Peanut butter. Tacky. Cake-powdered glue.

Those were the words bikers used to describe the muddy conditions at the Santa Rosa Cup CX, where cyclo-cross bikers raced through a course of mud, grass, sand and obstacles to designed to test their mettle.

"There's a whole lexicon for biking in dirt," said Laura Schniedwind, 30, a lawyer from San Francisco. "Beer, bikes, mud, good combo. It's like you're a little kid, you're going out there and getting dirty, and your mom's not yelling at you."

The race, now in its fifth year, was held at A Place to Play, a park in West Santa Rosa with an appropriately gritty history, considering that it was built on former wastewater storage ponds.

The sport began as a way for racers to stay fit in the winter, when the roads are muddy and wet, said Greg Fisher, 37, marketing director for Bike Monkey, which co-organized the event.

"There's dismounts, there's mud, there's sand in places," Fisher said. "The idea is to challenge the body in a way that you don't normally see."

The coveted muddy conditions changed quickly throughout the day. The course's sandy patches were wet enough in the morning that cyclers had to carry their bikes through the muddiest stretches, sloshing and panting, some drooling as they raced, testing and pushing their limits.

"Ignore the pain. Ignore common sense. Persevere," said David Gill, 43, an architect from Berkeley who spent his birthday at the race.

"You have to really think about what you're doing, and you have to keep your momentum going to keep the mud flying off," said Thom Fox, 59, an executive chef from San Francisco. "And don't be afraid to let the bike move around."

With mud speckles on his eyeglasses, Fox finished first in his category.

Early morning races started at 8:30 a.m., before the ground had a chance to dry out from yesterday's rains. Organizers expected 250 to 300 riders throughout the day.

In the junior race, Sam Ouzounian, 10, of Moraga, wound up carrying his bike through three-quarters of the course. Even so, he had fun.

"My strategy was to stay on the grass as much as I could," Ouzounian said. "It was just so muddy. I didn't want my bike to get clogged."

Ouzounian waited in a line of adult bikers for a hose to power-wash the mud chunks off his bike, the ground surrounded by chunks of dirt as big as small cats.

By late morning some of the roughest patches of mud had dried up enough that most bikers could ride through if they took the outside edges. Tire grooves, some six inches deep, wove through the hardening mud on the course.

Brian Staby, owner of CX Nation, a co-organizer of the event and company through which he coaches the cyclists, re-strung red tape along the barrier of the race route, a task that kept him busy throughout the day as bikers whizzed into the outer edges of the path.

"Go right! Go right!" he yelled to a biker heading for a thick mud pit. "That's kind of the challenge, to find the right groove in the line, without hitting the tape."

Some riders carried their bikes over the finish line, or pushed them along on one wheel, the other too clogged up with mud chunks to turn.

"The brakes aren't really working, and we've seen a bunch of derailleurs snapped already," Fisher said. "It's good for local bike shops."

Cyclists praised the family-friendly nature of the event, where men and women competed in separate heats of 30 to 60 minutes.

"I'm here with my husband and my baby, so we can take turns racing and watch the baby in-between," said Theresa Zaro, 34, a landscape architect from San Mateo.

Griffin Dole, 3, navigated through the shorter children's course during the kid's race on a lime green bike with no pedals, the better option for learning how to balance, said his father Krishna Dole, 34 of San Mateo.

"It was a little bit traumatic, he fell down in the mud and he couldn't get up," Krishna Dole said. "There was a lot of tears, but he was smiling by the end."

(You can reach Staff Writer Cathy Bussewitz at 521-5276 or cathy.bussewitz@pressdemocrat.com.)