Strain Energy
Potential energy is the energy associated with an object’s position (Blazevich, 2012). Strain energy is a type of potential energy. Strain energy, which is also referred to as elastic potential energy, is energy that is stored when an object is stretched out of shape (McGinnis, 2005) and works much like an elastic band in which the more the band is stretched the more recoil and potential energy it has. The human body works in the same way in which muscles and tendons can be stretched and can store strain energy and can then be released in the recoil to generate large amounts of force and power (McLester & Pierre, 2008)(Hopper, 2001).
The wind up is the main area of the serve in which strain energy is stored and then released. As the ball is tossed the mass of the player moves into the back leg and the knees bend. The arm which is holding the racquet also stretches behind the back. Once the player is ready to make contact with the ball, the strain energy is released as the legs and the arm extend to make contact with the ball. Much like a spring the more the legs and the racquet arm is stretched and coiled, the more power is released when they extend which in turn effects the power emitted on the ball (see kinetic chain).
Stiffness also effects strain energy (McGinnis, 2005). The stiffer an object that is being stretched is, the more recoil it will have and more elastic potential energy is released. This is why string tension in important on a tennis racquet. The tighter the strings the more power can be emitted from the serve and other strokes. However this can also compromise control and the life of the strings (Rutherford, 1999), so it may not be optimal for all areas of the game.
The wind up is the main area of the serve in which strain energy is stored and then released. As the ball is tossed the mass of the player moves into the back leg and the knees bend. The arm which is holding the racquet also stretches behind the back. Once the player is ready to make contact with the ball, the strain energy is released as the legs and the arm extend to make contact with the ball. Much like a spring the more the legs and the racquet arm is stretched and coiled, the more power is released when they extend which in turn effects the power emitted on the ball (see kinetic chain).
Stiffness also effects strain energy (McGinnis, 2005). The stiffer an object that is being stretched is, the more recoil it will have and more elastic potential energy is released. This is why string tension in important on a tennis racquet. The tighter the strings the more power can be emitted from the serve and other strokes. However this can also compromise control and the life of the strings (Rutherford, 1999), so it may not be optimal for all areas of the game.
The video above shows where elastic potential energy is stored as the knees bend and the racquet arm pauses.