Barbell Curls: Benefits, Muscles Worked, and More

No resistance exercise is more iconic than the classic barbell curl - a movement practiced in nearly every single weightlifting program ever created.

Despite its popularity however, not many lifters are actually aware of the specific reason for the barbell curl’s inclusion into so many training programs - or even what its more salient characteristics are.

The barbell curl is a biceps exercise known for its effectiveness at building stronger and larger arms. Unlike other kinds of curls, barbell curls feature several mechanical advantages that a lifter may take advantage of so as to push their biceps workout even further.

What are Barbell Curls?

In more technical terms, the barbell curl is a single-joint isolation exercise performed most often as an accessory movement within pull or back-and-bicep workout sessions. It is regarded as a solid exercise that has remained among the most effective bicep builders despite having been practiced for centuries.

Even with its simplicity and how common the required equipment is, some lifters may find issue with performing the exercise due to physiological incompatibility or simply poor form adherence. 

Who Should do Barbell Curls?

Barbell curls are widely accessible to all individuals, even novice lifters who are unfamiliar with basic exercise mechanics. 

In particular however, bodybuilders and individuals with excellent wrist mobility will benefit the most from the barbell curl, as it is quite effective at inducing biceps hypertrophy, but otherwise may be uncomfortable to perform for people with poor wrist mobility.

What Kind of Barbell is Used for Barbell Curls?

When speaking of the conventional barbell curl, a straight olympic barbell curl is meant to be used - usually alongside a pair of weight plates as well. 

Barbell curl variations that make use of other types of barbells (such as an EZ-bar or parallel bar) are not considered to be the same exercise, and will often have different muscular recruitment patterns and ranges of motion.

How-to Barbell Curl

To perform a repetition of the conventional barbell curl, the lifter will stand upright with a barbell gripped at their waist, hands in a supinated grip and in-line with the forearms as much as possible.

Then, keeping the elbows and upper arms as stationary as can be managed, they will bend the elbows and draw the barbell upwards, stopping once it has reached approximately shoulder-level elevation.

Squeezing their biceps at this point, the lifter will then return the barbell to its original position in a slow and controlled manner - thereby completing the repetition.

What Muscles do Barbell Curls Work?

Barbell curls are an isolation exercise and therefore will primarily work one muscle; the biceps brachii.

This is achieved through translated resistance and utilization of the elbow flexion biomechanic - two factors that also cause other muscle groups to be recruited in a stabilizing capacity, all of which are located in the forearms or are the brachialis muscle alongside the biceps.

What are the Benefits of Barbell Curls?

The barbell curl has stood the test of time, and fills a unique role in many training programs due to the various benefits it can provide.

Excellent Biceps Builder

Because of the high loading capacity and recruitment potential of the barbell curl, it is quite effective at inducing muscular hypertrophy of the biceps - as well as strength adaptations that carry over to other exercises that may involve the biceps.

When used as an adjunct exercise to other biceps builders like rows or pull-ups, barbell curls can help maximize the development of the arm muscles as a whole.

Reinforced Elbow Flexion

The biceps brachii are among the main muscles responsible for elbow flexion, making the barbell curl excellent for reinforcing said biomechanic and ensuring that the elbows are stabilized as much as possible.

This, in turn, reduces future risk of injury to the elbows, as well as aids in execution of other lifts that also involve elbow flexion as a mechanic.

Reinforced Arm Chain

Though the barbell curl primarily targets the biceps brachii, it also utilizes muscles like the brachialis and brachioradialis to some small capacity. 

This creates a general improvement of the entire arm itself, improving whole-arm stability and general grip, flexion and isometric contraction strength in its entirety.

Natural and Simplistic Form

In comparison to many other exercises, the barbell curl is quite easy to pick up, and does not contort the body in any way that may be seen as disadvantageous or will otherwise place tension on weak parts of the body. 

So long as the exercise is performed with proper form and a reasonable amount of weight, it is unlikely that a lifter will find the movement to be painful or injurious.

Common Mistakes of Barbell Curls

Despite the relative simplicity of the barbell curl, there are still several errors that even advanced level lifters can make - all of which should be avoided so as to maximize the safety and benefits of the exercise.

Bending the Wrists

Throughout the entirety of the movement, the wrists are meant to be firmly kept in a neutral position, reducing strain on the small connective tissues therein and better translating force produced by the biceps.

Whether by overpronating, over-supinating or rotating the wrists in some way, allowing the wrists to be pulled out of a neutral alignment can lead to discomfort and injury. 

This is the most significant mistake made during barbell curl performance, and is the reason why many lifters experience wrist or forearm pain when curling a straight barbell.

“Floating” Elbows or Upper Arms

In order to avoid recruiting the deltoids or any muscle groups other than the biceps themselves, it is important for lifters to keep their upper arms stationary at the sides of the torso, with the elbows moving as little as possible while going through a full range of motion.

Not only can making either mistake lead to the biceps failing to be recruited, but it can also lead to injuries if excessive weight is used.

Using Insufficient Range of Motion

Regardless of what exercise is being performed, ensuring that the full range of motion is utilized will also ensure that the muscles are trained as effectively as possible.

In the case of the barbell curl, this is all the more important, as failing to complete the full range of motion of the exercise can cause sticking points or instability of the biceps to be developed over time.

A full range of motion should involve the barbell at full-stop around the waist or pelvis, with the opposite end being at shoulder elevation. Deviating from this range can alter the mechanics or benefits of the barbell curl.

Swinging the Torso

Even if the upper arm or elbows are in a relatively stationary position, momentum can still be produced by the lifter swinging their torso backwards, thereby taking away stimulus from the biceps and potentially straining the lower back.

