Dumbbell One Arm Seated Hammer Curl
- Target muscle
- —
- Equipment
- Dumbbell
- Body part
- Upper Arms
- Type
- Strength
The dumbbell one arm seated hammer curl is a single-arm upper-arm exercise that uses a neutral (palm-facing-in) grip to target the brachialis and brachioradialis, with the biceps brachii assisting. Performed one arm at a time from a seated position, it minimizes momentum and lets you focus on strict form and even left-to-right development.
How to do the Dumbbell One Arm Seated Hammer Curl
- 1Sit upright on a bench with your feet flat on the floor and a single dumbbell held in one hand at your side.
- 2Turn your palm to face your torso so the dumbbell is in a neutral grip, with the handle vertical as if holding a hammer.
- 3Brace your core and pin your working elbow against your side to keep your upper arm still.
- 4Curl the dumbbell upward by bending only at the elbow, keeping the wrist neutral and straight throughout.
- 5Raise the dumbbell until it is near the front of your shoulder, squeezing the biceps and forearm at the top.
- 6Lower the dumbbell slowly under control back to the starting position with your arm fully extended.
- 7Complete all reps on one arm, then switch the dumbbell to the other hand and repeat.
Form tips
- Keep the wrist locked in a neutral position the whole set — the hammer grip is what shifts work onto the brachialis and brachioradialis.
- Use a controlled tempo, especially on the way down, to keep tension on the muscle instead of dropping the weight.
- Hold your torso still and avoid swinging or leaning back to start the rep.
- Rest your non-working hand on your thigh or the bench so you can fully isolate the working arm.
- Choose a weight you can curl with a still upper arm; single-arm work exposes momentum quickly.
Common mistakes
- Swinging the torso or jerking the dumbbell up, which uses momentum instead of the arm and reduces muscle tension.
- Letting the elbow drift forward or flare out, which shifts the work onto the shoulder and shortens the range of motion.
- Rotating the wrist toward a regular curl, which turns it into a standard curl and reduces the brachioradialis emphasis.
- Cutting the descent short or dropping the weight, losing the eccentric portion that drives growth.
- Going too heavy so only one or two clean reps are possible, forcing cheat reps for the rest.
Frequently asked questions
What muscles does the dumbbell one arm seated hammer curl work?
The neutral hammer grip primarily targets the brachialis and the brachioradialis of the forearm, with the biceps brachii assisting, building both upper-arm size and forearm strength.
Why do it seated and one arm at a time?
Sitting removes leg drive and body sway, and training one arm at a time lets you focus on strict form, fix side-to-side imbalances, and keep full tension on the working muscle.
How is a hammer curl different from a regular dumbbell curl?
A hammer curl keeps the palm facing in (neutral grip) instead of facing up. That grip recruits more of the brachialis and brachioradialis, working the forearm and the deeper arm muscle more than a standard curl.
How many sets and reps should I do?
For arm size and strength, 3 to 4 sets of 8 to 12 reps per arm with a controlled tempo is a solid range. Pick a weight you can move without swinging.
Is the seated one arm hammer curl good for beginners?
Yes. The seated position and single-arm focus make it easy to learn strict form, and you only need one dumbbell, so it is a beginner-friendly way to build the biceps and forearms.
