"I want to give you guys a reason to actually buy in and want to learn about the rotator cuff, since the general discussions of rotator cuff function wouldn’t make further learning any bit enticing. The reason I say that is because, typically, people just discuss the rotator cuff muscles’ rotational functions in isolation. However, they are actually far more relevant, as their tendons also blend with the fibrous joint capsule and serve as the stabilisers of the head of the humerus within the glenoid fossa. They do this via a phenomenon known as “concavity compression”, enhancing stability and load transfer by coordinating the position of the spherical humeral head within the glenoid fossa (Longo et al. 2017).

This is the problem with looking at muscles in isolation; it fails to give credit to the collective function of multiple muscles working together. So, essentially, with any upper body exercise that you do, your rotator cuff muscles are playing a key role in maintaining the integrity of the shoulder joint. Without this stability, we would have excessive translation of the humerus(generally anterosuperiorly when we have a rotator cuff lesion), which would not only reduce our ability to produce force, but also lead to pain and damage to structures in that area. This is often seen in patients post-stroke, who are at a high risk of shoulder subluxation/dislocation, which can result from rotator cuff paralysis (along with the other musculature), meaning that the shoulder joint is now given even more mobility (too much, in this case)."