Teen with MS becomes running star, wants to 'keep running forever'Play Video
Bernie Sanders Supporters Walk Out Democratic Convention
Bill Clinton Describes How He Once Told Hillary She Shouldn't Marry Him
'Mothers of The Movement' : They're With Hillary
Clinton Becomes First Woman Presidential Nominee of Major U.S. Party
She has gone from being one of the slower runners on her high school team to one of the fastest distance runners in the nation, a rise fueled by an improbable motivation.
Three years ago, Kayla Montgomery, 18, was diagnosed with multiple sclerosis, an incurable yet treatable disease of the central nervous system.
While Kayla can run long distances without feeling pain in her legs, when she stops, her limbs give out and she collapses. As she crosses the finish line, her coach catches her to keep her from falling.
"Probably a mile or so in, I start to lose feeling," she said on TODAY Saturday. But she keeps going. "I don't really focus on it. I just kind of ignore it and focus on finishing my race and everything else."
Kayla told TODAY's Erica Hill and Lester Holt that she kept running after her diagnosis because she didn't want people to think she was any different.
Kayla was also profiled in Tuesday’s New York Times, in a story that explained that her condition blocks nerve signals from her legs to her brain and describes how her legs gradually go numb as she races yet become uncontrollable when she stops.
At the time of her diagnosis, Kayla was among the slowest runners at Mount Tabor High School in Winston-Salem, N.C. But she was determined to improve her times, despite her condition.
"Instead of letting it stop me from running, I've used it to motivate me to break records,” she said last week on TODAY. "This past cross country season I was undefeated by any other North Carolina runner."
Now, she’s one of the nation’s fastest female distance runners, so good that she trains with the boy’s team, according to TODAY, and she receives no special treatment.
MS can cause muscle weakness, balance problems and in the most severe cases, paralysis. It’s not known how Kayla’s illness will progress, but she is making her running days count.
"Since I know that my mobility is a gift right now, I guess I make every day that I run as best I can, so I don't waste that gift," she told TODAY’s Natalie Morales.
When describing how it feels to run, she said "it kind of feels like I'm just kind of floating," adding, "there's nothing underneath me."
Teen with MS becomes running starPlay Video
Construction worker plays live action 'Where's Waldo' with kids at children's hospital
Give It Away: 5 lucky viewers win juicers from KLG, Hoda
'Percy Jackson' star Logan Lerman talks about new film 'Indignation'
NFL star Travis Kelce: I'm looking for love on 'Catching Kelce'
While some may say that the inability to feel pain is a competitive advantage, Kayla’s doctor says the key to her success is her attitude, not her illness.
"If any benefit is to be gained by her disease, it’s a mental edge, not a physical edge," says her neurologist, Dr. Lucie Lauve.
Kayla’s parents, Keith and Alysia, were devastated when Kayla was found to have MS.
"Finding out she had MS was gut-wrenching,” her dad said.
"I was thinking about, like all of the things that she maybe wouldn't get to do,” said her mom.
But they have been amazed by her accomplishments.
"I don't know how much faster she can get,” Keith Montgomery said. “I never thought she could get this fast, but at this point, I've quit doubting.”
Kayla’s coach, Patrick Cromwell, has also marveled at her progress.
"Is she going to be an All-American or Olympian?” he said. “I don't know. But I would have never thought she would improve eight minutes in four years either."
Later this month, Kayla is due to compete in the national indoor track championships in New York and she is headed to Lipscomb University in Tennessee in the fall.
She said on Saturday that she hopes to keep "running forever."
Lisa A. Flam is a news and lifestyles reporter in New York. Follow her on Twitter: @lisaflam