Inspired by military training, mud runs involve, well, running through mud, and overcoming challenges – like obstacles that must be climbed over or pipes that must be crawled through. The problem is, no matter how fit you are, mud runs are dangerous. Because mud is slippery, it’s easy to lose your grip and fall during challenges that involve holding on to ropes or monkey bars. Slipping and sliding with other bodies around also increases the risk of injury.
And it’s not just hypothetical. One U.S. man was paralyzed after an awkward landing in a mud pit and a Texas woman was badly burned on her arms after falling into a fire contestants were supposed to jump over.