Lie high up on low incline bench or reverse on decline bench on side with arm pit over leg pad (as demonstrated). Position legs lower on bench for support. Grasp dumbbell and position elbow against side and forearm across belly.
Lift dumbbell upright above elbow by rotating shoulder. Return and repeat. Flip body over and continue with opposite arm.
Maintain elbow against side and fixed elbow position (90° angle) throughout exercise. Position incline as low as possible so dumbbell can still be aligned against gravity.