MUSCLES:

The rotator cuff: subscapularis, infraspinatus, teres minor, and supraspinatus

Muscle:

Subscapularis

Origin:

At the inner surface of the scapula

Insertion:

At the lesser tubercle of the humerus and inferior shoulder capsule

Function:

Internal rotation of the humerus; assists in humeral adduction and stabilizes the humeral head in the glenoid cavity during arm abduction

Muscle:

Infraspinatus

Origin:

At the posterior medial surface of the scapula below the spine of the scapula

Insertion:

At the greater tuberosity of the humerus and the shoulder capsule

Function:

Externally rotates the arm along with the teres minor, assists in stabilizing the head of the humerus in the glenoid cavity while the arm is elevated; the superior fibers aid in abduction, and the inferior fibers in adduction.

Muscle:

Teres minor

Origin:

At the axillary border of the scapula on the dorsal surface

Insertion:

At the inferior aspect of the greater tuberosity of the humerus

Function:

Externally rotate the arm, along with the infraspinatus; it assists in stabilizing the head of the humerus in the glenoid cavity while the arm is elevated

Muscle:

Supraspinatus

Origin:

At the medial two-thirds of the supraspinatus fossa on the scapula

Insertion:

At the greater tubercle of the humerus

Function:

Assists in abducting the humerus and holding the head of the humerus in the glenoid fossa

Indications of Weakness:

Infraspinatus:

Weakness of this muscle may cause shortening and hypertonicity of the subscapularis due to agonist-antagonistic interaction. Identified by the scapula’s seeming to pull laterally when the arm is abducted.

Subscapularis:

When shortened or hypertonic, the subscapularis will decrease ROM for the humerus; if severe enough, this can manifest as a frozen shoulder or adhesive capsulitis. This muscle often gets many adhesions from excessive bench-pressing, which may be felt as pain in the front of the shoulder. The pain is caused by the muscle preventing the head of the humerus from moving forward when the bench-press bar is at the chest. This puts undue stress on the muscle, which often becomes inflamed. Inflammation creates adhesions and scar tissue, weakening the muscle.

Teres minor:

Weakness may cause internal rotation of the arm when relaxed at the side while the person is standing. Shortened or hypertonic teres minor decreases the ability to reach behind the back.

Supraspinatus:

Weakness can cause difficulty raising and keeping the arm parallel to the floor. If extremely weak, the torso bends laterally to initiate abduction of the arm. Shoulder joint crepitus (noise in the joint) is often due to adhesions in this muscle. The supraspinatus has a poor blood supply and is often damaged at the myotendinous junction, causing shoulder pain and weakness.

Optimal Training Principles:

The rotator cuff muscles are small muscles, with relatively narrow attachments. The rotator cuff muscles support and stabilize the arm and shoulder, and together assist with the wide range of movements that the shoulder is capable of achieving. Unfortunately, with the great mobility of the rotator cuff comes the risk of injury. Rotator cuff injuries account for a large percentage of joint dysfunctions.

The best resource for dealing with the care and prevention of rotator cuff injuries is the IFPA Body Building Certification Course. This course provides two extremely valuable texts as well as a very extensive DVD video that will not only provide you with a complete array of muscle and joint function tests for the rotator cuff, but also a complete array of strength and flexibility exercises necessary to correct any dysfunctions you discover when you test your client.

Better still, the texts and videos describe in detail the joint and muscle function tests you need to know to test for dysfunction in all of your client’s joints and muscles. The texts and videos teach you not only how to discover dysfunctions, but also teach you in great detail when and how to utilize the ideal strength and/or flexibility exercise to correct the dysfunction.

Imagine the power you will wield, when you alone, among all the trainers in your gym, your area, your city, gain a reputation as the Fitness Professional who can not only quickly identify dysfunctions-- therefore having the ability to protect your client from future damage-- but become known as the Fitness Professional who can CORRECT the dysfunctions.

For Example:

When someone comes to you complaining of shoulder pain, can you identify which muscle is the problem? Can you determine whether that muscle is weak and underdeveloped or shortened and overdeveloped?

One fairly common example of rotator cuff dysfunction is an imbalance in which the subscapularis (the primary internal rotator) is shortened and overdeveloped {Don’t forget that Monday is INTERNATIONAL BENCH PRESS DAY and the subscapularis gets plenty of work in bench presses} and the infraspinatus and teres minor muscles (the external rotators) are underdeveloped and weak.

This imbalance would require flexibility exercises to increase the ROM of the subscapularis and strengthening exercises for the infraspinatus and teres minor muscles.

Now think back, when was the last time you saw all those “bench pressers” doing external rotation or D-2 exercises?

For the few you do see performing the exercises, how many do them right? For the most part, the most effective rotator cuff exercises are performed on cable machines such as the VORTEX Machine , not with dumbbells or tubing.

Rotator cuff exercises should be performed at the very end of your chest and shoulder day. This prevents fatigue of these small rotator cuff muscles, which are needed when using the larger muscles such as the pectoralis major and anterior and/or lateral deltoid.

It is also recommended that you DO NOT work the chest one day followed by the shoulders the next. Since the rotator cuff muscles are used in both chest and shoulder exercises, it is very easy to overtrain the rotator cuff; this can lead to injury. That pain in the front part of your shoulder could very well be your subscapularis telling you it’s turning French and “It surrenders”.

The bulk of the rotator cuff muscle and joint dysfunction tests and their associated corrective exercises are too numerous, too nuanced, and too detailed to cover here. Once again, it is highly recommended that you take the IFPA Body Building Instructor Certification Course. Master all the exercises and tests described and displayed in the text and videos and become highly sought after as a Fitness Professional.

Become a MASTER OF YOUR CRAFT!

Good Luck!

Jim Bell

James T. Bell, PhD is the founder and president of the International Fitness Professionals Association, IFPA.

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