As a general rule, any sort of force produced by a muscle other than the biceps will negate the benefits of barbell curls. Just like the upper arms, it is best to keep the torso stationary and upright throughout each repetition.

Adding Too Much Weight

Though the barbell curl can allow lifters to load more weight than they would be capable of safely curling with dumbbells alone, this does not mean that the lifter should do so to excess.

As a general guideline, lifters should strive to always lift enough weight to allow for 1-2 repetitions beyond their set, avoiding the point of complete exhaustion unless it is within the scope of their training program.

Barbell Curls or Dumbbell Curls - What’s the Difference?

The two most common forms of the classic bicep curl exercise are the barbell curl and the dumbbell curl - of which are mechanically the same exercise, but utilize different forms of equipment. 

This difference in source of resistance creates slightly different characteristics, with either exercise being more suitable for certain types of training goals.

Bilateral vs Unilateral Contraction

Though both dumbbell and barbell curls can be performed with both arms moving simultaneously, the barbell curl alone recruits both muscles in a synergistic manner - meaning that they combine force output during the lift.

This allows for a greater amount of weight to be utilized, as well as a more efficient movement overall.

However, such a form of contraction also means that muscular imbalances may be developed or worsened if special care is not taken to prevent them. In cases like this, it is best for the lifter to perform dumbbell curls instead.

Easier Wrist Placement

When curling with a straight barbell, lifters may find that maintaining proper wrist neutrality and placement can be difficult, especially if they possess poor wrist mobility. 

This is a disadvantage that is not present with the use of dumbbells, as they are two separate objects and as such do not force the wrists to maintain a certain position.

For lifters experiencing forearm or wrist pain due to barbell curl performance, switching to dumbbells may help alleviate the discomfort.

Maximal Loading

One point of advantage that the barbell curl has over dumbbell curls is in its capacity for higher maximal loading - meaning that more resistance may be added to the exercise for the same amount of effort, leading to a greater training stimulus and more efficient strength adaptations over time.

Keep in mind that total resistance is not the sole source of development, and always training with heavy weights may in fact be detrimental to long-term muscular hypertrophy. A balance should be found between resistance, total volume and recovery so as to maximize the benefits of the barbell curl.

Barbell Curl Variations and Alternatives

If you’re looking for an exercise similar to the barbell curl but with some change in characteristics, performing a variation or even an alternative exercise could prove useful.

1. EZ-Bar Curl

If altering hand positioning is not enough to cause the cessation of forearm or wrist pain, switching to an alternative barbell curl that makes use of an EZ-barbell should help reduce - or entirely eliminate - symptoms of discomfort.

The EZ-bar curl is mechanically and physiologically identical to the barbell curl, only with a bend in the handles so as to aid in proper wrist and hand positioning.

2. Reverse Barbell Curl

For lifters seeking greater brachialis and forearm muscle recruitment alongside their biceps recruitment, performing a reverse barbell curl where the hands are in a pronated position rather than a supinated one is perfect for reaching their goals.

The reverse barbell curl is much the same as a regular barbell curl, only with the bar gripped in a different manner and muscles like the brachialis and forearm flexors utilized as primary mover muscles.

3. Barbell Cheat Curls

A more advanced barbell curl variation used by bodybuilders and athletes; the barbell cheat curl is simply an ordinary barbell curl performed with excessive weight and the usage of momentum, meaning that the ordinary form cues of a conventional barbell curl are only loosely followed.

This is done so as to overload the muscles of the biceps, breaking progression plateaus or conditioning the body to swinging large amounts of weight upwards.

Note that this exercise is unsuitable for novice lifters, and is often avoided due to its high risk of injury, even when performed with relatively correct form.

Frequently Asked Questions (FAQ)

What are Barbell Curls Good for?

Barbell curls are an excellent tool for building upper-body strength, as well as improving the appearance and size of the biceps muscles.

While other exercises can achieve much the same effect, barbell curls are particularly effective as they work both sides of the body in a simultaneous manner, allowing for greater weight to be used and a more natural movement in general.

Are Barbell Curls "Better" than Dumbbell Curls?

In certain respects, yes - barbell curls are indeed better than dumbbell curls. 

Barbell curls allow the lifter to move more weight per repetition, to perform said repetition with greater efficiency and to comparatively save time per training session.

How Many Times (Reps/Sets) Should I do Barbell Curls?

A good starting point for programming barbell curls is to perform 2-3 sets of 8-12 repetitions each, placing the lifter squarely in the moderate range of resistance and volume for the biceps.

This will allow both hypertrophy and strength adaptations to occur without excessively fatiguing the body, perfect for an accessory isolation exercise like the barbell curl often is.

Final Thoughts

Remember to always perform the barbell curl with as perfect form as you can manage, and to avoid performing the exercise with too much weight until you become more familiar with resistance training in general.

References

1. Coratella, Giuseppe, Gianpaolo Tornatore, Stefano Longo, Fabio Esposito, and Emiliano Cè. 2023. "Bilateral Biceps Curl Shows Distinct Biceps Brachii and Anterior Deltoid Excitation Comparing Straight vs. EZ Barbell Coupled with Arms Flexion/No-Flexion" Journal of Functional Morphology and Kinesiology 8, no. 1: 13. https://doi.org/10.3390/jfmk8010013

2. Schwarznegger, Arnold. Dobbins, Bill. (Nov 5, 1999) “The New Encyclopedia of Modern Bodybuilding : The Bible of Bodybuilding, Fully Updated and Revised EBook Edition” Simon and Schuster Publishing ISBN-10: 3200328452