Muscle outlines from Body Muscles by Ivan Vulović, Apache 2.0 — regrouped and recoloured for Muscle Train.
Lie on your side, upper body supported, lower body hanging. Hold a dumbbell with a neutral grip, hanging straight down. Engage your core and slowly raise the dumbbell in an arc until your arm is parallel to the ground, keeping a slight bend in your elbow. Pause, feeling the rear deltoid contraction. Lower slowly and repeat on the other side.
Maintain a slow, controlled motion. Avoid momentum; focus on rear deltoid engagement. Keep shoulders relaxed, core tight, and breathe out during the lift.
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