PORTLAND, Ore. -- Roxy Cate has just finished a 45-minute cyclocross race: furiously pedaling through mucky turns and along rain-soaked grassy straightaways, running several times up a nearly vertical hill with her bike slung over her shoulder, and leaping with it over wooden barriers.
She's exhausted from the difficult course. She's covered with mud. She's drenched.
So why is this 43-year-old smiling?
Like a growing number of cyclists in the United States, she's got cyclocross fever.
''We do it because it shows we can still get out there and race," she says of middle-age women like herself. ''It's an investment in our health."
Cate was among more than 600 giddily enthusiastic cyclists who showed up on a recent rainy Sunday for races at the Alpenrose Dairy, tucked into the forested hills just west of Portland.
The cyclocross season has just gotten underway and runs into December. In the Pacific Northwest, it coincides with the start of the rainy season. This pretty much assures that each race is a mudbath. You might think that would be a deterrent. Not among Portland area racers, some of whom are disappointed if they go home dry.
''Cyclocross is one of the most brutal introductions to bike racing there is," says Mike Geraci, a 39-year-old cyclocross racer in Jackson, Wyo. ''It takes a special kind of person to enjoy the abuse."
Still, the number of cyclists registered for cyclocross races sanctioned by the USA Cycling organization has more than quadrupled over the past several years: from 3,849 in 1995 to 17,255 last year.
''In the US market we have seen the great expansion of the regional scene over the past few years, and I would say that Portland is really leading in that role," says Bruce Fina, marketing director for the US Gran Prix of Cyclocross, a national series of cyclocross races.
Portland is hosting the national cyclocross championships on Dec. 10-12, for the second year running.
Cyclocross is just what the name implies -- a cross between two kinds of cycling. The bikes have lightweight road bike-style frames, but mountain-style tires and brakes.
The courses are also a blend of road and mountain bike riding, with straightaways on pavement and grass where elite riders reach 30 miles per hour, tight turns, steep hills, and wooden barriers. There is a fair amount of running involved, up the steep hills and over the barriers.
But depending on the type of race, a cyclocross bike is not necessarily required.
You see mountain bikes, fixed-gear bikes, commuter bikes, and even unicycles -- whatever is in your garage.
The sport was invented in Europe decades ago as a way for cyclists to stay fit through the winter. On the international scene, Europeans are the top racers. But that hasn't dampened the spirits of elite American riders.
''We never let racing get in the way of fun," says Erik Tonkin, a wiry 30-year-old from Portland who is one of the top racers in the country.
Young, trim riders with national recognition are the stars at the half-dozen or so races in the Portland area's Cross Crusade series. But they are in the minority. At the Alpenrose, the field of 610 riders had only 60 elite racers. The rest were beginners, teens, recreational riders, and baby boomers trying to fend off the aging process.
Riders race in categories based on ability and experience. They are timed. The fastest in each category is the winner.