“I tried to explain to her that every good race involved exceeding what felt like my physical limits. If I ran 800 meters as hard as I could in practice, I might run 2:10; in a race, I might run 1:55. Accessing that hidden reserve was anything but a foregone conclusion, and waiting to see how deep I would manage to dig was what made racing both exhilarating and terrifying. (I never did get a date with her.)”