Sleep and Ballar, main thing here is the stamina needed. Man-to-man defense is extremely demanding in that aspect. Nearly all of us, ANA basket-ballers/soccer-players are weekend warriors who work/go to school during the weekdays. To bulid up stamina you need to either run/hit the gym/play ball everyday which is a time-constraint luxury the Neps here can't afford! Its no wonder, the zone D is whats played here as the most challenging part of running after the guard is split between all players. BTW, I hate zone defense like no tomorrow but contradicting myself, I'd do that too if I see my teammate's short on wind (that way, we could all help the guy from choking to death!). LOL Gotta do all there is to win and help out your teammates.