You may have run a marathon before, but how about an ultra-marathon? The International Association of Ultrarunners considers three types of races to meet their standards: the 50k, the 100k, and the unique 24-hour race.

24-hour races aren't a new concept, but they aren't exactly well-known. Instead of trying to cross a finish line with the quickest time, the idea behind 24-hour races is to complete as many miles as possible in the full-day period.

Steve Ireland, a 30-year-old teacher from Westville, New Jersey, will be competing in his sixth Back on My Feet 20in24 race. “With the marathon, you have to be dead-on with every pace through the race; it’s stressful. With a 24-hour race, it’s not necessarily like that. You go out there in a more relaxed atmosphere and talk to people while you’re on the course," said Ireland.

Steadily gaining notoriety, 24-hour races could quickly become a regular thing. In May, the United States men's and women's teams won gold medals at the International Association of Ultrarunners World 24-Hour Championship. If the endurance-based marathon continues to gain popularity, it's likely that more official tournaments and events will arise.

Interested in testing your racing resolve? The Stroehmann Back on My Feet 20in24 takes place in Philadelphia tomorrow, and you can register for the event on-site. Back on My Feet is a nonprofit organization which teaches running skills to the homeless. Support a great cause and take your racing to new heights with a 24-hour marathon. But first, pick up one of The 10 Best Sneakers for Long Distance Running.

[New York Times]

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