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What is the Infraspinatus Muscle and What does it Do?

Improve your knowledge, enhance your body, become a fitter, better athlete.

Time to learn more about the Infraspinatus Muscle, how it helps you move and how to protect and strengthen it.

Do you suffer from back, neck, or even arm pain, but not sure where it’s coming from? Perhaps you spend too much time slumped over your keyboard and experience pain from it?

Have you ever heard of the Infraspinatus muscle? If you checked yes on any of the above, then you’ve come to the right place.

What is the Infraspinatus Muscle?

The Infraspinatus Muscle is a thick triangular muscle that occupies much of the infraspinous fossa of the scapula. It is a member of the rotator cuff, commonly remembered by the mnemonic “SITS” (supraspinatus, infraspinatus, teres minor, subscapularis).

These muscles contribute to help form the glenohumeral joint which aids in shoulder joint motion and stability.

These muscles allow the shoulder joint to have stability while being one of the most mobile joints in the body. The main functions of the infraspinatus are assisting in external rotation of the shoulder joint, scaption, and lateral rotation of the humerus.

What is the Purpose of the Infraspinatus Muscle?

Infraspinatus MuscleSource: Get Body Smart

The infraspinatus is a portion of the rotator cuff muscles that are composed of the supraspinatus, infraspinatus, teres minor, and subscapularis.

These muscles act to stabilize the glenohumeral joint. The tendons of these muscles are nonlinear, viscoelastic, and heterogeneous. A major component of these tendons is collagen, which creates a matrix providing extensibility.

The transition point of a tendon to bone insertion can be broken down into the following four zones: tendon midsubstance, fibrocartilage, calcified fibrocartilage, and bone.

In addition to the rotator cuff muscles, the glenohumeral joint is further stabilized by ligaments and connective tissues.

What is the Infraspinatus Muscle Strength Test?

According to Physiopedia “The patient should be standing, with the arm in a neutral position and the elbow flexed to 90 degrees.

The therapist will apply a medially directed force to the arm while the patient is instructed to resist. The test is considered positive if the patient reports pain or weakness when resistance is applied.”

What is the Action of the Infraspinatus Muscle?

Infraspinatus is the main external rotator of the shoulder joint. It assists in producing shoulder extension. With the arm fixed, it abducts the inferior angle of the scapula.

How does the Infraspinatus Muscle Work?

As one of the four muscles of the rotator cuff, the main function of the infraspinatus is to externally rotate the humerus and stabilize the shoulder joint.

Infraspinatus Muscle Pain

Pain in the infraspinatus is most likely caused by repetitive motion involving the shoulder. Swimmers, tennis players, painters, and carpenters get it more frequently. It also becomes more likely as you get older.

There are several potential causes of infraspinatus pain.

Infraspinatus tear

There are two types of infraspinatus tears:

A partial tear will damage the tendon, but it doesn’t go all the way through. It’s usually caused by repetitive stress or normal aging.

A complete, or full-thickness, tear severs the infraspinatus from the bone. It’s usually caused by an acute injury, such as falling.


  • pain at rest
  • pain at night
  • arm weakness
  • pain when lifting or lowering your arm
  • crackling sensation when moving your arm

if you have an acute tear, it’ll cause severe, sudden pain and weakness

Infraspinatus tendinopathy

Infraspinatus tendinopathy is a less severe injury to the infraspinatus. There are two types:

Tendonitis is an inflammation of the tendon.

Tendinosis is small tears in the tendon that don’t cause much inflammation.

Causes of tendinopathy include:

  • overuse, especially reaching overhead or throwing
  • shoulder trauma
  • arthritis or another inflammatory disease in your shoulder
  • normal wear and tear as you age


  • pain that increases with shoulder use
  • dull ache in your shoulder and upper arm
  • pain at night
  • shoulder weakness
  • shoulder stiffness
  • some loss of motion in your shoulder
  • pain while reaching overhead
  • pain while reaching behind you”

Infraspinatus Muscle Stretch

Try these Infraspinatus Muscle stretches to keep your movement and muscles healthy and supple.

“I start with the cross body stretch and then demo 2 variations of the chicken wing stretch.  After that, I walk you through 3 variations of the towel stretch. 

Next to last, we take a look at the sleeper stretch which is used by many baseball players and overhead athletes. 

Finally, we take a look at the multiple way you can stretch your infraspinatus and teres minor with the ROTATER.”

Infraspinatus Muscle Exercises

Release Exercises for the Infraspinatus

Try this exercise from MoveU.

“Take a lacrosse ball or tennis ball, whichever level of firmness you can tolerate, and press the ball between your Infraspinatus muscles and a wall, or other solid structure.

You may need to play around with the position of the ball to find that nice “area of sensation.” Once you find it practice breathing into the ball and relaxing around it. If this is causing you pain to the point that you cannot relax into it, back off on the intensity. If you are guarding because of the pain you aren’t going to achieve as much.”

Understanding the Infraspinatus Muscle

Now you have the information to protect, understand, improve and maintain your body and shoulders in relation to the Infraspinatus Muscle.

Try testing yourself with these Russian Kettlebell Swing or Kettlebell Clean and Press workouts.

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