The bicep curl is one of the most common and straightforward exercises that you can do with dumbbells, barbells, or by the use of various cable machines. It’s one of the essential exercises for building titanic arms, it’s part of almost any workout for the upper body. It can be done with various grips, tempos, and loads. There are also many variations for it, which we’re going to cover here as well.
But even though the bicep curl is a pretty well-known exercise, many don’t execute it correctly or use the wrong weights. Therefore, the first aspect that we’re going to cover here is the correct execution of this exercise.
What Is The Correct Form For The Bicep Curl?
First of all, you can do the standard bicep curl while standing or seated. It’s a matter of preference. Of course, while seated, you can benefit from the extra back support. But the motion is pretty much the same and uses the same muscles. Also, you can use alternate motions (one arm at a time), or lift and lower the dumbbells simultaneously.
The standard recipe for the classic standing bicep curl is this:
Step 1. Start by standing up, keeping back straight, feet apart at their hip width, knees slightly bent (not locked), and abdominal muscles engaged. Hold a dumbbell in each hand, with arms relaxed alongside your body with palms facing forward. Inhale before beginning the lift.
Step 2. Start lifting each weight (or both simultaneously) while keeping the shoulders and upper arms stable. Bend the elbow joint(s) steadily without lifting the elbow(s). Keep the elbow(s) close to the body, and bring the weights as close as possible to the shoulders. Exhale as you execute the lift.
Step 3. Lower the weights to their starting point. Control the lowering motion as much as possible; don’t let the weights drop. Inhale as you lower the weights.
Muscles Involved During The Bicep Curl
The bicep curl exercise is an isolation movement. It involves only the elbow joint and focuses clearly on the flexion of the bicep. Differently put, the bicep is the agonist of the movement or the prime mover.
The antagonist muscle (the one opposed to the agonist) of the bicep curl is the tricep. As you perform the lift, the bicep flexes while the tricep relaxes. Conversely, as you lower the weight and the bicep relaxes the tricep contracts. So, even though the curl focuses on the bicep, it puts the tricep to work quite a bit.
The synergist muscles for the standard bicep curl (or the ones that stabilize the motion and help the agonist execute the motion correctly), are the brachioradialis and brachialis. These muscles are high at work especially when you lower the weights, as you need to stabilize the motion in order to execute the lowering of the weight correctly.
Finally, the fixator muscles (the ones that stabilize the origin of the agonist and that help more or less with the movement) are the ones in the shoulder joint and the hip. The serratus anterior muscle also has partial involvement.
Bicep Curls: Weight Selection And Exercise Frequency Advice
As a general idea, for bicep curls it’s always best to work with weights that allow you to perform 10 quality repetitions, keeping a perfect form for each repetition. If by the end of your curl set, you feel like you can’t maintain the form, you can’t control the negative motion properly and pull the elbows up slightly for the lifts, that’s a sign that you should reduce the weight. It’s always best to still have at least 1-2 curls left in the bank at the end of the set.
If you’re a beginner, there is no shame to start with weights as low as 5 – 10 lbs. Also, if building big guns is one of your main fitness goals, as a beginner it’s best to start with 2-3 workouts per week involving curls, summing up a total of 80 – 120 weekly reps (or 8 – 12 weekly sets).
For intermediates (i. e. people who have been training for at least a year) the numbers should be higher when it comes to sets. The optimal set range for intermediates should be around 10 to 14 weekly, summing 100 to 140 reps weekly.
But regardless of your fitness level, it’s always best to avoid using extra heavy weights. Lifting heavy promotes cheating. You’ve probably seen people in the gym doing curls with extra-heavy dumbbells but without keeping their body steady, and using a lot of momentum. That’s far from being the correct form, and the results are never as great as they should be.
Also, lifting heavy prevents you from developing a correct mind-muscle connection. In other words, you can’t focus properly on the bicep contraction and the overall muscle activation. Conversely, by using lighter weights, you can be sure that you perform the movement correctly and focus on the complete contraction of the bicep, and even on the work of the synergist muscles.
