Alternating Dumbbell Curl with Supination

The alternating dumbbell curl with supination starts with the palms facing your thighs and rotates them outward as the weight rises, finishing with the palm facing the shoulder. That rotation is not decoration. The biceps has two jobs, bending the elbow and turning the forearm palm-up, and a curl that includes both produces a stronger contraction at the top than one that only bends the elbow. Alternating arms rather than curling both at once lets you give each repetition full attention and gives the resting arm a moment to recover, which usually means better quality across the whole set. Keep the elbow pinned to your side throughout, since letting it drift forward turns the movement into a front raise and hands the work to the shoulder instead of the muscle you came for. Time the rotation so it finishes as the dumbbell reaches the top, not before.