Written by Garett Reid | NSCA, CSCS, CISSN, M.S.E.S.S
Fact checked by Kirsten Yovino, CPT Brookbush Institute
FACT CHECKED
Curls are for the girls…or guys or grandparents or whoever else you want to impress with a full set of chiseled arms. Arm curls are the essence of gym life. They’re the one exercise that everyone knows how to do and probably does too much of if we’re going to be honest (more about that below!). However, this simple little action of arm flexion has a plethora of exercises that you can choose from, making it a bit difficult to understand what you should do. We won’t go over every type of arm curl in this article, but we will go over two of the most popular; hammer curls vs bicep curls.
The hammer curl versus bicep curl - this article will give you all the information you need to choose which is right for you for any given goal or on any given day:
- What are arm curls?
- The anatomy and function of the arm flexors
- Hammer curl muscles worked & Proper form
- Bicep curl muscles worked & Proper form
- Hammer curl vs Bicep curl: What’s the difference?
- Programming tips for arm curls
What Are Arm Curls?
Flexion and extension are the two primary movements that occur at joints. When a joint is extended, it opens; and when it flexes, it closes. The term “arm curls'' can refer to any number of isolation exercises that consist of the arm flexing at the elbow joint.
Sitting, standing, palms up, palms down, with dumbbells, performing barbell curls, with weight plates - there are literally dozens and dozens of different ways to do arm curls, and they all have their own little uniqueness in the way they train the arms. That being said, their main focus is to train your arm flexors...
The Anatomy And Function Of The Elbow Flexors: The Biceps, Brachialis, Brachiosradialis:
While most think of the biceps when they think of arm flexors, there are actually three different arm flexors. Two of these muscles are located on the upper arm and one muscle is located on the forearm. Together, these three muscles work to flex the elbow as well as with supination and pronation of the arm:
- Biceps Brachii: The biceps brachii, more commonly known as the biceps, is perhaps the most popular muscle on the human body. Most people don’t know that it’s actually a biarticular muscle, meaning that it’s actually responsible for flexion of the elbow and stabilization. This is one of the reasons people’s elbows will pull forward when performing curls. The biceps are also responsible for the elbow’s supination. The supinated position is also where the biceps are most powerful as an elbow flexor. However, it loses significant power as the arm rotates inward.
- Brachialis: The brachialis sits on the upper arm and is unique in that it only has one job: to flex the elbow. In fact, the brachialis is actually the primary flexor of the elbow, generating 50-60% of the force. The brachialis will receive more activation as the arm rotates from supinated to pronated. While the brachialis sits under the biceps, they still play a major role in the overall size of your arm.
- Brachioradialis: The brachioradialis is the elbow flexor that sits on the forearm rather than the upper arm. It sits on the lateral side of the upper forearm and acts as a flexor, supinator, and pronator. Similar to the brachialis, the brachioradialis will receive more activation in a neutral or pronated position. Forearm strength is crucial to curling, so make sure you're including dumbbell forearm exercises in your weight lifting routine!
What Are Hammer Curls (& Muscles Worked)?
Hammer curls are a popular arm exercise consisting of performing arm curls with a neutral grip. You can perform these with a range of different implements, but dumbbells or a rope attachment are most common.
Because the arm is in a neutral position, there is significantly more muscle activation in the brachialis and brachioradialis. While it would seem that being totally pronated, as in a reverse curl, would produce the highest activation for the brachialis, your wrist is, in fact, compromised, meaning that you are unable to lift as heavy of a load. This means that the hammer curl is perhaps the best exercise to train these other arm flexors because the wrist is strong. This allows you to lift a hefty load meaning more growth.
Often, having a solid exercise in your routine for your brachialis can mean the difference between having nice arms and impressive arms. As mentioned, the brachialis is the primary flexor but is often overlooked as the biceps sit on top and are what can be seen. However, even though you can’t see the brachialis, training them for greater hypertrophy will still create a noticeably fuller arm. Therefore, you definitely don’t want to forget to train the brachialis if you’re looking to grow your arms.
