The Best Hammer Curl Muscles Worked Guide. Find out which muscles the exercise works and why they are so important. The Complete Guide to Hammer Curls and How They Work.
This is a common exercise that most people don’t know the name of.
Hammer curls are important because they work out the biceps and brachialis muscles. They also work out the brachioradialis muscle, which is located on the outside of your forearm.
Introduction: What is a Hammer Curl?
A hammer curl is a weight-lifting exercise that primarily works the biceps and brachioradialis muscles.
The movement begins with an individual holding a dumbbell in each hand, palms facing inward. The hands are then brought up to the front of the body with elbows bent at 90 degrees, then back down to the starting position.
It is an alternative to the barbell curl for those looking for a less stressful form of exercise. This movement begins with an individual holding a dumbbell in each hand, palms facing inward.
Anatomy Of Your Arm Muscles

The muscles in the arm, or biceps, are responsible for moving the forearm and hand.
The biceps are made up of two different heads, which have three functions. The first function is to flex the elbow joint when the arm is bent at a right angle.
Secondly, they help to extend the elbow joint when the arm is straightened. Lastly, they help to rotate and adduct (bring towards oneself) the forearm when it is pronated (palm facing down).
The muscles worked in this exercise are called “Hammer Curl” because they work like a hammer hitting a nail into wood. The forearm rotates as it pulls back with each repetition so that you can feel your muscles working on both sides of your arms at once.
Biceps Brachii
The two-headed biceps or biceps brachii muscle is the main muscle in your upper arm. The word Biceps means “two”, hence the two muscles which make it up; Long Head, and Short Head.
The biceps brachii is quite a sizable muscle and is located on the front of the upper arms, between the shoulder and the elbow.
The muscle’s two heads emerge from the scapula and combine to create a single belly that attaches to the upper forearm.
The biceps muscle spans the elbow and shoulder joints, although its major use is to flex and supinate the forearm at the elbow. When executing twisting actions, such as opening a jam jar, both of these muscles are used.
Brachialis
The muscle in the upper arm that flexes the elbow is the brachialis (brachialis anticus), also referred to as the Teichmann muscle.
It forms a portion of the cubital fossa’s floor and is located deeper than the biceps brachii (elbow pit). The brachialis generates around 50% more power than the biceps as the main muscle responsible for bending the elbow.
Brachioradialis
A forearm muscle called the brachioradialis bends the forearm near the elbow. Depending on how the forearm is positioned, it can potentially pronate or supinate. The brachioradialis tendon connects it to the lateral supracondylar ridge of the humerus and to the distal styloid process of the radius.

Hammer Curl Muscles Worked
Bicep curls or hammer curls as they are commonly known concentrate on elbow flexion, or rather, elbow bending action of the body. Hammer Curls isolate and target all of the following muscles which are positioned on the front side of your upper arms.
- Biceps Brachii Muscles (Long Head – caput longum) & (Short Head – caput breve)
- Brachialis Muscle
- Brachioradialis muscle
Hammer Curl Forearm Muscles Worked

Hammer curls are one of the best exercises for strengthening your biceps. They also work on your forearms, which can be a problem area for many people.
Hammer curls target more of the long head of the biceps and are more effective in strengthening the forearm, wrist, and grip.
Barbell Curl vs Hammer Curl
The modest bicep curl is usually the first exercise that springs to mind when you think about arm workouts.
Every gym-training goer’s program must include the traditional arm curl, and for good reason. It’s a quick and efficient approach to strengthening your biceps while also training your shoulders and back.
But the hammer curl could be your best option if you’re looking to bulk up your arms more quickly. The hammer curl, a well-liked bicep curl variation, will leave you hurting (and proud) the next day.
Below is a comparison table that details the pros and cons of bicep curls vs hammer curls and explains which exercise you should concentrate on for the best results.
Hammer Curl Muscles Worked Comparison
Arm Exercise | Pros | Cons |
Hammer Curl | Hammer curls stimulate more muscular growth since they engage several different muscle groups. The forearm and thickness development benefits of this straightforward variation are superb. Hammer curls can help you increase the size of your arms and strengthen your grip if they are done properly. | The following are some hammer curl disadvantages: The biceps brachii is placed at a mechanical disadvantage during a hammer curl because the wrist is not fully facing up. Alternatively, since the biceps brachii cannot exert their full power, hammer curls may not cause as much biceps growth. |
Barbell Curl | Bodybuilders love bicep curls since they’re a superb isolation workout. A specific isolated exercise that directly targets the biceps brachii is the bicep curl. The short head can be worked on with a supinated (underhand) grip, whereas the long head may be worked on with a semi-supinated grip. | Only works the Biceps Brachii. The straight barbell’s immovable posture causes pressure and tension on the wrist flexors. Exercise combination is constrained by the grip. During the lift, one arm may assume control and lead to an unbalanced arm (one side stronger than the other) |
You can increase your muscular growth by performing bicep curls and hammer curls simultaneously. Or Alternatively use an exercise that involves using every muscle together such as the “EZ Barbell Curl”.
“EZ Bar” Alternative to Hammer Curls

The EZ bar bicep curl is a weight-training exercise that targets the biceps. It is performed by grasping an “e-z” or “straight” bar with both hands, and then bringing it up to chest level while contracting the biceps.
The EZ Olympic Curl Bar is a multi-purpose angled specialty barbell made to assist relieve elbow and wrist tension while working your biceps and triceps.
The bar’s slight “W Shape” form provides you with a variety of grip possibilities, making it a useful barbell.
The EZ Barbell Curl Exercise is a hybrid bicep workout, which unlike hammer curls or barbell curls actually works all of your arm muscles together for maximum stimulation and growth.
Types of Hammer Curl Exercises
The hammer curl is traditionally performed from a standing position with a dumbbell in each hand. There are several variations of the exercise, and all come with different benefits.
Twisted Alternating Hammer Curls

In order to strike the biceps from a different angle during this variant of the hammer curl, you lift one dumbbell at a time and rotate your wrists at the peak of the exercise.
Starting with your wrists facing each other, turn them to face you at the peak of the curl to recreate the standard biceps curl posture.
Seated Hammer Curls

Sit on the end of an adjustable bench with your back against it, and position the bench at a ninety-degree angle. With your hands facing each other, hold the dumbbells and let them dangle at your sides.
Curl the weights up to your shoulders and then gently drop them while keeping your back against the bench and your elbows tucked down.
Putting your back against the bench assures that your biceps are carrying the weight and momentum doesn’t carry the load of the weight.
Rope Cable Curls

When using a cable machine, you will experience constant resistance throughout the exercise. The resistance should be the same at the top and bottom of the action.
A cable machine’s low pulley should have a rope handle attached to it. Your core should remain tight throughout the exercise as you curl it up with your hands facing one another.
Conclusion: Start Doing Hammer Curl Exercises Today!
As you will now know, you should NOT only perform straight barbell curls and need to exercise with hammer curls for maximum upper arm muscle growth.
I’d highly recommend you also incorporate EZ barbell curls into your arm workouts to ensure you stimulate all muscles together and reduce stress on your wrists to minimize injury.
Make sure to eat enough protein and take the right supplements to ensure your recovery is faster.