Posterior Deltoid

The posterior deltoid works in every movement that brings the arm backward or outward. In the gym, you find it active in rows, face pulls, reverse flyes, and any horizontal pull. Unlike the anterior deltoid, which gets bombarded by every press, the posterior receives direct stimulus almost only when you specifically target it.

Having a weak posterior deltoid isn't just an aesthetic problem. Shoulders that fall forward, closed posture, impingement risk: all of this is connected to an imbalance between an overactive anterior deltoid and an underactive posterior. Cable face pulls are probably the most effective exercise for the posterior delt: they combine horizontal abduction and external rotation, hitting the muscle in its complete function. Reverse flyes with dumbbells in a bent-over position or on the reverse pec deck are the other pillar.

The posterior deltoid is a small muscle that recovers quickly. You can train it 3-4 times a week without issue, even with just 2-3 sets of face pulls at the end of each session. Use moderate loads and focus on the contraction: there's no need to go heavy. If you want three-dimensional shoulders and solid posture, the posterior deltoid deserves more attention than it gets in most programs.