Photo courtesy of the Reeve Foundation

That's what motivated John Carson, a triathlete who was struck by an SUV during a training ride just a mile from his home in Long Island, New York. He suffered a serious spinal cord injury that left him a quadriplegic. Carson threw himself into rehab, and (you know where this is going) within a few months, he stunned doctors by slowly, carefully putting one foot in front of the other. Carson still lacks sensation in his feet—his spinal surgeon refers to him as a "walking quadriplegic"—but just one year after his accident, Carson competed in the 2010 Lake Placid Ironman. He then raced in this year's Boston Marathon and, last weekend, in the Coeur d'Alene Ironman in Idaho.

Carson's near-miraculous recovery story provides inspiration for anyone facing insurmountable obstacles. But what really struck us was what Carson decided to do after he exceeded the expectations of his doctors, his family and himself. Carson told The New York Times last week that he was planning to retire from Ironmans after the Coeur d'Alene.

"Racing used to be the most important thing in my life," said Mr. Carson. "But ... this is a very selfish sport. I've done enough. That five or six hours I spend on a bike Saturday mornings, the run on Sunday, I want to take that time I'd be spending out there and put it to better use."

Carson, now 30, told The Times he would rather devote his energy to his wife, his family and his fundraising work with the Reeve Foundation.

It sounds as if his epiphany came not when he lost his physical abilities, but when he regained them. He reminded us that even when we go beyond where we thought we could...we still might need to go a little farther to get where we want to be.

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