“I used to jog 20 years ago, and I used to bike. I tried treadmills. Then, I got this,” Carol Haas is saying. “You get bored. You’ve got to change things up.”

With that, she unfolds her neon green 2009 Trikke T78 Air, grips the height-adjustable handlebar, squeezes the hand brakes and steps aboard the foot decks mounted atop each of the two rear wheels. Then off she goes, gracefully navigating the lakefront HarborPark bicycle path in a motion called “carving,” a kind of movement combining downhill skiing and in-line skating.

In seconds, she covers 50 yards before effortlessly executing a U-turn and returning up a slight incline.

“It’s a carving trike,” explains Haas, a Randall resident and the town’s treasurer. “They call it a ‘rock-and-roll’ motion. It’s fun, a good workout, good cardio. The only thing is, you kind of take up the whole (bicycle) path.”

The mother of two adult children, a son, 37, and daughter, 27, Haas started riding the three-wheeler a little at a time to get the hang of it after buying the Trikke in June. She soon bonded with the human-powered vehicle, which looks like a standup scooter with a wishbone frame, but it operates quite differently.

“Because I’m not athletically inclined, it took me a month off and on to be able to propel it without having to get off it to push (with her foot),” says Haas, adding that when she’s starting up slope she still pushes off to get rolling.

The Trikke first caught her imagination when she saw a rider aboard one in Burlington. “A guy whizzed past me, and I sort of stored it back in my brain,” she says.

Other wheeled models can go faster, but hers is speedy enough. “At my age, I need comfort more than speed,” she says with a laugh.

There is a model for skiers called, well, Skki, and The Tribred, for those who prefer electric motors rather than muscles for power. Haas isn’t tempted to try the former and doesn’t see the point of latter because hers keeps her in shape.

“I rode it through the summer. It’s a good muscle toner. That’s why I liked riding it. I felt the difference. Anything you can do to get a little flab off without starving yourself, you know,” Haas says. “And it’s pleasurable. If they can figure out how to warm the air outside, I’d ride it in winter.”

With decreased daylight hours, she has cut back from her five-mile rides seven days a week to riding her Trikke five days weekly, as long as there is pavement to ride on, pavement that isn’t strewn with wet leaves, a definite hazard when Haas is shifting her weight side to side to propel her from Point A to Point B. Nor does the Trikke move well, if at all, on gravel paths, according to Haas. In addition, she says, “it’s hard to find a long, flat surface ... that’s what you need.”

Her petite, 5-foot 3-inch frame comes in well below the 250-pound maximum carrying weight of the steel, 24-pound trike, although how far below Haas isn’t saying. “In my younger years, I was 105. That’s as far as I want to go with that,” she says.

“It will accommodate my husband, but he won’t ride it. He says it’s just too much work,” adds Haas, who got pulled over by a Department of Natural Resources warden this summer for Trikke-ing in a state park campground in Door County. “Can you believe it? He said I was riding a foot-propelled scooter in a campground, and that’s prohibited.”

According to Haas, the warden reluctantly relented but only after she produced the state park rule book and pointed out the Trikke technically doesn’t employ one’s feet for propulsion but is more akin to bicycling, albeit without pedals, chain or sprockets, a mode of permitted transport in campgrounds.

“Next year, it will be getting pulled over for speeding,” Haas says, laughing goodnaturedly.