Eric McElvenny was a U.S. Marines captain in Afghanistan when he stepped on an improvised explosive device in late 2011. After surgeons amputated most of his lower right leg, McElvenny received an email from his commanding officer who wanted to know when he'd be running his first marathon. McElvenny decided to take that motivational suggestion even further by competing in triathlons, including several at the Ironman level. Those consist of a 2.4-mile swim, a 112-mile bike ride and a marathon (26.2 miles).

For his latest challenge, McElvenny is preparing to tackle the 106° West Triathlon at Lake Dillon in Colorado on September 10. The distances are 1.2 miles of swimming, 56 miles of biking and 13.1 miles of running. But the real killer is the elevation, which starts at nearly 9,100 feet and maxes out at 10,291 feet.

Crazy? Yes. But as McElvenny says, "That sounds like a reason to go do it."

Here is more about McElvenny, 33, a U.S. Naval Academy graduate who now lives in the San Diego area and works as an inspirational speaker.

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