Are you looking for a bicep isolation exercise that will fire up your muscle fibers and help to build strong, thick biceps?
Choosing the right type of bicep curl can be challenging with so much conflicting information and advice available online.
Today, we’ll compare two popular variations of the standard bicep curl: the preacher curl and the concentration curl. We’ll explain the main technical differences, the pros and cons of each exercise, and how to perform each type of curl with the proper technique.
Let’s get into these two types of bicep curls to help you figure out which one is best for you
Preacher Curl vs. Concentration Curl
Difference between a preacher curl and a concentration curl
The main difference between a preacher curl and a concentration curl is that the preacher curl is more difficult in the first half of the rep. The concentration curl is most difficult at the top of the rep.
The bicep muscles are stretched at the bottom of the rep and contracted at the top of the rep.
Preacher curls and concentration curls are very similar movements that both focus on isolating the biceps. They engage the same muscles and both provide support for the elbow to eliminate any assistance from other muscles in the upper body.
Preacher curls have you rest your elbows against a padded preacher bench. In a concentration curl, you provide an anchor for the working arm by resting your elbow against your inner thigh.
The concentration curl has also been shown to have a slight advantage in engaging the short head of the biceps brachii, so it may be a preferable exercise for bodybuilders.
Pros and Cons of Each Movement
The preacher curl and the concentration curl target the same muscle groups in the body and both have benefits for adding strength and size to your upper arms. They share the benefit of an anchor to stabilize the elbow during the curl to isolate the bicep. However, they do have slight differences which might make one more suitable than the other.
Preacher Curl Benefits
Here are some of the advantages of preacher curls.
- They allow you to lift heavier weights. Preacher curls can be done using dumbbells, but are usually performed with a standard barbell or an EZ bar. For most lifters, this will mean you can lift heavier loads in the preacher curl than you can in a dumbbell concentration curl.
- Easier to progressively overload. The barbell preacher curl allows incremental increases in weight by adding 2.5-pound plates, making it easier to advance your lifts and increase your bicep strength over a longer period as compared to concentration curls.
- Easier to maintain proper form. The preacher bench helps you remain locked in the correct position to isolate your biceps. In a concentration curl, there is still room for error such as incorrect placement of the working elbow on the inner leg or an incorrect angle. Preacher curls may be more beginner-friendly in this way as they are easier to perform.
- Builds strength in the stretched position. Preacher curls are most difficult at the beginning of the rep when the bicep is in a stretched position. Many lifters find this to be a point of weakness, which preacher curls can effectively improve.
Preacher Curl Drawbacks
Here are some of the drawbacks of preacher curls.
- Greater risk of straining the wrist. Barbell preacher curls place the wrists in an unnatural position. Holding a heavy barbell in a locked supine position can strain this delicate joint, especially as the weight increases.
- Won’t improve muscular imbalances. Barbell preacher curls work both arms in unison. This imbalance may lead to your stronger or more dominant arm doing a majority of the work. The preacher curl can make it difficult to evenly distribute the effort and strengthen the weaker arm.
- Strains the forearms. The benefit of the preacher pad is that it locks your forearms in position. However, this position can also be a disadvantage when it leads to excessive forearm strain by loading the forearms in an unnatural supinated position. Some lifters experience pain in the forearm flexors which can develop into tendonitis.
Concentration Curl Benefits
Here are some of the advantages of concentration curls.
- Greater biceps brachii activation. One study compared eight different bicep curl variations and found that the concentration curl outperformed the others, including the preacher curl.
Source: ACE Biceps Study
- Strengthens the bicep in its shortened position. Unlike the preacher curl, the concentration curl is most difficult at the top of the rep when the bicep is in a shortened position. This position forces the muscle to contract repeatedly to move the weight, giving the muscle a great stimulus and creating an impressive bicep pump.
- Helpful for improving mind to muscle connection. Concentration curls were given their name for a reason: they are performed one arm at a time, in a seated position, with your arm locked in place and your gaze looking at the dumbbell you are lifting. This focussed attention can help you zone in on the muscle you are engaging, concentrating on squeezing the bicep to initiate the lift.
- Helps improve muscle imbalances. The concentration curl is usually done unilaterally, meaning you train one arm at a time. This can help you improve imbalances in the strength between your right and left arm.
Concentration Curl Drawbacks:
Here are some of the drawbacks of concentration curls.
