Understanding the traction of tennis surfaces

The traction provided by a footwear-surface interaction can have an impact on player safety, performance and overall enjoyment of sport. Mechanical test methods used for the testing and categorisation of safe playing surfaces do not tend to simulate loads occurring during participation on the surface, and thus are unlikely to predict human response to the surface. For example, the pendulum system routinely employed by the International Tennis Federation (I.T.F.) utilises a standard rubber ‘foot’, rather than a shoe sole, and does not apply forces comparable to those in real play. There is a requirement for an improved scientific understanding of the tribological interactions at the shoe surface interface and the effects footwear and surface parameters have on the traction mechanism developed. The relationship between normal force and the coefficient of traction for the forefoot of a tennis shoe in contact with different tennis surfaces was examined using a bespoke traction rig. The effects of surface roughness were also examined. A power relationship was found between normal force and traction. As normal force increased differences in surface traction were found. The normal force, stiffness, and roughness of the surfaces affected the adhesive and hysteresis friction mechanisms that contribute to the overall traction force.