First, read Leslie Jamison's essay, "Immortal Horizon." It's from her collection, The Empathy Exams. The whole book is great: I just finished teaching it to 4 sections of college writing (that's 82 copies, Leslie!) But "Immortal Horizon" really lays down what you need to know about this event--the Barkley Marathons. Jamison's brother, Julian, attempts the race in 2010: like most people, he doesn't finish. But Jamison is his support--a necessity for what's been dubbed "an un-runnable race," among other things. It's not surprising that this essay influenced a film. When my students read they essay, they Googled up pictures and videos that participants posted. They asked themselves (and me) whether this is a good thing or an insane thing. Maybe it's both. What most people learn from the race is who they are, how much they can take, and why they must stop. That used to be what running a marathon did; but these days, running a marathon is a very catered event: water and electrolyte drink at every mile, emergency services, roads closed to traffic, snacks, spectators, cheering squads, live music, and, by Barkley standards, virtually no elevation gain or loss. These days, Oprah can "run" a marathon. Barkley gets back to testing humanity--to reminding us that people are animals. This race isn't about negative splits or keeping your heart rate in an optimal place: it's about simple survival, and figuring out just exactly how far you can go. After you've read the article, watch the movie.