Exercise guide · evidence-graded

Hammer Curl

The hammer curl is a dumbbell curl performed with your palms facing each other, thumbs up, from the bottom of the rep to the top. It works the elbow flexors, with the brachialis and the forearm's brachioradialis sharing more of the work with the biceps than in a palms-up curl, and it is a common way to add arm and forearm size.

Also called: DB Hammer Curl, Hammer Curls, Hammer Curl (Dumbbell), Dumbbell Hammer Curl · Equipment: dumbbell · Pattern: pull

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How to do it

Step by step

Stand tall holding a dumbbell in each hand at arm's length by your sides, palms facing your thighs.
Set your shoulders back, bring your ribs down and keep your upper arms close to your sides.
Curl the dumbbells up by bending your elbows, keeping your palms facing each other the whole way.
Lift until your forearms are close to vertical and the dumbbells are near your shoulders, with your elbows still by your sides.
Pause briefly, then bring the dumbbells down under control until your arms are straight.
Keep your torso still on every rep. You can curl both arms together or alternate one arm at a time.
After the last rep, bring the dumbbells to your sides and set them down.

Coaching cues

Thumbs up the whole rep
Elbows pinned to your sides
Slower on the way down
Torso still, no swing
Straight arms at the bottom

In VALDA, these cues are one tap away on the exercise while you train.

Muscles worked

What it trains

Muscle	Role	Evidence
Brachialis	Prime mover	C
Brachioradialis	Prime mover	C
Biceps brachii: long head	Secondary	C
Biceps brachii: short head	Secondary	C
Forearm flexors	Stabiliser	D
Anterior deltoid	Stabiliser	C

Evidence grades: A = strong research base · B = good · C = limited · D = coaching consensus.

Common faults

What goes wrong, and the fix

Swinging the torso

Fix: Use a load you can curl with your torso still, or sit on a bench.

Elbows drifting forward at the top

Fix: Keep your upper arms vertical and your elbows by your sides.

Palms turning up near the top

Fix: Keep your palms facing each other from the bottom to the top.

Dropping the dumbbells on the way down

Fix: Bring the dumbbells down under control to straight arms.

Cutting the bottom short

Fix: Straighten your arms at the bottom of every rep before curling again.

Wrists bending

Fix: Keep your wrists straight, in line with your forearms.

Programming

What the research says

Muscle growth · first choiceRehab & prehabGeneral fitnessSport performanceEndurance

Grip — An EMG study in bodybuilders found the neutral (hammer) grip produced about 12% less biceps muscle activity than a palms-up grip, while brachioradialis activity was not higher. The hammer grip mainly shifts work away from the biceps. The deeper brachialis cannot be measured this way.
Alongside a palms-up curl — Many programmes use the hammer curl next to a palms-up curl, not in place of one, so both grips are trained. There is no direct research comparing growth between the two grips.
Stretched range — In an eight-week curl trial, training the bottom half of the curl, where the elbow flexors are longest, grew the biceps near the elbow more than training the top half.
Load and effort — Research comparing loads finds muscle growth is similar across a wide range of loads when sets are taken close to failure. Many lifters use about 8–15 reps.
Volume — Research links more weekly sets for a muscle to more growth, with diminishing returns. Rows and pulldowns also train the elbow flexors.

Alternatives · VALDA FLEX

Swap it mid-workout

With VALDA Pro, FLEX offers alternatives like these when you swap an exercise mid-workout.

Log the hammer curl in VALDA, with these cues one tap away while you train and your history for it in one place.

General information about exercise technique, not medical advice. If you have an injury or a health condition, your healthcare provider is the right person to ask.