Ginger Lambert ran her first marathon at age 50 ... in less than four hours. More than a decade later, you can find her at the Middlebury Parks and Recreation Department gym most Saturday mornings. There she teaches others — especially older women — to love fitness as much as she does.

Lambert is the force behind Fitness Boot Camp, a high-energy class she created and teaches in various locations around Addison County. When Seven Days attended one recent Saturday in Middlebury, 10 participants were sweating through her 8 a.m. class.

At 69, Jane Reilly is proud to acknowledge being the oldest member of Lambert's class. "This is where it pays to be old," she said while swirling two weighted hoops around her hips. "I grew up in the Hula-Hoop age."

Reilly, who lives in New Haven, attended the very first backyard class, held at Lambert's Weybridge home three years ago. "I can't run anymore," said the former marathoner. Reilly walks these days and does yoga regularly, but she wanted to round out her exercise regimen. "I was looking for something to get my heart rate up," she said.

Reilly has always been sporty; she's married to Russ Reilly, the former athletic director of Middlebury College. "Athletics are our life," she said. When it comes to keeping one's body in shape after a certain age, Reilly cautioned, you've got to move it or lose it.

"I want to be able to keep up with my grandchildren," said Reilly, who has seven. She was wearing a T-shirt emblazoned with the phrase she used to say to her three daughters when they were little: "Suck it up, Buttercup."

Wendy Bruso was next up at the Hula-Hoop station. The 57-year-old Addison resident admitted she was never athletic before starting Lambert's class. She got hooked on boot camp at work: She's a computer technology resource manager at Vergennes Union High School, where Lambert offers her boot camp as part of an after-school wellness program.

While talking to a reporter, Bruso casually twirled two weighted Hula-Hoops around her waist. "I couldn't do this before I started taking this class," she said. "Sometimes we do three. It's really good for your core."

Bruso said she felt intimidated when she first heard about the class. "But then I contacted Ginger and found out she was older than me," she said. "She's not this 22-year-old skinny blonde."

Lambert, in fact, is 62. And while it's true that she's not a skinny blonde, she is in enviable shape for any age. And she rocks a stylish silver pixie cut.

Lambert's class is decidedly down-to-earth and low budget. That's what many participants love about it. She doesn't have fancy equipment or playlists. In fact, she plays the same songs from her phone each time: "Love Shack" and "I Can't Go for That (No Can Do)" mingle with a few tracks by contemporary artists such as Bruno Mars.

The structure of the Middlebury class is the same every time, too. First, participants gather in a circle to stretch and introduce themselves. Next, Lambert talks boot campers through the dozen circuit stations she's set up. Each one features a different exercise, such as sprinting between cones, lifting weights, jumping rope or lunge walking. Participants do each station for 60 seconds. Then they gather together again to plank for several minutes. Finally, they go through the circuit again, this time for just 45 seconds at each station.

During the class Lambert keeps time, intermittently shouting out, "Can I get a 'Yes, ma'am'?"

She's currently teaching a class almost daily in Middlebury, Brandon, Cornwall, Vergennes or the Charlotte Senior Center. In the warmer months, the Middlebury class relocates to Lambert's backyard. To supplement her income, she offers personal training and bartends weddings.

The daughter of a Southern Baptist minister, Lambert was born in Oklahoma and went to high school in Florida. In 1977, when she was 23, she moved to Rochester, Vt., to join the creative alternative-lifestyle community Quarry Hill Creative Center.

"I would do yoga during the day, paint with watercolors at night," she recalled. "Evenings, I'd work as a waitress or bartender."

Quarry Hill residents helped to raise each other's children, including Lambert's daughter, who was born in 1980.

She took a circuitous route to becoming a boot-camp instructor. Lambert returned to school after the birth of her daughter, managed a cooperative art gallery, worked in real estate and tended bar.

In 2002, suffering from seasonal affective disorder, Lambert ran her first 5K at the urging of a boyfriend. She came in third in her age group. "I started running year-round," she said, "and I felt better and better."

In 2004, Lambert ran the Vermont City Marathon in Burlington for the first time and qualified for the Boston Marathon. She became hooked. Over the next several years, Lambert ran more than 120 races, including three triathlons a summer each of those years.

After earning a degree in exercise science from Castleton College (now University) in 2014, Lambert was inspired to start her boot-camp class. She wanted to help people "make lifestyle changes that stick," she said.

"So many people find exercise a drudgery, and it's why I like teaching the classes," Lambert explained. "Because I can demonstrate that exercise can be fun and something to look forward to."

Not everyone in the class is eligible for AARP. Joseph Eller, 24, tries to make the Saturday session whenever he can. He works in the Café Provence kitchen in Brandon. "I need to be loose, fast and energetic for my job," he said. Eller likes that the exercises are easily adaptable.

Lambert offers another Middlebury class on Wednesdays at 7 a.m. that also draws younger folks, including many mothers of young children. But her most devoted fans seem to be older ladies.

"When I started Ginger's class, I couldn't do a single push-up," enthused 50-year-old Sue Brileya of Shoreham. "Now I can do 22 without stopping."

Whiting resident Carolyn Schmidt, 65, was at Lambert's first class in 2014. She recalled participants rolling a 70-pound tractor tire around the backyard and carrying buckets up and down the hilly driveway. "I can see improvement," Schmidt said of her fitness level, noting that she can now balance on one leg with her eyes closed and keep a Hula-Hoop spinning.

Schmidt likes that Lambert is "independent." Her class isn't affiliated with any gym. "She does this all on her own; she doesn't spend [on] a lot of expensive equipment," Schmidt said. "It's stuff you can do at home."

She added that her commitment to exercising later in life was inspired by watching her arthritic mother, who didn't exercise, become increasingly frail over the years. "If I miss a couple days [of exercise], it's hard to get out of bed or get into the car," Schmidt admitted.

"Whenever I write a check to Ginger, I think about the price of my health," she added. At $12 a pop — $10 for a six-class pass — Schmidt said, "This is cheaper than the co-pay on my health insurance."