when i watched the race over and over, i finally noticed smarty jones, just as he released a sudden burst of energy. if you watch it several times, you can see the horse shift gears and start his kick for home.
i'm not a horse racing fan, but i had read somewhere that at the end of the race the horses that are not first have run out of oxygen and that is why the winner is the winner. toby read that the autopsy on sea biscuit showed an extra large heart, more capable of delivering oxygen rich blood to the muscles.
smarty jones looked like he was simply running until it became time to sprint home. amazing animal.