Athletes determine the sweet spot on a piece of sports equipment by using the equipment until they find the spot where a ball or other object achieves maximum momentum when they strike it. While experimenting with the equipment, they can mark circles in likely spots with erasable markers and adjust the locations as needed. Although physicists have attempted to find sweet spots on equipment through experimentation, their attempts may be redundant because they do not perform them under playing conditions.
Athletes in various sports have their own criteria for determining the sweet spots in the equipment they use. For instance, the sweet spot on a golf club depends on the size of the clubface and its weight distribution, known as perimeter weighing. The sweet spot on a baseball bat is the point where there is minimum vibration between the butt end and barrel end. The sweet spot on a tennis or squash racket is not at the center, because rackets are not circular but elliptical. Additionally, other factors such as the grip, throat, shaft and construction material of the frame also influence play.
Physicists in laboratory experiments have attempted to find the sweet spots on tennis rackets by throwing balls against stationary rackets and measuring resultant vibrations, and by blasting sound vibrations against rackets and measuring the string vibrations with lasers. Other physicists argue that the results are irrelevant because the experimenters clamp down the handles and use objects other than balls in their tests.