Which phase of throwing is most taxing on the shoulder?

The deceleration phase of throwing is the most taxing on the shoulder due to the high forces generated as the arm rapidly slows down after the ball is released. This phase occurs immediately after the acceleration phase and involves a significant amount of eccentric loading on the shoulder muscles, particularly the rotator cuff and the scapular stabilizers. These muscles work to control and prevent excessive movement of the shoulder joint, which is critical at this moment to avoid injury.

During the deceleration phase, the arm has reached its peak velocity, and the significant momentum must be absorbed and controlled. The shoulder experiences considerable stress as the body attempts to dissipate the kinetic energy generated from the throw. This can lead to fatigue or even injury over time, especially if proper mechanics or conditioning are not maintained.

Understanding the mechanics of this phase highlights the importance of strength and stability in the shoulder region. Athletes and individuals involved in throwing sports often focus on conditioning the muscles involved in deceleration to reduce the risk of shoulder injuries associated with overuse or poor throwing technique.