If it weren’t for the margaritas, Allison George may never have registered for the Warrior Dash.
George, 37, admits to rarely visiting her gym, and counts walking her dog as her main form of exercise. But while vacationing in Mexico last December, she and her sister, Michelle, signed up for the event, which bills itself as a “mud-crawling, fire-leaping, extreme run from hell.”
“I secretly thought we'd back out come race time, because the prospect was terrifying,” said George, from Tigard, Ore. “But we did it!”
Obstacle races like the Warrior Dash have exploded in popularity over the last decade, with hundreds all over the country. The first Warrior Dash, in Joliet, Ill., in 2009, sold out with 2,000 participants. This year, 650,000 Warrior Dashers have competed in 33 events, from Florence, Ariz., to New South Wales, Australia. And though the very first mud runs were Marine Corps events, today’s obstacle races are open to everyone — serious athletes, weekend warriors and couch potatoes alike.
More from TODAY.com
TODAY's Takeaway: 'Princeton Mom' says mate, don't wait; Miles O'Brien talks life after amputation
- Oscar selfie drawn with pencils in new time-lapse video
- Smartie pants! New clothing line's models are all women with Ph.Ds
- Debunked: Cohabitating couples not more likely to divorce
- Awww! Rolling Stones' Keith Richards pens picture book for kids
- TODAY's Takeaway: 'Princeton Mom' says mate, don't wait; Miles O'Brien talks life after amputation
The races are typically off-road, 5K or 10K in distance (3.1 and 6.2 miles, respectively), with lots of mud and obstacles in between. Warrior Dash participants have been asked to climb over cars and slog through waist-high puddles. The original Mud Run, started by former Marine Paul Courtaway, takes participants through grueling, military-style challenges such as climbing up an 8-foot tower and leaping into a pit of mud.
Why would anyone want to do this? “It seemed like a fun challenge,” said Eric Yeaney, a 43-year-old stay-at-home dad from Marietta, Ga. Yeaney participated in a Warrior Dash last May, and then the Down & Dirty race on Oct. 16. And though he’s a seasoned distance runner with a half Ironman under his belt, Yeaney said his first obstacle race was really tough. “I was in pretty good shape, and I was dogging it the whole way.”
Yeaney incorporated weight training into his workout regimen, and finished the Down & Dirty 10K event in 61 minutes. He’s already signed up for next year’s Warrior Dash. “They’re fun. It’s different. It’s like an adult playground. You’re climbing and getting dirty and I think that’s the appeal,” he said.
And really, said Courtaway, you don’t have to train for an obstacle race at all — though the Mud Run site includes tips on how to get conditioned for each challenge. You can come out and walk it and even skip obstacles if they freak you out. “But if you’re an athlete, the harder you attack the course, the harder the course attacks you back,” said Courtaway.
There are few places wetter and muddier than Seattle in November — and that’s what makes the Winter Pineapple Classic such a blast, said organizer Wilma Comenat. “The worse the weather, the more fun people will have.”
It doesn’t hurt that the 5K race, held in North Bend, Wash., has a Hawaiian-style luau at the finish line. Participants register in teams of two or four, and costumes are encouraged. The kicker: Someone on each team must carry a pineapple at all times. “It’s really, really fun to see the expression on people’s faces when they see that they have to carry the pineapple,” laughed Comenat.
And even people who are serious about fitness, like Yeaney, say that they love the fact that these races aren’t serious. Allison George, the Warrior Dash participant from suburban Portland, loved the crazy costumes people wore to the event, and the camaraderie.
“It wasn’t a bunch of macho guys trying to run you off the course. Everyone was supportive — they’d run by you and say ‘Go! Keep it up! Good job!’” she recalled. And when the obstacles were tough, total strangers would work together to help each other out.
The races, though, aren’t without risks. A 28-year-old man died from heat stroke after competing in the Kansas City, Mo., Warrior Dash in July; another participant collapsed during the same race and died days later from an infection. A 32-year-old woman from Arlington, Tex., fell from an obstacle at a Bakersfield, Calif., race and dislocated two vertebra.
Courtaway said that he’s never seen a serious injury at a Mud Run, and that heat-related injuries and deaths can be avoided by not holding the events when temperatures are historically averaging in the 90s or 100s. Still: “No one comes out of a mud run without a cut or scrape,” he said. “You’re climbing a 20-foot tower. If you fall, it’s not going to be good.”
For many, though, the rewards outweigh the risks. Michelle Posey, of Little Rock, participated in Little Rock’s Dirtiest 5K on Oct. 29 because she wanted her two boys “to see that mommy was cool enough to run through the mud.” Posey, 42, had shot the event several times while working as a staff photographer for the Arkansas Democrat-Gazette, and had always wanted to try it.
“We tell our kids so much, 'Stay out of the mud,' but it’s actually OK for them to not care sometimes and get dirty and enjoy themselves,” she said. “It’s part of being a kid, and it’s also part of being a grownup, too.”
© 2013 NBCNews.com Reprints