I'm sure Fadi or Nick will be along shortly to tell us how it works. However, as I understand it, they do low reps and high sets, and never go to failure.
My own experience is that when I've gone to failure on a compound exercise, that's when I get the DOMS; if I go to failure on three or more compound exercises, in my next workout my max lifts will have dropped - that is, 48 hours wasn't enough rest!
I think whether you're going to or close to failure is the key issue in how fast you recover. That experience matches what I know of the physiology of it, too.