What is ISR?
Part 2: The Forehand

John Yandell

In the first article in this series (Click Here), we explained what external and internal shoulder rotation are and how they work together on the serve. But these rotations are present to a greater or lesser extent on all the strokes, so in Part 2 let's see how they work together on the forehand.

Terminology

Again, these are biomechanical terms that can seem confusing, and I believe understanding them isn't really necessary to develop high level technical strokes. You won't find them, for example, in my articles in the Teaching Systems section (Click Here). But the terms have passed into tennis teaching lingo and are often misunderstood and misused, so let's try clarifying all that.

To review, external shoulder rotation is the backwards counter clock wise rotation of the upper arm in the shoulder joint. Internal shoulder rotation is the clockwise rotation of the same upper arm segment. The arm and racket rotates as a unit in the shoulder joint.

So what happens on the forehand with those 2 rotations? At some point, usually, as the racket is moving back in the backswing, there is internal rotation, meaning the racket face is turning down toward the court. This happens to a slight or greater extent, depending on the player.