Would you sign up for an event that could paralyze or kill you? A lot of people are – it’s mud-run races! Those are outrageous obstacle courses where you run through electric wires, crawl through muddy trenches and swim fully dressed. They go by names like Warrior Dash, Spartan Race, and Tough Mudder – and millions of people compete annually.

They’re so tough, a lot of times you have to sign a death waiver ahead of time. Unfortunately, that waiver isn’t just to scare off the weak.  It’s legit – because a lot of people are getting injured, paralyzed and even dying while competing.

One Texas man recently died after drowning on a mud run. And other people have suffered paralyzing injuries, and E. coli infections from contaminated mud. And after one mud run in Wisconsin, 26 competitors were hospitalized – including one with a fractured neck vertebra.

Also - know this. The biggest danger in mud runs isn’t the electric wires-obstacle or even slogging through the mud – it’s the swimming part. Researchers from the Minneapolis Heart Institute Foundation analyzed fatalities in 3,000 mud run type events and found that 92% of deaths occurred in the water.

Researchers explain that no matter how strong a swimmer you are, water-logged clothes and boots can pull you under water. It’s like tying weights to your legs. In fact, the study found that the more competitors were in the water, the greater your odds of drowning because panicked racers would try to grab onto other people to save themselves – pulling both of them underwater.

But organizers defend the mud runs. They say that there’s risk of injuries during any sporting event. But insurance underwriters say that mud runs have gotten so out of control – and are refusing to issues policies for new events. And if the events become too dangerous – they’ll disappear.