How to do it
Pin your shoulder blades down and back throughout all three phases.
- 1
Stand with feet shoulder-width apart, holding a dumbbell in each hand with palms facing forward.
- 2
Perform 7 curls from the bottom of the movement to halfway up.
- 3
Follow with 7 curls from halfway up to the full curl position.
- 4
Finish with 7 full range of motion curls from bottom to top.
- 5
This completes one set of '21s'.
Expert tip
Keep your elbows stationary and close to your body to isolate the biceps and prevent using momentum.
Common mistakes
- ✕Letting wrists hyperextend during the curl
- ✕Cutting the range short on each partial phase
- ✕Letting the weights drop on the way down