How to Do Hammer Curls — The Way I Do Them

Hammer curls are another great exercise for building size through the arms, but for me they do a slightly different job to a normal curl.

Once I’ve done something like a straight-bar curl and properly worked the biceps, hammer curls are normally the sort of movement I like to move onto next.

You’re still using the biceps, but because your hands stay in a neutral position — basically with your palms facing each other — the movement also brings the brachialis and brachioradialis heavily into the job of bending the elbow.

The easiest way I think about it is this: I’ve already worked the main bicep curl, and now I want to start building out the rest of the arm as well.

The brachialis sits underneath the biceps, while the brachioradialis runs down into that upper-forearm area. I’m not pretending a hammer curl somehow switches the biceps off or isolates one tiny part of the arm. It doesn’t. I just like the neutral grip because it gives me a different way of loading the elbow flexors.

If you’re new to this sort of training, I’ve also broken down the bigger picture in my beginner’s guide to building muscle.

How I Hold the Dumbbells

Start by grabbing two dumbbells.

Instead of turning your hands over like you would with a normal dumbbell curl, keep the dumbbells lengthways.

The easiest way I can describe it is that the plates are facing towards the mirror in front of you rather than out to either side.

Your palms are basically facing each other.

That’s your hammer grip.

I don’t try to make the grip complicated. I just make sure both dumbbells feel secure in my hands, my wrists feel comfortable and I’m not letting them twist around as I start the rep.

How I Do the Hammer Curl

From there, the movement is basically folding at the elbow.

I try to keep my elbow in roughly the same position rather than letting the whole upper arm start travelling forwards as the dumbbell comes up.

Then I bring the dumbbell straight up towards my shoulder.

That’s the bit I’m thinking about: bend at the elbow, bring the weight up, squeeze, then control it back down.

I don’t want to throw my back into it or start swinging the dumbbells just because the weight is getting difficult.

If I have to turn it into a full-body movement from the first rep, I’ve probably gone too heavy for what I’m trying to achieve.

So I keep it simple.

Elbow controlled.

Weight up.

Squeeze.

Control it back down.

What Muscles Are Working?

The biceps are still working during a hammer curl. The brachialis is an important elbow flexor as well, and the brachioradialis also contributes strongly when you’re bending the elbow.

What changes with the hammer curl is the position of your forearm and hand. Research looking at different grip and forearm positions shows that changing that position changes how the elbow-flexor muscles share the work rather than simply turning one muscle on and another one off.

That’s why I prefer saying hammer curls emphasise the arm differently rather than claiming they completely isolate the outer bicep or forearm.

Cross-Body Hammer Curls

There are variations you can use as well.

One I like is the cross-body hammer curl.

Instead of bringing the dumbbell straight upwards towards the same shoulder, I bring the arm slightly forward and curl the dumbbell across my body.

So if I’m curling with my right arm, the dumbbell travels more towards the left side of my chest rather than straight upwards.

You’re still keeping that hammer grip. You’re just changing the direction the dumbbell travels.

I like using both versions because they feel slightly different, and once I’ve finished my heavier straight-bar curls it gives me another way of working the arms and forearms without just repeating exactly the same movement again.

I’ve also got a separate guide on how I do straight-bar curls, which is the movement I’d normally think about before moving onto something like hammer curls.

What I Try to Avoid

The biggest thing I try to avoid is turning the exercise into a swing.

Once the dumbbell gets heavy, it’s very easy to start rocking backwards, throwing the shoulder forward and using momentum to get the weight up.

A difficult final rep might not look absolutely perfect, but there’s a big difference between a little movement when you’re working hard and choosing a weight that forces you to cheat every rep.

I’d rather lower the weight, keep the elbow under control and actually make the muscles I’m trying to train do the work.

Where Hammer Curls Fit Into My Arm Training

For me, hammer curls make most sense after I’ve already done a heavier bicep movement.

I’ll normally think of the straight-bar curl as my main curl, then move onto something like hammer curls afterwards so I’m training the arm through a different grip and feel.

That’s the way I like building an arm session: don’t just repeat the same curl five different ways. Give each movement a reason for being there.

Hammer curls are one part of the arm session rather than the entire thing. I normally pair their neutral-grip work with a heavier supinated movement, which is why my straight-bar curl guide is the natural next read. If you struggle to feel the target muscles working, the guide to mind-muscle connection explains how I approach that without pretending the pump is everything.

Research & References

I use research here to check the anatomy and mechanics behind what I’m describing, not to pretend an EMG study proves one exercise will build more muscle than another over the long term.

Grip variation during curls: A 2026 study compared supinated, semi-supinated and neutral grips during curls and measured biceps brachii and brachioradialis activity across the lifting and lowering phases. PubMed: Effects of grip variation on biceps brachii and brachioradialis electromyographic activity.

Hand position and elbow-flexor coordination: A study of pronated, neutral and supinated hand positions found that hand position changed the coordination between the biceps brachii and brachioradialis during elbow flexion. PubMed: Muscular coordination of biceps brachii and brachioradialis in elbow flexion with respect to hand position.

Brachioradialis and elbow flexion: Research measuring the biceps, brachialis and brachioradialis found all three were active during resisted elbow flexion across different forearm positions. PubMed: The Role of the Muscle Brachioradialis in Elbow Flexion.