A hammer curl is a variation of the biceps curl and targets muscles in the upper and lower arm. While this exercise is almost always performed with a dumbbell, you can do it with cables or bands. Hammer curls are a great addition to your upper-body strength routine.

How to Do Hammer Curls

Maintain a straight posture (without being rigid or locked) and place your knees beneath your hips. With a dumbbell in each hand and the weights positioned next to your outer thigh, you have your arms by your sides. With your shoulders relaxed, your thumbs pointing forward and your palms toward the thighs.

1. Bend at the elbow, lifting the lower arms to pull the weights toward the shoulders. Your upper arms are stationary and the wrists are in line with the forearms.
2. Hold for one second at the top of the movement. Your thumbs will be close to the shoulders and palms facing in, toward the midline of your body.
3. Lower the weights to return to the starting position.

Engage your abdominals throughout hammer curls to prevent movement in the lower back as you lift and lower weights.

Benefits of Hammer Curls

Hammer curls work the biceps brachii, considered a “vanity muscle” because it is easily visible on the front of your body.1 People looking to get a muscular appearance often target the biceps for a more athletic look.

Within the body, biceps brachii is an elbow flexor because it is responsible for the bending movement at the elbow joint. It also helps to rotate (supinate) the forearm.2

In everyday movements, strong biceps help you lift and carry heavy objects. These muscles assist with other arm-based movements, like closing a door or pulling objects toward or across your body.

Hammer curls are one way to build stronger biceps muscles and provide greater definition and increased strength.3 Including it in your exercise program may also help increase wrist stability and grip strength.4

Other Variations of Hammer Curls

You can modify hammer curls to better align with your fitness level and goals.

Alternating Hammer Curls

If you try hammer curls and find they’re too challenging to maintain proper form, try alternating. Instead of lifting both arms simultaneously, lift the right arm and lower, then lift the left and lower. Continue to alternate sides.

Incline Hammer Curls

Another variation is to use a seated incline bench to perform hammer curls. When seated, the starting position places the arms behind your hips and helps to reduce shoulder involvement. Otherwise, the same movements apply. Lift the weights to the shoulders before lowering them again.

We’ve tried, tested, and reviewed the best weight benches. If you’re in the market for a weight bench, explore which option may be best for you.

Preacher Hammer Curls

Some exercisers use a preacher bench to perform hammer curls. A preacher bench is an angled, padded armrest that allows you to hold the upper arm in an isolated position so you can lift more weight and better target the biceps at Hammer Curls: Learn Proper Form to Maximize Your Results.

Adjust the padded armrest so its top is just touching your armpits. Rest your upper arms against the padding, extend your elbows, and hold the weights so your palms face each other. Lift the weights to your shoulders, then lower them back down.

Hammer Curls Power Squat

Make hammer curls more challenging by adding a squat. This helps you work your legs and glutes while also working your arms. After lifting the weights to the shoulders, drop into a squat position. Hold briefly, stand back up, and return the weights to your side.

Hammer Curls: Common Mistakes

Avoid these common errors to keep hammer curls safe while maximizing their effectiveness.

Using Momentum

Using momentum decreases your ability to build strength during hammer curls. Swinging motions may also put you at higher risk for injury because you lose control when momentum takes over.

You can tell if you’re using momentum if you start hammer curls by leaning forward slightly and bringing the weights behind your hips. This body position helps you to wind up for the workload.

Using momentum is often a sign that you are lifting too much weight. If you notice yourself winding up before each repetition, decrease the weight and focus on form.

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Curling Too Fast

Hammer curls employ a relatively small range of motion, so it’s easy to rush through this exercise and use quick movements, especially during the lowering phase.

Taking your time on the way up and down allows you to control the movements and focus on form. Slowing your movements also adds more challenge because you must engage your muscles for a longer time.

Curling too fast can also be a sign that you’re not lifting enough weight. Both the concentric or shortening phase (when you lift the weight) and the eccentric or lengthening phase (when you lower the weight) should last about two breaths at Hammer Curls: Learn Proper Form to Maximize Your Results.

Floating Elbows

It’s easy to allow the elbows to float away from the body during hammer curls. While this engages other muscles in the lift, such as the deltoids (shoulders), the more you engage other muscles the less you target the biceps.

Keep your elbows in a stable, fixed position and concentrate on moving only the lower arm during hammer curls. If you can’t lift weight without moving your elbow, the weight is too heavy.

Safety and Precautions

While hammer curls are appropriate for most exercisers, those with lower arm injuries (such as carpal tunnel syndrome) may need an alternate exercise or modification.

Tension in the biceps indicates that the movement is working and effectively targeting your upper-arm muscles. However, stop if you feel pain when performing hammer curls.

When first starting, try two sets of 7 to 10 repetitions each. As you get stronger and more flexible, add repetitions first. Then add more weight at Hammer Curls: Learn Proper Form to Maximize Your Results.

If you are new to this or any weight training exercise, try the movements without weight (or with very little weight) to get comfortable with the movement. You can also work with a fitness trainer to get tips and advice.

Try Hammer Curls

Incorporate hammer curls and similar moves into one of these popular workouts: