Dumbbell Curls: Muscles Worked & Techniques To Supercharge Arm Size

When it comes to developing the biceps and other muscles of the upper body, dumbbell curls are one of the most effective.

When performed correctly, this excellent exercise can also help to improve your grip strength and forearm muscle endurance. It’s easy to build bigger arms with just a pair of dumbbells.

The dumbbell curl is a free weights exercise that will work the brachialis and brachioradialis.

seated bicep curl

Both muscles are responsible for elbow flexion with the brachialis being located to the front of the upper arm, whilst the brachioradialis is located to the forearm.

Different variations of the curl exercise will isolate a variety of other muscles including the shoulders, biceps and triceps.

Typically, people who undertake dumbbell curl exercises will have the aim of building bigger biceps. The dumbbell curl is an isolation exercise that will give you the best results when it comes to building strong biceps.

When compared to doing curls with a straight barbell or ez bar, using dumbbells will allow you to work on any muscle imbalances that you may have to your arms, this is because you will be working each arm independently allowing for greater muscle contraction.

In this article, we will take a look at which muscles are worked by dumbbell curls and how you can use them to get the most out of your workout.

Also, we will look at the different variations of dumbbell bicep curls, the proper form for undertaking the exercise and some common mistakes.

What Are The Muscles Of The Arm Called?

The muscles that make up the arms are known as secondary muscles, meaning that they are supportive to the primary muscles such as the chest. Let’s take a look at the different muscles that make up the arm.

The Biceps Brachii

The biceps brachii, more commonly referred to as the biceps, is a two-headed muscle that sits between your shoulder and forearm and starts at the coracoid scapula and ends at the radial tuberosity.

These muscle groups combined will help you to bend at the elbow joint and twist your forearm.

It is the most commonly known muscle within the arm and is typically characterised by it’s peak shape, most often identified in athletes with well developed muscles such as bodybuilders.

The Brachialis

The brachialis muscles are a smaller muscle group located at the anterior part of the upper arm. It is flat in shape and sits between the triceps and the biceps aiding with elbow flexion.

The brachialis is a powerful muscle that can help to increase the strength of your dumbbell curls, it sits deep within the arms and by focussing on this muscle will help to improve that bicep ‘peak’.

The Brachioradialis

The brachioradialis muscles are located at the lateral side of the forearm and are classed as a posterior forearm muscles that cross over the elbow joint.

They work in conjunction with the brachialis and biceps brachii in order to flex the elbow.

It is a superficial muscle, which means it sits close to the surface of the skin. Specific exercises that can target this muscle include movements such as the zottman curl and hammer curls.

Which Part Of The Biceps Are Worked With Dumbbell Curls?

Dumbbell curls work both the short head and long head of the bicep muscle, with a greater emphasis being placed on the the long head of the biceps.

This is because when you curl a dumbbell, your palm is facing up (supinated). A supinated grip puts your bicep at a mechanical advantage, meaning it can better contract and produce force.

How Many Dumbbell Curl Reps Should I Do?

When it comes to rep range, how many curls you perform very much depends upon your fitness goals.

For example, if you’re trying to build big biceps, you’ll need to do less reps with heavier loads.

On the other hand, if your aim is to simply tone up your arms and gain some lean muscle, you can do more reps with light weights.

Here are some general guidelines for how many reps of dumbbell curls you should do:

  • For building muscle mass: 4-6 sets of 6-12 reps
  • For strengthening muscles: 3-4 sets of 8-10 reps
  • For toning muscles: 2-3 sets of 12-15 reps

When it comes to the frequency, it’s not uncommon for some people to train the biceps everyday.

However, we wouldn’t recommend training them to your max each day as this could lead to overtraining which is counterproductive to muscle growth.

Remember, these are just guidelines. The best way to determine your training volume is to experiment and see what works best for you.

Variations Of The Dumbbell Curl

There are a few bicep curl variations that you can perform if you want to target different muscles groups. These include the following:

Standing Dumbbell Curl

The standard dumbbell curl is performed with both palms facing forward.

The starting point of your hands is an important point to remember as often times people start with their hands in a semi-supinated position, sometimes known as a neutral grip (palms facing in).

By twisting the arms to a supinated position as your curl them, means you won’t be working the biceps as effectively.

Alternating Dumbbell Curl

Another variation is the alternating dumbbell curl, also known as the single arm bicep curl.

It’s performed by curling one weight up while keeping the other at your side. This technique allows for a better mind-muscle connection and full range of motion to really tear up those muscle fibres.

Hammer Curl

The hammer curl is another great variation that primarily targets the brachioradialis, located on the inside of your upper arm.

To perform this exercise, simply maintain a neutral grip (palms facing inwards) throughout the entire movement.

standing hammer curl both arms

There is less focus on the biceps brachii during this variation so for overall arm development this is a good one to alternative with a regular dumbbell curl.

Concentration Curl

Concentration curl is an isolating exercise that really zeroes in on those biceps.

This is performed whilst seated with one weight in each hand. You would lean forward slightly so that you can rest the elbow of the working arm on your knee with your palm facing up towards the ceiling.

concentration curl seated on bench

From this position, you would curl the dumbbell up and towards you. It’s quite similar to if you were curling on a preacher curl bench but without as much stability.

