I overheard someone talking about these ten years ago, but I misinterpreted what he said and accidentally started doing them my own way. I go halfway up, two thirds and then full, which counts as one, and repeat it seven times to get to 21. I throw these in at the end of a curling session sometimes. I’ve always loved them.
I’ve seen those done A LOT at my gym, and have done them myself. I can’t say for growth though, because I never eat to grow. However, I prefer strick form Zottman’s FAR MORE than 21’s.
Ian King does use them in his programs and he uses them for many body parts depending on goals. Mind you, he only does this in phases and then changes to a different type of loading.
Nothing wrong with this routine. It shocks the body part into growth if you are not used to them. This is what my program for my legs called “Crazy Eights” does.
Anything that pushes you, and that changes the norm, can have a positive effect on growth and developement!
I love 21’s as they are a good way to shock the system. I usually do them when I feel that my normal workout has hit a stopping point. I also like doing 21’s while doing skull crushers.