I heard Jim Boeheim on ESPN last night explain why he decided to start playing the 2-3 zone defense, his players were under sized back then and he felt like it was the best opportunity for his team to be able to compete and win against the bigger teams, he also said that they had very little depth so they needed to keep their starters on the floor and out of foul trouble, they did such a good job at playing this that he decided to continue playing it even after they started getting good big men. He also said that when you get into playing conference tournaments that it really saves his players legs and feels that is why his team is able to play 3 or 4 games in as many days, he also went on to talk about why so many teams play mostly a man defense because it is a macho thing.