Your biceps could probably use some work. No offense, but if youโre not a professional bodybuilder or the strongest man in the world, then your muscles could always use a little improvement.
Maybe you think youโve hit your own ceiling. If you feel like your growth has plateaued, and you truly canโt get any more out of your arms, then 21s are probably the solution.
Youโll improve your connection to your body, youโll improve your range of motion, and most importantly, youโll get the size and definition youโve been seeking out this whole time. All of this from a minor tweak in your technique. Sound too good to be true? Weโve got science and Arnold Schwarzenegger to back us up.
21s are a seven-rep three-part curl. Theyโre designed to take advantage of your bodyโs anatomy, the effects of gravity, and your muscle growth mechanisms.
From an outside perspective, they sound like a magic hyper-advanced technique that should take years to master, but in reality, they can be applied to any exercise you do with any part of your body with a little examination of your natural range of motion and a touch of critical thinking.ย
The three parts of these barbell curls are:
Youโll notice that youโre not going to need any special equipment or any extra discipline, all youโre doing here is breaking your exercise into two halves and putting it back together to put a bow on things.ย
The idea here is to maximize the amount of time you spend putting tension on your muscles. Tension is one of the best ways to wear your muscles down and encourage hypertrophy.
By stopping short of your full range of motion (full ROM) for two-thirds of your sets youโre forcing your body to put a lot of tension on your working muscles. You donโt get to take a break at the end of each rep by reaching a neutral position and resting on your laurels. The three-part curl is all about exposing hiding places and eliminating them.ย
Switching out your regular curls for 21s is an excellent way to build muscle for those simple reasons. If youโre taking the time to make it out to the gym, you might as well be making the most of it. Itโs also a great way to break out of a rut, if you feel like youโve plateaued, then this is a great way to put your muscles to the test. You might find that part of your range of motion has been suffering from neglect.
21s force you to evaluate your entire range of motion by focusing on each half. Maybe youโve been accidentally relying on momentum to get your weights half of the way up. By forcing yourself to methodically perform your curls youโll find your weak spots immediately and work past them. When youโve worked your muscles evenly and fully youโll be lifting heavier weights without a second thought in no time.ย
Youโre also going to be spending a lot of time increasing your mind-muscle connection. If this is your first time thinking about the mind-muscle connection, it may sound like a lot of pseudoscience, but itโs been proven to increase max reps by a great deal.
The reason for this is simple. Youโre not doing anything more than fully engaging your muscles in the exact way they need to be in order to more efficiently lift your weights. We spend so much of our lives moving our bodies without thinking about it, but something like three-part curls forces you to really confront the minute movements of your biceps, and how those movements apply to lifting weights. When you fully understand your body and its mechanisms you can really exploit that knowledge to push yourself further than you ever thought possible.
With that in mind, letโs talk about your biceps. Since youโre going to be spending this time getting to know your biceps so well, itโs important to learn how they work, where they really are, and what they do for your body.
The Latin name for your biceps is โmusculus biceps brachii.โ That translates to "two-headed muscle of the arm.โ That fantastic sounding name comes from how your biceps are shaped. The two heads of your biceps start on the scapula and merge together into one larger muscle and attach to your upper forearm.
That single muscle belly where the two heads of your biceps converge is what youโre seeing when you flex your arms. The two-headed shape of your biceps makes them responsible for supination and flexion. Imagine doing a punch in reverse. The twisting motion is the two heads allowing your arm to twist, this is supination, and when you pull your arm back in towards your body this is the flexion.
21s are a great exerciseย for burning fat. If youโre looking to drop weight while lifting weights or if youโre looking for increased muscle definition this exercise is great to have under your belt. Burning fat in your body is a matter of burning through all of the energy your body has stored up. Three-part curls are great for this. Maintaining tension in your muscles is one of the best ways to expend energy during your workouts, and thatโs what 21s are all about.
The primary adjustment in this exercise is targeted directly at all of the wasted potentials in standard biceps curls. You can supplement this fat-burning effect by watching your diet closely. Keeping an excess amount of fat out of your diet is one of the best ways to clear this obstacle to fat burn. Monitoring the number of carbohydrates and unused calories you add into your system is also going to help in preventing your body from secreting away excess energy into fat cells for use later in the week.
Building muscle is a tough thing to pin down. 21s try to take the best from each potential hypertrophy trigger and bundles them all together in a handy package. Youโre going to be keeping tension on your muscles throughout the entirety of this exercise, and lifting progressively heavier weights each time you come back to 3-part curls. Youโre also doing these three relatively intense exercises back to back, keeping your body in a hypoxic state. All of this together is a surefire way to add mass to your muscles no matter what your body tends to require as a trigger.
