(for the 2011 50k American Record, go here)
Elite marathoner (and now ultramarathoner) Josh Cox used the 2009 Rock n Roll Arizona Marathon as a starting point to set a new USA Track & Field record for 50 kilometers with an official time of 2:47:17. He bettered the previous road 50K record by over four minutes set in 2002 by Alex Tilson of Palo Alto, CA.
(from RunnersWeb)
"My legs felt fine, but I was having a hard time keeping fluids down," said Cox, who leading up to the race had his sights set on the world best 2:42:10. "It was tough out there, but the crowd support really helped, especially once I got going around the track. I was training such that even though it was an off day, I still got the American record."
Cox overcame two bathroom breaks and an upset stomach, which plagued him over the first 20 miles of the race. His marathon split of 2:20:32 was his best time in the last two years and good for ninth place overall. His final lap on the track was clocked at 71 seconds.
"Marathon is still my sport and 2012 is my goal," added Cox, referring to the Olympic Games in London. "But like when running 50 miles helped my performance in college track, these types of efforts will hopefully help my marathon running. I'd love to come back again and try to lower my time."
(for the 2011 50k American Record, go here) 
