I don't see why stumbling and falling would stop you at all. Not just me but anyone I know would stand back up right away like nothing, a few scratches ain't a problem.
@ViEmlleSzDias Serious answer, it's basically just an anime trope. They participate in a race then fall flat at the end. I've seen it too many times now.
You can see he's athletically better than Ohga since he outran the person but at the end, when he fell, his healing and reaction rate isn't as good as a high schooler. :> Well.. that's the answer I'll go by