The rising popularity of extreme obstacle events such as Tough Mudder, the Spartan Race, and Warrior Dash suggests that Ironman triathletes, ultra-runners, and ultra-cyclists no longer own the title of the most insane athletes on the planet.

Indeed, the suffering brought on by ultra-endurance events–which can include heat stroke, horrific blisters, and just general body pain and tiredness that lasts for weeks at a time–is oh so yesterday. Today, all the cool kids are happily subjecting themselves to electrocution, freezing water, barbed wire, and other hardships common to this new breed of obstacle-course racing.

The Tough Mudder–which has grown from three events and 20,000 participants in 2010 to 35 events and a projected 460,000 participants this year, according to Tough Mudder–asks its racers to endure 25 to 30 obstacles spread out over a distance of 10 to 12 miles.

The “Arctic Enema” is one of Tough Mudder’s more insane obstacles, as it consists of a giant pool of ice that must be swum through. (Just be sure to complete the obstacle before hypothermia sets in!) Another deranged obstacle is “Electroshock Therapy,” which is made with exposed wires that the company claims carry as much as 10,000 volts of electricity. (“Watch out for hay bales and deep mud, or you will face-plant into some electrifying mud,” the race’s website says.) And then there’s the “Gauntlet,” where racers run through high-pressure streams of water that make them “feel like [they're] at a South American political demonstration,” Tough Mudder’s site said. (Yes, they went there.)

The Spartan Race, which is expecting three times the participants in its 36-event series this year than last year, according to a release, offers similar obstacles. But unlike Tough Mudder, it chooses not to tell participants which obstacles will be at which race site. Instead, it simply says that there will be “fire, mud, water, barbed wire, and occasionally Hell on Earth.”

Word to the wise: if Hell on Earth isn’t quite your style, perhaps you should stick to your triathlons and marathons. (Alas, you may have already suffered enough.) But if Beelzebub’s fiery pits pique your interest, you’re in luck. All three race series have several events scheduled for the remainder of the year.

Photos courtesy of Tough Mudder.