Hammer Curl: What It Works & How to Do

The hammer curl is a resistance exercise designed to increase muscle mass and hypertrophy of the biceps, while also strengthening the forearms and improving grip strength.

It’s an excellent addition to an upper body workout routine and can be done sitting or standing, using dumbbells, a cable machine, or a barbell. Because it uses a neutral grip, this exercise puts less strain on the wrists than a traditional biceps curl.

Hammer curls should always be performed under the supervision of a fitness professional, who can recommend the most suitable variations and the correct weight to use based on each person’s physical condition and training goals.

What it works

Hammer curls help build muscle mass and increase the size of the biceps brachii, located in the upper arm and shoulder area, making the arm more toned and defined.

This exercise also strengthens the forearms by engaging the brachioradialis muscle and can be combined with other arm exercises for a more complete workout. Check out this complete arm workout.

In addition, hammer curls improve grip strength, which is the ability of the hands to perform activities that require effort or resistance.

How to do dumbbell hammer curls

To perform hammer curls with dumbbells, try following these step-by-step instructions:

• Stand upright holding a dumbbell in each hand with your palms facing inward and arms extended alongside your body;

• Keep your back straight, core tight, and elbows close to your torso throughout the movement;

• Bend your elbows, raising your forearms until the weights reach shoulder level;

• Avoid moving your wrists or shoulders during the curl to prevent injury;

• Lower your arms slowly back to the starting position;

• Perform 2 to 4 sets of 8 to 15 repetitions, resting 60 to 90 seconds between sets, as directed by your trainer.

During the exercise, inhale when your arms are down and exhale as you curl your elbows upward.

Other variations

Other variations of the traditional dumbbell hammer curl include:

1. Rope hammer curl

The rope hammer curl is performed using a cable machine and is also known as the cable hammer curl or cross cable hammer curl.

To perform this variation, load the machine with the appropriate weight as recommended by your trainer and secure the safety clips. Stand facing the machine, grab the ends of the rope attachment, keep your elbows close to your body, and pull the rope toward your torso until your hands are near your shoulders.

As you lift your forearms, slightly spread the rope apart, then bring it back together as you lower the weights.

2. Alternating hammer curl

The alternating hammer curl is performed with a dumbbell in each hand, lifting one arm at a time in an alternating motion.

3. Barbell hammer curl

The barbell hammer curl is done using an H-shaped bar (also called a hammer curl bar). Add the desired weight plates to each side and secure them with safety clips to prevent slippage.

The movement is the same as with dumbbells or a cable rope, with both forearms moving simultaneously.

4. Unilateral hammer curl

The unilateral hammer curl involves lifting the dumbbell with one arm at a time. Complete all repetitions on one side before switching to the other.

5. Simultaneous hammer curl

The simultaneous hammer curl is performed by lifting the weights at the same time with both arms, maintaining symmetry and balance throughout the exercise.

6. Scott hammer curl

The Scott hammer curl is done while seated on a preacher curl bench (also known as a Scott bench), which provides elbow support for better isolation of the biceps.

Safety precautions

Some important precautions when performing hammer curls include:

• Keep your spine straight and aligned, with your head and neck in a neutral position;

• Keep your elbows close to your body and palms facing inward;

• Engage your core throughout the movement;

• Inhale as you raise your forearms and exhale as you lower your arms;

• Keep both feet flat on the floor, pressing slightly through your heels;

• Avoid fast or jerky movements.

It’s essential to maintain correct posture and use the proper weight. Hammer curls should always be done under professional guidance to prevent injuries.

Hammer curl vs biceps curl

Both hammer curls and biceps curls target the biceps brachii muscle, but they differ in hand position and in the muscle fibers they emphasize.

In a hammer curl, the wrists maintain a neutral grip with the palms facing each other, while in a biceps curl, the palms face upward.

This difference activates distinct muscle fibers: hammer curls focus more on the long head of the biceps, while biceps curls emphasize the short head.