How To Do Bicep Curls With Dumbbells

Bicep curls are one of the most popular exercises for strengthening and toning the arms. 

You can undertake the movement with dumbbells, barbells, and even resistance bands.

Below we have listed the steps for executing a dumbbell curl exercise whilst standing.

  1. Stand with your feet shoulder-width apart with a dumbbell in each hand.
  2. Keep your grip supinated so that your palms are facing away from you throughout the entire movement.
  3. Make sure your elbows sit just in front of your hips and keep them there throughout.
  4. Retract your scapula (slightly pull your shoulder blades backwards), this will help you to maintain strict form.
  5. Brace your core to provide stability.
  6. Slowly curl your arms until your hands are at shoulder height.
  7. Hold for 2 seconds and then, with control, begin to lower back down to the starting position.

If you are a beginner or have a weak core, then you could consider performing a bicep curl whilst seated. The execution of the movement will remain the same whilst removing use of the stabiliser muscles.

What Is The Most Effective Dumbbell Curl?

The dumbbell curl is an effective exercise for developing the biceps brachii muscle and can be performed whilst seated, standing, or in the supine position.

The seated and standing versions of the dumbbell curl are recommended to beginners as they provide support to the back through stabilization by either a chair or the body’s upright posture.


The supine version of this exercise requires greater stability at the shoulder joint, so this version is most appropriate for those with more experience.

One of the concerns that many people have is about the most effective ones that can yield positive results for the targeted muscles. In that case, the most effective ones include the following:

Standing Dumbbell Curl

Standing dumbbell curl is one of the most effective exercises for building upper-body strength whilst also working many other muscles. This exercise targets the biceps muscles, which are responsible for bending the elbow.

As well as targeting multiple muscles, the standing position also allows for a greater range of motion.

Seated Dumbbell Curl

The seated dumbbell curl is a better variation when compared to standing as you will better isolate the biceps .

This exercise is effective because it allows you to keep good form while working your biceps. Additionally, the seated position helps to stabilize your body so that you can focus on contracting your arm muscles.

The Concentration Curl

The reason the concentration curl is so effective is because it allows you to really focus on mind muscle connection when contracting the biceps.

When you undertake a regular bicep curl, your body can engage other muscles to assist with the movement. But when performing a concentration curl, you will completely isolate the biceps.

An important point to note, be sure not to use your elbow as leverage during the movement. If the elbow is positioned incorrectly, then you may notice your deltoid muscle coming into play taking emphasis away from the target muscles.

Incline Dumbbell Curl

This variation of a curl exercise is perhaps the most challenging as it requires you to execute a standard curl whilst in an incline position. To perform this one, lie back on an adjustable bench with the back pad in an incline position.

Hold a dumbbell in each hand and have them down by your sides to begin with.

Resist the urge to simply swing the dumbbells up to your shoulders and instead slowly curl the dumbbells up until they reach your arm pits whilst keeping your elbows locked into position.

You’ll notice that you have a longer range of motion curling this way so proper form is important to reduce the risk of injury.

Will Curls Make My Arms Bigger?

Dumbbell curls alone can stimulate muscle growth to the biceps brachii and brachialis.

However, for overall muscle development and strength improvements to the entire arm, you’ll want to incorporate other exercises. These may include drag curls, cable curls and barbell rows.

By developing a multi exercise programme for your arms and upper body will give the best results for muscle gains.

Dumbbell Curl Mistakes

Whilst any variation of a bicep curl exercise is not overly taxing, that’s not to say people don’t make mistakes when performing the exercise.

Below, we’ve listed some common mistakes that you’ll want to avoid to get the most out of the exercise.

Not Using Full Range Of Motion

It has been said that by lowering your arm all the way down or, conversely, curling it all the way up can take tension away from the exercise.

This is not true, if you don’t train with a full range of motion you’re simply not maximising your strength gains.

Improper Start Position

Don’t be tempted to start with your palms facing inwards. After you’ve taken a dumbbell in each hand, make sure the initial position of your hands is supinated, palms facing away from you.

This will give you that perfect form and allow for full bicep activation.

Going Too Heavy

If you find you are having to throw the dumbbells up rather than executing the exercise with a slow and controlled movement, then it’s likely you’re trying to lift too much weight. To maintain the best form drop to a lighter weight.

Dumbbell Curls Benefits

If you’re looking for a way to improve your biceps, dumbbell curls are a great option. This exercise is simple to perform and can be done with minimal equipment. Some of its benefits are:

  • Dumbbell curls are an effective exercise for building muscle mass in the biceps. They can be done with heavy weights for low reps to build strength, or with lighter weights for high reps to build endurance.
  • The exercise also improves grip strength and forearm development. Additionally, because dumbbells are easier to control than barbells, they can help you focus on isolating the bicep muscles.
  • Properly executed curls can help to improve elbow flexion.
  • By improving the overall strength to your arms can carry over to daily activities that involve lifting and carrying.


For a targeted approach to building mass to the arms, you’ll certainly want to consider incorporating dumbbell bicep curls to your upper body workout.

Not only will working the arm muscles lead to an improved body aesthetic, an increase in lean muscle will help you to burn more calories and carry over to activities such as swimming and cycling.

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