. >> reporter: here's john crandall and his friend. when you spend 10 hours or so and 100 miles on someone, you become close. they do endurance racing, a marathon for man and horses. the horse is checked several times by veterinarians to make sure he can continue. these two race in style. he was the only horse to win the triple crun for endurance racing in 2006. >> in the 50 years of endurance racing in america, nobody's been able to have the same horse or same ride erwin all three of the majors, and this horse did it with me, all three of them in the same year. >> reporter: but in 2008 he suffered a life lettenning injury to his back leg. it equates to a professional football player blowing his knee out. >> very close call. you wouldn't expect any horse to come back from that. >> coming back into the sport. >> reporter: they claim back strong. they just took the silver med dpal in an endurance race in -- medal in an endurance race in chile. it would be like leaving annapolis, running four complete marathons and ending up at the beach