Bigger biceps are a desire for many people who participate in resistance training. They add size to the arms and are visible to the lifter as well. Most people know the standard biceps curl for its focus on the bulge of the biceps.

However, to work on overall girth of your arms, the hammer curl is a perfect exercise to add to your routine. The hammer curl is a deceptively simple exercise, but good form is vital.

There are multiple ways to modify the hammer curl to add variety and use the equipment you have available. Hopefully this will encourage you to add this terrific exercise to your routine.

The hammer curl may help add mass to your arms because the grip positioning often allows you to lift heavier weight. As a result, it’s a good exercise to build strength in all three muscles that bend your elbow.

In part because of the neutral grip (palms facing each other), hammer curls have a slightly different muscle activation pattern than the traditional biceps curl, which is performed with a supinated grip (palms facing up).

The hammer curl grip allows more focus on the short head of the biceps.

In addition, this type of curl may be easier to tolerate than traditional curls if you’re experiencing shoulder or forearm pain. Injury to the long head of the biceps is a common cause of shoulder pain (1).

Sometimes adjusting your forearm position can help alleviate this while still working your biceps (2).

Nevertheless, It’s best to perform hammer curls with a light weight first. If you experience any pain, then it may be better to hold off and consult a medical professional.

Summary

Hammer curls are biceps curls performed with your hands facing each other. They’re beneficial to add mass to your arms and can help focus more attention on the short head of the biceps. They may be easier to tolerate than the traditional biceps curl.

Hammer curls work the elbow flexors — the muscles that bring your hand to your shoulder by bending your elbow. The elbow flexors are made up of the biceps brachii, brachioradialis, and brachialis (3, 4, 5).

The biceps brachii is the most superficial of the flexors and is the most visible mass on the front of the arm. It has two heads that originate at the shoulder joint and a bony prominence on the front of the shoulder blade. It inserts on the radius bone, just below the elbow.

Because the biceps brachii crosses both the elbow and shoulder joints, it creates motion for both joints. Namely, it flexes the elbow and assists in flexion of the shoulder.

The brachioradialis originates on the upper arm, closer to the elbow joint, and terminates on the forearm, just before the wrist. This muscle helps to flex the elbow but also gives visible mass to the front of the forearm (4).

The brachialis also originates on the lower portion of the upper arm bone, and it attaches at the large inside bone of the forearm, called the ulna. It’s the least visible but also the strongest flexor of the elbow during the hammer curl (5).

Summary

Hammer curls work the biceps brachii, brachioradialis, and brachialis muscles. These are the muscles responsible for bending the elbow.

This exercise is best performed with a set of dumbbells.

  1. While standing or sitting, hold dumbbells at your sides with your palms facing each other.
  2. Keep your back straight and your elbows against your sides.
  3. Bend your elbows, bringing the dumbbells up toward your shoulders while keeping your upper arms in line with your trunk. Your palms will stay facing each other.
  4. Pause for a 1–2 count, and then slowly lower the dumbbells back to the starting position at your sides.
  5. Perform 2–3 sets of 8–15 repetitions.
Summary

Hammer curls are similar to biceps curls but are performed with the palms facing each other throughout the movement.

Cross-body hammer curl

  1. While standing or sitting, hold dumbbells at your sides with your palms facing each other.
  2. Keep your back straight and your elbows against your sides.
  3. Bend your left elbow, bringing the dumbbell up toward your right chest/shoulder. Your palm will be facing your chest.
  4. Pause for a 1–2 count, and then slowly lower the dumbbell back to the starting position at your side.
  5. Perform 2–3 sets of 8–15 repetitions. Then repeat with the other arm.

Cable rope hammer curl

This version will challenge your grip more than performing the move with a dumbbell.

  1. Stand in front of a low cable pulley machine. Connect the rope attachment to the pulley.
  2. Grasp the ends of the rope with your palms facing each other.
  3. Keep your back straight and elbows against your sides.
  4. Bend your elbows, bringing the ends of the rope up toward your shoulders while keeping your upper arms in line with your trunk. Your palms will stay facing each other.
  5. Pause for a 1–2 count, and then slowly lower the rope back to the starting position.
  6. Perform 2–3 sets of 8–15 repetitions.

Resistance band hammer curls

This is performed exactly how the traditional hammer curl is performed. However, you will stand in the middle of the band and grasp the ends. The resistance will be less intense at the beginning of the movement and increase as your hands approach your shoulders.

Summary

There are multiple variations on the hammer curl, including the cross-body hammer curl, the cable rope hammer curl, and resistance band hammer curls.

  • Start with a light weight. There is a tendency with all exercises to want to lift the heaviest weight possible. However, until you feel comfortable with the movement, it may be better to focus on your form.
  • Keep your back neutral during the entire movement. When fatigue sets in, it’s easy to bend forward as you lower the weight and extend back as you lift the weight.
  • Avoid swinging the weight or using momentum to try to lift the weight. If this is happening, try using lighter weights or doing fewer repetitions. It’s not worth a back strain.
  • Perform the movement slowly, lifting the weight for a count of 2, pausing for 1 count, and then lowering the weight for a count of 4.
Summary

Start with a light weight to get comfortable with the movement. Keep your back neutral, avoid using momentum or swinging the weight, and perform the exercise slowly.

The hammer curl is a great exercise to add to your program to build your upper arms and increase your curling strength. It can also be a good alternative to the traditional biceps curl if you’re looking for more variety.

Either way, give it a go, stay the course, and you’ll reap the rewards.