What Muscles Do Hammer Curls Work?

What Do Hammer Curls Work
Photo Credit: Andres Ayrton / Pexels

Hammer curls are a popular bicep exercise that targets several upper arms and forearm muscles. This exercise involves holding dumbbells with palms facing each other, resembling a hammer’s grip.

Let’s closely examine the benefits of hammer curls and the muscles involved in performing this exercise.

Understanding Hammer Curls

Hammer curls are a great exercise to add to your workout routine to target your biceps and forearms. But before we dive into the muscle groups worked by hammer curls, let’s take a closer look at how to perform this exercise for maximum results.

Begin by standing straight with your hips and feet shoulder-width apart. Hold the dumbbells by your sides with your palms facing your thighs. This starting position is crucial for maintaining proper form throughout the exercise.

What is Hammer Curls?

Hammer curls involve lifting the dumbbells up to shoulder height while keeping your elbows stationary. As you perform the lift, your forearms contract, and your biceps stretch. This movement targets the brachialis muscle, located underneath the biceps, which helps increase your arms’ overall size.

Lower the weights slowly to the starting position and repeat to complete one rep. It’s important to control the movement on the way down to avoid any sudden jolts or jerks that could lead to injury.

How to Perform Hammer Curls Correctly

It is essential to perform hammer curls correctly to avoid injuries and achieve optimal results. To do so, ensure your elbows remain close to your sides throughout the exercise and only your forearms move. This will help isolate the biceps and forearms and prevent unnecessary strain on your shoulders or back.

Keep your wrists straight and grip the dumbbells tight throughout each rep. This will help to engage your forearm muscles and give you a stronger grip on the weights.

To avoid swinging or jerking movements, tense your biceps and forearm muscles while lifting and lowering the weights. This will help you maintain control and prevent momentum from taking over.

Remember to breathe throughout the exercise and take breaks as needed. It’s better to perform fewer reps with proper form than to rush through the exercise and risk injury.

Incorporating hammer curls into your workout routine can help you to build stronger, more defined biceps and forearms. By following these tips for proper form, you can ensure that you are getting the most out of this exercise and avoiding any unnecessary strain or injury.

Primary Muscles Worked by Hammer Curls

Hammer curls are a popular exercise for building upper arm strength and size. They are a variation of traditional bicep curls and are performed using a neutral grip, with the palms facing each other. While the biceps brachii muscle is the primary muscle worked during hammer curls, other muscles are also activated and contribute to the overall effectiveness of the exercise.

Biceps Brachii

The biceps brachii muscle is located in the front upper arm and is crucial in elbow flexion and forearm supination. It is the primary muscle worked during hammer curls. The alternating movement targets both the muscle’s long and short heads, leading to a defined and toned look. Additionally, the biceps brachii muscle provides stability to the shoulder joint during the exercise.


The brachialis muscle is located below the biceps brachii, and its main function is elbow flexion. Performing hammer curls with a neutral grip, instead of a supinated grip, places more stress on the brachialis muscle. Thus, it helps to strengthen and build thicker arms. The brachialis muscle is often overlooked in traditional bicep exercises, so incorporating hammer curls into your workout routine can help target and develop this muscle.


The brachioradialis muscle is located near the forearm and plays a critical role in elbow flexion and wrist extension. This muscle becomes more active as you perform hammer curls. As a result, this exercise helps build forearm strength and size. The brachioradialis muscle is also important for grip strength, which can benefit athletes who need to maintain a strong grip, such as rock climbers or weightlifters.

When performing hammer curls, it is important to maintain proper form and technique to avoid injury. Start with a weight that is comfortable for you and gradually increase the weight as you become stronger. Aim for 2-3 sets of 10-12 repetitions, with a rest period of 30-60 seconds between sets. Incorporating hammer curls into your workout routine can help target and develop the muscles in your upper arms and forearms, increasing strength and size.

Secondary Muscles Involved in Hammer Curls

Hammer curls are a popular exercise for building bicep strength and definition. While the brachioradialis is the primary muscle targeted during hammer curls, several other muscles are also involved in the movement. Understanding the secondary muscles worked during hammer curls allows you to maximize your workout and achieve better overall results.

