Hammer Curls Muscles Worked Plus 3 Benefits For Full Biceps

Hammer Curls Muscles Worked

When it comes to building bigger biceps, it’s important to focus on isolation exercises that can help to target this small muscle group.

Comprising of two distinct muscles, the biceps brachii are responsible for bending and raising the elbow, bringing the arm to the thorax, and placing the forearm into supination (underhand grip).

Recommended Reading – Biceps vs Triceps : Critical Differences You Need To Know

The best way of activating the biceps is to incorporate curl exercises into your workout routine.

There are a number of bicep curl variations, and these can help to target both the long head of the biceps and the short head of the biceps.


These include dumbbell curls, the traditional curl and hammer curls.

In this article we’ll look at the hammer curl muscles worked and how the exercise can help you build bigger arms

What Is A Hammer Curl?

A hammer curl is an upper body resistance exercise that activates the biceps brachii and muscles of the forearm.

When compared to a standard dumbbell curl, the hammer curl utilizes a neutral grip (palms facing one another) as opposed to a supinated grip (underhand with palms facing up).

There are a couple of key differences when it comes to hammer curls vs bicep curls and you can read more about that here.

How To Do Hammer Curls

Below we provide step-by-step instructions on how to execute a dumbbell hammer curl exercise

When you’re starting, use a weight that you can comfortably control and lift for two or three sets of around eight to 12 reps.

  1. Taking hold of each weight, stand with knees slightly bent with feet around shoulder width apart.
  2. Keep your core engaged and maintain a neutral spine.
  3. Start by holding the dumbbells down by your sides with your palms facing inwards and wrists straight.
  4. To keep the biceps engaged throughout the movement keep the elbows just in front of your hips. This will be your starting position.
  5. Slowly raise the dumbbells up towards your chest to just beyond 90 degrees.
  6. Hold briefly at the top of the movement before slowly lowering them back down to the starting position

Hammer Curls Muscles Worked During The Exercise?

The hammer curl is a compound exercise that will target the long head of the biceps brachii and the brachialis muscle, both muscles are located at the front of the upper arm.

It will also activate the brachioradialis, a lateral forearm muscle. To a lesser degree it will also engage the extensor carpi radialis brevis and longus.


Long Head Of The Biceps

Collectively, both heads of the biceps cross over at the elbow joint and shoulder joint with. As it mobilizes more than one joint, the action is quite complex.

The primary function of the long head of the bicep brachii is that of elbow flexion and forearm supination.

Interestingly, it only accounts for around 10% of muscle strength


The brachialis muscle crosses just one joint, that being the elbow. The simply mobilizes only this joint and is responsible for forearm flexion only.

This muscle is stronger than the biceps brachii.


The brachioradialis is located at the lateral part of the forearm and is responsible for flexing the forearm at the elbow joint.

It also aids with supination and pronation and helps to stabilise the elbow joint during flexion and extension.

What Are The Benefits Of Hammer Curls

The hammer curl is an effective exercise for working multiple muscles and a worthwhile addition to your training program, especially when combining it with other biceps curl variations.

Below are some hammer curls benefits when you incorporate this exercises into your arm day training.

Better Grip Strength

By holding the dumbbell in a neutral-grip position, you’ll strengthen more elbow flexor muscles including the flexor carpi radialis and extensor carpi ulnaris tendons when compared to a normal dumbbell curl.

The hammer curl is an effective way of working the brachioradialis. In doing so, you’ll improve both wrist stability and grip strength.

Grip strength is not only important for strength and mobility it can offer excellent carry over to big compound exercises, such as the deadlift.

Wrist Stability

When compared to traditional bicep curls, the hammer curl keeps your elbow and wrist in a neutral position.

This allows you to use more weight without putting unnecessary stress on your wrists while also making sure that you develop strong forearms and grip strength at the same time.

Good wrist stability will also help with overall stability to the arms. This is important for a range of exercises including the bench press and overhead shoulder press.

