This is how you prepare your shoulder for the training session, as part of the mobilisation in the warm-up program – before you go on the court!

Stand up straight with your legs about waist wide. Let your arms hang loosely.
Now tense your muscles and make a fist with your left hand. This will stabilize your body..
Now relax your right arm, turn the palm of your right hand forward and lift your arm. If possible, touch your ear with your upper arm.
When you reach the top, turn your hand outwards. In this position, lower your arm backwards until you reach your anatomical limit.
When moving it back, rotate the arm again. While doing so, move the arm close to your head again.

Repeat on each side 2 to 3 times

The joint fluid and the cartilage layer take over the function of a shock absorber in every joint and reduce the frictional forces that arise. The more synovial fluid and the thicker the layer of cartilage, the better the joint is protected against injuries and the longer it remains optimally efficient. In order to achieve this, it is important to regularly activate blood circulation and synovial fluid.

My recommendation: mobilize each joint at least once a day with circular movements.