A lone runner emerges on the horizon, covered completely in mud that falls from his arms in chunks. He soldiers up a hill, stopping only briefly before throwing himself between hanging car tires swaying from ropes. He’s smiling a big, goofy grin as he’s battered by the tires and exhausted by the distance—but he wouldn’t be here if he wasn't up for the challenge. Sierra Recon’s muddy courses traverse 4-, 7-, and 11-mile stretches with walls, beams, nets, and ice awaiting runners between the starting line and the after party. The race, which boasts at least two such creative obstacles each mile, attracts both daredevils and their enthusiastic entourages, who holler their encouragement from a dry deck with views of the course. Runners can choose both their difficulty and distance for the race, though all routes promise mud and creative obstacles built by licensed contractors.