Tennis players activate their shoulder blade muscles much more when doing a shoulder exercise lying face down than when doing the same movement standing with a resistance band.

When tennis players do a shoulder exercise lying face down with arms raised high, their shoulder blade muscles don't fire as strongly as in other athletes—sometimes less than half as much.

When people do a shoulder exercise standing with a resistance band, tennis players and other athletes use their shoulder blade muscles about the same—so this exercise doesn't reveal the differences seen in other exercises.

People who play tennis don't use the shoulder blade muscles as much as other athletes when doing a specific exercise where they lie face down and pull their shoulder blades together, especially when their arms are raised high.

Both tennis players and other athletes have some imbalance in how strongly each shoulder blade muscle works, but tennis players are more balanced when their arms are raised high, and more unbalanced when their arms are at a lower angle—like during a tennis stroke.