Dumbbell Hammer Curl
The dumbbell hammer curl is a biceps curl with your palms facing each other, thumbs up, as if you were swinging a hammer. It trains all the elbow flexors, the biceps, the brachialis underneath it and the brachioradialis on the forearm, and it is an easy way to add variety to your arm training.
How to do the dumbbell hammer curl
Stand tall with a dumbbell in each hand, arms hanging straight, palms facing your thighs.
Pull your shoulders back and down and keep your elbows close to your sides.
Curl the dumbbells up with your thumbs leading, keeping your palms facing each other the whole way.
Keep your upper arms still and stop when your forearms are close to vertical and the dumbbells are near your shoulders.
Squeeze briefly at the top, then lower the dumbbells under control until your arms are straight again.
Setup for the dumbbell hammer curl
Pick dumbbells you can curl for the top of your rep range without leaning back. Stand with your feet about hip width apart, knees soft, and let the dumbbells hang at your sides with your palms facing your thighs. Pull your shoulders back and down and brace your midsection, so your upper body stays still for the whole set.
Grip and wrist position
Hold the handle in the middle and squeeze it firmly. Your thumbs point forward and stay up through the whole rep, which is what makes it a hammer curl. Keep your wrists straight in line with your forearms; a bent wrist moves the weight off the line of your arm.
Elbow position and range of motion
Your elbows stay close to your sides and act as the hinge of the movement. Curl until your forearms are close to vertical and the dumbbells are near your shoulders; going higher only works if the elbows drift forward, which takes the load off your arms. At the bottom, straighten your arms fully before the next rep, so every rep covers the same range.
Tempo and breathing
Breathe out as you curl and in as you lower. Lift the dumbbells smoothly, squeeze for a moment at the top and lower them at least as slowly as you lifted them. The lowering half trains the elbow flexors as well, so do not let the weight drop.
Both arms, alternating or cross-body
Curling both arms at once is the standard version. Alternating arms lets you rest one side briefly and watch your form. In the cross-body version you curl each dumbbell toward the opposite shoulder; it trains the same muscles with a slightly different path.
Muscles worked by the hammer curl
- Primary
- Biceps
- Forearms
Three muscles bend your elbow, and the hammer curl trains all of them. The biceps and the brachialis, which lies underneath it, do most of the work; the brachioradialis on the thumb side of your forearm joins in as the weight rises. In an EMG study with competitive bodybuilders, the palms-up curl excited both the biceps and the brachioradialis more than the hammer grip, while the hammer grip asked more of the front delts to steady the shoulder. In a strength test, the elbow flexors were about as strong with the palms facing in as with the palms up.
Common hammer curl mistakes
Swinging the dumbbells up
A hip kick or a lean back lets momentum lift the weight, so the arms work less. Stand tall, brace your midsection and go lighter if you need to swing.
Letting the elbows drift forward
When the elbows travel forward, the front delts lift part of the weight and the top of the rep gets easy. Keep your upper arms close to your sides.
Turning the palms up
Rotating the dumbbells on the way up turns the lift into a regular curl. Keep your thumbs pointing up from bottom to top.
Cutting the bottom short
Stopping halfway down skips the stretched part of the rep. Lower until your arms are straight before the next rep.
Bending the wrists
Curling the wrists in or letting them sag takes tension off the elbow flexors. Keep your wrists straight in line with your forearms.
Hammer curl tips from the Muscla training logic
- Do hammer curls after your compound lifts. Muscla puts isolation exercises at the end of a session and plans no warm-up sets for them.
- End each set with about one rep in reserve, two if you are new to training. Taking every set to failure adds little or no extra muscle, but more fatigue.
- Rest 75 seconds between sets when you train for muscle, 90 seconds for strength and 60 seconds for other goals.
- Earn the next dumbbell with reps. When every set reaches the top of your range, go up one step and restart at the bottom: 12 kg becomes 14 kg. Otherwise add one rep.
- After three sessions without progress, Muscla lowers the weight by 10 percent and builds back up. After every third 4-week block comes a deload week at 90 percent of the weight with one set fewer.
Dumbbell hammer curl sets and reps by goal
| Goal | Reps | Rest |
|---|---|---|
| Strength | 8–12 | 90 s |
| Muscle | 10–15 → 12–20 | 75 s |
| Lose fat | 10–15 | 60 s |
| Fit | 10–15 | 60 s |
| Comeback | 10–15 | 60 s |
An arrow marks the range for the next 4-week block.
The hammer curl counts as isolation in the Muscla training logic: higher rep ranges and shorter rests than compound lifts. For muscle, start at 10–15 reps and move to 12–20 in the next 4-week block. Biceps and triceps are separate patterns, so both can appear on the same day.
Dumbbell hammer curl alternatives
- EZ Barbell Curl
- Dumbbell biceps curl
- Cable curl
- Dumbbell incline biceps curl
- Lever preacher curl
- Barbell curl
- Band alternating biceps curl
- Biceps leg concentration curl
- Bodyweight side lying biceps curl
- Pull-Up
Dumbbell hammer curl questions
Hammer curl or regular curl: which is better?
For the biceps, the palms-up curl. In EMG testing it excited the biceps and the brachioradialis more than the hammer grip. Hammer curls are a good second variation, and the authors of that study advise using different grips to vary the stimulus.
Do hammer curls make your forearms bigger?
They train the brachioradialis, the muscle on the thumb side of your forearm, as an elbow flexor. In one study, though, palms-up curls activated it even more, so regular curls train it as well.
Should I curl both arms at once or alternate?
Both work. Curling together saves time; alternating lets you focus on one arm and makes swinging easier to notice. Count the same number of reps for each arm.
How heavy should hammer curls be?
Muscla's first suggestion for a man new to training is about 0.08 times body weight per hand, rounded down to your dumbbells: 6 kg at 80 kg. Your first working sets then show whether to go up.
How many sets of hammer curls per week?
Count them with your other biceps work. When you train for muscle, Muscla plans 8–12 hard sets a week for the biceps for beginners, 10–16 for regular lifters and 12–20 for experienced ones. Up to a point, more weekly sets build more muscle.
Train it with Muscla
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Sources
- Coratella G, Tornatore G, Longo S, et al. Biceps brachii and brachioradialis excitation in biceps curl exercise: different handgrips, different synergy. Sports (Basel). 2023;11(3):64. PubMed
- Smart RR, Kohn S, Richardson CM, Jakobi JM. Influence of forearm orientation on biceps brachii tendon mechanics and elbow flexor force steadiness. J Biomech. 2018;76:129-135. PubMed
- Refalo MC, Helms ER, Trexler ET, et al. Influence of resistance training proximity-to-failure on skeletal muscle hypertrophy: a systematic review with meta-analysis. Sports Med. 2023;53(3):649-665. PubMed
- Schoenfeld BJ, Ogborn D, Krieger JW. Dose-response relationship between weekly resistance training volume and increases in muscle mass: a systematic review and meta-analysis. J Sports Sci. 2017;35(11):1073-1082. PubMed