Experience Explosive Arm Growth with the High-Volume 21s Bicep Curls

June 20, 2024

21s bicep curls bring your arms through a partial and full range of motion.

Bicep curls are foundational exercises for enhancing muscle mass and arm strength (1). Developing robust arms improves your lifting capabilities, enriches your workout routines, and contributes to a visually appealing upper body. The 21s bicep curl is an advanced and iconic arm curling technique that accelerates bicep development and ensures a substantial muscle pump.

Popularized by Arnold Schwarzenegger, this exercise was a key component of his strategy for achieving impressively muscular arms. The 21s bicep curl technique is distinguished by its combination of full and partial reps, utilizing three ranges of motion, typically divided into three sets without rest in between.

This article thoroughly explores the 21s bicep curl, focusing on the muscles it targets. It offers an in-depth, step-by-step guide to executing this exercise effectively. Moreover, it outlines the significant benefits of this potent arm-strengthening workout. Lastly, we consider alternative arm exercises that target similar muscle groups, aiming to augment the effectiveness of your training regimen.

Techniques & Muscles Worked

21s bicep curls primarily work your biceps and, by extension, the elbow flexors and brachioradialis (the muscle of the forearm that flexes the forearm at the elbow). It also works on your wrist flexors, depending on your grip. This exercise activates core muscles, like the abs and obliques, which help with stabilization, too.

The 21s employ three movements of seven reps, each making twenty-one reps per set without rest. You can use free weights like barbells, dumbbells, kettlebells, or EZ bars for this exercise. If you’re looking for more resistance for extra muscle gains, resistance bands can also help target the muscles. Below is a list of movements for the 21s bicep curl.

The first seven reps employ a partial range of motion from the bottom, curling your arms until they are parallel to the floor.
The second seven reps employ a partial range of motion from the top. With your arm fully contracted, slowly drop your upper arm until it’s parallel to the floor.
The last seven reps employ a full range of motion, fully extending and flexing your biceps.

For this exercise guide, we look at doing 21s bicep curls with an EZ bar because it helps improve your range of motion. Below is a step-by-step guide highlighting how to do this.

Stand straight with your feet shoulder-width apart and hold the inside curved part of the EZ bar using a supinated grip.
Keep your arms extended to your sides, chest up, and back straight. Tighten your core, then squeeze and pull your shoulder blades back. This is your starting position.
Slowly lift the EZ-bar, keeping your elbows tucked to your sides until your elbows are bent 90 degrees and your forearms are parallel to the floor.
Repeat this movement seven times and return to the starting position.
Next, initiate the second movement from the position of your elbows at 90 degrees without any break and slowly curl until your arms fully contract.
Lower the bar back to the position of your elbows at 90 degrees, repeat this movement seven times, and return to the starting position.
Finally, without resting, from the starting position, curl the bar slowly, fully contracting your arms.
Repeat this full range of movement seven times and return to the starting position.

Benefits

The 21s bicep curl is an excellent exercise for strengthening and building yoked arms. Below is a list of benefits for performing this staple exercise.

Bigger & Stronger Arms

This exercise primarily targets the biceps, brachialis, and brachioradialis. It isolates and targets the biceps’ long head and short head, leading to muscle hypertrophy.

An Insane Pump

21s bicep curls isolate your arms and target the muscles there. They also give you an insane pump, which you’ll notice after doing the partials and full ranges of motion.

Greater Grip Strength

21s bicep curls require strength and control with your hands, wrists, and elbows. You’ll also spend much time holding onto the weight for the curl, increasing your grip strength.

Improves Your Range of Motion

The 21s bicep curl uses a combination of partial reps and full reps. This puts constant tension on joints and targeted muscles. The constant flexion and extension of these joints and muscles improve your range of motion, ultimately leading to more muscle growth. A study shows that performing a combination of partial and full ranges of motion is effective for muscle growth (2).

Longer Time Under Tension

During 21s bicep curls, your biceps spend a longer time under tension than they would with regular curls. This can help you overload them, leading to more myofibrillar and sarcoplasmic growth and, ultimately, muscle hypertrophy.

21s Bicep Curls Alternatives

We agree that 21s bicep curls are staple exercises for building big guns. However, experts advise mixing up your exercises to avoid hitting a plateau when training. Below are some alternative exercises you can incorporate into your arm-building workouts.

Chin-Up

Chin-ups are bodyweight exercises that target your back, and the supinated grip activates your biceps. You need a chin-up or stable bar overhead to do this routine. During this exercise, you can use a weighted vest or resistance bands for more gains.

One-Arm Dumbbell Row

The one-arm dumbbell row is a variation that targets your back, biceps, and core muscles. It’s a unilateral exercise, which means you can equally train one part of your body at a time. You can also use it to correct muscle imbalances.

Cross Body Hammer Curl

This is another isolation biceps exercise that hits your arms, including your forearms, from a different angle. As the name suggests, you’ll cross your body to perform this movement while curling.

FAQs

How to do a 21s bicep curl?

Stand straight with your feet shoulder-width apart and hold the inside curved part of the EZ bar using a supinated grip. Keep your arms extended to your sides, chest up, and back straight. Tighten your core, then squeeze and pull your shoulder blades back. For more information, check out the comprehensive step-by-step guide above.

Are 21s bicep curls effective?

Yes, 21s bicep curls are effective for building sleeve-ripping arms. This routine isolates the arms from every other muscle group and focuses on these muscles, which induces muscle hypertrophy. The longer time under tension and range of motion are also effective.

What is the 21s method of exercise?

The 21s employ three movements of seven reps, each making twenty-one reps per set without rest. It utilizes two partial ranges of movement and a full range of movement. As a result, you put your arm muscles under tension for a long time, which can improve other metrics like your grip strength.

References

Coratella, G., Tornatore, G., Longo, S., Toninelli, N., Padovan, R., Esposito, F., & Cè, E. (2023). Biceps Brachii and Brachioradialis Excitation in Biceps Curl Exercise: Different Handgrips, Different Synergy. Sports (Basel, Switzerland), 11(3), 64. https://doi.org/10.3390/sports11030064
Schoenfeld, B. J., & Grgic, J. (2020). Effects of range of motion on muscle development during resistance training interventions: A systematic review. SAGE open medicine, 8, 2050312120901559. https://doi.org/10.1177/2050312120901559