Another benefit of hammer curls is they are less stressful on the elbow joint. Curls done in a supinated position can place significantly greater tension on the elbow’s tendons. Being able to perform an arm curl in a neutral position greatly relieves any built-up pressure, making this an excellent choice for anyone with issues in their elbows.
Taken as a whole, hammer curls are probably the most accessible arm curl variation to perform. Further, they hit the other arm flexors that are often forgotten about, meaning you are able to fully train your arm flexors.
How To Perform Hammer Curls:
Hammer curls can be performed with either dumbbells or the rope extension on a cable pulley system, in fact, we prefer the cable pulley for training the arms due to the constant angle of resistance and for how easy it is to swap exercises. In fact, you can perform a hammer curl with any object that allows a neutral position, such as holding onto a plate. Regardless of what you use, the form will be relatively the same.
- Stand with a comfortable stance and knees slightly bent.
- Hold onto your implement and hold with a neutral grip. Your palms should be facing towards each other with the weight of the implement pulling down.
- Tuck your elbows so that they are flush against your body. Your arms should be as close to shoulder-width apart as possible. In other words, your arms should go straight out.
- Flex your arms while maintaining a neutral grip for the entire range of motion.
- Bring the implement as far up as you’re able to.
- Let the implementation down in a slow and controlled manner.
- Minimize any amount of body movement that may occur.
What Are Bicep Curls (& Muscles Worked)?
Bicep curls could actually mean many things depending on who says it, but generally speaking, they refer to dumbbell bicep curls, which we are going to discuss. Therefore, bicep curls are a type of arm flexion exercise which involves performing a curl using dumbbells and a supinated grip (palms up). Still, you can perform these while sitting or standing and can perform them in unison or using an alternating pattern.
These are often one of the very first exercises that people will perform when they go to the gym. This is due to them being extremely easy to use and practical at the same time. These are great exercises to hit the biceps as the hands are in a supinated position, which is when the biceps contribute the most to flexion. Therefore, dumbbell biceps curls are a great choice if you’re trying to hit the biceps.
That being said, as the wrist is in a more compromising position when compared to a neutral grip, you will likely use a lighter load for more reps. This is because it’s much more difficult to maintain the correct form when using heavier loads. Further, bicep curls are generally more difficult to perform as the body’s joints are in an odd place biomechanically. So even though these are more popular than hammer curls, they are actually more challenging to perform, especially with high loads.
How To Perform Bicep Curls:
While everyone has done bicep curls, many will perform them incorrectly with poor form. Here is the proper way to perform bicep curls with the most common mistakes.
- Stand with a neutral and comfortable stance. Feet should be about shoulder-width apart.
- Grab a pair of dumbbells (same size) and hold with a supinated grip.
- Tuck the elbows so that they are near the waist. They should remain in the same position during the entire range of motion.
- Maintaining a supinated grip, flex the arm to bring the dumbbells as far up as possible.
- Do not sway when you curl the dumbbell up. One of the most common mistakes with arm curls is the trainee will exhibit excessive swaying to get the weight up. While a minimal amount could be allowed for intermediate lifters using a lot of weight, excessive amounts are never OK.
- Allow the dumbbells to lower in a slow and controlled manner.
- The body should be as still as possible during the entire exercise and the elbows should remain stationary.
The only time excessive body movement is allowed when doing any type of curl is when you are performing negatives which is when you only concentrate on the eccentric contraction. With these, you will use some body-motion to “cheat” the weight up. You then slowly let the weight down in a controlled, slow manner. These are awesome for massive muscle growth as studies have shown the eccentric portion of a movement has been found to be more responsible for muscle damage and thereby can elicit greater growth gains.
So unless you’re performing negatives, keep your body still!
