Hammer Curl

The hammer curl is a arms movement that works the ['brachialis', 'brachioradialis', 'biceps']. Two things decide whether it produces results: the load relative to your one-rep maximum, and the number of hard sets per week. For strength, three to five sets of one to five repetitions at 85 per cent or more of your one-rep max is the classic prescription; for muscle size, three to four sets of six to twelve repetitions at 65 to 80 per cent, taken close to failure; for endurance, two to three sets of fifteen or more at under 65 per cent. Ten to twenty hard sets per muscle group per week is the range most training research converges on, and progression comes from adding a little weight or a repetition rather than from changing the exercise. The calculator below estimates your one-rep max from a set you have actually completed, which is the number every percentage above refers to.

Hammer Curl Strength Standards (kg)

Body Weight	Novice	Intermediate	Advanced	Elite
120 kg	10	25	45	70
130 kg	10	25	50	75
140 kg	10	30	50	80
150 kg	15	30	55	85
160 kg	15	35	60	90
170 kg	15	35	60	95
180 kg	20	40	65	100
190 kg	20	40	70	105
200 kg	20	45	70	110
210 kg	25	45	75	115
220 kg	25	50	80	120

How to Perform the Hammer Curl

Stand with feet shoulder-width apart, holding a dumbbell in each hand at your sides with a neutral grip, where your palms face each other. Keeping your upper arms stationary and elbows close to your torso, curl the dumbbells upward by bending at the elbows. Maintain the neutral grip throughout the entire movement, without rotating the wrists. Squeeze at the top when your forearms are vertical, then lower under control to full extension.

Muscle Activation

The hammer curl shifts emphasis from the biceps brachii to the brachialis and brachioradialis. The brachialis lies underneath the biceps and, when well-developed, pushes the biceps up for a taller arm appearance. The brachioradialis is the largest forearm muscle and contributes significantly to arm thickness when viewed from the side. The biceps still contribute but are less active due to the neutral grip position.

Common Mistakes

Rotating the wrists during the curl, turning it into a standard dumbbell curl and reducing brachialis emphasis.
Swinging the body for momentum rather than using strict elbow flexion.
Not keeping the elbows pinned to the sides, allowing them to drift forward.
Performing reps too quickly without controlling the eccentric phase.

Variations

Cross-body hammer curls, where the dumbbell is curled across the body toward the opposite shoulder, increase brachialis emphasis. Rope hammer curls using a cable machine provide constant tension. Incline hammer curls performed on an incline bench increase the stretch at the bottom. Preacher hammer curls eliminate momentum entirely.

Programming Tips

Include hammer curls for 3-4 sets of 10-15 reps, 2-3 times per week. They pair well with standard bicep curls and can be performed in the same session. Hammer curls are also beneficial for improving grip strength, which transfers to pulling exercises like deadlifts and rows.

Frequently Asked Questions

Hammer curls use a neutral grip and emphasize the brachialis and brachioradialis, while regular curls use a supinated grip and target the biceps brachii more directly. Both are important for complete arm development. In practice, the hammer curl loads the brachialis, brachioradialis, biceps and needs dumbbells; an intermediate lifter of average bodyweight handles about 35 lbs, so judge your own numbers against that rather than against a gym record.

Yes, the neutral grip heavily recruits the brachioradialis, which is the largest forearm muscle. Hammer curls are one of the best exercises for building forearm size and grip strength. In practice, the hammer curl loads the brachialis, brachioradialis, biceps and needs dumbbells; an intermediate lifter of average bodyweight handles about 35 lbs, so judge your own numbers against that rather than against a gym record.

Yes, including both ensures complete arm development. Standard curls target the biceps peak, while hammer curls build arm width and thickness through the brachialis. In practice, the hammer curl loads the brachialis, brachioradialis, biceps and needs dumbbells; an intermediate lifter of average bodyweight handles about 35 lbs, so judge your own numbers against that rather than against a gym record.

Most people can hammer curl about 10-15% more than they can strict dumbbell curl with a supinated grip, due to the mechanical advantage of the neutral grip position. In practice, the hammer curl loads the brachialis, brachioradialis, biceps and needs dumbbells; an intermediate lifter of average bodyweight handles about 35 lbs, so judge your own numbers against that rather than against a gym record.

Related Exercises

Progressing on the hammer curl

Progression on a dumbbells movement for the arms follows the same logic whatever the exercise: add a little load or one repetition once the last set stops being hard, and change nothing else. Dumbbells usually jump in 2 kg steps, which is a large relative increase on a small load, so adding repetitions before adding weight is the practical route: work from eight to twelve at a given pair, then move up and start again at eight.

Stalling is normal and usually means one of three things: total weekly volume for the arms has drifted too low, recovery is short because sleep or calories are, or the load has been pushed while form quietly deteriorated. Filming a set from the side settles the third question faster than any cue. Ten to twenty hard sets per muscle group per week is the range most training research converges on, and a stall at the bottom of that range is a volume problem rather than a programme problem.

Common mistakes on arms work

Arm work is where momentum creeps in first, because the loads are small enough to swing. Keeping the upper arm still and the torso motionless makes a lighter weight harder, which is the point. Full extension at the bottom matters more than the number of repetitions.

Where the hammer curl fits in a week depends on how demanding it is rather than on the muscle it trains. A movement using a dumbbells across the arms is best placed while you are fresh if it is heavy and technical, and late in the session if it is a single joint. Two sessions a week touching the same muscle group beat one for most people, because protein synthesis after a session returns to baseline within about forty-eight hours, and a muscle trained once a week spends five of those days doing nothing.

Across all of them, the same two rules apply. Warm up with the movement itself at progressively heavier loads rather than with general cardio, and leave one repetition in reserve on all but the last set: training to failure on every set raises fatigue considerably without adding much to the result.

Hammer Curl 1RM Calculator