Ryan Bak and Julie Lossos weren't particularly creative with their costumes for the GO! Halloween 10K on Sunday. They dressed as competitive runners, both in the team colors of Big River Running, and performed as such, winning the men's and women's divisions of the inaugural race.

Bak crossed the line in 30 minutes, 18 seconds, ahead of teammates Dan Strackeljahn of Lockport, Ill., and Adam MacDowell of St. Louis, who finished in 30:50 and 30:54, respectively.

The trio ran with a handful of other runners for the first couple of miles before Bak made a solo move from the pack about 2 1/2 miles into the 6.2-mile race, which started and ended at the Soldiers Memorial and traversed through downtown and Soulard.

"It's a fun course, running through the different neighborhoods," Bak said, "but it's a tough nut."

Bak moved to St. Louis over the summer, when he became assistant cross country and track coach at St. Louis University. He was the 2002 NCAA Division III cross country and 1,500-meter indoor champion, running for Trinity College in Hartford, Conn. He later moved to Eugene, Ore., competed professionally and was a member of the U.S. team at the 2008 world cross country championships.

"I knew about Big River and some of the runners here," Bak said. "St. Louis has a really strong running community, and they've reached out to me."

Just as the Big River men dominated the men's race, Lossos lived up to the honor of wearing race bib No. 1, given to her by race director Brian Lyons.

"He said, 'Women never get Number 1, so we're going to give it to you,'" Lossos said. She crossed the line in 35:29, ahead of Jackie Pirtle-Hall of St. Charles and Katie Hauser of Columbia, Mo., who finished in 37:03 and 37:09, respectively.

Lossos, winner of the 2001 St. Louis and 2006 Lewis and Clark marathons, said she kept pace with masters runners Juan Arias and Mitch Figas "as long as I could. I learned I'm a better uphill runner than a downhill runner. There are some tough hills out there, but it was great. I can't remember the last time I entered a 10K, so I think we need this race every year."

GO! President Nancy Lieberman declared the first-time event "wholesome fun" and said she hopes to see the run grow.

"New runners like to start with 5Ks, but as they mature, they want to try a longer distance," Lieberman said. "The 10K is what they graduate to. We're trying to tap into a bigger community, not just the serious runners."

Trailing the winners were about 2,600 runners of varied abilities and costumes. Among them were Cortney and Ryan Schroeder, transplants from frigid Milwaukee. With the temperature in the mid-30s, they shivered before the start, burying their faces and noses behind matching ghoulish-green bandannas.

"We've got to get acclimated," Ryan said, leaning for warmth against wife Cortney, who added, "We figured it's the first annual race, how could we miss it?"