The muscle-up is a rare beast – an upper-body exercise that requires both pulling and pushing power and phenomenal core strength to boot.
Those unfamiliar with the move say it's just a pull-up combined with a dip, but a muscle-up is much more than that. It's an unparalleled assault to the upper body, and you have to be strong just to do one.
In Part One of my "no curls" arm specialization training series, I talked about the absurdity of most arm specialization routines. I proposed that most trainees do more than enough biceps curls and triceps press downs and don't really need more of either of them.