Hammer Curls

Stand with feet shoulder-width apart, holding a dumbbell in each hand with a neutral grip (palms facing each other). Curl the dumbbells up toward your shoulders while keeping the neutral grip throughout the movement. Lower with control, keeping your elbows pinned at your sides.

Pro Tips

• The neutral grip shifts emphasis to the brachioradialis and forearms
• Keep your wrists straight — don’t let them rotate during the curl
• Excellent for building arm thickness and grip strength

Muscles worked

Primary: Brachioradialis — the large forearm muscle that runs from the outer elbow to the wrist and is most active during elbow flexion with a neutral grip (palm facing in). The hammer curl is the primary exercise for directly loading the brachioradialis, which contributes significantly to the appearance of arm thickness.

Supporting: Biceps brachii (active in elbow flexion throughout, though less mechanically advantaged in the neutral grip than in full supination), brachialis (the deep elbow flexor under the bicep — strongly active in all grips regardless of forearm rotation).

Common mistakes

Rotating to supination at the top: Allowing the wrist to rotate from neutral (palm in) to supinated (palm up) at the peak of the curl shifts the load from the brachioradialis to the bicep, changing the exercise. Maintain the neutral grip from start to finish.

Alternating arms and losing control of the non-working side: When performing alternating hammer curls, the arm not curling tends to swing or internally rotate. Keep both arms controlled throughout — the resting arm hangs straight with a neutral grip, not dangling loosely.

Excessive elbow drift: As with any curl variation, elbows drifting forward to assist the lift reduces the target muscle load and involves the anterior deltoid. Elbows stay pinned at the sides.

Using hammer curls as the only curl variation: The hammer curl prioritises the brachioradialis and brachialis but underloads the bicep brachii relative to a supinated-grip curl. Complete bicep and arm development requires both supinated curls and hammer curls.

Programming notes

Hammer curls are most effective as a complement to supinated-grip curls (barbell curls, EZ-bar curls, cable curls) in a well-rounded arm training programme. The two grips together train the full arm flexor system across its complete range of recruitment patterns.

Typical programming: 3–4 sets of 10–15 repetitions, placed alongside or after a supinated-grip curl variation in the same session. The heavier loading possible in the neutral grip (due to brachioradialis and brachialis engagement) means hammer curls can also serve as the primary curl when a heavier arm exercise is the goal.

Frequently asked questions

Are hammer curls better than regular bicep curls?

Neither is better — they do different jobs. Regular supinated curls place the biceps in their strongest mechanical position and are the primary driver of bicep peak development. Hammer curls shift emphasis to the brachioradialis and brachialis, muscles that supinated curls underload. You get the best arm development by training both, not by choosing one over the other.

Why can I lift more weight on hammer curls than regular curls?

The neutral grip recruits the brachioradialis and brachialis alongside the biceps, giving you more total elbow flexor muscle contributing to the lift. Regular supinated curls rely more heavily on the biceps alone. The broader muscle recruitment in the hammer position means more force production overall — which is why hammer curls are useful when you want to overload the arm flexors with heavier loads.

Should I do hammer curls with both arms at the same time or alternate?

Both work. Simultaneous reps keep tension even and shorten session time. Alternating reps allow you to focus on each arm in isolation and can improve mind-muscle connection, but require discipline to keep the resting arm from swinging or rotating. Start simultaneous if you are new to the movement, and switch to alternating if you notice a strength imbalance between arms or want a more controlled stimulus.