I also think it's eaiser to change from zone blocking to man blocking than going from a 4-3 on the D-Line to 3-4 on the D-Line. That's alot more beef you're taking on when going from 4-3 to 3-4 and having to provoke a constant double team on yourself. In regards to Man blocking as opposed to zone blocking the difference is verymuch fulfilled through the difference in names. Man blocking you are to take your accounted for defender out of the play and once you do engage to move up field and block the 2nd level of the defense. In Zone, the OL has to engage in a specific area to create holes which are more consitant (3-5 yard runs) yet may not be as large gains at times as man blocking because it does not consist as much of blocking beyond the first level and therefore the RB is to make one cut and accelerate from there. Man blocking the RB must wait more for the blocks to evolve and then burst,it's very common to have to make more than one cut. The more fluid the RB is in his cuts in this scheme the more effective the RB should be, thus the Felix Jones factor. Barbarian is very effective in the 1 cut scheme.