3 Part Curls {21S} Exercise to build Bigger Biceps


What makes 3 Part curls so effective arm exercise?

Biceps are difficult to build as they get continuous stimulation from all upper body exercises. This is precisely the reason they need exercises like 21 S and One dumbbell, two arm curls.

3 Part Curls is an excellent Biceps exercise to build biceps through an entire range of motion. It was popularized by the legendary Arnold Schwarzenegger.

Its a test of your endurance and it will test you if you train with heavy poundages and low reps regularly.

Check the correct exercise technique and blast your arms now. I will also show a killer one dumbbell, two arm curls for maximum biceps stimulation.

P.S. 3 part Curls is also called21S Exercise or 21S Curls as the exercise involves 21 repetitions.

Purpose - To Build Biceps through a combination of Partial and full range motion.


This exercise is done either standing or seated with a pair of dumbbells.


  1. Grab a pair of dumbbells and hold them at arm's length.

  2. Curl your arms as in standard dumbbell curls but stop midway and lower back to start position. Perform 7 such repetitions.
  3. Now curl full range but on the way down stop midway and perform 7 more repetitions from top to midway. This is real difficult as weights in the sticking positions are the toughest to lift.
  4. Finish this endurance test by doing 7 more full range repetitions.

P.S. - Sticking Point is the part of the range of motion in which a weight is the hardest to lift. As in case of biceps curl, the top half is tough to lift than the lower half.

How to incorporate 21S or 3 part curls in your arm workout routine

Essentially the 3 part curls is a combination of partial range and full range movement.

Although I highly recommend that olympic bar curls and chin ups be the mainstay of your biceps training, you can add 3 part curls to the moderate intensity, higher rep workouts in your training cycle.

Remember this is more of a endurance exercise and not a muscle building one as the reps are higher and intensity { in terms of one rep max} lower.

Many bodybuilders use this exercise in the final parts of pre-contest training. You can do the same. If you are non-competitive muscle builder, then do them at the end of training cycles, by the end of which you will have more toned arms.

One Dumbbell, Two arms biceps/arm curls

High rep biceps work as in 21 S and the following exercise helps in the muscle growth phase.


Execution Technique: Grab hold of a moderate hex dumbbell with both hands, each placed under the bell of the dumbbell.

Please see I said under the bells, and not on the sides. Imagine you are crushing the bells. This small technique used mostly in kettlebell training but applicable to all types of iron increases muscle stimulation and help you lift better.

Perform 21 S exercise as shown above.

Hammer Curls - You can hold the bells on the sides to make a hammer curl out of this exercise.

Don't have a HEX dumbbell? Get innovative! Try holding a plate with both hands and perform 21S with this special way to blast your biceps.

Points to Remember

Biceps Exercises

ExerciseGoals.com Recommends the Best Exercises ebook...

Just click here to find out 53 new innovative exercises
to eliminate boredom, plateaus from your workouts
and take your workouts to next level.

Back to top of 3 part curls or 21S exercise

Back from 3 part curls or 21S to Weight Training Tips Homepage.