The supraspinatus and infraspinatus may have long names, but they're relatively small muscles. These two shoulder muscles make up half of your rotator cuff, and they help you lift your arm away from your body, making activities like bathing, dressing and reaching overhead possible.
Needless to say, it'd be quite difficult to go about a single day without using these important muscles.
Whether you're dealing with a shoulder injury or you want to build strength, there are plenty of exercises you can perform to strengthen your supraspinatus and infraspinatus muscles and to help prevent injury in the future.
What Is the Infraspinatus?
The infraspinatus muscle in particular helps with external rotation, or rotating the shoulder away from the body, which is what you do when you're washing your hair or putting on a seat belt, according to an August 2020 article in StatPearls.
The infraspinatus muscle is attached to the back of the shoulder blade on one end and to the back of the upper arm bone on the other. It helps rotate the arm to the side while keeping the shoulder stable, per the StatPearls article.
Exercising the infraspinatus regularly can help the muscle function effectively and may prevent certain shoulder injuries. Talk to your doctor or physical therapist if you experience pain or other discomfort while exercising.
What Is the Supraspinatus?
The supraspinatus muscle is a small muscle in the upper back that supports the rotator cuff, which surrounds the shoulder, according to the National Library of Medicine. Tears in the rotator cuff generally begin in the supraspinatus tendon, per an October 2020 article in StatPearls, and without proper care, can extend to other muscles within the rotator cuff.
The supraspinatus muscle supports the top of the upper-arm bone during upper-body functional movements, according to Ortho Bethesda. When the supraspinatus is weak or injured and it can't provide this support, you're more likely to have shoulder issues.
How to Strengthen the Infraspinatus and Supraspinatus Muscles
Several different infraspinatus and supraspinatus exercises can be performed to strengthen these important muscles. Always talk to a doctor or physical therapist before starting a new exercise routine, especially if you have shoulder pain.
Your doctor or PT may recommend doing two or three weekly workouts consisting of 2 to 3 sets of 10 repetitions of some of the following exercises.
Shrugging your shoulder while you complete these exercises can worsen pain, so be mindful to avoid this as you work out.
1. Prone External Rotation
- Lie on your stomach with your right upper arm hanging halfway off the side of a bed or bench at shoulder level.
- Holding a 1- to 2-pound weight in your right hand, rotate your forearm and hand upward until your forearm is parallel with the ground.
- Hold this position for a second or two, then return to the initial position.
- After completing 10 repetitions, perform the same exercise with the other arm.
Prone external rotation strengthens both the infraspinatus and supraspinatus muscles and helps improve shoulder posture.
2. Resisted External Rotation
- Stand with your left side facing a door. With one end of a resistance band secured in the door handle, hold the other end in your right hand. Keep your right elbow bent at a 90-degree angle and resting firmly against your side.
- Rotate your right forearm away from the door as far as you can without turning your trunk. As you do this, squeeze your shoulder blade down and back. Don't let your elbow leave your side.
- After a 1- to 2-second hold, release your shoulder blade as you rotate the forearm back to the starting position.
- Do 10 reps before switching to the left side.
3. Prone Elevation
- Lie on your stomach with your right arm hanging off the edge of a bed. Hold a 1- to 2-pound weight in your right hand.
- With your right thumb facing up, raise your arm slightly above ear level until it is even with the bed. Do not shrug your shoulder or lift your shoulder off the bed as you perform.
- Hold your right arm in this position for one to two seconds and then lower it back down.
- After completing this 10 times, repeat with the left arm.
Prone elevations target both the infraspinatus and the supraspinatus as they incorporate shoulder rotation and elevation.
4. Side-Lying External Rotation
- Lie on your left side with your right elbow bent at a 90-degree angle and your palm resting against your abdomen. Hold a 1- to 2-pound weight in your right hand.
- Set your right shoulder blade down and back. Then, rotate your right palm and forearm away from your stomach until your forearm is straight up and down.
- Maintain this position for 1 to 2 seconds and then slowly rotate your arm back to your belly.
- After 10 reps, repeat with the left arm.
5. Full Can
- Stand on one end of a resistance band and hold the other end in your right hand. You can also use 1- to 2-pound hand weight in place of a resistance band.
- With a straight elbow and your thumb positioned up, raise your arm at a 45-degree angle with your body.
- Once you have lifted the arm slightly above ear level, hold this position for one to two seconds and then slowly lower back to your right side. Do not shrug your shoulder as you perform.
- After 10 repetitions, repeat the exercise on the left side.
The full can exercise specifically targets the supraspinatus muscle by challenging it to lift a weight away from the body.
6. Prone Full Can Raise
- Lie flat on your stomach on a bench or bed.
- Start with your arms facing down toward the ground, slightly in front of your shoulders, as opposed to directly under the shoulders, with your palms facing forward.
- Raise your arms directly to the side until they reach about shoulder height, then slowly lower.
The prone full can or shoulder T, also known as horizontal abduction in external rotation, is designed to provide dynamic stability, optimal muscle length and tension and proper positioning of the scapula and shoulder girdle, according to the American College of Sports Medicine (ACSM).
7. T-Band Rows
- Wrap a band around a pole or any immovable object at bellybutton height.
- Hold on to both ends of the band so that there is equal length on each side, while also keeping tension in the band at the starting position.
- Begin with your elbows extended with an upright trunk (maintained throughout), and then pull your elbows straight back, keeping them tucked in.
- Pinch the shoulders while pulling the band back. Imagine trying to squeeze a pencil between your shoulder blades.
8. Incline Reverse Lateral Dumbbell Raise
- Lie face-down on an inclined bench.
- Hold a dumbbell in each hand below your chest with your arms fully extended.
- Lift your arms to shoulder height, arcing the weights away from each other
- Return to the starting position.
Infraspinatus and Supraspinatus Stretches
There are many supraspinatus and infraspinatus stretching exercises that a physical therapist may recommend if you're dealing with shoulder pain or recovering from an injury.
Stretching the infraspinatus requires lengthening the muscle by either adducting your shoulder horizontally — pulling your arm across your upper chest — or rotating it inward.
1. Seated Bent-Over Infraspinatus Stretch
- Lean forward from a seated position, placing your hands on your waist with your thumbs pointed down and elbows flexed. Press your elbows toward the floor until you feel light tension through your shoulders and upper back.
- Hold the end position for 10 to 30 seconds, deepening the stretch slightly with each exhalation as you breathe normally.
You can do this exercise from a standing, bent-over position as well.
2. Isometric Horizontal Abduction
- Place the back of your hand against a wall with your arm extended at shoulder height.
- Press your hand into the wall for five to 10 seconds at a time.
- Repeat on other side.