Have you tried 21s yet? If you haven't, then you don't know what you're missing.

If you really want to blast your arms into new growth then 21s are what you're looking for. The technique works particularly well with biceps, but you can use it on triceps, shoulders, chest, or any other muscle for that matter.

The Warmup

Make sure your bis are good and warmed up . . . believe me, you don't want to be doing this cold.

The Technique

Here's what you do. I'll use the basic standing barbell curl as an example (this happens to be my favorite exercise for 21s).

Now take a barbell loaded with about 50% of the weight you would normally use on a heavy set of 6-8 reps.

That's right, only 50%.

I like to use a slightly narrower grip than shoulder width, but you can experiment.

Start curling the weight slowly, but stop when you're halfway through the motion and lower the weight. Repeat these partial reps, bringing the bar only halfway up, for a count of seven.

Now, on the seventh rep, bring the bar all the way up. Squeeze hard at the top, and begin lowering the weight.
Only this time, stop lowering the weight when you're halfway down and pull it to the top again.

Be sure to squeeze your biceps hard at the top of each rep.

When you've completed seven reps of these partials, immediately do seven full reps with the best form you can. Rack the weight and feel your arms explode!

To Sum It Up

You're doing 21 total reps (thus the name 21s); 7 partial reps where you come halfway up; 7 partials where you go halfway down; and 7 full reps with excellent form.

You can repeat 2 or 3 sets in this manner. One caution here: this is an extremely intense training technique, you don't want to do this every time you train arms. If you do, you'll overtrain and not make the types of gains that you should.

I use a couple of sets of 21s every two or three weeks to blast my biceps to new growth. You'll like what you feel and see!

Source:musclesurf.com

this method is hard-core and will def make your biceps grow if your resting between workouts, good for breaking through sticking points

if you dont feel it burning your arm, you are in-human, i sweat scream and shout when i do this it plain BURNS!

I just came back from my arm workout and tried this exercise it really works!my biceps felt like exploding!thanx trainwiser!

Sounds to be a great exercise, I'll try it this week.

This works for me... or at least, this is how i do any sets with 21s

Use an actual curling bar firstly do a set on a lightish weight for yourself, straight after you're done bang out 1 set of 8 hammer curls on the heaviest you can do, then next set a slightly heavier 21s weight and try keep the same hammer weight. If you can manage a 3rd set then congratulations it aint easy and you probably wont do alot else that workout

Your arms look pumped without gear on this great if youre going out on the pull

I love 21's! Good stuff! Don't be afraid to use light weight on these, quality reps is way more important than quantity reps in front of a mirror.