It’s 14 degrees and your feet are numb.

Keep pedaling.

That’s cyclocross, or cross, as some call it. And a bullet proof crusting of snow over a tough, rolling course laden with obstacles is perfect.

The century-old sport is known for mixing brutal temperatures and winter conditions with running, cycling and pain.

“It’s kind of like being in circuit training at the gym,” says cyclocross racer Chad Cheeney, splattered in mud, with gunk and slush falling from his bike. “You’re doing one thing and then you switch to the next. And when conditions are like this, every lap things are changing.”

Professional cyclist Ben Sonntag says a sloppy course was ideal.

“That’s cyclocross,” he says. “Sounds a little crazy, but that’s what we live for.”