Instead, runners have to make notes from a master map and then navigate their way through often thick undergrowth with nothing more than a compass. Oh, and there are no fixed trails to follow. Gradients are commonly steeper than 40 degrees. Runners who make it to the end will ascend and descend 120,000 feet - the equivalent of climbing up and down Mount Everest twice. What makes the Barkley so fiendishly tough is the unforgiving terrain of Frozen Head State Park in Tennessee. There are many longer ultra-marathons, some of which take place in 40-degree heat. To complete the Barkley Marathons, you need to navigate five 20-mile loops of the course within 60 hours. Indeed, in its 33-year history, there have only been 15 finishers in a field containing the world’s most elite ultra-marathon runners. It took place last weekend, but you will not find any list of winners: for the second successive year no-one completed it. More mean-spirited than Jose Mourinho protecting a 1-0 first-leg lead, more devious than an Eddie Jones press conference.

Billing itself as the “Race That Eats Its Young”, the Barkley Marathons is the most evil event in sport.

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