Adam Chase won a contest at the World Snowshoe Championships in Colorado a few years ago for having done the most interesting thing on snowshoes. He proposed to his wife. Chase, a Boulder, Colo., lawyer and accomplished ultra-marathoner, has been doing some more common things on snowshoes as well. Namely, he stays in shape.

"I definitely do both snowshoeing and trail running as a way to be on trails at altitude moving fast in the mountains, all year round," says Chase, who races in the winter for Atlas Snowshoes.

Chase is not alone. As manufacturers emphasize the fitness aspect of snowshoeing to further boost the rapidly expanding sport, the public is responding.

Consumers are buying specialized "performance" shoes and lining up for races. The Eldora Nordic Center in Boulder is providing a test site for the Tubbs Snowshoes Winter Fit Program. If the training regimen catches on, Tubbs and Reebok will seek to implement one in every snow-covered resort and city.

Snowshoes have served as a transportation tool for thousands of years. But snowshoeing remained an obscure recreational activity until the late 1980s, when a handful of companies modernized materials and design.

Bill Perkins, former owner of the Denver-based Redfeather Snowshoes, crafted lightweight shoes with a metal frame to out-run his competitors in an Avon, Colo., winter triathlon. Many credit his design for the birth of modern snowshoeing.

Recreation industry analysts began monitoring the sport two years ago. According to SnowSports Industries America, 112,121 pairs of snowshoes were sold during the 1997-98 season. That number jumped to 135,723 pairs last season, making it one of the fastest growing winter sports. The Outdoor Recreation Coalition of America reports 3 million people tried snowshoeing at least once in 1998.

Numbers from Leisure Trends show that anticipation for the 1999-2000 season is high. In specialty ski shops alone, 6,627 pairs of snowshoes were sold between August and October of this year. That's almost twice the amount sold in the same period last year.

Nancy Colton of the Eldora Nordic Center says the resort already had plans to expand its snowshoe trails before Tubbs recruited it for Winter Fit.

"I think this is the fourth year we've had snowshoeing," Colton says. "The first year, not much happened. The second year, here and there. Last year, we routinely sold out of our rentals. This year, we tripled our inventory and expanded our trails."

Eldora now has nearly 100 pairs of snowshoes, about half from the Tubbs Aerobic Series, shoes designed for "serious on-snow training."

Julia Day of Boulder-based Leisure Trends says the sport's segmentation signals its expansion. "The sport is growing, but has become more specialized," Day says. "You don't just buy a pair of snowshoes. As it becomes more popular, people want to buy a snowshoe that fits their activity."

Running snowshoes are considerably smaller than traditional models. They are lighter and shaped to accommodate a runner's stride. Some have a titanium crampon to further reduce weight. The shoe "deck" is made of material similar to that in white-water rafts. The smaller surface area of fitness shoes provides less flotation in fresh powder, making them better suited for a packed trail.

New this season, Reebok is offering a "Winter Runner" a high-top running shoe made of waterproof materials to use on snowy trails or with snowshoes. Boulder-based Crescent Moon Snowshoes will mount a consumer's own running shoe to eliminate the additional weight of a binding.

Snowshoeing is a good source of exercise, a fact that becomes clear to anyone spending a few minutes or more trudging through fresh snow at 10,000 feet.

Ed Kiniry, president of Tubbs, says his company aims to make serious athletes take snowshoeing more seriously. "If you look at the growth of snowshoeing in the 1990s, it's been putting people outside where they hike in the summer," he says. "By changing the message to fitness, we get a different consumer."

The idea is catching on.

"It's a great workout. It's nice to be somewhere without a bunch of people," says Tracy Long, while strapping on her shoes for a run at the Eldora Nordic Center.

Professional triathlete Steve Senior agrees. "It's good cross training in the winter," says Senior, a Tubbs-sponsored athlete.

Tina Burghardt, a recreational triathlete who races for Atlas Snowshoes in the winter, says it adds variety. "It's something different to do. We all get tired of the same runs or swims," she says.

To underscore the fitness message, Redfeather signed on Olympic gold medalist Frank Shorter as a spokesman.

"It's perfect for bikers and runners, anybody who wants to keep fit when their sport sort of goes away in the winter," says vice president Lynn Cariffe. "The snowshoes are more than a way to get around in the snow. They create a much more aerobic workout."

The few extra pounds attached to a person's feet ups the level of exertion, and snow absorbs the stride, Cariffe says. A rubber ball bounces easily on asphalt, but will hardly respond when dropped on snow. The same holds true for a footstep, requiring more energy to propel forward.

A few years ago, Vermont-based Tubbs set out to quantify the exercise benefits, with the help of Ray Browning, a former top professional triathlete.

"We were committed to the fitness aspect," says Browning, who lives in Nederland, Colo. "It was important to develop this Winter Fit program based on science, not our assumption."

So Tubbs collaborated with researchers at several universities to conduct a battery of tests on snowshoeing subjects. Among the findings: Depending on the snow conditions, terrain and level of activity, snowshoeing burns 420 to 1,045 calories per hour. An hour of snowshoe running on a packed trail burns 600 to 700 calories. Snowshoers burn 50 percent more calories than when they walk at the same speed.

The Winter Fit program is intended to provide efficient, challenging workouts for snowshoers of all abilities. "People typically go to a snowshoe area as a destination, and they are told, 'Here are your snowshoes, go left.'" Browning says. "With this program, we hope to offer another level."

(Carol Kauder writes for The Daily Camera in Boulder, Colo.) © 1999 Scripps Howard News Service.