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.

Rear Delt Flys

Our favorite exercise to strengthen the posterior deltoid (along with other important shoulder stabilizers) is call the 'Rear Delt Fly'.

Watch the video below to learn how to properly perform the rear delt fly.