Are they not training to go all out for at least 30 minutes? Heavyweights...seems to me that if they simply hit the heavy bag, full power for 45 minutes without rest, they wouldn't gas after throwing 6 combos in a fight. Rewatched Hunt vs Lewis and still don't understand how Beast gassed from throwing a bunch of lazy kicks and a few punch combos. They didn't grapple at all, no Greco...nothing but walking around and casually throwing a technique every 30 seconds and he fetal positioned on his feet from exhaustion. Crazy.