Sweetspot

The sweet spot is a place where a combination of factors results in a maximum response for a given amount of effort. In tennis, squash, racquetball, baseball, cricket or golf a given swing will result in a more powerful hit if the ball strikes the racket, bat or club on the latter’s sweet spot.

The sweet spot is the location at which the object being struck, usually a ball, absorbs the maximum amount of the available forward momentum and rebounds away from the racket, bat, club, etc. with a greater velocity than if struck at any other point on the racket, bat or club.

A tennis racquet, like a baseball or cricket bat, has a sweet spot. If a ball impacts at the sweet spot, the force transmitted to the hand is sufficiently small that the player is almost unaware that the impact has occured. If the ball impacts at a point well away from the sweet spot, the player will feel some jarring and vibration of the handle. The sweet spot is a vibration node, located near the centre of the strings. Another potential sweet spot is the centre of percussion (COP).

Contrary to popular opinion, the sweet spot does not coincide with the point at which the ball rebounds with maximum speed, nor does it locate the spot where the force on the hand is zero. Forces on the hand arise from three independent motions of the handle, namely rotation, translation and vibration.

The vibrational component is absent when a ball strikes the vibration node. The rotational component, arising from recoil of the racquet head, exerts a torque on the hand, causing it rotate about an axis through the wrist. As a result, a force is always exerted on the upper part of the hand, and a force in the opposite direction is always exerted on the lower part of the hand.