The Most Undertrained Muscle of the Shoulder and How To Strengthen It

The Posterior Deltoid

The deltoid muscle in a large muscle that surrounds the shoulder joint. It has three distinct set of fibers that make up the anterior (front), middle, and posterior (back) portion of the muscle. Traditional training programs of the deltoids focus on the anterior and middle fibers, while neglecting the posterior fibers which, combined with increased hours of sitting (further stretching and weakening the posterior deltoid) creates an imbalance in muscle strength and function.

These imbalances contribute to shoulder pain and potential shoulder injury. Serious trouble for throwing athletes or those that work overhead.


Our favorite exercise to strengthen the posterior deltoid (along with other important shoulder stabilizers) is call the 'Clock'. The exercise can be performed with no equipment, elastic bands (optimal), or cable rows found at the gym.

To perform with no equipment: Standing or seated with arms at side, thumbs pointed forward, raise both arms straight above your head to the twelve o' clock position. lower arms and repeat in 10-2 and 9-3 o' clock positions. In 9-3 position, pinch your shoulder blades together as you bring your arms back. Progression would be to perform on stomach (against gravity) or use bands or cables.

When performing with bands or cables, be sure to cross to assure the right pull. Our video gives you an example of how to perform with bands.: