All it takes is one tiny thing to go wrong in any area and you're done.' After that, that's where it really starts to go to pieces and you have to hold it together. 'It was a heck of an experience,' said Kelly, who grew up near the course in Joyner, Tennessee, and now works for Lockheed Martin in Maryland. No other runner completed more than two laps. Only one other runner, John Kelly, a 30-year-old electrical engineer from Rockville, Maryland, completed three laps this year before quitting. It was a boundary I wasn't prepared to cross, and I quit.' Three Laps I spent some time thinking about what that might mean and where I was going. 'I passed out or collapsed,' said Bixley, 42, a quantitative geneticist with New Zealand's AgResearch. Instead, he found himself lying, passed out, on the ground after completing more than 48 miles in about 28 hours of running and climbing through the mountains of Frozen Head State Park. His said his goal was to see what he could find out about himself. Matt Bixley traveled from Dunedin, New Zealand, to compete. Cantrell and others contemplated organizing a search party for Coury if he doesn't return by nightfall. iStock Missing runnerĪs of Monday afternoon, one runner - Jamil Coury of Phoenix, Arizona - hadn't returned to the start/finish area in the 24,000-acre park, 17 hours after beginning his fourth lap. 'You don't come here to be victorious, you come here to be humiliated,' says one runner who failed to complete the 100-mile Barkley Marathons in Tennessee.

With a finisher rate of about 1 percent, the Barkley has been labeled by many as the world's hardest race.

In 30 years, 14 out of about 1,100 runners have completed the race, made up of five loops around a mountainous 20-mile course. It's a competition between the humans and the mountains.' 'The mountains won,' said Gary Cantrell, who created the event in 1986.

None of the 40 runners who attempted to finish the 100-mile Barkley Marathons in the mountains of eastern Tennessee completed the race, the first time since 2007 that the race had no finishers.

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