- Limits how much weight you can lift. Concentration curls are highly effective isolation exercises but you can’t lift as heavy as you could in a preacher curl. For strength athletes, this may limit progression in the gym and negatively affect motivation.
- More difficult to overload. Unless you have access to an unlimited amount of increasingly heavy dumbbells, you may eventually hit a plateau for progressing the concentration curl. Dumbbells usually increase in 5-pound increments, and you may find yourself struggling to select the appropriate weight as you progress.
- Easier to get ‘wrong’. The concentration curl requires a solid understanding of where to anchor the elbow against the inner thigh. Setting up incorrectly at the beginning of your set can work the bicep at an incorrect angle and prevent you from getting the full benefit of the exercise.
When to do an exercise
When to do a preacher curl
If you want to lift as much weight as possible to target your biceps, the preacher curl may be preferable. Preacher curls are especially useful if you find your strength is limited when your bicep is in a stretched position. Preacher curls may be more time-efficient as you can train both arms simultaneously, making them suitable for people with time constraints in the gym.
When to do a concentration curl
If you want to isolate the short head of the biceps as much as possible and get an impressive bicep pump, the concentration curl is for you. The concentration curl is great for lifters wanting to improve their bicep strength from a contracted position, improve mind-to-muscle connection, and rectify muscular imbalances by training the biceps unilaterally. The concentration curl is a convenient exercise as it requires minimal equipment.
Preacher Curl vs. Concentration Curl – Muscles Used
The preacher curl and the concentration curl are very similar movements which both primarily target the short (inner) head of the biceps brachii. In both exercises, the weight is anteriorly loaded, meaning your arms are in front of your body as you curl the weight.
Preacher Curl Muscles Used
- Primary: Short head of the Biceps Brachii, Long head of the Biceps Brachii
- Secondary: Brachioradialis, Brachialis, Forearm Flexors
Concentration Curl Muscles Used
- Primary: Short head of the Biceps Brachii, Long head of the Biceps Brachii
- Secondary: Brachioradialis, Brachialis, Forearm Flexors
Form Differences Between the Concentration Curl and Preacher Curl
The main form difference is the training of both arms simultaneously or each arm individually. At a dedicated preacher curl station, both are trained at the same time. Concentration curls train one arm at a time with dumbbells and use the leg as an anchor.
Preacher curls and concentration curls use the same muscle groups and follow a very similar movement path.
How to do a preacher curl with proper form
- Set up a barbell in the rack of a preacher curl machine and sit on the seat behind the preacher pad.
- Lean forward and brace your triceps against the preacher pad so that your armpits are at the top of the pad.
- Reach down and grip the barbell with a supinated (underhand) grip with your hands about shoulder-width apart.
- Grip the barbell firmly to take slack out of the bar and then squeeze your biceps to curl the barbell towards your shoulders.
- Curl the barbell until you reach full contraction, or when your forearms and your biceps make contact with each other.
- Hold at the point of maximum contraction for a second or two before slowly lowering the barbell to its starting position.
- Repeat for the desired number of repetitions.
For a visual aid, check out this video demonstrating the correct form for a preacher curl.
How to do a concentration curl with proper form
- Grasp your dumbbell with an underhand (supinated) grip with the arm you will use for your first set. In unilateral exercises, it can be useful to start with your weaker arm first.
- Sit down on a bench with your feet planted and your knees apart to create space for the dumbbell to move.
- Tilt forward at the waist to lean over your legs and brace the tricep of the working arm against your inner thigh.
- Use your non-working arm to hold your opposite leg for additional support and stability.
- Keep the palm holding the dumbbell facing forward and breathe out as you squeeze the biceps to bring the weight towards you.
- Lift the dumbbell until your hand is close to the front of your shoulder and your bicep reaches maximum contraction.
- Hold for a moment. Breathe in as you slowly release the barbell back to a fully extended position. Ensure the arm remains braced so you don’t hyperextend at the bottom of the lift.
- Repeat for the desired number of reps and then repeat on the opposite arm.
For a visual aid, check out this video demonstrating the correct form for a dumbbell concentration curl.
Helpful Form Cues
Preacher curl form cues
- Grip the barbell firmly to stabilize the wrists. Preacher curls can strain the wrist joint. You can minimize this discomfort by actively gripping the barbell and keeping the wrists in line with the forearms throughout the lift and preventing them from bending backwards under the weight.
- Don’t forget your core. The preacher curl is a bicep isolation exercise, but that doesn’t mean you can neglect your core stability. Make sure you brace your core to prevent any spinal arching as you curl the weight to prevent any injuries.
