, when during each tennis tournament the use of particular balls is imposed. First, an experimental analysis is carried out on six different balls, the tennis ball hardness and restitution coefficient are measured and compared. Then the power of a racket is analyzed versus the ball used and the racket settings (string tension, added mass), a dedicated test bench was used. Balls are thrown with a cannon, the speed ratio is the observed parameter. It is shown that the racket balance is most influent parameter followed by the ball characteristics in terms of power. A detailed analysis of the influence of each parameter is given. The second part of the work was concerned with the field tests where the performances of the rackets were evaluated in terms of players’ sensations. The tests were blind as the players did not know which ball among the six different they were hitting. Each ball was hit four times by each player following specific instructions. The players were asked to qualify the balls depending of the power and the general sensation (comfort) they had felt during the stroke. A global synthesis of the results obtained is presented, it shows that during a stroke, the power felt by the players is related to the general sensation.