Ball/Court Interaction (Page 2)

For example, below is a still from a video of a US Open ball with no spin on a hard court (specifically, the court used for the Lipton tournament). This was our close up view. Watch the black line on the ball before and after the bounce. Before the bounce the line barely moves - as you can see, there is no spin. What happens after the bounce? The ball spins - with topspin to be exact. As a matter of fact, regardless of the type or amount of spin before the bounce (flat (no spin), topspin or underspin) after the bounce the ball had topspin.

Download Movie: Hard Court - No Spin - US Open Ball

Why is that? Think about this - what if there was no rebound angle out? The ball hits the court and just starts to roll towards you. What type of spin would the ball need to keep rolling towards you? Topspin.

As the ball moves forward and strikes the ground, the friction between the ball and the court slows the bottom of the ball. This means that the top of the ball moves forward and rotates the ball.

Here are two other videos. The first is the Slazenger ball used at Wimbledon on a grass court with underspin; the second is topspin on the green clay court using a Wilson clay court ball. In all cases after the bounce there is topspin.

Download Movie: Grass Court - Underspin - Wimbledon Ball

Download Movie: Green Clay Court - Topspin - Wilson Clay Court Ball