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How to do a one arm barbell curl

Single arm barbell curls will let you see how strong your biceps really are.
Written By  Liam Brown
Last Updated on 10th August 2021
A man performing a one arm barbell curl

We know that the main biceps brachii action and movements are forearm supination (turning your palms up) and elbow flexion (moving your forearms toward your biceps). The reason that Olympic bar curls are so effective is that they train both of these functions together.

However, regular, two-handed curls, despite being one of the best barbell exercises for your biceps, can often lead to muscular imbalances, which can make your physique look unsymmetrical.

The solution is to do a one arm barbell curl, which makes for a very quirky bicep workout. Not only does this drill help you to build proportional biceps, but it's also ideal for arm wrestlers and anyone else who wants to perform impressive feats of strength with their arms.

Single arm barbell curl exercise details

  • Main Muscles: Biceps brachii
  • Secondary Muscles: Brachioradialis, brachialis, forearm flexors
  • Exercise Type: Strength
  • Exercise Mechanics: Isolation
  • Difficulty Level: Advanced
  • Equipment Needed: Barbell, weights

How to do one arm barbell curls

  1. Hold the middle of a barbell (Olympic or fixed bar) with an underhand grip. You can add weights to each side if you're really strong.
  2. While keeping your elbow still, curl the bar to your shoulder by moving your forearm toward your bicep.
  3. Keep curling until your bicep is maximally contracted.
  4. Lower the weight under control until your elbow is completely locked out.
  5. Repeat the exercise with your other arm and do 3-4 sets of 4-10 reps per side.

One arm barbell curl benefits

A man performing a single arm barbell curl

One hand barbell curls are a highly underrated exercise for both muscle growth and strength development. If you start doing them in your gym, then you'll probably earn yourself the nickname trendsetter; or perhaps even the crazy one if you train in a Globo gym!

You can also give the unilateral cable curl a try if you're a beginner and are looking for an exercise that has less of a stability requirement.

Increases your supination strength

The one-arm barbell curl forces your forearm supinators to work overtime to stabilize the bar. As I mentioned in the intro, forearm supination is a primary biceps function, so by training it along with the other major function—elbow flexion—you'll be well on your way to building the bicep size that you desire.

Reduces muscular imbalances

Like the one arm dumbbell curl, single arm barbell curls help you to correct your muscle imbalances (or prevent them from cropping up in the future) by ensuring that both of your biceps receive equal work. This is excellent news if you're a bodybuilder because it will make your upper body look more symmetrical and score you maximum points with the judges.

Promotes the proper form

You can't use much momentum on a one arm barbell curl because doing so will cause the bar to become unbalanced. As such, the movement is helpful for promoting the use of good form because your biceps have to perform the heavy lifting seen as you can't swing the weight up with your back, legs, hips, etc., as effectively.

Keeps you progressing

Some people train in gyms where the heaviest dumbbells are only 70-80lbs. While this amount of weight is fine for mere mortals like me, you might reach a point in your training career where 80lbs simply doesn't suffice for the strength of your gargantuan biceps. Doing a standing curl one arm at a time is the solution because you can load virtually infinite weight onto a barbell; hence, you'll never max out its capacity.

See Also: Barbell curl to press

The verdict: Are single arm barbell curls effective?

While the one arm barbell curl certainly isn't popular, it sure is effective if you want to build biceps that are muscular, symmetrical, and strong. So in this regard, they're ideal for both bodybuilders, arm wrestlers, and any kind of strength athlete who wants to impress their fellow lifters with a true feat of strength.

You can also do a single arm eccentric barbell curl to make your biceps work harder on the negative portion of the rep.

In practice, you could curl the weight up with two arms and then lower it with one. However, since this would be hard to do without the bar becoming unbalanced, a better option is to have your training partner help you lift the weight and then lower it slowly by yourself.

Overall, one arm barbell curls are a strength training trade secret that few lifters know about. This actually isn't all that surprising considering that one arm barbell curls are one of the most advanced bicep exercises that there is. Feel free to share this post with your gym buddies if you want to spread the gains, or keep it to yourself if you want to maintain your competitive advantage.

Liam Brown
Liam Brown has been coaching clients as a personal trainer for more than 12 years. Raised by his athlete mother and physiotherapist father, he understands the critical importance of learning the proper technique for both avoiding injury and building muscle.
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