Barkley is not a sports competition in traditional sense. It is more like an ultra-ultra running event meets performance art and the very point of the event is to make it harder. Participants understand this and they are not there to compare their performance (sic) to the previous competitors.

Also, competitors are screened by totally different criteria than their previous ultra running successes: they have to write a letter to the organizer explaining why they should participate. Reasons can be something personal, not that they won Spartathlon in Greece in 2010.

There is a short documentary about the event available https://vimeo.com/97270099, and a full-length documentary making rounds at film festivals at the moment https://barkleymovie.wordpress.com/