If you've only been doing traditional biceps curls, here's why you should add hammer curls to the mix.
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Gymgoer performing a hammer curl
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Biceps have a reputation as being just mirror meat. But far more than just a vanity muscle, your biceps support the health of your shoulders and elbows.

"Every time you bend your elbow or use your shoulders, your biceps muscles play a supporting role," says certified strength and conditioning coach Mia Nikolajev C.S.C.S. who competes in powerlifting. (Related: The Biceps Workout You Can Do Without a Huge Rack of Dumbbells)

Unfortunately, she says, many people skip out on bicep work altogether because they're afraid of looking like Popeye. (Spoiler alert: Popeye arms don't happen by accident!) Or, if they do train their bicep muscles, they skimp on one of the best bicep-strengthening exercises there is: the hammer curl.

Need more reason to add hammer curls to your workout routine? Below, learn everything there is to know about the exercise.

What Are Hammer Curls?

Also known as the neutral-grip biceps curl, hammer curls are a biceps curl variation. Unlike traditional biceps curls that entail curling a weight with a supinated (palm-up) grip, hammer curls takes on a neutral grip, with palms facing in toward each other.

Can't visualize? Think about the way you'd hold a hammer if you were going to decimate a nail. Palm perpendicular to ground, right? That's exactly how your hands should be positioned during a hammer curl.

Because this prescribed hand position can't be achieved with a barbell or kettlebell, hammer curls must be performed with dumbbells. (Related: How to Perform the Perfect Biceps Curl, According to Jen Widerstrom)

Hammer Curl vs. Bicep Curl

The tiny hand position tweak between the traditional bicep curl and hammer curl may seem like NBD, but it's why the two bicep curl variations target different parts of the bicep, according to Emily Hutchins, certified personal trainer with RSP Nutrition.

There are three main muscles in the bicep:

  1. The short head of the bicep brachii: Located on the front-side of the bicep, the short head of the bicep brachii contributes to the size of the bicep peak.

  2. The long head of the bicep brachii: Located along the outer-portion of the bicep, the long head of the bicep brachii contributes to the strength of the outer, upper arm.

  3. The bicep brachialis: Located under the bicep brachii, the bicep brachialis contributes to overall thickness of the upper arm.

The traditional biceps curl primarily works the short head of the bicep brachii, while the hammer curl works the long head of bicep brachii and the bicep brachialis. So, while traditional biceps curls build that baseball-like mound of muscle, the hammer curl builds your entire upper arm.

What Other Muscles Does The Hammer Curl Work?

While the main benefit of hammer curls is for your biceps, says Hutchins, it also works your:

  • Wrists
  • Forearms
  • Triceps
  • Deltoids (aka shoulders)
  • Trapezius (upper back)

If you're performing the movement from a standing position hammer curls also work your core, glutes, and legs, to a certain extent. (Related: This Simple Dumbbell Biceps Workout Will Help You Sculpt Stronger Arms)

Hammer Curl Benefits

The first benefit is obvious: Hammer curls build strong, sculpted biceps. Why does this matter? Well, again, beyond filling out the arms of your tee, strong biceps support your elbow and shoulder joint — especially during pulling movements, says Nikolajev. So any time you're carrying groceries to the kitchen, schlepping a suitcase up the stairs, playing on the monkey bars with your kids, or pulling a wagon, your biceps are involved at least a little, she says.

Due to the angle of the weight against gravity, "many people are able to curl more weight with a neutral grip during a hammer curl, than during a traditional bicep curl," she says. Because heavier weight usually translates to greater muscle growth, hammer curls may actually result in faster arm gains.

Hammer curls are also especially great for working your forearm and grip strength, says Nikolajev. These muscles come in handy for all of the aforementioned day-to-day moves, she says. "Having strong forearms and grip is also useful for increasing the weight you can use during other movements like the snatch or deadlift," she says. "And it's important for protecting the forearm against carpal tunnel syndrome symptoms. (Related: Can Your Workout Cause Carpal Tunnel Syndrome?)

Oh, and a 2018 study published in the journal PLoS One found a relationship between physical activities like biceps curls and cognitive performance in older adults. Basically, big biceps = big brains.

Hammer Curl Form Tips

You can do hammer curls seated, standing, or even kneeling. But doing them standing challenges your core and lower half to a greater degree, which is why Nikolajev recommends doing them standing.

You also have the option to curl both arms at the same time or to alternate them. The risk of messing up the movement is higher when alternating arms, according to Nikolajev. That's why she recommends starting with the double-arm hammer curl. (Related: 5-Minute Arm Workout with Dumbbells)

A. Start standing in an athletic position, feet shoulder-width apart. Hold a light dumbbell in each hand with straight arms in a neutral grip, palms facing each other. Tuck ribs to brace core and squeeze glutes to start.

B. Keeping elbows tight to sides and shoulders back, engage bicep muscles to simultaneously draw both dumbbells toward their corresponding shoulder until thumbs nearly touch shoulders.

D. Pause, then lower the dumbbells back down to sides with control. That's one rep.

Once you master the traditional double-arm hammer curl, you can move on to alternating hammer curls — when you curl one arm at a time. One important form tip: If you're doing an alternating standing hammer curl, "when you're moving just one dumbbell, your body is going to want to lean to the side the weight is on," says Nikolajev. This could put your back in a not-so-great position. "You're going to have to really activate and engage your core to keep this from happening," she says. If you notice your body is making a "C" shape while you're doing these, stop. Decrease the amount of weight you're using and try again. Or, return to double arm hammer curls.

How to Incorporate Hammer Curls Into Your Training

Keep these tips in mind when bringing hammer curls into your workout routine.

1. Start light.

Hutchins recommends starting conservatively. "Start with a weight you can easily use for 10 to 12 reps per side relatively easily, and then progress from there."

2. Play with time under tension.

Using medium-weight dumbbells and slowly moving through a rep to increase time under tension (aka the amount of time the muscle is being challenged) is incredibly effective for increasing muscle breakdown, and therefore muscle strength, post-repair, says Nikolajev. But so is going as fast as possible for as long as possible with a very light weight. That's why she recommends varying time under tension. (Related: Why You Should Add Partial Reps to Your Training and How to Do It)

3. Don't only do hammer curls.

When it comes to muscle health and integrity, symmetry is the name of the game. "It's important to incorporate hammer curls and traditional biceps curls into your routine in order to keep the [bicep] symmetrical and functional," says Hutchins. And, of course, be sure you're working the other important muscles in your arms (such as the triceps and deltoids) so you keep your overall strength balanced, too.

4. Eventually try alternating hammer curls.

Whether seated or standing, once you have the core strength, go ahead and give the alternating hammer curl a whirl!