Why do you ask? Did you tear yours [hopefully not]?
It's a bone, so probably not.
Pretty much the whole body is used in a good tennis stroke. But there's not much point in paying overly much attention to the scapulae...for most.
The one thing that maybe bears mentioning is the alignment of the upper arm with respect to the torso in both serves and forehands. It needs to be pulled back far enough that it can rotate freely in the shoulder socket, or shoulder rotation is limited.
This happens automatically in the one-handed backhand, and requires no effort in either the serve or forehand IF you've got excellent posture (and isn't a major issue in the 2HBH). But for many people in this coach-potato/desk-jockey world, posture is compromised, usually by way of kyphosis -- an exaggerated forward rounding of the upper back.
This postural issue has the side effect of pushing the shoulders forward and out of alignment with the internal bits that cause efficient internal and external shoulder rotation. The
intentional act of retracting the racquet-side scapula during the preparation phase of those two strokes can put the humerus into a slot that allows increased freedom of rotation for people whose posture is compromised this way.
That's very easy in a forehand -- a raised elbow during the unit turn pretty much guarantees this action. It's also pretty much automatic in an "elbow the enemy," Salzenstein-style service motion, but might not come so naturally to those with classical trophy poses. It's still not exactly
difficult in a classical motion, it just becomes something you need to be aware of in that case. I was able to solve that problem for one student by having him retract his scapula on the racquet side as a preparatory element to his serves -- before the toss and/or the raising of the racquet arm. Like a "c0cking of the pistol." Works for him.
