We have chosen to discuss topspin in our lesson plans after first explaining the flat ball. The reason for this is that, by learning a flat ball first, you know when you are hitting the ball cleanly and thus most efficiently, whereas, if you learn topspin first, you might never know if your topspin is the best it can be because it inherently requires a shearing force that can be produced very inefficiently and even by accident.

Topspin refers to the direction of the spin of the ball as it crosses the court. The ball is spinning in the direction that it is traveling.

Spins are produced by shearing forces between the racquet and ball. Professor Howard Brody at the University of Pennsylvania has studied the physics of tennis in great depth. His book Tennis Science for Tennis Players summarizes much of his work in this area and is recommended reading.

Topspin can be produced in several ways, but the most efficient way is to bring the racquet from a low position (relative to the ball path) to a high position, using the forearm to rotate the racquet during this motion. Other ways are to use the legs to raise your body from low to high to produce the shearing force between the racquet and ball.

In this series of lessons on topspin, we discuss these variations in detail. In this introduction, we only mention some basic points.

First, the grip you use determines to a great extent how you must configure your body to produce topspin. For example, the figure below left shows the eastern grip, and the figure below right shows the extreme western grip (Both figures are part of a sequence that uses forearm rotation to produce spin.)

The western grip requires a more extreme tilt of the body as well as a more pronounced position of the elbow than the eastern grip. The continental grip has a less pronounced tilt than either of these grips. In both cases, the face of the racquet is in a more downward position than when hitting a flat ball.

Another point is that the lower you are able to start the racquet relative to the ball, the more spin you can produce.

Last, though it is favorable to hit a flat ball near the apex of the bounce, it better to hit a topspin ball on the way down. The lower the ball drops, the faster it is going in a vertical direction, and thus the greater the relative velocity between the racquet and ball. It is this relative difference in velocity that provides the source of the shearing force between the racquet and ball.

By contrasting topspin and flat balls, you can learn both of them faster than by studying either alone. For this reason, we are presenting this contrast in our lessons as they proceed.