The shoulder is an unstable joint if the muscles around it do not stabilize it.
The rotator cuff holds the shoulder head in the socket and has a central role in shoulder stabilization. That's why it's so important to strengthen it!
And that's what you do with these exercises:
-> External rotation: Stand or sit upright, arms are bent 90° at the elbow, elbow joints are against the body and remain there throughout the exercise. Now bring the forearms outward away from the body. 10 repetitions.
-> Internal rotation with theraband: The band is attached to a door handle, you stand sideways, parallel to the door. Hold the other end with the nearest hand, the forearm is parallel to the floor. Now bring the forearm to the body and the elbow remains applied to the body. 10 repetitions per side.
-> Support: Any form of support exercise strengthens the entire rotator cuff. You are in a quadrupedal position and consciously drop into your shoulders. Then support yourself back up. Again 10 repetitions.