It was during a particularly wet and cold training session on the streets of Excelsior in the early 1970s that cross-county skier Ed Pauls wondered whether he could build an indoor exerciser that would duplicate the skiing motion. The key to such a device was to imitate the unique properties of ski vs. snow, a subtle resistance that Pauls was able to capture through the use of a patented flywheel and one-way clutch mechanism.

In his basement, he invented NordicTrack, initially popular with skiers but quickly a hit with exercise enthusiasts on a much wider scale. By 1984, the family-run company became a major competitor in a growing fitness craze.

Pauls, 80, who skied until early last year, died Oct. 9 from complications of Alzheimer's disease at his home in Montrose, Colo.

His daughter, Terri Pauls of Anchorage, Alaska, recalled an early NordicTrack model that had real wooden skis and a living room sofa cushion for hip padding.

"Early on, when we would sell one, my father would gather the family in a circle in the dining room to sing and dance in celebration," she said.

Pauls grew up on a dairy farm near Wausau, Wis., and graduated from the University of Wisconsin at Madison as a mechanical engineer. He married his wife, Florence, in 1959 and they moved to Excelsior. They spent a year in Europe, and Florence taught school at a U.S. Air Force base in Germany. While visiting her relatives in Norway, they were given cross-country skis.

This sparked Pauls' passion for skiing, and he trained for local races. As an engineer, he would get home about 5 or 5:30 p.m.; during fall and winter, it was dark. He trained by running around the dark, icy streets of the neighborhood but thought there had to be a better way, his daughter said.

NordicTrack was about to be born, and Pauls received a patent in 1976. Taking the advice of a family friend to sell the NordicTrack to others, Pauls began to manufacture the machines in his garage, investing $10,000 of his own savings. As news of the device spread by word of mouth in the cross-country skiing community, the business was moved to Jonathan Industrial Park in Chaska.

Florence Pauls was the office manager and son Glenn played a key role in production. Terri Pauls, who later won collegiate championships in cross-country skiing at the University of Minnesota, worked summers at the plant.

Ads for the machine were originally placed in ski magazines, but it became apparent the device was attractive to non-skiers looking for an aerobic workout, Terri Pauls said. The advertising campaign was extended to such high-end general interest publications as Smithsonian and Scientific American, accompanied by the tag line "The World's Best Aerobic Exerciser."

The company, which employed up to 400 people, was sold to CML Group in 1986. Pauls had also invented the Flipski outrigger for adaptive skiing, and the Rosemount ski boot and binding system.

Ed and Florence Pauls moved to Utah in 1998, where they relished years of powder skiing. Montrose was their most recent home, and they donated 290 acres to Durango, Colo., for preservation.

Pauls is survived by his wife, Florence; daughter Terri; son Glenn, of Telluride, Colo., and two grandchildren. A celebration of his life will be held at 10 a.m. Sunday at the University of Minnesota Landscape Arboretum, 3675 Arboretum Drive, Chaska.

David Chanen • 612-673-4465