hi, juss wonderin how would i develop fast twitching muscles, especially for my legs (wanna jump higher). Would i need to do a lot of low weight & high rep sets? and how low is low weight, and when do i increase the weights.
ps. wat is HIIT exercise, my cardio is juss 20 minutes, but i tried to change intensity, so it is like high intensity cardio. Is there difference btw wat i'm doing and HIIT program?
please advise, thanks!