You can help this along by adding plenty of protein to your diet andย allowing yourself to rest your arms. Building muscle is all about patching together your body with protein and increasing the efficiency of your muscle fibers. When you push your muscles to the brink your body wants to repair that microtrauma, and youย need raw material to pull that off. When youโre building muscle youโre replacing and augmenting your torn muscle fibers.
Your body used the protein in your diet to make your individual muscles bigger than they were when you started, youโre making your body more effective at the tasks youโve been subjecting it to. Your body also makes your muscles more effective at storing glycogen. That means less storage in fat cells, and thicker, stronger muscles.ย
You need rest to get those bigger muscles. Traumatizing your biceps daily without a rest day in sight means youโre blunting the effects of your exercise. Always allow your muscles at least one day off, that doesnโt mean you have to completely leave the gym behind. At the very least, switch up the muscles youโre working from day to day if you absolutely canโt bring yourself to take even a single day fully to yourself, and youโll come out the other side more swole than you can possibly imagine.
21s are easy to remember. All you have to keep in mind is a standard biceps curl. Break it in half and put it back together, and youโre good to go.
7 reps of the lower range of motion
7 reps of the upper range of motion
Seven reps of your full range of motion
21s are a little dated. Theyโre the exercise that Arnold Schwarzenegger popularized in his Encyclopedia of Modern Bodybuilding, and that still holds a lot of water to this day. Heโs one of the most popular bodybuilders to this day. Heโs a household name, and heโs been the Chairman of the President's Council on Physical Fitness and Sports. He knows what heโs talking about, and heโs put in the work to prove it works. But over time weโve figured out how to build on the foundation he laid out for us.
For example, we know now from a study published in the Journal of Strength and Conditioning Research in May of 2019 that one of the more effective ways to induce hypertrophy is through tension on the muscles applied by utilizingย your partial range of motion. This means a few things. Arnold in the 80s was right on the money. His 21s were forcing him to apply tension for extended periods of time by using his partial range of motion, but with this new knowledge, we can expand on that, if youโre up for the challenge.ย
Advanced 21s are the same basic idea as 21s. Youโre still breaking down your basic curl, but weโre going to take into account the full range of motion your biceps are capable of. Weโre also adding in more isometric movements. The full set of Advanced 21s is:โ
7 reps of mid-range partial reps
7ย seconds of Isometric mid-range holds with wrist twists
ย 7 reps of the full range of motion
The most interesting thing about 21s is their flexibility. Now that you know the secret to their success you can apply these to any part of your body that youโre trying to get an edge on. Nearly every exercise you do has some kind of motion to it. Take the time to learn about your body, and you can fully deconstruct every exercise and put it back together into a 21 modified version of it.ย
Have you been working on your abs? Do you think they could benefit from something more intense? Try applying this method to your sit-ups. Your abs, or the rectus abdominis muscles, are responsible for flexing the lumbar spine. Experiment with that full range of motion. Your abs bring your ribs down towards your pelvis when youโre doing a crunch, but if you fix your upper body in place your abs also bring your pelvis up to your rib cage.ย
Now that you know which movements your abs are specifically responsible for, you can create a 21 style crunch. You could try alternating between fixing your upper and lower body in place.
You could crunch halfway off the ground for one half and lower your body to your halfway point for the other half. Donโt forget that isometric exercises are also important in the three-part curl, so you could keep that spirit alive by holding your upper or lower body off of the ground for an extended period of time. Round out your two pronged approaches by moving through your full range of motion, and youโll haveย reinvented your routine.
Youโll notice for that example that you donโt need and free weights to take advantage of 21s. Isometric exercises are just about maintaining tension in your muscles. Lots of isometric exercises can be done with your bodyweight alone.
This is something you can apply to every single one of your muscle groups and every body part, so keep your mind open, watch for areas you may be struggling in, and take the time to break them down.ย
3-part curls arenโt a magic heaven-sent workout. Theyโre a carefully considered technique that takes knowledge of the human and applies it from a different angle. Your workout is all about harnessing the processes of your body and working them to the absolute limit. 21s are a simple change you can make to your routine right now without upsetting the rhythm of your workout routine in the slightest. Being willing to take new knowledge and apply it to your already existing workout will push you further and get you more visible and satisfying results.
