What Muscles Do Hammer Curls Work?

One of the most common advice you get from the bulky gym guys is doing hammer curls. They promise it’ll fill your shirt sleeves and give you a more athletic body. But what muscles do hammer curls work, exactly?

Hammer curls work your biceps, brachioradialis, and brachialis, which involve most of your upper and forearm. They also stretch some parts of your delts, traps, and wrist flexors. But that only occurs with the correct form, techniques, equipment, and variations.

In the following, we’ll tell you more about the muscles worked and other benefits of hammer curls. We’ll also teach you how to do the exercise properly and get the most out of it. In the end, you’ll be familiar with different types of hammer curls along with instructional videos.

Muscles Worked in Hammer Curls

Hammer curls are an isolation exercise. So, they only trigger one muscle group, which is the biceps in this case.

However, unlike their more general variation—bicep curls—that exclusively activate the biceps brachii, they also flex two other main muscles in the biceps region: the brachialis and brachioradialis.

These two muscles work in cooperation with the biceps to bend the forearm toward your arm.

The brachialis sits right beside the bicep brachii but deep to its muscle belly (imagine the biceps in an anterior-inferior position to the brachialis). It has a spindle shape and is considered a deep muscle.

The brachioradialis, on the other hand, is a superficial muscle that also resembles a fusiform. It originates from the humerus and descends in the middle of the lateral forearm. Among the upper arm areas, this muscle gets the most attention in hammer curls. That’s because it bears the most burden to flex your arm.

But hammer curls also recruit some stabilizers such as your anterior delts, traps, and extensor carpi radialis longus.

Other Benefits of Hammer Curls

The most notable advantage of hammer curls is that they target one of your vanity muscles—biceps. Besides your abs, chest, and shoulders, this part is one of the first areas noticed by people. And if you fire it up, you’ll get the athletic figure sooner.

Plus, their hammering movement puts more stress on your biceps than other forearm exercises due to their hammering movement. And it means more gains in a shorter period. 

However, hammer curls aren’t only there to give you wider arms. Other than adding bulk, they can also strengthen this area, letting you pump heavier weights and do more intense exercises like deadlifts. You’ll even see increases in your endurance.

The third benefit is your grip improvement. Hammer curls let you hold a neutral grip, which is different from the common underhand and overhand styles. This variation makes your grip stronger, and your wrist more stable after a while. So, you’ll be more powerful for rows, power cleans, and shrugs.

If you know how to properly perform hammer curls and contract your abs while lifting, they can even work your torso.

All these factors make hammer curls ideal for athletes, bodybuilders, and fitness workers alike.

The Standard Way to Do Hammer Curls

The following steps teach you how to do hammer curls properly and reap their highest benefits:

1. Stand erect with your feet shoulder-width apart and a dumbbell in each hand.
2. Make sure you take a hammer grip (palms pointing to each other), keep your elbows next to your torso, and hang the dumbbells on your sides.
3. Brace your stomach muscles as if someone wants to punch you. This forms a sturdy foundation for the move.
4. Now, lift one of the dumbbells in a curl-like motion and toward your shoulders until your forearm is parallel to your body. At the same time, try to pinch your biceps to emphasize it more, and don’t bend your wrist.
5. Wait a moment or two until you slowly reverse the motion and do the same with your other arm.
6. Do 2-3 sets of 8-2 reps with each hand.

Hammer Curl Tips and Warnings

It’s not all about the execution process; to maximize the effects of hammer curls, you need to keep a few additional tips in mind:

Don’t Go Heavy from the Beginning

Although beneficial for all exercisers, hammer curls may work best for beginners and those who haven’t left a single weight in their life. So if you have no experience in weightlifting, start by zero or minimum poundage.

This ensures you learn the proper posture and don’t bear injuries in the process.

Don’t Rush to Raise the Dumbbells

Due to professional opinion, moving the dumbbells too quickly can wreak havoc on your workout and compromise your potential gains. They say the ideal break for any weightlifting move is about two inhales and exhales, and the law holds true for both the concentric or eccentric phase.

So, count your breaths to avoid raising or lowering the dumbbell too fast.

Don’t Rely on Momentum

Momentum lets you accelerate the tempo of exercise and perform the reps more quickly. But it’s counterproductive when it comes to weightlifting, especially hammer curls.

That’s because you’ll toss your arms in an uncontrolled manner, which in turn decreases stress on your muscles, and affects your strengthening or sculpting efforts. It even makes potential injuries more probable.

Avoid Shrugging Your Shoulders

Keep your shoulders at ease and your torso straight while rotating the dumbbells because otherwise, you’ll work your shoulder muscles instead. This will lower the impact of exercise on your biceps. It may also cause strain and injuries as it’s not the proper way to shrug the shoulders.

Don’t Sway Your Elbows

Swinging your elbow to the sides, up, or down position can shift the stress to your other muscles, just the way shrugging your shoulders does.

So it’s important to keep your elbows firm and stationary, putting your focus only and only to the frontal arm. If your elbow still wobbles, maybe you should decrease some poundage.

Skip It If You Have Arm Injuries

Those with arm fractures, broken wrists, sprains, strains, bicep tendon injuries, elbow conditions, and other types of injuries shouldn’t do hammer curls. If you doubt you can do it, consult your doctor first.

Different Types of Hammer Curls

Although all the hammer curl variations follow the same principle steps as above, they come in different versions. Some have slight variations in form, while others work with special types of weights.

Here are a few hammer curls variations along with short instructive videos:

• Seated hammer curls: Doing hammer curls in a seated position lets you lift more weight than usual and further compress your biceps. Also, it doesn’t require a stabilized core as you have a strong base to lean on.

Here’s how to mimic the same hammer curls in seating stats:

• Cross-body hammer curls: This type of hammer curl stretches the forearm and brachialis more than the bicep brachii and brachioradialis. So if this is where you’re going to target, here’s how:

• Cable hammer curls: Cable or rope hammer curls can add variety to your workout routines and become handy in the absence of dumbbells. But they’re no different from regular curls regarding the targeted muscles.

This video shows you how to do them:

• Kettlebell hammer curls: This hammer curl variation distributes weight more evenly to your different arm muscles.

If you don’t have a Kettlebell to reap the benefits of this type of exercise, Amazon Basics Cast Iron Kettlebell from Amazon.com is a good choice to buy. It’s made of supreme cast iron and will last a whole life for you. The kettlebell weighs 20 pounds with a comfortable, secure handle.

• Swiss bar hammer curls: Using a swiss barbell, you can do hammer curls with both hands at a time. Watch this video if you can’t figure out how to do it:

Final Thoughts

Hammer curls can blow up your whole upper arm and some part of the forearm. They can also make your arms stronger and your wrist more stable. However, you should follow some principles if you want to take these advantages.

Don’t let your elbows travel to the sides, forward, or backward during the curls. Don’t raise and drop the dumbbells too quickly, and leave your shoulders unworked. Start with a poundage you can easily handle, and do the exercise only when you master the correct posture.