The Rotator Cuff: Small Muscles That Make a Big Difference

by Scott Shetler
October 6, 2006

I want to begin this article by thanking Half Square reader Tom Althauser for the idea for this month's article. Tom corresponded with me via email and we got on the subject of the muscles of the rotator cuff and he expressed that an article devoted to strength training concerns for these often over-looked muscles might make an interesting topic. Tom, I can't agree more!

In my experience I have worked with numerous clients that have experienced rotator cuff problems. From strains to full tears and everything in between, I have seen it all. In my experience most of these injuries could have been prevented with two simple steps strength training and flexibility work.

Before we outline some stretches and strength exercises for the rotator cuff let's briefly discuss the anatomy and function of the rotator cuff muscles as well as the surrounding musculature.

There are four muscles that make up the rotator cuff and they may be remembered quite easily by the acronym SITS - Supraspinatus, Infraspinatus, Teres Minor, Subscapularis. In addition to the four muscles that make up the "rotator cuff" other muscles contribute to the rotational capacity of the shoulder joint. Here is a list of the muscles of the rotator cuff, as well as the other muscles that rotate the shoulder, and their specific functions.

Rotator Cuff
- Subscapularis - internal rotation of the shoulder
- Supraspinatus - abduction and stabilization of the shoulder
- Infraspinaturs - external rotation of the shoulder
- Teres Minor - external rotation of the shoulder

Additional Muscles that Rotate the Shoulder
- Pectoralis Major - internal rotation of the shoulder
- Anterior Deltoid - internal rotation of the shoulder
- Latissimus Dorsi - internal rotation of the shoulder
- Teres Major - internal rotation of the shoulder
- Posterior Deltoid - external rotation of the shoulder

When looking at the list above we can see that there are far more muscles that internally rotate the shoulder than external rotators. Couple this with the fact that many sports tend to be internal rotation dominant (i.e. tennis, baseball, volleyball, rowing, swimming, etc.) and we can quickly see why there are so many instances of rotator cuff injuries. In the gym, any lift that incorporates the pecs and lats (i.e. virtually all presses and pulldowns or pull-ups) will also over-develop the internal rotators. Very few movements and exercises incorporate the external rotator and this is typically the result of many rotator cuff injuries.

Since there is such a high degree of internal rotator work already performed in the gym and in sports we need to establish a program that will help balance out the work placed on the internal rotators to restore balance and health to the shoulder joint and hopefully prevent future injury. For this we need a two-pronged approach, stretch the pecs and lats and strengthen the external rotators.

Flexibility Exercises - Internal Rotator Specific

The Latissimus Dorsi Stretch
- Hold onto a vertical bar or other immovable object as in the above diagram
- Lean back and feel a stretch through the side of the back underneath the arm
- Hold for 15-30 seconds performing 2-3 stretches per arm

The Pectoralis Major Stretch
- Stand in a doorway and place your hand against the wall as in the above illustration
- Turn away from the wall slowly until you feel a stretch into the pec and through the front of the shoulder
- Hold the stretch for 15-30 seconds performing 2-3 stretches per arm

Strength Exercises - External Rotator Specific

1-Arm External Rotation with a Dumbbell
- Grab a light dumbbell (a 3-5 lb. bell is good for most to start with) and brace the elbow against the leg as in diagram 1. Keep the arm bent in a 90 degree angle.
- Externally rotate the arm maintaining the 90 degree bend as in diagram 2.
- Reverse the movement and return to the starting position.
- Perform 2-3 sets of 10-20 repetition 2-3 times per week.

There you have it! Three simple steps to help prevent rotator cuff problems. If you do experience a rotator cuff injury of any kind, be sure to get it diagnosed by your physician before attempting any sort of rehabilitation exercises. Remember, it's tough to treat a problem before you know what the problem is!