Lie back on an incline bench with a dumbbell in each hand, arms hanging straight down below your shoulders. The incline pulls your arms behind your torso before you even start moving, so you'll feel a deep stretch in your biceps at the bottom of every rep — that extended range is the whole reason to choose this over a standing curl. Curl one arm up toward your shoulder while the other stays extended, keeping your elbow behind your body throughout. Lower back to a full stretch under control rather than letting the dumbbell drop. Keep your shoulder blades pinned to the bench so your shoulder doesn't roll forward to shorten the range.