Which exercise works the posterior deltoid eccentrically and concentrically?

The exercise that works the posterior deltoid both eccentrically and concentrically is the Back Rowing prep-Plow. During this exercise, the arms are engaged as they pull back in a rowing motion, which requires the posterior deltoid to contract concentrically when moving the arms toward the body. This action strengthens the muscle as it shortens.

As the arms return to the starting position, the posterior deltoid works eccentrically. This happens when the muscle lengthens under tension, allowing for controlled movement, which is crucial for joint stability and overall strength development. The dual action of the muscle during the Back Rowing prep-Plow highlights its effectiveness in engaging the posterior deltoid throughout the entire range of motion, reinforcing both strength and control in this area.

The other exercises listed do not adequately focus on the posterior deltoid in both phases of contraction. While they may involve shoulder movements, they do not target the muscle in the same specific manner as the Back Rowing prep-Plow does.