Build Big Arms with 21s

Bicep Curl 21s

Big arms are the immediate sign of a strong man and women love to wrap their hands around a guy’s big arms.  Let’s be honest, it’s a major turn on.  A lot of guys struggle with how to build big arms, even for guys who up the volume they only see minimal results.

I have read of users obtaining bigger arms in very short time periods by implementing 21s into their routine.  I personally incorporate 21s into my routine and have seen great results.  Some have even reported that their biceps grew so quickly that they had stretch marks on their arms!

21s are not easy, you may cry when you are finished.  The lactic acid is strong with this workout and the burn will be massive.

What are 21s?

21s are a type of bicep curl that is typically performed with a EZ curl bar.  21 refers to the total number of reps performed in a set.  The reps are split into 3 different movements, each movement has 7 reps.  The first 7 is performed by going from the bottom of the movement to the middle, the next 7 goes from the middle to the top, and the last 7 are full range of motion, bottom to top.

Make sure to choose a weight that you can properly lift at this volume.  Take what you normally curl then reduce it by 25%.  If you do not have an EZ curl bar just use dumbbells instead.  You can use a straight bar, as long as you do not encounter any wrist or forearm pain.

How to Perform 21s

  • Grab the bar with an underhand grip while standing.
  • Your hands should be shoulder width apart on the bar.
  • Allow your arms to hang towards the floor.
  • Your elbows should be tucked in, towards the sides of your body.
  • Bring the curl up to a 90 degree angle at your elbow, halfway up.
  • Bring your arms down and proceed with 6 more reps at this range.
  • For the next 7 reps go from that 90 degree elbow position to the top, close to your shoulders, then back to the halfway point.
  • Bring your arms back down to full extension.
  • For the final 7 reps curl in full range, from bottom to top.
  • Your arms should be on fire now.

Here is a video demonstrating 21s,

Why do 21s Build Bigger Arms?

21s are effective due to increasing the muscle’s time under tension which makes for an amazing pump. Time under tension increases metabolic stress, which is an important factor for building muscle. 1

Recommended Workout

Perform 3 sets of 21s while only taking a 1 to 2 minute rest in-between sets. Utilize a mirror if you have on available to make sure that your elbows are tucked in close to the sides of your body.  Don’t let your elbows move from your sides while performing the movements.  If you are incorporating 21s into your existing arm workout it’s best to save them for last.

  1. Schoenfeld BJ. The mechanisms of muscle hypertrophy and their application to resistance training. J Strength Cond Res. 2010;24(10):2857-72.