Exercise guide

Hammer curl: muscles worked and how to do it

The hammer curl is a dumbbell curl with your palms facing each other the whole way, like holding a hammer. GymTribe's library lists it as Dumbbell Hammer Curl, with the brachialis, the muscle under your biceps, as its target.

Illustration of a hammer curl, showing the start and end positions

How to do a hammer curl

Stand with a dumbbell in each hand at your sides, palms facing your thighs.
Keep your elbows at your sides and your shoulders back.
Curl the dumbbells up toward your shoulders without turning your wrists.
Pause for a moment at the top.
Lower them under control until your arms are straight.

These steps describe common technique. If something hurts, stop and ask a qualified coach or clinician.

Common hammer curl mistakes

Turning your palms up
Keep them facing in the whole way. Turning them makes it a regular curl.
Swinging
Stand still and use a weight you can curl cleanly.
Elbows travelling forward
Pin them to your sides.
Rushing the lowering
Lower at least as slowly as you lift.

How to track your hammer curl

Log the weight and reps of every set. Over a few weeks, the heaviest weight you lift and your estimated one-rep max show whether you are getting stronger, even when your sets use different rep counts.

Estimated 1RM, Epley formula

14 kg × (1 + 10 ÷ 30) ≈ 19 kg

A set of 10 at 14 kg estimates a one-rep max of about 19 kg.

Try the 1RM calculator →Strength tracking in GymTribe →

Hammer curl questions

What muscles do hammer curls work?

Mostly the brachialis, which lies under the biceps, with the biceps and the forearm muscle on the thumb side, the brachioradialis. In GymTribe's muscle map, each set of Dumbbell Hammer Curl counts toward the brachialis, shown with the biceps.

Hammer curls or regular curls?

The neutral grip puts more of the work on the brachialis and forearms; palms-up curls work the biceps more. Many programs include both.

Should I curl both arms together or alternate?

Either works. Pick one and keep it, so your logged reps mean the same thing. GymTribe also lists Cross-Body Hammer Curl and Cable Rope Hammer Curl.

How do I estimate my hammer curl one-rep max?

Use the Epley formula, weight × (1 + reps ÷ 30). A set of 10 at 14 kg estimates about 19 kg. The 1RM calculator on this site does the sum for any set.

How do I track my hammer curl in GymTribe?

Log each set's weight and reps under Dumbbell Hammer Curl. Every session adds a point to its charts: heaviest weight and estimated 1RM, best set volume and most reps, and best session volume and max session reps. A New PR alert appears when a set beats your heaviest weight, estimated 1RM or rep record.

More brachialis exercises in GymTribe

GymTribe counts these toward the brachialis too. The ones with a guide are linked.

Cable Rope Hammer Curl
Cross-Body Hammer Curl
Incline Hammer Curl
Bayesian Hammer Curl
Preacher Hammer Curl

More arms guides

All exercise guides →