The Art and Science of Victory
The Physics of Tennis
Physics !? Yuckos! What do I need to know physics for?
Why a Closed Stance on the
One Handed Backhand Topspin?

Closed stance on the one-handed backhand topspin.

Why must the stance be closed on the one hander? Here is why (it is all about balance):

  1. To hit topspin, the racquet must get below the ball and follw through high - that means a long stroke -longer than just the shoulder turn and thus longer than the two hander.
  2. The backhand stroke brings the arm from across the body to even with the shoulders. The forehand stroke goes the opposite way, so the players weight ends up on the left foot in the forehand and the right foot in the backhand.
  3. The follow through on the forehand ends up over the left shoulder and close to the body.On the backhand it inds up paralel to the right shoulder and away from the body. This means that there is a centrifugul force late in the backhand stroke that points foreward and to the left.
  4. Therefore, in order to stay son balance throughout the stroke the weight catching (right) foot has to be to the left of the lone of flight of the ball.
Angle-of-Attack

Legend

Whenever the racquet face is travelling in one direction and pointing in another at the point of contact, spin is created. The angle between the direction of travel and the direction the face is pointing is called the angle-of-attack (AOA). If the racquet is travelling up but the face is pointing foreward, you get topspin. If the racuuet is travelling down you get underspin.

This is not the only way to produce spin (see the Federer Forehand), but it is the most fundemental - it is part of every stroke you hit because nothing in tennis is hit flat, at least not intentionally.

Spin

Legend

Spin has three effects on the flight of the ball - two are obvious and the third is important but not so obvious:

  • Aerodynamic effect - the flight of the ball will tend to follow the direction of the front of the ball. In topspin, for example, the front of the ball goes down relative to the balls flight path. This causes the ball to tend to dive. In underspin the front of the ball is going up and the ball tends to fly - to defy gravity. Right-to-left spin causes the ball to arc left and vice versa. The degree of arc depends on the speed of rotation and the speed of the ball.
  • The Bounce - The spin affects the bounce in two ways - court bite and flight path. Court bite is how the ball interacts with the court surface - underspin bites hard and that tends to make the ball bounce slow and low. Topspin rolls across the surface so the ball tends to accelarate after it bounces. The flight path of underspin is very flat - again keeping the bounce low. Topspin dives at the end of its flight, leadking to a higher bounce. In summary - underspin bounces low and slow, topspin bounces high and fast.
  • Adding spin controls pace - the steep angle-of-attack that puts spin on a ball means that less of the racquet head energy is transferred to the ball as pace. This means that you can hit a spin second serve with as much 'ummph' as your first serve - the steeper angle of attach takes pace off of the ball and helps keep it in the box. You can also hit your ground strokes and volleys with more authority.