Posterior Deltoid Stretch (Cross-body Stretch)

Posterior Deltoid Stretch — Cross-body Stretch

The posterior deltoid is the rear portion of the shoulder muscle. It works in synergy with the infraspinatus to stabilize the glenohumeral joint. When tight, it limits internal rotation and horizontal adduction of the shoulder, causing pain during everyday gestures like fastening a seatbelt or reaching for an object on the back seat. The cross-body stretch is the most direct and effective stretch for this area.

Targeted Anatomy

• Posterior deltoid — rear portion of the deltoid, responsible for extension and external rotation of the shoulder.
• Infraspinatus — rotator cuff muscle located on the scapula, a key shoulder stabilizer.
• Teres minor — auxiliary external rotator, often tight simultaneously.
• Posterior shoulder capsule — connective tissue that stiffens over time, benefiting from this stretch.

Step-by-Step Instructions

Step 1 — Position the Arm

Stand or sit with a straight back. Bring your right arm straight across your chest horizontally at shoulder height. The arm crosses the body to the left.

Step 2 — Apply Pressure

With your left hand, grasp the right elbow or just above it. Gently pull the arm toward your body, pressing it against the chest. Keep the right shoulder low — do not let it rise toward the ear.

Step 3 — Adjust Rotation

Slightly turn your head to the right (opposite the stretched arm) to accentuate the stretch on the posterior deltoid and infraspinatus. Feel the tension at the back of the right shoulder.

Step 4 — Hold

Hold the position for 30 seconds per side. Breathe calmly. Switch sides. Perform 2 to 3 sets per side.

Duration and Frequency

• Hold: 30 seconds per side
• Sets: 2-3 per side
• Frequency: daily or after each upper body workout

Safety Tips

• Do not pull too hard — moderate stretch is sufficient. Sharp pain in the shoulder signals excessive pressure.
• If you feel pinching at the front of the shoulder, adjust the arm height slightly lower.
• Keep shoulders relaxed and down throughout the exercise.
• Do not bounce the arm — this is a static stretch, not ballistic.

Variations

• With a towel — wrap a towel around the arm for better leverage if mobility is limited.
• Against a wall — press the extended arm against a wall for constant pressure.
• Sleeper stretch (lying) — lie on your side, arm forward, push the forearm toward the floor to stretch external rotators.

Target Audience

Ideal for swimmers, throwers, weight training enthusiasts and anyone working on a computer. The cross-body stretch suits all levels and can be practiced anywhere without equipment.