Supine Shoulder 90/90s (How To, Benefits, Common Mistakes)
Supine Shoulder 90/90s are a shoulder mobility and stability drill designed to improve external rotation range of motion and rotator cuff control. Performed while lying on your back with the shoulders and elbows at 90 degrees, this movement helps strengthen the rotator cuff and maintain healthy shoulder mechanics
They are especially useful for overhead and pressing athletes.
Primary Muscles Worked: Rotator Cuff (Infraspinatus, Teres Minor)
Secondary Muscles Worked: Posterior Deltoids, Scapular Stabilizers
Equipment Needed: Light Dumbbells, Small Plates, or None (Bodyweight)
Step-by-Step Instructions
- Set-Up:
- Lie flat on your back with knees bent and feet on the floor.
- Raise your arms so your elbows are at shoulder height and bent 90 degrees (think of a “goalpost” position).
- Upper arms should be resting lightly on the floor, forearms pointed toward the ceiling.
- Execution:
- Keeping your elbows in line with your shoulders, slowly rotate your forearms backward toward the floor (external rotation).
- Stop when you feel a gentle stretch through the front of your shoulders or when your hands reach the floor.
- Then, rotate your forearms forward (internal rotation) toward your hips without letting your upper arms lift off the floor.
- Move slowly and with control through the full range.
- Tips for Proper Form:
- Keep your elbows directly out from your shoulders. Don’t let them drift down toward your ribs.
- Maintain contact between your upper arms and the floor throughout.
- Move within a comfortable range (avoid forcing motion).
Key Benefits
- Improves shoulder external rotation and overall joint mobility.
- Strengthens and stabilizes the rotator cuff.
- Helps prevent shoulder impingement and improves overhead movement quality.
Modifications and Variations
- Easier Option:
- Perform without weights to focus on range of motion.
- Use a rolled towel under your upper arm if it’s difficult to keep contact with the floor.
- Harder Option:
- Hold light dumbbells or plates (1–5 lb).
- Pause briefly at end ranges for more control and activation.
- Perform one arm at a time to challenge stability.
Common Mistakes
- Elbows Drifting Downward: Keep elbows level with shoulders to maintain proper mechanics.
- Lifting Upper Arms Off the Floor: Keep shoulders grounded for stability.
- Rushing the Movement: Move slowly to improve mobility and control.
Reps and Sets Recommendations
- For Mobility/Warm-Up: 1–2 sets of 10–12 slow reps.
- For Strength/Stability: 2–3 sets of 8–10 reps with light resistance.
- For Rehab/Prehab: Perform daily with a light load or no weight for 1–2 sets of 12–15 reps.
