Long ago, I went a couple of times to serve as "handler" for a friend who was attempting the Old Dominion 100, a race for which humans may go afoot 100 miles, a

Long ago, I went a couple of times to serve as "handler" for a friend who was attempting the Old Dominion 100, a race for which humans may go afoot 100 miles, and horses may compete over 50 or 100 miles. I was interested to see that at intervals the horse had to be checked by a veterinarian, who as I recall checked the horse's heart rate at arrival, then after a few minutes of rest. The humans were checked for health problems the day before the race, not thereafter. (A handler drives about with dry clothing, spare shoes, snacks etc. At the Old Dominion 100, a handler may also accompany the runner over some portion of the end of the course--33 miles the second year. This I think is chiefly to provide a second source of judgment for the exhausted runners.)