It's still plausible. There's never been much daylight through 40 yards when you're comparing the quickest football players & the quickest sprinters. Football speed IS burst speed. The difference between an elite running back like Bo & an elite Olympic sprinter is the sprinter maintains his top speed significantly longer than the RB does. Bo's mass was almost certainly a drag on his sprint potential, too. He weighed 225 pounds when he ran his 10.39 PR in college. That's a lot of inertia. Bo actually was hoping to make it to the Olympic trials that year but he didn't hit the cutoff mark.