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Arms Barbell Intermediate Compound Video

How to do the Barbell 21-s

Primary: Biceps · also works Forearms, Shoulders.

Barbell 21s or '21s' is a specialized bicep exercise where the range of motion is divided into three parts: 7 reps of lower half-curls, 7 reps of upper half-curls, and 7 reps of full curls. This exercise is designed to target the biceps from different angles, providing a comprehensive workout that enhances muscle endurance, strength, and size. The technique requires precision and control to maximize the effectiveness of each segment.

Demo video: Barbell 21-s · from the Fitbe exercise library Open in Fitbe →

Step by step

  1. 1

    Stand with your feet shoulder-width apart, holding a barbell with an underhand grip at your thighs.

  2. 2

    Perform 7 reps of curling the barbell from your thighs to a 90-degree angle (lower half-curls).

  3. 3

    Immediately continue with 7 reps starting from the 90-degree position to your shoulders (upper half-curls).

  4. 4

    Finish with 7 reps of full range of motion curls, from thighs to shoulders and back down.

Coaching cues

  • Maintain a steady pace to keep tension on the biceps.
  • Avoid using momentum to lift the barbell; focus on muscle contraction.
  • Keep your elbows slightly in front of your body to maximize bicep engagement.

Sets, reps and where it fits

Muscle

3–4 × 21–21

rest 60–90 s

Strength

4–5 × 4–6

rest 2–3 min

Fat loss

3 × 21–21

rest 45–60 s

Impact: low Knee stress: low Spine load: low Gym only

Barbell 21-s alternatives

Same movement pattern, different equipment or difficulty. Swap one-for-one in any plan.

Barbell CurlBarbell · beginner Close Grip Barbell CurlsBarbell · beginner Ez Bar Curl Inside GripBarbell · beginner EZ Bar Preacher CurlsBarbell · beginner Close Grip Preacher CurlsBarbell · intermediate Drag CurlsBarbell · intermediate

Frequently asked questions

What muscles does the Barbell 21-s work?

Primary: Biceps. Secondary: Biceps, Forearms, Shoulders

How many sets and reps of Barbell 21-s should I do?

For muscle: 3–4 sets of 21–21 reps. For strength on compound lifts: 4–5 sets of 4–6. Rest 60–120 seconds between sets.

What can I do instead of the Barbell 21-s?

Same movement pattern, different equipment: Barbell Curl, Close Grip Barbell Curls, Ez Bar Curl Inside Grip, EZ Bar Preacher Curls, Close Grip Preacher Curls, Drag Curls.

Is the Barbell 21-s good for beginners?

With some training experience, yes. Beginners should start with one of the easier alternatives listed and progress to it.