The most effective way to stretch the infraspinatus is by using internal rotation movements with your shoulder blade stabilized, preventing the stretch from dissipating into surrounding muscles. Two stretches stand out for targeting this muscle specifically: the sleeper stretch and a modified cross-body stretch. Both work by rotating the arm inward against the resistance of the infraspinatus, which sits on the back of your shoulder blade and is responsible for rotating your arm outward.
Why This Muscle Gets Tight
The infraspinatus spans most of the back surface of your shoulder blade and attaches to the top of your upper arm bone. Its job is to rotate your arm outward and help stabilize the shoulder joint during movement. Any activity that demands repeated or sustained outward rotation, like throwing, swimming, or even holding your arms at a keyboard, can leave this muscle chronically shortened or knotted.
Tightness here doesn’t always feel like it’s coming from the back of your shoulder. Trigger points in the infraspinatus most commonly refer pain to the front and outer side of the upper arm, above the elbow. Less frequently, the pain shows up in the outer forearm, the upper back of the neck, or even the thumb side of the hand. If you’ve been chasing pain in those areas without finding a cause, a tight infraspinatus could be the source.
How to Tell If Yours Is Tight
A quick self-check: stand in front of a mirror and bend both elbows to 90 degrees with your upper arms at your sides. Rotate both forearms inward toward your belly. If one side rotates noticeably less than the other, or if you feel pulling or discomfort at the back of the shoulder, your posterior shoulder is likely restricted. In clinical terms, a loss of more than 20 degrees of internal rotation compared to the other side qualifies as a significant deficit. Every centimeter of lost motion when measured by a therapist corresponds to roughly 5 degrees of internal rotation loss.
The Sleeper Stretch
This is the gold standard for isolating the infraspinatus and the posterior shoulder capsule. Lie on your side with the shoulder you want to stretch on the bottom. Bend your bottom elbow to 90 degrees so your forearm points toward the ceiling. Your body weight pins your shoulder blade against the surface, which is the key detail. Without that stabilization, the stretch leaks into your shoulder blade muscles instead of targeting the infraspinatus.
Using your top hand, gently press your bottom forearm toward the floor (rotating your shoulder inward). You should feel a stretch deep in the back of the shoulder, not a pinch in the front. Stop at the point of mild tension. Hold for 30 seconds, then release. Repeat three to five times.
If the standard position feels too aggressive or pinches the front of your shoulder, place a folded towel under your upper arm just above the elbow. This slight elevation changes the angle and takes pressure off the front of the joint while still targeting the posterior tissues. You can also roll your torso slightly forward (about 30 degrees off fully side-lying) to add a horizontal adduction component to the stretch.
The Modified Cross-Body Stretch
The standing cross-body stretch, where you pull one arm across your chest, is popular but has a design flaw. In a standing position, nothing prevents your shoulder blade from sliding forward with the arm. That scapular movement absorbs much of the stretch before it ever reaches the infraspinatus. The arm also tends to rotate outward as tension builds, which further reduces the stretch on the very muscle you’re trying to target.
The fix is to perform this stretch lying on your side, the same starting position as the sleeper stretch. With the target shoulder on the bottom and your body weight stabilizing the shoulder blade, use your top hand to guide the bottom arm into horizontal adduction (across your chest). To prevent the arm from rotating outward, align both forearms together with the top forearm resting on top of the bottom one. This locks the rotation and keeps the stretch focused on the posterior shoulder. Hold for 30 seconds, three to five repetitions.
Contract-Relax Technique for Deeper Results
If static stretching isn’t making much progress, a contract-relax approach can coax the muscle into releasing further. This method uses a brief contraction of the infraspinatus right before stretching it, which triggers a neurological relaxation response that temporarily allows greater range of motion.
Get into the sleeper stretch position. Instead of passively pressing your forearm down, push your forearm gently upward (outward rotation) against the resistance of your top hand for about 5 to 6 seconds at roughly 20 to 30 percent effort. Then relax completely and use your top hand to guide the forearm further into internal rotation. You’ll typically find you can move a few degrees further than before. Repeat this contract-relax cycle three to five times per session. Keep the contractions light and pain-free throughout.
How Often to Stretch
Research on posterior shoulder stretching supports holds of 30 seconds performed for three to five repetitions per session. For maintenance, two to three sessions per week is reasonable. If you’re actively trying to recover lost internal rotation, daily stretching produces faster results. Many overhead athletes stretch the posterior shoulder before and after training as part of their warm-up and cool-down.
Gains in flexibility tend to show up within the first few weeks of consistent work, but lasting changes to tissue length take longer. Expect four to six weeks of regular stretching before the improvements feel permanent rather than temporary.
Precautions Worth Knowing
If you have shoulder impingement symptoms, pinching or sharp pain when raising your arm, be careful with how aggressively you stretch. Posterior shoulder tightness actually contributes to impingement by altering how the shoulder blade and arm bone move together, so stretching is part of the solution. But during flare-ups, keep your movements within a comfortable range. A useful guideline is to work within an imaginary two-to-three-foot rectangle in front of your body, avoiding extreme positions behind your back or overhead until symptoms calm down.
The stretch should produce a pulling sensation in the back of the shoulder, never a pinch or sharp pain in the front. Front-of-shoulder pain during the sleeper stretch usually means the arm is positioned too high (closer to overhead) or the stretch is too forceful. Lowering the arm slightly toward your waist or reducing pressure typically resolves this. If it doesn’t, back off and try the modified cross-body version instead, which tends to be gentler on the front of the joint.