Forearm Muscles

In addition to the brachioradialis, hammer curls also work other muscles in the forearm, including the extensor carpi radialis and flexor carpi radialis. These muscles are crucial for wrist and hand movement and help add definition to your forearms. You can strengthen these muscles and improve your grip strength by performing hammer curls regularly.

It’s worth noting that the muscles worked during hammer curls can differ depending on the exercise you perform. For example, if you perform hammer curls with a neutral grip (palms facing each other), you may feel more activation in the wrist flexors and extensors. On the other hand, if you perform hammer curls with a pronated grip (palms facing down), you may feel more activation in the brachialis muscle.


The deltoid muscles, a group of three muscles in the shoulder girdle, are also involved in hammer curls. As you lift the weights, your shoulders move slightly, leading to increased activation of the anterior deltoid muscles. This can help improve your shoulders’ overall shape and definition, giving you a more balanced and aesthetic physique.

It’s important to note that while the deltoids are involved in hammer curls, they are not the primary muscle targeted during the exercise. If you want to target your deltoids specifically, you should incorporate other exercises into your workout routine, such as shoulder presses or lateral raises.


The trapezius muscle extends from the base of the skull to the lower thoracic vertebrae and is involved in shoulder and neck movement. During hammer curls, the upper back and neck trapezius muscles stabilize the shoulder blade, leading to better posture and stability. This can help prevent injuries and improve your overall performance in the gym.

Additionally, by strengthening your trapezius muscles, you can improve your posture and reduce the likelihood of developing neck and shoulder pain. This is especially important if you spend a lot of time sitting at a desk or using electronic devices, which can lead to poor posture and muscle imbalances.


Overall, hammer curls are great for building bicep strength and definition. By understanding the secondary muscles worked during hammer curls, you can maximize your workout and achieve better overall results. Incorporating variations of the exercise and other exercises that target the deltoids and trapezius muscles can help you achieve a balanced and aesthetic physique while reducing the risk of injury and improving your posture.

Benefits of Hammer Curls

Hammer Curls
Photo Credit: Andres Ayrton / Pexels

Hammer curls are a popular exercise that can help you achieve toned and defined arms. They are a variation of the traditional bicep curl and are performed with a neutral grip, which means your palms face each other throughout the movement. Here are some of the benefits of hammer curls:

Improved Grip Strength

As mentioned earlier, hammer curls work the forearm muscles, including the brachioradialis, which can lead to improved grip strength. This is beneficial, especially for individuals who engage in activities that require strong grip strength, such as rock climbing and weightlifting. Improved grip strength can also make everyday activities like opening jars and carrying heavy bags much easier.

Enhanced Arm Stability

Engaging multiple muscle groups during hammer curls helps to improve arm stability. This is particularly important in everyday activities such as carrying groceries or picking up children. Additionally, improved arm stability can help prevent injuries and improve your overall posture.

Balanced Muscle Development

Hammer curls help develop the biceps brachii, brachialis, and brachioradialis muscles equally, leading to a well-balanced and aesthetically pleasing appearance. Additionally, working the smaller muscles in the forearm can help prevent muscle imbalances and potential injuries.

It’s important to note that hammer curls should be performed in addition to other exercises that target the biceps and forearms. This will ensure that you are targeting all the muscles in these areas and achieving a well-rounded arm workout. Other exercises you can include in your arm workout routine include bicep curls, tricep dips, and wrist curls.

Overall, hammer curls are an excellent exercise to include in your arm workout routine to target several upper and fore-arm muscles. These exercises have numerous benefits and can help improve your grip strength, arm stability, and overall muscle development. So, if you want to achieve toned and defined arms, add hammer curls to your workout routine!

Written by James Kosur

James is a 20-year veteran of the digital media industry, an avid gym builder, and a dad to four kids, three dogs, and two cats. He's a DIYer who loves building stuff with his hands and a gamer who enjoys all facets of gaming.