Setting Up the Shoulder Rotations on a World Class Serve

External followed by internal shoulder rotation—but how are they created and enhanced?

In part one of this series, (Click Here) we looked in detail at the critical role of upper arm rotation in high performance serving. We saw how internal shoulder rotation, producing forward racket motion, was the largest contributor to racket head speed as the racket moves to impact with the ball.

We also saw that the effectiveness of this internal rotation depended on the external rotation of the upper arm prior to the upward swing. This backwards rotation stretches the muscles used in the upward swing, increasing their explosiveness and top speed.

This pre-stretching of muscles, followed by their rapid contraction, what is known as a stretch shorten cycle.

The first article was devoted simply to describing these two rotations that combine in a stretch shorten cycle. Now in this second article let’s go deeper. Let’s address the specific motions that set it up. Not what the stretch shorten cycle is, but what makes it happen.

A basic characteristic of a muscle, like a rope, is that it can only pull in one direction. A muscle cannot pre-stretch itself. Therefore, to stretch muscles always requires external forces. Here’s…