If you’d like to improve your wrist strength why not try out some exercise wrist strengthening exercises.

Increased Bicep Size

By working the long head you’ll not only help to build strong biceps, but you’ll also focus on adding mass to the biceps peak.

Sometimes, referred to as a vanity muscle it can help with the overall aesthetic of the bicep muscles.

Recommended Reading – Understand The Role Of The Short Head Of The Bicep

Hammer Curl Variations

You can make modifications to this exercise to better fit your fitness level and goals. Here are a few suggestions:

Incline Hammer Curl

You can perform incline hammer curls on an incline bench.

seated incline hammer bicep curl
  1. Take a seat on the bench with a dumbbell in each hand.
  2. Lie back on the back pad and keep the dumbbells down by your sides.
  3. Flex at the elbow and bring the dumbbells up towards your chest, try and keep the upper arm stationary throughout the exercise.

The hammer curl variation will increase the range of motion thereby improving muscle activation.

Alternating Hammer Curl

If you find it difficult to maintain the correct form with a standard hammer curl exercise, then consider alternating hammer curls.


Alternating hammer curls are performed the exact same way as a regular hammer curl but lifting one arm at a time.

The benefit of this is that it can help with stability and improve the mind-muscle connection.

Cable Rope Hammer Curl

You’ll need access to a rope attachment and a pulley machine to perform a cable hammer curl.

tricep rope bicep hammer curl
  1. Position the rope attachment at the bottom of the pulley machine and take hold of it with both hands.
  2. Stand upright and maintain a strong core throughout.
  3. Start by holding the attachment down with your hands close together and palms facing in wards.
  4. Bend at the elbows bringing the rope up and towards your chest whilst maintaining the position of your upper body.

The benefit of this variation is that is keeps tension on the biceps throughout.

Preacher Hammer Curl

You’ll need to use a preacher bench to perform a preacher hammer curl.

Curling on a preacher bench is a great way of isolating the upper arm whilst providing stability helping to reduce the risk of injury.

This allows you to lift more weight and focus on mind muscle connection.

  1. Place the armrest at a height where your armpits can comfortably rest.
  2. Position your elbows against the pads and then extend them.
  3. Make sure your palms are facing inwards whilst holding the dumbbells.
  4. Slowly curl the weight up towards you
  5. Hold at the top before slowly lowering back down.

Common Mistakes To Avoid For Safe Hammer Curls

Maintaining proper form is crucial for safe and effective.

Below we list some common mistakes you should try and avoid when perform the hammer curl exercise.

Gripping The Dumbbells In The Wrong Place

The hammer curl exercise is all about building muscle mass and whilst you will, by default, improve grip strength you don’t want this to be the overriding result.

By placing your hands to the top of the dumbbell handles will allow the weight to rest on your hands therefore reducing the need to hold the dumbbells with a vice like grip.

This one small change could mean you can curl more weight and improve your form.

Curling Too Quickly

Don’t rush through this exercise, especially during the lowering phase (the negative portion).

Your movements need to be deliberate and controlled at all times. This is not only better for muscle hypertrophy, it will also limit the chance of injuring your muscles and joints.

A slower pace allows you to control the movements and focus on form, which is important for engaging the muscles for a long period.

Swaying With Momentum

If you have to throw the dumbbells up or use the legs as momentum you could inadvertently be placing stress on your elbow and wrist joints.

Not only will this result in other, stronger muscles taking over, you could injure yourself.

The likely cause of this is that you may be lifting a heavier weight than the target muscles can cope with.

Remember, this is a movement that targets small muscles groups so going too heavy is unnecessary.

seated alternate bicep hammer curl exercise

If you want to perform a hammer curl but use a heavier weight, a good option is to perform it whilst seated.

This reduces the need for core stability potentially allowing you to curl a heavier dumbbell.


By incorporating hammer curls into your upper body workout, you can engage your brachialis and brachioradialis, increasing grip, strength, and muscle mass.

Perform this exercise often and utilise some of the suggested variations to reap the benefits of this great exercise.

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