One last aspect to mention here regards the size of the dumbbells (not the weight). Especially if you’re using large dumbbells like the adjustable Bowflex SelectTech 1090 or the PowerBlock Elite, for example, you may not be able to keep your arms correctly aligned alongside your body, with palms facing forward at the starting point of the lift. Therefore, you can start the motion while holding the dumbbells with the palms facing your body (with a neutral grip) and supinate each hand as you start the lift. Conversely, at the end of the lowering phase, twist the arms back to the starting position, re-assuming the neutral grip position. But as a general idea, if you’re doing the curls this way, it’s best to execute the motion slower, to avoid any damage to your wrists.
8 Bicep Curl Variations To Try Out
Doing the standard curl over and over can get pretty tedious. However, there are many variations for the bicep curl that you can experiment with. All of them have the bicep as the agonist muscle, but some will put more focus on the helper muscles. Also, some of the variations that we’re going to point out below also require different equipment than dumbbells.
The Concentration Curl
The concentration curl can be done standing, but it’s best done seated. It’s also an exercise typically
done with one set per arm. So, while seated, lean forward and rest your elbow against the inside of your thigh. Hold the dumbbell close to the floor with the palm of your hand facing forward.
Bring the dumbbell up towards your chest focusing on the bicep flex, then bring it back all the way down to the starting point. Evidently, exhale as you lift, and inhale as you lower the weight.
To get even more out of the concentration curl, you can also slightly twist the dumbbell as you bring it up, squeezing the pinky and bringing it closer to the shoulder while facing the thumb forward.
The Hammer Curl
The hammer curl is pretty similar to the standard curl but doesn’t require you to keep your palms facing forward or twist your arms to turn your palms forward. It focuses more on the width of your bicep and your forearm. The starting position is just as for the standard curl but as you lift the dumbbells you need to keep your hands with a neutral grip, palms facing each other, and bring the weights close to your shoulders. Maintain the position of the weights as you lower them but always keep a slight bend on the elbows at the beginning of the lift.
The Reverse Curl
For the reverse curl, you need to hold the dumbbells with a pronated (overhand grip), resting on your thighs in front of you at the starting point of the lift. As you do the lift, also slightly flex the wrist up in order to activate more of the forearm muscles. The elbows need to remain close to your body as is the case for the standard curl; if you tend to move them away from your body, it’s already cheating. As you perform the lift, it’s not necessary to keep the dumbbells in perfect parallel position, but keeping them that way adds difficulty to the exercise.
The Zottman Curl
The Zottman curl is an advanced form of the bicep curl exercise. It’s not recommended for beginners as it puts more strain on your wrists. The starting position for the Zottman curl is similar to the reverse curl, holding the weights with a pronated (overhand) grip in front of you, resting on the front of your thighs. But as you lift the dumbbells, you have to supinate, turning your hands face up. As you lower the weights, you need to pronate, twisting your hands with the palms facing down and resuming the starting position.
Due to the many dumbbell twists throughout the exercise, it’s recommended to use slightly lighter weights than your average. Also, the tempo of the exercise should be slower to avoid injury and give you the possibility to focus well on the whole movement.
The Preacher Curl
The preacher curl requires a preacher bench or a preacher pad. It can be done with dumbbells, 
with a barbell, or with a special attachment to a cable machine.
It requires the user to rest the elbows on the preacher bench or pad and lift the weight up to the shoulder(s), then lower it and keep it down for a few seconds before repeating the lift.
This exercise puts more focus on the biceps as you keep your elbows on the bench or pad, which takes the stability factor out of the equation. Of course, the brachioradialis and brachialis muscles are also focused better.
The Barbell Curl
The barbell curl follows the same principle as the standard dumbbell curl but requires the use of a barbell. This takes away some of the stabilization needed for the work with two dumbbells as both hands hold the same bar.
The starting position for this type of curl requires keeping the barbell with both hands in front of you with a supinated (underhand) grip, elbows slightly bent and close to the body, knees also slightly bent, not locked. As you lift the barbell up, focus on the flexion of the biceps without lifting the elbows at all. Bring the bar up to your chest, then lower it back to the starting point stabilizing the movement as much as possible. Don’t use a super heavy bar, don’t throw the bar up, and control the negative motion as much as possible.
