Tough Mudder is a 10- to 12-mile course in which participants run, jump, and crawl their way through obstacles, each testing different physical limits. The event pops up in cities worldwide; Becky Smith took on the Tough Mudder event near Chicago for Businessweek.

Photograph by Daniel Shea for Bloomberg Businessweek

Tough Mudder is a 10- to 12-mile course in which participants run, jump, and crawl their way through obstacles, each testing different physical limits. The event pops up in cities worldwide; Becky Smith took on the Tough Mudder event near Chicago for Businessweek.

Photograph by Daniel Shea for Bloomberg Businessweek

Weekend Adventure: Tough Mudder

Tough Mudder is a 10- to 12-mile course in which participants run, jump, and crawl their way through obstacles, each testing different physical limits. The event pops up in cities worldwide; Becky Smith took on the Tough Mudder event near Chicago for Businessweek.

Photograph by Daniel Shea for Bloomberg Businessweek

Smith runs an early part of the course through red smog.

Photograph by Daniel Shea for Bloomberg Businessweek

A major factor of Tough Mudder is camaraderie, as the obstacles often require teamwork. Here participants run through an opening in the course.

Photograph by Daniel Shea for Bloomberg Businessweek

Smith crawls through “Kiss of Mud,” an obstacle that has barbed wire set eight inches above the ground.

Photograph by Daniel Shea for Bloomberg Businessweek

Smith wrings the mud out of her clothes.

Photograph by Daniel Shea for Bloomberg Businessweek

Participants climb the 15-foot-tall “Ladder to Hell.”

Photograph by Daniel Shea for Bloomberg Businessweek

Participants run from one obstacle to another.

Photograph by Daniel Shea for Bloomberg Businessweek

Smith walks over an obstacle called “Twinkle Toes,” which puts participants on a narrow beam of wood over an ice pool.

Photograph by Daniel Shea for Bloomberg Businessweek

A participant works his way through “Dong Dangler,” formerly known as “Ball Shrinker”—due to the body dipping into the ice pond the rope hangs over.

Photograph by Daniel Shea for Bloomberg Businessweek

Smith runs the last stages of the course.

Photograph by Daniel Shea for Bloomberg Businessweek

Smith squeezes through “Boa Constrictor,” an obstacle that forces participants to pull themselves along, due to the narrow width.

Photograph by Daniel Shea for Bloomberg Businessweek

Beers at the finish line are the prize for those who make it.

Photograph by Daniel Shea for Bloomberg Businessweek