With dummbell in hand, arm bent, and palm facing shoulder, place back of arm on pad.
Lower dumbbell until arm is fully extended. Raise dumbbell until forearm is vertical. Repeat. Continue with opposite arm.
Body should be positioned to allow arm pit to rest near top of pad. Back of upper arm should remain on pad throughout movement. Long head (lateral head) of biceps brachii is activated significantly more than short head (medial head) of biceps brachii since short head enters into active insufficiency as it continues to contract.