Size doesn't always tell the tale man. I said speed does that's what I mean by velocity. How else are smaller guys knocking the hell out of larger ones in real life. It's because of the velocity. And velocity and momentum are not equivocated in this sense. Velocity refers to the speed at which the defender and ball carrier are traveling. Momentum is the measure of velocity and mass. Thus it is not the same thing although it may be entailed in it. So when you take a scenario, like a back just receiving the handoff and a guy blitzing from 10 to 12 yards deep and by the time he hits the LOS he's at full speed, who's going to win? It's not even a question. The RB's is not at top speed. The velocity of the defender allows him to plant the RB in the dirt no matter his size. How else do you think Steve Atwater destroyed and retired the Nigerian Nightmare. It sure as hell wasn't size. It was the speed at which Atwater was moving vs the speed at which Okoye was moving. Atwater was at full speed Okoye was not. Atwater was only 220 lbs. Christian Okoye was 260 + lbs. Now if it was just size and if size was such a big factor Atwater should have had no chance in hell. But he hit Okoye and not only did Okoye go down, he went BACKWARDS.