Source: http://www.thewire.com/culture/2014/03/h...

18-year-old Kayla Montgomery is one of the best runners in the country. She also suffers from multiple sclerosis. Those two facts are not unrelated.

The New York Times detailed the surprising rise of Montgomery, who has turned the seemingly debilitating disease into an athletic advantage. MS is a degenerative disease that blocks some of the nerve endings connecting Montgomery's legs to her brain, particularly when exercising, and so she loses feeling in her legs when she's running at top speeds. That means that her legs don't feel tired — in fact, they don't feel anything — during races, and she can maintain a sprint in cruise control all the way to the finish line.