How to Do Hammer Curls: Proper Form, Variations, and Common Mistakes

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 also perform it with cables or bands. The hammer curl is a great addition to an upper-body strength routine.

How to Do a Hammer Curl

Stand with your legs straight (but not stiff or locked) and knees aligned under the hips. Your arms are at your side with a dumbbell in each hand, the weights resting next to the outer thigh. Your palms are facing the thighs, the thumbs are facing forward, and your shoulders are relaxed.

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 the body.
3. Lower the weights to return to the starting position.

Benefits of Hammer Curls

A hammer curl works the biceps brachii. This muscle is considered a "vanity muscle" because it is easily visible on the front of the body. People looking to get a muscular appearance often target the biceps for a more athletic look.

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

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

The hammer curl is one way to build stronger biceps muscles and provide greater definition and increased strength. Including it in your exercise program may also help increase wrist stability and improve grip strength.

Other Variations of the Hammer Curl

You can modify this exercise to better align with your fitness level and goals.

Alternating Hammer Curl

If you try the hammer curl and find that it is too difficult to maintain proper form, consider doing alternating hammer curls. Instead of lifting both arms at the same time, lift the right arm and lower, then lift the left and lower. Continue to alternate sides.

Incline Hammer Curl

Another variation is to use a seated incline bench to do the hammer curl. 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 lowing them again.

Preacher Hammer Curl

Some exercisers use a preacher bench to perform this move. 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.

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 are facing each other. Lift the weights to your shoulders, then lower them back down.

Hammer Curl Power Squat

Make this move even 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.

Common Mistakes

Avoid these common errors to keep the hammer curl safe while maximizing its effectiveness.

Using Momentum

Using momentum decreases your ability to build strength with this exercise. 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 the exercise by leaning forward slightly and bring 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.

Curling Too Fast

The hammer curl employs 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 on the way down allows you to control the movements and focus on form. Slowing your movements also adds more challenge, because you must engage the muscles for a longer period of time.

Floating Elbows

It's easy to allow the elbows to float away from the body during the curl. 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.

Try to keep the elbows in a stable, fixed position and concentrate on moving only the lower arm during your hammer curl. If you are unable to lift the weight without moving the elbow, you are lifting too much weight.

Safety and Precautions

While the hammer curl is 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 likely working—that it is effectively targeting your upper arm muscles. However, stop if you feel pain when performing the hammer curl.

When first starting out, try two sets of 7 to 10 repetitions each. As you get stronger and more flexible, add repetitions first. Then add more weight.

Try It Out

Incorporate this move and similar ones into one of these popular workouts:

• Back and Biceps Workout for Strength
• Beginner Upper Body Workout
• Upper Body Tri-Set Challenge Workout