PERFORMANCE MEASUREMENT OF TENNIS EQUIPMENT

Abstract

Equipment is exerting an increasing influence on the nature of tennis. The International Tennis Federation (ITF) Technical Centre was set up to ensure that the challenge and identity of the game is retained, while not discouraging technological innovation. As the physiological characteristics of the player are not under its control, the Technical Centre must pursue its mission through the understanding and control of equipment. This requires systematic testing to establish its characteristics, and research and development projects to identify methods of measuring those characteristics that are not currently covered by the Rules of Tennis. This paper describes tests, test methods and current research programs that the ITF has devised to measure the performance of tennis equipment. Although tennis balls are currently tested for size, mass, compression and rebound, two further variables are being researched to more fully specify its characteristics: dynamic coefficient of restitution and aerodynamics (lift and drag). The former project has suggested an inverse second-order relationship between coefficient of restitution and impact speed. A racket performance machine is described, which is designed to replicate the impact characteristics of tennis serves, and which will be used to benchmark the performance characteristics of tennis rackets. Initial results demonstrate the relationship between "power" and both impact speed and impact location. Surfaces, too, play an important role in determining ball rebound characteristics. A test that measures the frictional interaction between the ball and surface during impact, which is converted to a measure of surface "space" is described. The results of these projects will allow the ITF, in its role as guardian of the game, to make informed decisions on the rules relating to equipment, and help ensure that tennis retains its identity.