Technique: The Kinetic Chain

(The information in this article was taken or adapted from the High Performance Coaching Program Study Guide.)

The parts of the body act as a system of chain links, whereby the energy or force generated by one link (or part of the body) can be transferred successively to the next link. The link system in the service action, which starts from the ground, can be explained in the following way (Elliott and Saviano, 2001; Elliott & Kilderry, 1983):

  • Leg drive
  • Trunk rotation
  • Upper arm elevation
  • Forearm extension, upper arm internal rotation and forearm pronation
  • Hand flexion

The optimum coordination (timing) of these body segments and their movements will allow for the efficient transfer of energy and power up through the body, moving from one body segment to the next.   Each movement in the sequence builds upon the previous motion and they all contribute to the generations of racket speed.

This transfer of energy in sequential coordination is also enhanced by the stretch-shortening cycle of muscle action.  The stretch-shortening cycle involves the active stretching (the muscle is activated but is elongated by another force) of a muscle in a countermovement immediately followed by a more forceful shortening of the muscle in the desired direction.  In the forehand, for example, the chest and shoulder muscles are actively stretched (coaches often use the cue “loading” here) as the trunk rotates into the shot and the inertia of the arm and racket cause them to lag behind. 
The active stretch of the muscle stores energy in the elastic elements of muscle and associated tissues such as tendons, which is reused as the muscle begins to shorten. This sequence of muscular coordination tends to be chosen naturally by the brain, but sometimes this must be coached in players who develop pauses, that in turn lead to missed segment rotations or problems in sequencing segments.

The most effective tennis strokes begin with leg drive generating ground reaction forces that can be transferred up the segments of the kinetic chain to the racket.  Proper timing of the segments in the kinematic chain and stretch-shortening cycle muscle actions maximize the transfer of energy to generate the greatest racket speed.

Example—One-handed backhands tend typically involve five kinematic links that the player has to coordinate (Groppel, 1992).  In most cases the one-handed backhand is based on a sequential summing of the motions of the legs, trunk, arm, forearm, and wrist/hand.  Two-handed backhands during early learning use fewer body segments, so many young players find this stroke easier to coordinate.  In the modern two-handed stroke a similar number of segments are rotated as for the on-handed stroke.