Work Sets of 21's?

Bigger Stronger Leaner Competitive Bodybuilding
1

if a program says work set: 21’s . For curls for example, what does this mean?

thanks

2

7 reps lower portion of the lift…
7 reps upper portion of the lift…
7 full reps of the lift…

lower portion would be from (lets say) straight arm to about 90degrees

upper would be from above 90 to full contraction

then do 7 full reps straight to full contraction…Good luck!