Sometimes I feel like this group of muscles gets overcomplicated and misunderstood. It usually only gets any attention in the gym world when we are discussing a strain or tear. As trainers, we know the rotator cuff is an important group of muscles, but where does it fit into a weight loss client’s exercise prescription? What if they don’t have any past or present shoulder issues? To answer these questions, it is extremely important to understand where most trainers make mistakes in rotator cuff training, and include the best exercises for your clients.
Let’s start with the basics and go from there. The combined goal of all of the rotator cuff muscles together is to stabilize the humerus in the glenoid fossa. Individually they play roles in rotation and abduction of the humerus. The infraspinatus and teres minor are humeral external rotators, the subscapularis contributes to humeral internal rotation, and the supraspinatus initiates abduction of the humerus.
Now this all becomes important when we discuss upper body posture of our clients. Due to how most people are positioned throughout the day, its quite common for our clients to display rounded shoulders and forward head. This leads to a static state of humeral internal rotation. We would expect pectoralis major and minor, subscapularis, and teres major to be short and overactive. As I mentioned before, the subscapularis is the primary rotator cuff muscle responsible for internal rotation. Therefore most people don’t need more internal rotation activation. Instead I would recommend considering Self-Myofascial Release followed by stretching of the pectorals major and minor.
So now to the external rotators. This is where you should focus your rotator cuff strengthening efforts. Due to the short and overactive internal rotators, the infraspinatus and teres minor are more likely to be weak. Remember the combined goal of the rotator cuff is to stabilize the glenohumeral joint throughout upper extremity motion. If there is imbalance in length-tension relationships in some of these muscles, they will not properly stabilize this joint.
Not all external rotation exercises are created equal. Lots of research regarding peak force of the infraspinatus and teres minor has been done to find the most optimal positioning of the arm for these exercises.
Standing humeral external rotation is best performed at the 30/30/30 position. Have your client in 30 degrees of abduction, 30 degrees of shoulder flexion, and 30 degrees relative forearm pronation. Basically they should hold their arm 30 degrees in the scapular plane. Having their arm back and at their side will bias posterior deltoid over the rotator cuff. Squeezing a towel with their elbow will also help engage more rotator cuff and less deltoid.
If training humeral external rotation in side lying, have your client place a small towel between their side and just above the elbow. Perform the slow and controlled external rotation motion with about 75 degrees of elbow flexion.
As far as resistance goes, less is more. Our goal for rotator cuff training is not necessarily hypertrophy, but rather correct activation. In regards to reps, these are meant to be endurance and stabilizing muscles, so rep ranges of 20 to 25 should be appropriate.
In my opinion, understanding the anatomy and function of these muscles is the first step to designing the most effective rotator cuff training plan. With that said, I hope you will start applying this info and incorporating some of these exercises into your client’s workouts. Let me know what you think!
P.S. – Quick Reference of RTC muscles and actions:
Supraspinatus – initiates abduction of humerus
Infraspinatus – humeral external rotation
Subscapularis – humeral internal rotation
Teres Minor – humeral external rotation
Doctor of Physical Therapy Candidate, Corrective Exercise Specialist, Certified Personal Trainer
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