Side-lying shoulder internal rotation strengthens the muscles that turn your arm inward, mainly the rotator cuff muscle at the front of the shoulder blade (subscapularis). You lie on the side being worked with the elbow bent to a right angle, then lift a light weight from the mat up toward your chest. Physios usually bring it in once standing holds or band work for the same direction feel easy.

How to do the side-lying shoulder internal rotation

Lie on the side you are working, with your knees slightly bent for balance and a small pillow or folded towel under your head.
Bend the bottom elbow to a right angle. Rest the upper arm on the mat a little in front of your body, so you are not lying right on the point of the shoulder.
Hold a light dumbbell with the forearm resting on the mat, pointing forward away from you. Your top hand can rest on your hip.
Keep the elbow in place and turn the forearm up toward your chest, lifting the weight off the mat.
Pause, then lower the weight slowly back to the mat and repeat.

What you should feel

Work at the front of the bottom shoulder and into the chest. Your neck and the top shoulder should stay loose.

Common mistakes

Sliding the elbow along the mat, or lifting it, as the weight comes up.
Rolling your body forward to help the weight rise.
Letting the weight fall back to the mat instead of lowering it.
Starting too heavy. A small water bottle is enough for many people at first.

How often

Many programs start with 2 to 3 sets of 10 to 15 slow repetitions with a light weight, once a day or every other day. Your physio will adjust this.

Stop and check with your physio if

The shoulder feels like it is slipping out or suddenly unstable.
Lying on the shoulder or turning the arm gives a sharp pain or a catch.
Pins and needles or numbness start in the bottom arm or hand.
Pins and needles in your arm or hand that do not go away after you stop, or part of your arm or hand goes numb. Get medical advice the same day. If one side of your face or body suddenly goes numb or weak, or your speech becomes slurred or muddled, call emergency services, even if it goes away.
A sudden pop or tearing feeling in the shoulder that brings sharp pain, new weakness or trouble lifting the arm. Stop and contact your surgical team the same day, or get medical advice the same day if you have not had surgery.
The shoulder feels as if it has slipped out of place, looks a different shape or suddenly locks so you cannot move the arm, or your hand turns cold, pale or blue. Go to an emergency department straight away, without driving yourself, and do not try to put the shoulder back in yourself.

From the clinic

Lying on the working shoulder is uncomfortable for some people, and a folded towel under the upper arm can take some of the pressure off. If that side still hurts to lie on, isometric shoulder internal rotation works the same muscles standing, and shoulder internal rotation with a band is another choice. For the opposite direction, side-lying external rotation is done lying on your other side.

After shoulder surgery, including a rotator cuff repair, or after a shoulder fracture or dislocation, follow your surgeon's or physio's plan, and do only the movements and range they have cleared. Many plans allow only passive movement at first, where the arm is moved for you and its muscles stay relaxed. Stop if the joint feels like it is slipping out. Some operations to stabilize the shoulder, and most shoulder replacements, go through the tendon at the front of the joint, so turning the arm inward against a weight usually waits until your surgeon allows it. If your shoulder has slipped out toward the back, ask your physio first, as they may want to limit how far the arm turns in.

If you have had a hip replacement, get the go-ahead from your surgeon or physio before you try side-lying shoulder internal rotation. Lying on your side lets the top leg slide forward or drop across the lower one, and many surgeons ask you to avoid that for the first months after some operations. A pillow between your knees helps keep the legs apart.

Written and checked by the PocketPhysio editorial team. Last updated 2026-09-28.

This page is general education, not a diagnosis or a personal treatment plan. If you have pain, an injury or a health condition, see a physiotherapist or doctor before starting new exercises.

Side-lying shoulder internal rotation