Hammer Curls vs Bicep Curls – 2 Clear Differences For Biceps

Hammer Curls vs Bicep Curls

Biceps curls are pretty much a staple exercise for most people looking to add size to their upper arms.  

It’s an easy to do isolation exercise which you can perform using a pair of dumbbells. 

However, there are several variations which are just as effective for targeting your biceps brachii.  

Recommended Reading – Discover The Average Bicep Size & Growth For Males In 2024

One great option is the hammer curl.  

But what’s the difference between that and the traditional bicep curl?

In this article, we’ll look at hammer curls vs bicep curls to discover if one is better than the other for muscle and strength development. 

Hammer Curls vs Bicep Curls: How Are They Different

The main difference between hammer curls compared to bicep curls is how you hold the dumbbells.  

Hammer curls require you to hold the dumbbells with a neutral grip so that your palms face inwards.  


On the other hand, bicep curls should be performed with a supinated grip with your palms facing away from you.

This variation in hand position will place more emphasis on different arm muscles.  

The primary muscle activated when doing standard bicep curls is the biceps muscle which includes both the short head and the long head of the biceps.  

average biceps size

When performing a hammer curl, you’ll be activating your brachioradialis muscles which is a forearm muscle and the brachialis muscle, which is a small muscle set deep in your upper arm.  

While your biceps brachii are also engaged, they act as a synergistic muscle meaning they are helping the other muscles do more of the work.  

Essentially, the hammer curl and bicep curl work the same muscles but in different ways.  

The hammer curl primary muscle worked is the brachialis and brachioradialis with the biceps brachii helping to complete the exercise.  

Whereas the bicep curl primarily works the bicep brachii with the brachialis and brachioradialis now assisting both stages of the curl movement.  

 Bicep CurlsHammer Curls
Prime Mover MuscleLong & Short Head of the BicepsBrachialis & Brachioradialis
Synergist MuscleBrachialis & BrachioradialisLong & Short Head of the Biceps

In both cases, elbow flexion (bending at the elbow joint) is undertaken to curl the dumbbell up towards your chest while keeping your elbow in a fixed position.

Locking your elbow in place ensures proper form and effective isolation of the targeted muscle groups.  

If your primary goal is to develop bigger arms, then regular bicep curls would be better than hammer curls.  

As the hammer curl is going to work more of your brachioradialis muscle, this contributes to more definition and helps you to achieve more of a ‘3D’ look for your biceps.  

The hammer curl also hones in on your brachialis muscle.  

bigger biceps

While it may be a small muscle, as it’s positioned deep beneath the biceps brachii it can help to develop more of a biceps peak when focused on during exercise.  

A combination of hammer curls and bicep curls will allow for the best overall arm development with the bicep curl adding more muscle mass but the hammer curl helping to develop definition and a bigger biceps peak.  

Whatever your personal preference, it’s a good idea to add both variations to your training program to maximize the benefits.  

What Are Common Mistakes When Performing Bicep Curls

One of the most common mistakes when performing a bicep curl is to go too heavy and swing the weight up.  

However, that’s not the only mistake we’ve seen in the gym.  

Let’s look at some others below to help you keep your form in check.  

The best way to elicit the most muscle hypertrophy (growth) is to lower the dumbbells as slowly as you can.  

This is known as the eccentric phase of the movement.

During the eccentric phase, your muscle stretches under tension as it works to decelerate the exercise.  

When you concentrate on lowering the dumbbell slowly this can help to induce more damage to muscle fibers.  

While this may sound like a bad thing, it’s not.  

As your muscles work to repair themselves following on from this damage, they grow back stronger and bigger.  

However, it’s important to avoid overtraining.  

When you’ve performed exercises, you may notice muscle soreness set in one or two days after.  

This is called delayed onset muscle soreness and is a normal and expected part of strength training.  

Always make sure you allow for enough time for your muscles to repair and the soreness to dissipate before you train your biceps again.  

Keeping your elbow in one position when doing a bicep curl or hammer curl is important as this will help to properly isolate your biceps and encourage better form.  

It’s also going to help you control the movement which puts less stress on your elbow joint minimizing the chance of injury.  

By keeping your elbow locked into place, you can ensure that the target muscle group is doing most of the work.

This can lead to better muscle development and strength gains over time.

You’ll always see someone in the gym that’s trying to curl a weight that’s too heavy.  

They might be performing plenty of reps which will be activating your muscles.  

However, the form is probably going to be off as they have to use their legs for momentum to help them swing the weight up to their chest.  

All this will do is reduce tension on the biceps, where you want it, and place it on other muscle groups.  

Don’t be an ego lifter.  It’s much better to stick with lower weights, proper form and full range of motion.  

When many people perform a standard dumbbell bicep curl it’s common to see them starting with their arms in a semi-supinated position, usually referred to as a neutral grip.  

This means their palms are facing inwards.  But that’s not the best way of doing it.  

For increased bicep muscle activation, it’s better to start with an underhand grip which involves rotating your hands out, so the palms face away from you.  

It’s very common to see people perform a bicep curl without fully extending their arms.  

If you don’t train with a full range of motion this is going to lead to weakness within specific areas of your biceps.  

For full engagement of your biceps, make sure to lower the dumbbell all the way down so that your arm is fully extended. 

The same goes for raising the dumbbell to your chest.  

Don’t be fooled into thinking that you don’t have to go all the way to the top.  

While it’s true that there is less tension on your biceps at the top of the movement, you’re allowing for an increased rep range when you perform the eccentric phase.  

Don’t forget, this is when you’ll induce most muscle gains.  

Bicep Curl Variations

Some great bicep curl variations include exercises like the Zottman curl, cross body curl and the concentration curl all of which will work the front of your arm in different ways.  

If you’re looking for some bicep curl or hammer curl variations to work different parts of the bicep, why not consider adding some of these into your bicep workout routine.  

  • Preacher Curl – perfect if you want to eliminate any swinging of your arms as the preacher curl keeps them in a fixed position throughout. 
  • Reverse Curls – performed with an overhand grip on a barbell, this is a great option if you want to focus on increasing forearm strength. 
  • Concentration Curls – working each arm at a time, this will focus more on the long head of the biceps helping to create a biceps peak.  
  • Wide Grip Barbell Curls – Doing this with a wider than shoulder width grip will concentrate more on the short head of the biceps. 
  • Narrow Grip Barbell Curls – By positioning your hands at a shoulder-width distance (or narrower), you can target the outer portion of your biceps.
  • Zottman Curl – this is a combination of a regular bicep curl and a reverse curl where you would rotate your hands at the top of the movement working all the muscles of your bicep brachii. 
  • Cross-Body Hammer Curl – this is another alternative that will work the outer head (long head) of your biceps.  

All the variations above are a great way of working both heads of your biceps, but if you’d like a little more detail on the differences between the bicep long head and short head, why not head on over to our article; Bicep Long Head VS Short Head.

Wrapping Up

Now that you know the differences between hammer curls vs bicep curls you can make an informed decision as to which exercise you’d like to incorporate into your arm workouts.  

Better still, perform them both for maximum strength and muscle gains.  

Whether you chose one over the other, or both, always remember that consistency and proper form are key to seeing the results you desire.

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