Dumbbell Seated Single Arm External Rotation

Muscles worked

Setup

1. Sit on the edge of a flat bench with your feet flat on the floor.
2. Place the foot of your working side on the bench so your knee is elevated and bent at roughly 90 degrees.
3. Rest your working elbow on the top of your raised knee, holding a light dumbbell with a neutral grip.
4. Position your non-working hand on the bench behind you for stability and sit with a tall, upright spine.

How to do it

1. Inhale and slowly lower the dumbbell toward the bench by rotating your shoulder inward, keeping the 90-degree elbow angle fixed.
2. Lower the weight until your forearm is parallel to the floor or you feel a mild stretch in the back of the shoulder.
3. Exhale and rotate the dumbbell upward until your forearm is vertical, focusing on the muscles in the back of the shoulder.
4. Perform the movement with a controlled tempo, typically 3 seconds for the lowering phase and 1 second for the rotation upward.

Form checklist

• Keep your elbow pinned to your knee; do not let it slide or lift during the rotation.
• Maintain a strict 90-degree angle at the elbow throughout the entire set.
• Keep your wrist neutral and firm; do not let the weight pull your wrist into extension.
• Ensure your torso remains stationary and upright to avoid using body momentum.

Pro tips

• Focus on the 'mind-muscle connection' by imagining your humerus (upper arm bone) spinning in place like a spit-roast rod.
• Use a very light weight to start; these small stabilizer muscles fatigue quickly and form is more important than load.

Make it harder

• Slow the eccentric (lowering) phase to 5 seconds to increase time under tension for the rotator cuff.
• Add a 2-second isometric hold at the top of the movement where the forearm is vertical.

Frequently asked

What muscles does the dumbbell seated single arm external rotation work?

The dumbbell seated single arm external rotation primarily targets the rotator cuff, and also works the biceps, deltoids, and forearms as secondary muscles.

What equipment do you need for the dumbbell seated single arm external rotation?

The dumbbell seated single arm external rotation uses dumbbell.

Is the dumbbell seated single arm external rotation good for beginners?

The dumbbell seated single arm external rotation is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.

Related exercises

• Bodyweight Side Lying Shoulder External RotationBeginner · rotator cuff
• Cable Low Shoulder 90 Degrees External RotationIntermediate · rotator cuff
• Cable Shoulder Internal RotationBeginner · rotator cuff
• Dumbbell Empty Can ExerciseBeginner · deltoids and rotator cuff