BOULDER, Colo. (AP) _ Some came to mountain bike in their underwear and others were motivated by the promise of free beer. But it was the prospect of getting really dirty that brought Chris Phillips to town for an offbeat, obstacle-filled running and biking race.
``One thing was on my mind the whole time: the mud pit,'' Phillips said after finishing the final obstacle of the Muddy Buddy race. ``Plus, it was hot, and I was ready for a little cool down.''
The Muddy Buddy, a six-mile duathlon that ends with an Army-style crawl through a 50-foot-long mud pit, attracted more than 1,600 racers recently to the Boulder Reservoir. Two-member teams traded off between trail running and mountain biking, with each leg divided by a giant air-filled wall, monkey bars or some other kind of obstacle.
Some racers dressed up as pigs or superheroes with red capes and tiaras taped to their bike helmets. One scantily clad couple wore white tank tops and briefs.
``It's definitely different,'' said Phillips' race partner, Andrea Pietka, a first-time Muddy Buddy racer who thought the event would be a good break from her marathon training. ``All the mud and the water and the obstacles, it makes you not feel the pain of running. Well, you still feel the pain, but it's more fun.''
Thousands of active people are getting creative when it comes to competition, finding odd or at least more entertaining ways to race outside the typical 5K and 10K runs. The Muddy Buddy is among dozens of offbeat events around the country gaining in popularity, from mud-filled relays to so-called Red Dress Runs, where everyone _ and that means everyone _ wears a dress.
A 10K run scheduled for Oct. 22 with river crossings, five-foot walls in mud pits and other obstacles at Camp Pendleton, Calif., sold out in August. The base also sold out its Mountain Warfare Training Challenge, a 10K off-road run with a tire course, tunnel crawl and water obstacles held at the remote, high-altitude Marine Corps Mountain Warfare Training Center.
In Kansas City, Mo., entirely underground 5K and 10K runs are held to celebrate Groundhog Day at a subterranean business complex. There are ``Urban Assault'' races in Seattle, Richmond, Va., and other cities that allow mountain bikers to maneuver bridges, railroad tracks and other city obstacles.
``I think it's tied to the whole extreme sport mentality. Traditional sports, for some people, just don't cut it,'' said Ryan Lamppa, spokesman for the Running USA trade group.
For the more relaxed athletes, Red Dress Runs in San Diego, Washington, D.C., and a host of other cities around the world call for runs of three or four miles along city streets, usually with several pub stops along the way.
``Some people love this kind of stuff, but it's still a very small percentage of our population. If it were more, I'd be scared for our country,'' Lamppa said.
The Muddy Buddy race series began seven years ago and now brings its mud pit and laid-back atmosphere to seven cities around the country _ including Chicago, Boston, Richmond, Va., San Jose, Calif., and Austin, Texas. The series will wrap up in Los Angeles on Oct. 23.
The races will attract about 11,000 participants this year, race founder Bob Babbitt said.
``A lot of people are just getting into the fitness thing. And this is where it starts, events like Muddy Buddy,'' said Babbitt, an Ironman triathlete who wears a lime green frog costume during the Muddy Buddy races. He said finishing times range from 40 minutes to 1 1/2 hours.
``You can do this, your 80-year-old grandma can do this, everyone can do this,'' he said.
During the Boulder event, racers started with a jaunt down the sandy banks of Boulder Reservoir and slogged through thigh-deep water before starting their first running or biking leg. The most anticipated obstacle _ for racers and spectators _ was the giant mud pit at the end of the course.
Phillips and Pietka, both 26, crossed the finish line and headed straight to the reservoir to join dozens of other racers washing off. Still dirty, they picked up some free tacos and joined their friends for free beer.
``The race was fun, but the fish tacos and the beer garden helped, too,'' Phillips said. ``It was that kind of race. Just fun.''