Recently, International Tennis Federation researchers reported that the same movement that was observed by Kawazoe with lubricated strings occurs with copoly as well. Copoly strings-slippery and stiff-generate more spin not because of more friction, but because of less. The old argument was that the better the grip between the strings and the ball, the more spin we would get, but that was not true. Many experiments has started to investigate whether the lateral movement and snap-back of the main strings increase spin, which strings generate the most spin, and so on. The research has also started to investigate the effect of a inter-string friction upon the main strings movement against the cross strings. Furthermore, the research has started to investigate how tennis strings "Go Dead". This paper clarified a mechanism for impact that is able to account for the effects of various parameters on ball control, spin performance and string performance life, which is seen in the literature with laboratory experiment compared with experiment by the author who paid its attention to string-to-string friction in player tests.
The Proceedings of Joint Symposium: Symposium on Sports Engineering, Symposium on Human Dynamics
