Running is getting dirty.

Not in a backstabbing sort of way, but in a jump-in-a-mud-pit, run-through-the-river, climb-a-wall sort of way.

In the past two years, there’s been an explosion of “challenge” races, races that invite runners to form a team, dress up, and push themselves past just running.

“A lot of people are getting into off-road events,” said Jenny Scothern, director of the Ogden-based GOAL Foundation.

This year, GOAL put on its own dirty event for the second time with Hurt in the Dirt, a trail run and bike route that optimizes natural obstacles at Fort Buenaventura. Participant numbers more than doubled this year, with roughly 442 participants versus last year’s 133 participants.

“There’s a huge influx of these events,” said Scothern. “People are living and working and looking for fun and recreation and I think we speak to the people that want to live this recreation lifestyle.”

It seems to have started with the Wasatch Back Ragnar Relay, a race started in 2004 that put a twist on the regular running routine, combining 12 runners into teams that raced throughout the night. From there race directors jumped on the “running with a twist” trend and began offering all sorts of variations on the traditional race.

Rob Leishman, director of the Kiss Me Dirty race series, said Wasatch Area Race Productions decided to put on an adventure race for the first time this year to provide participants with a great party atmosphere. The organization’s women-only event sold out at 1,900 participants at Wheeler Historic Farm in Murray and fielded 800 participants at Ogden’s Golden Spike Arena this summer.

“People have just been really enthusiastic about these races because they want to go out and have a good time, and adventure race directors are setting the atmosphere,” Leishman said. “People want to get together, have a good time, and do something that’s fun and requires a little fitness and that gives them a little challenge in their day-to-day lives.”

There were plenty of running races in 2010, but only a few, like Hurt in the Dirt, or the Dirty Dash in Salt Lake, offered obstacles. In 2011, runners could choose from a huge variety of races that included challenges other than mud: The Spartan, a fire, mud and gladiator race; The Battle for Nobility Foam Fest, which incorporated slip n’ slides, climbing obstacles and foam; The Vigor Stairs, with participants running more than 3,500 stairs; or the Gut Buster, an obstacle race that tests balance, speed and agility. Racers can be either extremely hardcore or extremely party, depending on the person and the race.

Julie Davis, a Clinton resident, participated in the Golden Spike Kiss Me Dirty race, which also raises funds for cancer research. She said that as a cancer survivor she not only appreciated the opportunity to raise funds for cancer research, but the opportunity to let her hair down. She and her team, The Dirty Mother Truckers, dressed up like Larry the Cable Guy and had fun throwing mud and climbing obstacles.

“We all dressed up as a team, and we felt united as a team,” said Davis. “I have some bruises on my shins from trying the obstacles. I didn’t come away very clean. I was really surprised that my shoes came clean. I did throw away my socks, and I found dirt in places I shouldn’t.”

Melissa Watkins, a West Haven resident, tried her first dirty run for her 30th birthday this year. She ran the Kiss Me Dirty race with friends at Wheeler Historic Farm.

“The thing that was nice was that you could tell everyone was having fun,” said Watkins. “Everyone was wrestling in the mud; we got in mud fights. It was fun to be in that kind of atmosphere. I was surprised. I thought it would be fun, but I was surprised at how fun it was. I’m not a girl that likes to get dirty, and I still got dirty. It was just fun to be with all friends, running and having fun and not worrying about when you finished.”

Jordan Strebel, a Roy resident, started running regular races this past year and is signed up for her first obstacle/mud run on Sept. 17. She’s been strength training to prepare for the obstacles and hopes that running will be even better when there are obstacles involved.

“It sounds more fun,” said Strebel. “It‘s an obstacle course for the fun of it, and you get to dress up and make a fool of yourself. I think it really helps with when you run a race and all you’re doing is running and you’re just cussing things, but with an obstacle course you’re jumping over hay bales, climbing over a wall and it’s exciting. Running can get redundant.”

There are still two local challenge races to sign up for this year: The 5K Foam Fest Race for Nobility in Ogden Sept. 23-24, or The Dirty Dash 10K at Solider Hollow taking place on two weekends, Sept. 17 and 24.