Anatomy Lesson #1- Rotator Cuff Part 1

When I am supervising a training session, the side-lying rotator cuff exercise is one that often needs the most correction and fine tuning.  It seems simple enough, yet if you lose focus and don't pay attention to what your arm and shoulder are doing, you're not getting the most out of the exercise.

Here's a bit of information about what exactly the rotator cuff is, because we tend to hear about it a lot in sports that involve overhead throwing.  The "cuff" is actually a group of four muscles- 3 are on the outside of your scapula (shoulder blade) and the fourth one is on the other side, sandwiched between the underside of the scapula and the ribcage.

The muscles are called a "cuff" because their tendons wrap around and attach to the top of your humerus (upper arm bone)...this is why when you are doing any rotator cuff exercise (properly), you start to feel the burn at that one specific spot.  The rotator cuff muscles have a couple of different functions- the three on the back of your scapula (supraspinatus, infraspinatus and teres minor) are needed to externally rotate your shoulder, similar to what Kara and Korrie are demonstrating:

The muscle on the other side of the scapula (subscapularis) is needed for the opposite action- shoulder internal rotation.  When we talk about doing rotator cuff exercises we're usually not concerned with this one, because it is already very strong since it works together with pectoralis major (your big chest muscles that we work with bench press or push-ups).

When we are throwing overhand, the rotator cuff has many different roles, which is why it is so important.  First, it allows us to generate torque around our shoulder, so that we can throw with more velocity.  Check out the picture of this baseball pitcher below, his rotator cuff is contracting to allow his arm to be parallel with the ground as he gets ready to throw:

 

Your arm might not look exactly like this when you throw, but it would be pretty close depending on your technique and the flexibility in your shoulder. When we do our shoulder external rotation exercises while laying on our side, this is building strength in the rotator cuff so that we can rotate our shoulder back with more force.  The type of contraction that is occuring in this situation is called a concentric contraction, because the muscles are shortening.

As mentioned above, the rotator cuff has many different roles...stay tuned to Part 2 for the rest!  And do your exercises properly!

Manager/Athletic Therapist/Umpire/#1 Ball Shagger Val