EXERCISES

Hammer Curl: What Makes It Different From the Classic Bicep Curl

The hammer curl looks like a simple variation of the classic curl - it isn't. The neutral grip changes which muscles end up doing most of the work.

10 Reps Editorial

September 23, 20265 MIN READ

Exercise animation dumbbell hammer curl - full range of motion in a neutral grip

The hammer curl looks at first glance like a simple variation of the classic bicep curl from our article "Barbell Bicep Curl" - just with dumbbells instead of a barbell. In reality, though, the neutral grip changes which muscles end up doing most of the work. Here's how to perform the hammer curl correctly, what sets it apart from the classic curl - and which mistakes cancel out the effect.

STEP-BY-STEP FORM

1Starting position:
Hold the dumbbells in a neutral grip (palms facing each other) at your sides. Arms nearly fully extended, elbows close to your torso, shoulders relaxed down and back.
1Starting position: Hold the dumbbells in a neutral grip (palms facing each other) at your sides. Arms nearly fully extended, elbows close to your torso, shoulders relaxed down and back.
2Upward movement:
Curl the dumbbell(s) up by bending your elbows. The neutral grip stays fixed throughout the movement - unlike the classic curl, your palms don't rotate upward.
2Upward movement: Curl the dumbbell(s) up by bending your elbows. The neutral grip stays fixed throughout the movement - unlike the classic curl, your palms don't rotate upward.
3Brief squeeze at the top:
Briefly hold the contraction without carrying momentum from the previous movement.
3Brief squeeze at the top: Briefly hold the contraction without carrying momentum from the previous movement.
4Downward movement:
Lower under control until your arms are nearly fully extended again.
4Downward movement: Lower under control until your arms are nearly fully extended again.
5Execution style:
Works either both arms at once or alternating - alternating makes it easier to keep your core stable.
5Execution style: Works either both arms at once or alternating - alternating makes it easier to keep your core stable.
6Breathing:
Exhale on the way up, inhale on the way down.
6Breathing: Exhale on the way up, inhale on the way down.

The decisive difference from the classic curl is at the wrist: as long as the grip stays genuinely neutral, instead of unconsciously rotating toward supination, the hammer curl's specific training stimulus stays intact.

Why this exercise is so effective

The neutral grip changes which muscles take on the largest share of the work. Alongside the biceps brachii, that's mainly the brachialis - a muscle that sits underneath the biceps and flexes the elbow independently of forearm rotation - and the brachioradialis, a forearm muscle that becomes especially active in a neutral grip.

Three reasons the hammer curl is a valuable addition:

A different division of labor than the classic curl: Because the biceps can't play its role as a forearm supinator here, the brachialis and brachioradialis take on a bigger share - which makes the hammer curl a useful complement, not a replacement, for the classic bicep curl.

Grip strength and forearm size: The brachioradialis is a visible part of the forearm - if you specifically want to build forearm size and grip strength, you'll get more out of the neutral grip than the supinated one.

Easier on the wrist: Because there's no rotation happening at the wrist, many people find this exercise more comfortable than the classic curl with a straight barbell.

Common mistakes

The grip rotates during the movement: If your palms unconsciously rotate upward, the hammer curl unintentionally turns into a regular curl - the specific training stimulus on the brachialis and brachioradialis gets lost.

Momentum from the shoulders: Just like with the classic curl, a weight that's too heavy often gets compensated with a jolt from the shoulders or hips.

Elbows drifting: If your elbows drift forward, the lever arm shortens and the exercise gets easier, but less precise.

Lowering too fast: If the dumbbell drops at the bottom instead of being guided under control, a meaningful part of the training stimulus is lost.

Variations

Alternating instead of both arms at once: Makes it easier to keep your core still and focus on each side individually.

Cross-body hammer curl: The dumbbell travels diagonally across the body toward the opposite shoulder instead of straight up - changes the movement angle and, with it, how the load feels.

Cable rope hammer curl: Provides more constant tension throughout the movement, similar to the cable triceps pushdown.

Performed on an incline bench: Reduces your ability to generate momentum with your torso, which increases control.

Sets and reps

As a complementary isolation exercise, the hammer curl is typically programmed similarly to the classic bicep curl in training practice: around 3 sets of 10-12 reps, with 1-2 reps left in reserve at the end of each set (RIR 1-2). This, too, is a general guideline, not a rigid rule.

OUR APPROACH AT 10 REPS

In the 10 Reps app, the hammer curl is part of several training plans, including arm-focused and upper-body-focused programs. The ProgressionEngine doesn't lock weight and reps in place - it adjusts them based on your feedback from the last session. Train consistently and cleanly, and the load goes up; need more recovery, and you get it, without the plan grinding to a halt.

Built-in deload weeks also make sure load gets reduced automatically on a regular basis, so you don't have to keep track of that yourself.

Conclusion

The hammer curl isn't just a substitute for the classic bicep curl - it's a targeted complement: the neutral grip shifts more of the work onto the brachialis and brachioradialis, reaching a part of the arm the classic curl alone doesn't optimally hit.

Combine both exercises and you cover the upper arm more completely than with either one alone.

Part of our arm-exercises series - discover more essential arm exercises here: The 4 Best Exercises for Strong Arms.