My older sister is a runner too. She ran at the same college as I did, in the same events, but she was always faster than me.  I used to think I would beat her someday, if I just trained a little harder or ate a little better or slept a little longer. But the years ticked by, and I was down to only two races left, with more than 10 seconds to cut in a race that lasts less than 5 minutes. But in…