The 21s method is a classic bodybuilding method. Here's a reminder of what it is, and here's how to improve it and apply it to your shoulders.
The classic way of doing the method is by applying them to bicep curls. Your set would look like this:
- Curls in the bottom range x 7 reps
- Curls in the top range x 7 reps
- Curls using full range of motion x 7 reps
There's no arguing that they're hard. Plenty of sleeve-popping biceps have been created using this technique. But we can do better. We can also stop limiting the 21s technique to curls. If it works well for your biceps then surely other muscles will benefit too.
A Twist on 21s
There's a difference between an exercise or technique being hard, and one that's both hard and makes sense. Classic 21s just don't make any sense when thinking about them from a mechanical perspective.
We're not going to get into the weeds here and talk about moment-arm lengths and length-tension relationships and, blah, blah, blah. Let's avoid all this for now and just use common sense.
The next time you do bicep curls just note what portions of the exercise are easiest and which are hardest. You'll likely find that using full ROM is the hardest, followed by the top portion of the curl and then the bottom. Right now you've just flipped classic 21s on their head. A number of coaches have spoken about the benefits of doing this before.
So just start your 21s with the portion of the exercise that's hardest, followed by easier, then easiest. This will allow you to lift more weight, create more tension and keep your reps more honest. And by flipping them you'll make an effective mechanical drop-set that actually makes sense.
Yes, think of this like a mechanical drop-set. With mechanical drop-sets you change the mechanics of the exercise to squeeze out extra reps and extend the set. In this case, the mechanics of the curls have been changed by simply doing reps in an "easier" range of motion after every 7 reps. This helps you accumulate more volume using the same weight throughout the set.
Unlike a mechanical drop-set though, these should stick to the classic rules of performing 21 reps. Seven is a number of reps that works really well here anyway and allows you to select a weight you could normally lift for full ROM for about 10-12 reps.
It also gives you a good target to aim for instead of just saying: "Do 7 reps, then as many as you can, then finish with as many as you can." Most of us like a number to aim for.
Adding a Reset
To get 21 total reps in this new fashion you're going to add short rest periods after each range of motion. This brief "reset" is often used in standard mechanical drop-sets, and will offset just enough fatigue to allow you to hit full 21 reps with good form.
Your improved 21s should look like this:
- Hardest portion of the exercise x 7 reps, rest 5-10 seconds
- Easier portion of the exercise x 7 reps, rest 5-10 seconds
- Easiest portion of the exercise x 7 reps, rest 2-5 minutes then repeat.
Note that it doesn't necessarily have to start with full ROM. The hardest portion of an exercise isn't always in its full active ROM.
And although a muscle will tend to fatigue first in its fully shortened state, because of leverage factors, it's not necessarily where you'll fail first. So when applying this idea to any exercise, just think of it like this: hardest ROM for 7 reps, easier ROM for 7 reps, then easiest ROM for the final 7 reps.
Better 21s For Shoulders
Now let's apply it to delts.
The Big Hitter
Seated dumbbell shoulder presses are a staple strength and bodybuilding exercise that activate all portions of your delts. These can be done standing too, or with a barbell, a kettlebell, or even a landmine.
- Shoulder press with full ROM x 7 reps, rest 5-10 seconds
- Shoulder press with top ROM x 7 reps, rest 5-10 seconds
- Shoulder press with bottom ROM x 7 reps, rest 3-5 minutes
Rear Delt Destruction
Rear delt flyes are one of the best ways to hit your neglected and under-activated posterior delts. Research shows turning your thumbs inwards gets more activation from your posterior fibers. Although think of this more as "elbows flared and spread wide" versus just pointing your thumbs more inward and lifting the weight.
These can be done supported on a bench, bent over, or using cables instead of dumbbells. When using dumbbells, the point of maximal load is as your arms raise parallel to the floor. This is where it's hardest and where you'll want to start. You won't need much weight here.
- Rear delt flye top ROM x 7 reps, rest 5-10 seconds
- Rear delt flye full ROM x 7 reps, rest 5-10 seconds
- Rear delt flye bottom ROM x 7 reps, rest 2-3 minutes
Leveled-Up Lateral Raises
Lateral raises are a pretty good all-round isolator, especially for the medial portion of your delts. You don't need a heavy weight to get maximum effect here. Try raising slightly forward rather than directly out toward the sides and see how that feels on your shoulders.
The hardest portion of these is at the top, while the easiest is at the bottom of the raise. Your 21s should reflect this.
- Lateral raise top ROM x 7 reps, rest 5-10 seconds
- Lateral raise full ROM x 7 reps, rest 5-10 seconds
- Lateral raise bottom ROM x 7 reps, rest 2-3 minutes
If you want a complete set of delts then front raise variations are important. Front raises can be done with a plate, dumbbells, cables, or even a medicine ball.
A kettlebell might offer some unique advantages though due to its unique design and load distribution when raised fully overhead.
- Front raise top ROM x 7 reps, rest 5-10 seconds
- Front raise full ROM x 7 reps, rest 5-10 seconds
- Front raise bottom ROM x 7 reps, rest 2-3 minutes
As a finisher: 21s can be applied in many different scenarios and for a number of purposes. Since they can be taxing, both physically and mentally, you can finish on a high note by placing them near the end of your workout.
Any time equipment is limited: If you're stuck lifting in the same rep range because your loading options are limited, this is a good way to mix it up and add some intensity to an otherwise lifeless workout.