Journalist David Epstein tells the story of Jill Viles, who has muscular dystrophy and can’t walk. But she believes that she somehow has same condition as one of the best hurdlers in the world, Priscilla Lopes-Schliep. (36 minutes)

David Epstein is the author of The Sports Gene: Inside the Science of Extraordinary Athletic Performance. Read more from David about Jill and Priscilla and see photos at ProPublica.