Another infamous obstacle, and a postcard image for Tough Mudder, the Fire Walker is truly one of the most badass obstacles. You’ll run through a trench of kerosene-soaked straw, blazing in four-foot high flames licking around your feet and legs and behind. Get out quickly, and don’t look back. Watch out for wet straw underfoot, sometimes kerosene makes the floor slippery.
Hint: Train by building up your lung capacity with explosive aerobic exercise. Do 100-yard sprints in sets of 5 on a local football field. This way, when you’re mid smoke-cloud, you’ll have the capacity to hold your breath and avoid inhaling nasty carcinogens.