As the name of the obstacle implies, you’ll be running through a trench of blazing, kerosene-soaked straw. You can expect flames at least 4 feet tall. While the flames might seem like the most intimidating aspect of this obstacle, Mudders℠ often forget that with fire comes smoke. Take a deep breath before you enter this obstacle because believe us, you don’t want your lungs full of this thick smoke. Build up your lung capacity while training for Tough Mudder or you’ll be forced to inhale some nasty carcinogens.