21's Bicep Curl (Barbell)
A high-volume hypertrophy technique that divides the standard bicep curl into three distinct seven-rep segments to maximize metabolic stress. This accessory movement targets the biceps through partial and full ranges of motion to induce a significant muscle pump.
Since 21s rely heavily on metabolic fatigue and volume tolerance, the AI analyzes your RPE and recovery data—specifically HRV and sleep—to determine if you have the capacity for this high-intensity finisher. If your recovery scores are low, the AI may suggest a standard barbell curl to avoid overreaching; if recovery is high, it tracks your performance to ensure you don't drop weight prematurely, optimizing the hypertrophy stimulus.
Form Cues
- Pin your elbows firmly against your ribcage throughout the entire set.
- Perform the first 7 reps from full extension to 90 degrees.
- Perform the next 7 reps from 90 degrees to full contraction.
- Finish with 7 full-range repetitions without resting.
- Squeeze your glutes and brace your core to prevent swaying.
- Don't swing your hips to generate momentum.
- Don't let your elbows drift forward during the curl.
- Don't rush the tempo; keep the movement controlled.
- Don't lean backward to counterbalance the weight.
Common Mistakes
- Selecting a weight that is too heavy to complete all 21 reps.
- Blurring the distinction between the partial and full ranges.
- Resting between the three segments.
- Using lower back momentum to lift the bar.
Muscles Worked
This exercise intensely targets the entire biceps brachii complex, utilizing partial ranges of motion to overload the muscle at different mechanical sticking points. The high time-under-tension also places significant demand on the brachialis and the forearm flexors, contributing to overall arm thickness and grip endurance.
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Secondary
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