U.S. Open Ball Bounce (Ball/Court Interaction) (Page 2)

Our data also included a number of balls that were traveling with underspin before the bounce, hit by both the men and the women players. In general, the friction between the ball and the court during the bounce was sufficient to convert even substantial underspin to topspin.

The team recorded 5 underspin balls hit by the men that averaged underspin of 1979rpm before the bounce. After the bounce, the same balls averaged topspin of 1074rpm. These balls were among the very few hit studied where the topspin on the players' shots after the bounce exceeded the topspin generated by the bounce itself. On these 5 balls, 2 hit by Andre Agassi and 3 by Tomas Muster, the average tospin was 2717rpm.

Men: Oncoming Balls with Underspin Before Bounce

Number of Incidents	Avg Underspin Pre Bounce	Avg Topspin After Bounce	Avg Topspin On Hit
6	1979rpm	1074rpm	2717rpm

Average Topspin Gain After Hit: 1643rpm

Underspin and the Bounce in Women's Tennis

On the women's side we were able to record 13 hits traveling with underspin before the bounce. The average underspin was virtually the same as the men (1979rpm), an average of 1928rpm. The ball bounce also converted the spin on these balls to topspin, with an average spin rate of 1045rpm, again almost exactly the same as the the effect had on the mens' underspin shots (1074rpm). The women were also able to generate additional topspin; hitting these balls, topspin exceeded the topspin caused by the bounce, although less than the men. Average topspin in these hits was 1345rpm.

Women: Oncoming Balls with Underspin Before Bounce

Number of Incidents	Avg Underspin Pre Bounce	Avg Topspin After Bounce	Avg Topspin On Hit
13	1928rpm	1045rpm	1345rpm

Average Topspin Gain After Hit: 300