Lie prone on incline bench with shoulders near top of incline. Knees can rest on seat or legs can be straddled to sides. From low rack or partner, grasp curl bar with shoulder width underhand grip.
Raise bar until arms are flexed. Lower barbell until arms are fully extended. Repeat.
Also known as Barbell Spider Curl. The 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.