WEST ALLIS, WIS., DEC. 20 -- Take heart, couch potatoes. You, too, will be represented at the Winter Olympics.

This weekend, in an upset that left her almost as baffled as it did the rest of the speed skating community, Mary Docter, 26, beer and cheesecake queen of Madison, Wis., won a place on the U.S. team. Not just a place, either; she proved to be the top women's 3,000-meter performer at Olympic trials here.

This is the Mary Docter who, after finishing sixth in the 1984 Olympics in Sarajevo, Yugoslavia, sold her equipment and vowed never to speed skate again, "unless I have a complete personality change."

Docter moved back to Madison, went to the University of Wisconsin, ate too much, drank beer, gained weight, speed-skated not a whit and found herself on graduation last May jobless and without prospects.

She took up waitressing part-time at the Ovens of Brittany, where her cheesecake obsession flowered, she said, until the day before Halloween, when a patron scolded her. Docter recounted their fateful chat:

Customer: "Why aren't you skating?"

Docter: "It's out of my life."

"You must be talented."

"It's a lot of work."

"When are the Olympics?"

"Three or four months."

"What would it take?"

"Look, you're stirring a lot of feelings in me that I don't want."

But Docter said she quickly realized "I needed the sport. I wasn't doing anything with my life. I was going out every night, drinking loads of beer and smoking. I was in a rut."

So she intensified the occasional gym workouts she'd been doing, went roller skating on off hours and, when the Madison ice rink opened four weeks ago, strapped on a pair of speed skates for the first time in almost four years.

Entry fee for the Olympic trials here was $10. She watched some of the Olympic hopefuls "and I thought to myself, 'I think I can beat those chicks.' "

In her first race Dec. 13, Docter was second to the top U.S. 3,000-meter skater, Leslie Bader. This weekend she beat Bader by 3 seconds to become the top U.S. prospect at the distance.

"It makes all of us who trained hard just sick," said Angela Zuckerman, who may lose her place on the team because of Docter. "It hurts. The only thing we can think is, she's rested."

Said Bader: "It's amazing, after such a long time. I'm happy for her, but it's hard, deep down. I did all this training and here she just blew me away."

Even Docter conceded it is "a little insulting to the women's distance program."

Coach Mike Crowe initially was distressed that someone without hard training, "skating half-throttle," as he put it, would wind up his best prospect for a medal at 3,000 meters against a strong East German women's contingent.

But this weekend he mellowed. "She definitely belongs on the team," he said after her defeat of Bader in a cold rain Saturday night. "She was far and away better than anyone else {at 3,000 meters}."

Crowe said he suspects Docter has been working out in the gym more than she admits to. Now that she's on the team, he said he'd work with her, which Docter said she'd welcome.

For her part, Docter is both euphoric and bewildered.

"I don't know what's going to happen," said the frizzy-haired veteran of two Olympics. "I'm ready to train hard. I'm excited to come down here and skate."

She said 1984 was a bitter disappointment she wouldn't want to repeat.

After seven years of training, she said, "I didn't get what I trained for. I had great potential, but when the time came I was a mental, physical and emotional wreck. I was eating too much baklava and not sleeping. I couldn't maintain my mental status; my attitude was bad."

Now, she says, "Speed skating is just what I need to get out of my rut. It's the most exciting thing I've ever done."

Nor does she expect to get so wound up that she collapses at Calgary the way she did at Sarajevo. She's approaching this one very differently.

Will 1988 be Mary Docter's revenge?

"No," she said with an ear-to-ear grin, "it will be Mary's vacation."

Although Docter is a long-distance specialist, the top U.S. speed skating medal prospects all compete in shorter, sprint distances of 500, 1,000 and 1,500 meters.

There were no major suprises in team selection of sprinters here, as women's champion Bonnie Blair and the top men, world record holder Nicky Thometz and Dan Jansen, made the team easily. Thometz was ill and didn't race, but has a designated spot as world record-holder at 500 meters, and Jansen and Blair led the pack in their trials.