The biceps does more than bend the elbow. It also supinates the forearm, and combining both is what loads it fully.
PrimarySecondaryNot worked
Biceps brachii has two heads crossing both shoulder and elbow. It flexes the elbow, supinates the forearm — turning the palm up — and assists shoulder flexion. Brachialis, underneath, flexes the elbow whatever the hand position; it pushes the biceps up and adds arm thickness.
Eight to fifteen sets a week is enough, given every pull you do adds more. Vary shoulder position: incline curls for the stretched position, preacher curls for the short one. Hammer curls, neutral grip, target brachialis and brachioradialis.
Heaving the weight with the lower back. If the torso moves, the set is over — what follows no longer trains the biceps.
Names are the ones the app uses.