Picture a skier hurtling down a slalom course with arms out front, body tucked and skis scraping against icy snow. Now imagine gray or balding hair under the helmet?and perhaps some arthritic knees bouncing down a mountain.

That's a picture you can see each winter as older men and women in the northeastern United States compete in the New England Masters Ski Racing Program.

Witness a recent race at Killington, Vermont and you might think you were at a World Cup event. There's a roped-off ski slope with a challenging course?lots of guys standing around with walkie-talkies?and, of course, a bunch of athletic-looking skiers wearing high-tech helmets and skin tight Lycra racing suits.

But, unlike most World Cup events, the participants seem incredibly relaxed -- perhaps because so many of them have been skiing for decades.

Bob Craven, 71, jokes with his fellow skiers near the starting gate. "I'm ready, I'm ready," he says. "Release the beast!" He points to his padded racing suit and laughs. "This is secondhand?it's third hand, actually," he admits. "I bought it from a guy who was a Masters racer who got it from a former British Olympic skier. So it's well broken in." Then he excuses himself and heads down the course.

"You might not do the part, but you sure have to look the part!" says one of the racers, laughing. "Some of these old dudes like to show off their body. They don't realize that nobody's looking at it!"

The skiers who take part in these competitions come from all over New England and range in age from 21 to 87. But a surprising number of the 120 skiers running the course today are elderly.

Bob McGrath, 69, from Hanover, New Hampshire, says his group of friends has been racing against each other since they were 18. "And the definition of insanity," he points out, "is doing the same thing over and over again and expecting a different result. And that's what we do. We think we're going to win every time we go out."

Larry Young, 69, a professor at the Massachusetts Institute of Technology, was on his college ski team in the 1950s. But he says many in the Masters group started competing later in life -- after they saw their kids race. He points across the slope at a fellow skier, who was on the 1960 Norwegian Olympic team.

While the athletes here are not all former Olympians, they're not lightweights. They may tease each other, but they carve a mean turn, and one woman boasted that she was clocked at 122 kilometers an hour in last year's downhill championships.

As the crowd cheers a racer down the slope, Larry Young reflects on competing as a senior. "The usual reaction I get is one that I really dislike, and it's 'Boy, I hope I can do that at your age.' And I think, 'How old do you think I am?'"

His advice to those who question his sanity is: don't knock it until you've tried it. "There is this sort of surprise that they think skiing is a young man's sport," he says, "especially ski racing is not something that's carried on later."

After racing for 25 years, Alice Pepper, 76, says she too gets strange looks when people first learn she's a competitive skier. "They think it's rather weird, that we're still doing it," she says, "Sometimes I think they think we're crazy to keep pushing yourself like this?people who don't ski especially."

Ms. Pepper has arthritis in both knees, so she no longer competes in the downhill races. But she loves the giant slalom. The fact that she's the only one in her age division doesn't bother her. Besides, she says, the competition will pick up later this month at the national championships in Montana. "There might be as many as four women in my class," she says.

Jane Cook, 74, began skiing right after World War Two and raced in college. The equipment and clothing have changed over the past six decades, she remarks, but not the feeling. "The thrill of having the hill all to yourself?to try to go as fast as you can," she says. "That's the fun of racing. The fun is the camaraderie. We're all really good friends."

Ms. Cook says her grandchildren sometimes come to watch her race. "My granddaughter came last year to Cranmore," she recalls, "and she wasn't too impressed. She said, 'Grandma, you went by too fast!'"