Participants in the annual Barkley Marathons are allotted just 60 hours to claw through more than 100-miles of unmerciful wilderness, enduring extreme temperatures and changes in elevation that equate to climbing up and down Mount Everest. Twice. Since 1986, only fourteen out of over 1,000 participants have finished the event.

In "Barkley 100," filmmaker Brendan Young's spellbinding documentary on the world's most ruthless trail race, veteran Barkley-runner Ed Furtaw says the event is "purposely adjusted and created to be at the limit of possibility." And Furtaw would know. In 1988, the accomplished ultramarathoner became the first person to complete the then-55-mile event. The next year, Gary Cantrell – the race's cigarette-smoking creator and director, who comes across as the kind of sadist you'd love to share a beer with – responded by nearly doubling the course's mileage. A competitor would not complete the newly updated 100-mile route (which, given that participants must navigate not by GPS, but by map and compass, is often experienced as 130 miles or more) for another six years.

The Barkley, in other words, is not impossible, but it's close. In this way, the event is presumably different from the Kobayashi Maru test, the infamously "unwinnable" mission simulation administered to Starfleet cadets in the Star Trek Universe .

In both cases, however, what is said to be "possible" or "impossible" ultimately boils down to technicalities. The various ways in which Starfleet cadets have circumvented the Kobayashi Maru's "irremediable" circumstances indicate that the test is a no-win scenario in name only. Similarly, with a completion rate of less than 2%, The Barkley is, for all intents and purposes, an unfinishable race. "All the other big races are set up for you to succeed," Cantrell is famous for saying. "The Barkley is set up for you to fail."

Of course, neither the Kobayashi Maru nor The Barkley is about "winning" or "losing," as such. The objective of the Starfleet test is not for the cadet to rescue the Kobayashi Maru, but to evaluate that cadet's constitution in the face of a seemingly impossible task. It is, by its nature, an exceptionally revealing test of one's personal makeup. The most individualized of assessments.

That Cantrell allows not just elite athletes, but anyone, to race the Barkley suggests his race serves a similar purpose. People who run the Barkley, he says, thrive on challenges, and while most of them are used to succeeding, "they're not afraid to try something where they'll probably fail." It appeals to them, he says, "to know that they have to fight the odds."

"It comes down to each person's individual mental strength and physical capability," Cantrell says in the documentary, his eyes bright and mischievous:

We set up the lottery so that it's not just for the elite athletes, because I think everyone should have chance to really put themselves to the test. And you haven't really tested your limits until you try something you can't do. Then you know where your limit is. It's right there where I quit. That was it.

[Brendan Young - "Barkley 100"]