- Use your breath. Breathe out in the concentric (lifting) phase of the curl and breathe in as you slowly lower the barbell to its starting position.
- Control both phases of the lift. In any lift, you control the eccentric (lowering) portion of the lift and the concentric (lifting) phase with speed and power. In a preacher curl, lifting the weight too quickly can harm the elbow joint as it is resting against the preacher pad. Control both phases of the lift to get more time under tension and prevent unnecessary strain on the elbow.
Concentration curl form cues
- Lock your working arm in place. Get the most out of your concentration curl by ensuring your arm is properly locked into place. Dig the outside of the upper arm you are curling into your inner thigh, around the tricep just above the elbow. Make sure the position is comfortable and one you can maintain throughout the set so that only your forearm is moving.
- Maintain a slight internal rotation. Conversely to a standard curl where your palms face out in front of you, in a concentration curl, your working arm should face inwards. Your working bicep should almost be facing your opposite leg, with your pinkies rotated to maintain the supination of the arm and maximize bicep engagement.
- Lower the weight slowly. The support of your leg propping up your working arm can cause some lifters to speed up their reps. Not only is this less effective as it reduces time under tension, but it can also lead to dropping the weight too quickly and overextending at the elbow. Instead, squeeze the biceps with force to lift the dumbbell, and lower it slowly and with control.
Common Form Mistakes
Preacher curl form mistakes
- Not moving through the full range of motion. Make sure you get the most out of your preacher curls by moving through the full range of motion. Preacher curls are particularly good at strengthening the bicep in its stretched position, but only if you fully lower the barbell for each rep to stimulate the muscle every time.
- Hyperextending the elbows. The support of the preacher pad can provide a false sense of security that leads some lifters to lose control of the eccentric phase of the lift. Control the weight on the way down to prevent overextending the elbows which can strain or injure the joint.
- Letting the triceps lift off the preacher pad. Make sure your triceps maintain contact with the preacher pad at all times. Letting the arm move may shift the emphasis away from your biceps and onto your shoulders.
- Overshooting your weight. The preacher pad likely allows you to lift more weight, but you should still be conscious not to fall prey to ego lifting. Start with a more conservative weight to save yourself from an injury that would prevent you from training altogether.
Concentration curl form mistakes
- Not moving through a full range of motion. The \muscle activation in a concentration curl primarily takes place at the top of the lift when the hand is closest to the shoulder. Skipping this part of the movement to do partial reps at the bottom phase of the lift will eliminate much of the muscle activation and potential for strength and size gains.
- Overextending the elbow at the bottom of the lift. If you release the weight down too quickly, you risk overextending the elbow and straining or injuring the joint. Lower the dumbbell with control and stop when the elbow is straight but not hyperextended.
- Not maintaining constant tension. Having the support of your leg to prop up the working arm can make it tempting to relax in between each rep, reducing the number of motor units being used and the overall stimulus for strength and size gains. Maintain bicep activation for the entire set by not letting the weight ‘hang’ at the bottom of each rep.
Frequently Asked Questions
Are preacher or concentration curls better for generating muscle mass?
Both types of curling exercises are effective, but the concentration curl may be slightly better at targeting the biceps brachii. One study by the American Council on Exercise found that among several types of bicep curls, the concentration curl triggered significantly more bicep activation than the other variations, including the preacher curl. It also found the concentration curl caused less engagement of the anterior deltoid, which may explain why it is so good at isolating the biceps.
That said, preacher curls have their unique benefits and may enable you to lift heavier weights and progress more over time which can also have advantages for hypertrophy.
Which bicep curl variation should I be doing?
The concentration curl and the preacher curl are not identical exercises. They look similar and target the same muscle groups, but they do have several important differences.
Both the preacher curl and the concentration curl are useful exercises when isolating and targeting the biceps. The best exercise for you will depend on whether you want to lift as much weight as possible or if maximal muscle isolation and engagement is your goal.
In a 2014 study, dumbbell concentration curls were more effective at engaging the biceps than other variations. However, preacher curls may allow you to lift heavier weights which can also yield impressive strength and size gains.
Having a variety of bicep movements is a good idea for most lifters, as it allows you to experiment and find what works best for your unique body. Additionally, it can also make you a more adaptable and resilient athlete. Variations can also keep your program interesting and fun, helping with mental stamina and the consistency you need to get the best results.
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