Yet we all hold out hope that on this Patriots' Day the stars will align for us—my body will respond to all the hard training I've done, Mother Nature will hear my heartfelt pleas, I'll put together the race of my dreams. In this way, preparing for a marathon is a bit like planning for a miracle.

The marathon is the essence of the unknown transforming into the known; there's always as much potential for destruction as there is creativity, as much chance of misery as there is elation, as much room for heartbreak as there is for triumph. That's the fun of racing a marathon. It's about seeing if you can go to the very edge without going over the cliff.