Exercise guide
Shoulder - Medial Rotation Internal Rotation
- Beginner
- Isolation
- Timed hold
- Shoulders
This isolation exercise strengthens the internal rotators of the shoulder, including the subscapularis, pectorals, and lats, to improve joint stability and rotational power. It uses manual resistance to build foundational strength and shoulder health without the need for external weights.
Reviewed by the Crucible Fit team · Updated June 2026
Muscles worked
Setup
- Stand or sit tall with your feet shoulder-width apart and your core engaged.
- Bend your working arm at a 90-degree angle, tucking your elbow firmly against your side.
- Position your forearm parallel to the floor, pointing straight ahead.
- Place the palm of your non-working hand against the inside of your working wrist to provide manual resistance.
How to do it
- Exhale as you rotate your forearm inward toward your stomach, using your opposite hand to provide steady, moderate resistance throughout the range of motion.
- Inhale as you slowly return the arm to the starting position, maintaining constant tension against your resisting hand.
- Maintain a controlled tempo of 2 seconds for the inward rotation and 3 seconds for the return phase.
- Complete the set on one side before switching to the other arm.
Form checklist
- Keep your elbow 'glued' to your ribcage; do not let it flare out or move away from your body.
- Ensure the rotation occurs at the shoulder joint rather than bending or twisting at the wrist.
- Keep your shoulders down and back, avoiding the tendency to shrug toward your ears.
- Maintain a vertical torso and avoid rotating your hips or spine to assist the movement.
Pro tips
- Place a rolled-up towel between your elbow and your ribs; if the towel falls, your elbow has moved too far from your body.
- Focus on the mind-muscle connection by visualizing the muscles deep in the front of your shoulder and chest doing the work.
- Apply just enough resistance with your non-working hand so that the movement is challenging but remains smooth and fluid.
Make it harder
- Increase the manual pressure applied by the non-working hand to create higher mechanical tension.
- Perform the movement in a side-lying position on the floor, using the weight of the forearm itself as resistance against gravity.
Frequently asked
- What muscles does the shoulder - medial rotation internal rotation work?
- The shoulder - medial rotation internal rotation primarily targets the rotator cuff, and also works the biceps and lats as secondary muscles.
- What equipment do you need for the shoulder - medial rotation internal rotation?
- The shoulder - medial rotation internal rotation requires no equipment — just your body weight.
- Is the shoulder - medial rotation internal rotation good for beginners?
- Yes. The shoulder - medial rotation internal rotation is a beginner-friendly movement and a strong foundation to build on.