Despite feeling ill and being unable to keep liquids down for over 1/3 of the race, Josh Cox still managed to set the American mark in the 50k in 2:47:17. That beats Alex Tilson‘s 2:51:48 set back in 2002, but was a bit short of Thompson Mugwana‘s 1988 world record time of 2:43:38.

Cox ran his record at the Arizona Rock ‘n’ Roll Marathon, where he went over the marathon finish line in 2:20:32 only to continue on to a nearby track to run 19 laps and bring his distance up to a full 50 kilometers.

“I felt good at about mile 14, and then for the final two laps,” Cox said. “I had a lot of stomach issues, I don’t know why. Maybe I overcompensated for going the longer distance. Maybe I took on too many fluids early in the race. I just kept throwing down fluids. But I didn’t have any after 20 (miles).”

If you are curious about just what type of training you need to do in order to run an American record in a race like this, just watch this workout that he ran with Ryan Hall last November:

(More Info: USA Today)