As a former Offensive Lineman in college and high school I can give a little insight on these blocking schemes: Zone blocking is the best scheme for quick, smaller lines. Lots of combo blocks & cutoff blocks are used. To run Man-on-Man schemes you have to have strength, power, and size. Also, in Man-on-Man schemes it is VERY VERY important to have offensive tackles that are talented enough to consistantly block smaller & faster defensive ends. Personally, I loved using the zone blocking scheme. Made my life easier. Just to clear things up, teams don't zone block every single play. Some plays require man-on-man and some do not. But the different schemes are used as base blocking schemes from one team to the next. It's hard to say which scheme NT should use. IMO, they should stick with Zone blocking primarily due to their OT's. The offensive tackle on one side is way undersized(unless he's been permantly replaced) and the other is average at best. NT's best lineman are both gaurds. Regardless of blocking style, NT won't have success running when the opposing D has ZERO respect for the passing game. I can't stress this enough. The pathetic play at QB is the main cause for the anemic running game.