Rotator Cuff Basics for Rock Climbers
The cuff is like the core.
Rotator cuff basics
Here's a 3D view of the right shoulder. It starts on the backside showing 3 of the 4 muscles: Supraspinatus, Infraspinatus, and Teres minor.
When the video rotates around the tip of the shoulder it moves to the front showing the Subscapularis. The pneumonic SITS is commonly used to remember the names.
Even though these muscles can manipulate the glenohumeral joint (shoulder joint) they aren't considered prime movers (agonists). This is because of their proximity to the center of rotation. The further a tendon attaches away from its center of rotation the more torque (force) it can produce.
So, the job of the cuff is to create concavity compression of the humeral head (spherical part of the arm bone) into the glenoid fossa (small depression on scapula) during arm movements. It pulls the arm bone towards the socket creating negative pressure to stabilize the joint. Its job is primarily synergistic through quasi-isometric contractions.
These muscles need to create force rapidly and help coordinate the position of the arm while the other larger muscles perform the more intense work.
In general I think we use too much "isolation" exercise for the rotator cuff and totally miss this point. Warming up these muscles through a full range of motion slowly and controlled with low intensity does little to prepare them for the dynamic demands of a sport.
Key takeaways:
Many isolation exercises for the rotator cuff aren’t helpful.
I consider the cuff more like the core. If we train with more specific positions (arm position) to our sport and progress force, velocity, and volume we should be addressing these muscles adequately.