The race itself is as freakish as the horses. At 10 furlongs (1.25 miles), the distance is much further than what most of the horses have been asked to run before (most preparatory races top-out at about a mile- racing young colts farther can be dangerous.) If that's not tough enough, the Derby is also a 20-horse race, making for a much more congested and physical field than any of the horses are used to.