The EZ-Bar Curl
The EZ-Bar curl is the same as the straight bar curl but you’re going to be using an EZ-Bar. This type of bar features Z-type grips allowing you to keep your wrists at different angles as you hold it. This can reduce strain on the joints but without taking away from the effectiveness of the exercise on the main muscles involved.
Again, start by holding the EZ-Bar in front of you, with the palms facing forward, knees and elbows slightly bent, elbows close to the body. As you execute the lift don’t bring elbows forward or backward, don’t shrug, and don’t throw the weight up. Lift slowly focusing on the bicep contraction. As you bring the weight down, control the movement without dropping the weight.
The Cable Curl
The cable curl requires the use of a cable machine with a weight stack or a moving carriage loaded with weight plates. You’ll be using a bar connected to the lower pulley of the machine. The principle is the same as for the barbell curl, but as you pull the bar up to the starting position of the lift, you’ll notice that the cable will pull you diagonally. So, for the cable curl, you need to lean back a little for extra balance.
The movement is the same as for the barbell curl but requires extra stability as the force on the cable is slightly inclined not vertical. Keep the knees and elbows slightly bent, elbows close to the body, and bring the bar up to the chest. As you lower the bar, control the movement as much as you can. The principle is the same for using a D-handle and executing the curl with only one hand.
Now, to avoid repetition for each type of curl described, we didn’t mention how to breathe because it’s basically the same for each variation. Essentially, for any exercise, you need to exhale when you work against gravity and inhale when you move with the gravity force. So, for any type of curl, you need to inhale as you lower the weight(s), and exhale as you lift.
Common Mistakes For the Bicep Curl
Although the bicep curl exercise is pretty simple, there still are mistakes that you can make during its execution or relating to other aspects. We’ve already mentioned some of them above, but in this section of the article, we’re going to cover them in more detail. So, here are the most common mistakes to avoid while doing curls.
1. Improper elbow position. If you’re doing curls while standing without any type of support, the movement requires a bit more control. So, due to fatigue, or heavier weights than necessary, you may be tempted to slightly bring the elbows forward or backward, which clearly reduces the impact on the bicep. For most types of curls, elbows need to be close to the body describing little or no movement throughout the lifting and lowering of the weight.
2. Using momentum. For the whole execution of a bicep curl, your body needs to stand as still as possible. If you swing your body during each lift, you take away from the effectiveness of the exercise. The same goes for jerking the weights and throwing them up, or letting the gravity do the lowering instead of controlling the movement.
3. Lifting too heavy. We’ve already mentioned above that it is of the essence to use weights that you’re comfortable with. If you lift too heavy, the tendency to cheat several reps, especially as you’re close to the end of the set, severely increases. It also prevents you from developing a correct mind-muscle connection.
4. Performing only a partial motion. This is also typically related to not using a comfortable weight for your dumbbells or barbell. If you’re not completing the lift bringing the weight all the way to the top, or not extending the elbow properly definitely takes away from the effectiveness of the exercise.
5. Locking elbows and knees. Locking the elbow at the end of the negative motion can lead to an injury to the elbow joint. Also, especially if you’re doing heavy barbell curls, locking your knees can lead to a knee injury even if the exercise mainly interests the arm muscles. Therefore, never overextend the arms and keep the knees loose, slightly bent.
6. Not breathing properly. We’ve already mentioned this above. For any type of curl, it’s important to breathe in as you lower the weight, and breathe out as you lift the weight. This pretty much stands for any exercise. It’s important to always exhale as the agonist muscles are at work, and inhale when they relax.
7. Lifting too fast. The bicep curl needs to be executed at a pretty low pace controlling both the lift and the drop as much as possible. A fast execution promotes cheating, doesn’t allow you to focus on the flexion, and can even lead to injury.
Wrap-Up
The bicep curl is a low-difficulty exercise and just about anyone should be able to do it. It doesn’t require hard-to-come-by equipment; even in the lack of dumbbells or a barbell, you can do it with an elastic band, or even with a bucket of water. It’s pretty much the best exercise for working the biceps, so at least a version of it is part of anyone’s arm-building workout routine. We’ve covered here, the correct execution of the standard bicep curl with dumbbells, several variations of this exercise, and the most common mistakes that you should avoid while doing curls. Thus, we hope that you’ve found this post at least a little bit helpful.