Trainer: This Forgotten Delt Exercise Is a Game Changer for Shoulder Size originally appeared on Men's Fitness. Most guys chasing bigger delts rely too much on overhead presses and overlook mixing up ...

Your shoulders are composed of three primary muscle groups: the anterior, lateral, and posterior deltoids. The rear delts are a key muscle group responsible for shoulder joint stability and balance.

A well sculpted set of posterior deltoids or ‘rear delts’ give the body a thicker look that screams ‘strong AF’, and telegraphs that you don’t just spend your time in the gym polishing those mirror ...

It's easy to focus on biceps and triceps exercises during my upper-body workout. Sometimes I even throw in some back moves. But my go-to arm routine was missing a major muscle group: rear deltoids.