Hammer Curls Vs Arms Curls: Which One Is Better?
Choosing a better curl variation is difficult due to the fact that different people have different goals. This means that what is best for you may not be best for your friend. Therefore, we will instead write out the situations in which one may be best for you.
Hammer Curls:
- If you want to use place a heavy load on the arm flexors.
- If you are having issues with discomfort in the elbow.
- If you want to train the other arm flexors other than the biceps.
- Easier form.
Bicep Curls:
- If you want to train the biceps brachii specifically.
- And, that’s about it.
So as we can see, the only real advantage that bicep curls have over hammer curls is that they will train the biceps more so than hammer curls. Therefore, the bicep curl is the best if you want to train the biceps. Other than that, the hammer curls offer many more advantages. Further, being that there are actually plenty of other exercises to train your biceps, and less to train your brachialis, we would have to say that the hammer curl is a much more beneficial exercise than the bicep curl.
How To Program Hammer Curls And Bicep Curls:
Depending on your training split, here are several different training days where training either curl would be appropriate. Since the biceps are “pulling” muscles, you could train these during your pulling sessions. If your training split is divided by body part, training the biceps could be put on the same day as training your back. The last day would be if you have an arm day.
Arm curls are almost always trained for hypertrophy. This means they are performed with moderate weight and moderate reps. You should aim to use a weight that allows you to perform 8-12 reps, while using high reps (12+) could even be appropriate to do once in a while. The more important variable to consider is you want to bring the muscles close to failure. This ensures that you’re performing maximum volume and while also using enough volume to activate all the muscle fibers.
When training the arms, you should try to train them twice a week using 10-15 total working sets, 20 at the absolute max. This means on average, you should perform some 4-5 exercises with 3 sets a piece per muscle group. However, we also need to consider that you perform arm flexion with literally ever pulling exercise. Bent over rows, pull-ups, dumbbell rows; they all use arm flexion. Therefore, the number of actual arm flexion specific exercises you should perform could even be less than that.
Still, performing isolation exercises may not even be suitable for you. Check out this article for more information but the short story is beginners don’t need the specific stimulus and multiple studies have shown that adding isolation work provides no benefits in terms of strength and hypertrophy.
Several training methods work well with arm curls. The first is to establish a solid mind-muscle connection. Establishing a mind-muscle connection simply means that you will actively think about squeezing the muscle as you perform the exercise. We actually wrote an extensive article on this entire subject matter, so check it out here!
Arm curls are also popular to use for supersets. This is when you will pair exercises to train agonist and antagonist muscle pairs. This would consist of performing an arm curl and then an arm extension for the arm. For example, you could perform a hammer curl with the rope and then immediately perform arm extensions with the rope.
Lastly, you could also perform compound sets quite easily. A compound set is when you perform two exercises that use similar biomechanics as if you are “compounding” the stress on the muscle. In fact, you could even perform dumbbell hammer curls with dumbbell bicep curls. Now you don’t even need to think about what you should do! When performing compound sets, you will usually train the more challenging exercises first so that you are able to complete the more straightforward exercise when your muscles are fatigued. In this case, perform the dumbbell bicep curls first and move directly into hammer curls.
Hammer Curls Vs Bicep Curls: You Can’t Go Wrong
Both of these arm curls, the hammer curl, and bicep curl, are very effective at what they do. Therefore, you really can’t go wrong either. You will need to look at your own program and goals and determine what exercise is best suited for you to reach your goals. And again, if there’s any doubt, just do both! The main takeaway from this article should be that two other arm flexors should be trained but are often ignored. Therefore, be sure to hit those with the hammer curl, and you’ll start seeing some much fuller development in your arms…you’ll see some serious sleeve busting arms.
Related Content:
- Long Head Biceps Exercises
- Short Head Biceps Exercises
- How To Do Concentration Curls Correctly
- Average Arm Size: Building 16-19 Inch Arms
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Garett Reid
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