The hammer curl trains the brachialis — 4 form cues to lift heavy without swinging
In short
The hammer curl uses a neutral grip (palms facing each other) that shifts emphasis to the brachialis, a prime mover of elbow flexion. Because the forearm does not rotate into supination, it allows heavier loads than a standard curl; Men's Health recommends 3 sets of 6–8 heavy reps, or 3–4 sets of 15–20 lighter reps for volume. Tightening the glutes, abs and shoulder blades and moving only at the elbow removes the swing.
A hammer curl looks like a regular dumbbell curl, but turning your palms to face each other changes which muscle does most of the work. The neutral grip makes the brachialis, which sits beneath the biceps, the main driver, and a thicker brachialis pushes the biceps up for a fuller-looking arm.
How is it different from a standard curl?
In a palms-up curl, the biceps both bend the elbow and rotate the forearm outward (supination). The hammer curl drops that rotation, which makes it easier to handle heavier weights. An EMG study comparing four curl variations found the lowest biceps signal in the hammer curl, consistent with the work moving to the brachialis (related article).
How do you set up to avoid swinging?
- Brace everything: stand with feet hip-width apart and tighten your glutes, abs and shoulder blades to remove the points you could cheat from.
- Grip hard: actively squeezing the handles gives you more control and trains your forearms and grip at the same time.
- Squeeze at the top: curl only as high as you can without the elbow drifting forward, then hold a hard contraction for about half a second.
- Kneel if you still sway: kneeling makes the hip-rocking cheat almost impossible.
Keep the upper arms still and perpendicular to the floor, move only at the elbow, and lower the weight under control back to the start.
How many sets and reps?
Add it to an upper-body or arm day and start with 3 sets of 6–8 reps using more weight than your standard curl. For extra volume, go lighter for 3–4 sets of 15–20 reps. It does not count toward your Big 3 total, but it trains grip and forearms, so log the load and reps and add weight once you hit the top of your range. For more grip work, see the reverse curl article.
Frequently asked questions
What muscle does the hammer curl build?
The hammer curl's neutral grip mainly trains the brachialis beneath the biceps. A bigger brachialis pushes the biceps up so the arm looks thicker, and gripping the dumbbells hard also trains the forearms and grip.
Why can you lift more on a hammer curl than a standard dumbbell curl?
In a standard curl the biceps also rotate the forearm outward (supination) while bending the elbow. The hammer curl leaves out that rotation, so heavier loads are easier to handle.
How many sets and reps should you do for hammer curls?
Men's Health recommends starting with 3 sets of 6–8 reps using more weight than a standard curl, and 3–4 sets of 15–20 reps with lighter weight when you want more volume.
How do you stop swinging during hammer curls?
Tighten your glutes, abs and shoulder blades first, keep the upper arms perpendicular to the floor, and move only at the elbow. If you still rock at the hips, doing the curl kneeling removes most of the swing.
Source: Men's Health