For most of her 63 years, Sharon Merges hated exercising, and for a long time her rheumatoid arthritis and chronic back pain provided a convenient excuse to skip it.

All of that changed in June 2012, when the Minnetonka-based life coach was invited to give a talk on chronic pain at Welcyon, a fitness club for people over 50. She was impressed by the welcoming staff and the friendly feeling of the place. Now she works out three times a week at Welcyon’s Edina location, following a program adjusted for her physical condition.

“When I’d go into gyms before, I’d feel intimidated, like I didn’t belong,” Merges said. At Welcyon, “there are people who look like me.”

Welcyon is intended for people who aren’t necessarily in peak physical shape and might not feel at home in a gym filled with loud music and taut, Spandex-clad flesh.

“It’s for the 80 percent of us who maybe have never worked out, who maybe were not in fabulous condition, but they want to stay strong and want to be healthy,” said CEO and co-founder Suzy Boerboom.

Bill Kostner, 73, of Edina works out at Welcyon even though he also has a (prepaid) membership at a national fitness chain. The chain attracts “a lot of muscle builders and fitness fanatics,” he said, whereas those who work out at Welcyon “just want to stay fit and age gracefully.”

Welcyon’s staff coaches develop customized workouts based on members’ health history and physical condition. The workouts are entered into a computer and loaded onto smart cards that, when plugged into the gym’s air-powered weight-training equipment, automatically set the weight and record the repetitions. As strength increases, the computer adds weight, a pound at a time.

Older people who don’t stay in shape “can’t do the things they want to do, can’t travel, can’t run with the grandkids,” Boerboom said. The inactive are at higher risk for chronic disease and falls, among other health problems. “We have a lot to gain and a lot to lose at our age,” said Boerboom, 65. “The good news is, it’s never too late — the muscle fiber responds.”

The American College of Sports Medicine lists fitness programs for older adults among its top 10 fitness trends, based on a survey of 3,800 fitness professionals.

But the fitness industry has been slow to respond, said Colin Milner, CEO of the International Council on Active Aging. Welcyon is one of only a handful of gyms designed specifically for older adults (the largest, Nifty After Fifty, has about 40 locations in six states, though none in the Midwest). Other organizations — senior centers, retirement communities, corporate wellness programs, YWCAs and YMCAs — offer fitness opportunities for older people. But mainstream fitness clubs have not done much to attract aging clientele.

Apparently that’s because they’re successful enough already that they don’t feel the need, Milner said. On the contrary, many of their offerings have become more intense, potentially alienating people who are new to exercise or have physical limitations.

“They have created an industry for the fit, but not an industry for those who need help,” Milner said. Yet given the size and purchasing power of the baby boomer demographic, they’re overlooking a lucrative market, he said. “People have the desire, and they have the money to put behind that desire.”

Boerboom, a nurse by profession, co-founded Welcyon with her husband, Tom, who operates senior housing developments. She had previously owned half a dozen locations of Curves, the fitness club for women. That’s how she started thinking about the importance of physical fitness for a different population group.

The Boerbooms opened two Welcyon locations, in Edina and Bloomington, in 2010. Two franchise operations have since opened up in Sioux Falls, S.D., and Fargo, N.D.

“Hopefully by the end of 2014 we’ll have 20,” Boerboom said.

Sandy Foley of Minnetonka started working out at Welcyon about a year ago, after she injured her back and a doctor told her she’d need cortisone shots for the rest of her life.

“No way — I have four boys,” said Foley, 50. “I am too young to settle for that.”

With exercise, Foley conquered the back pain and lost 20 pounds. She was even more impressed when she noticed she was gaining strength.

“All of a sudden, I thought, whoa, I have muscles!” she said. She has gained energy she needs to stay active with her sons, ages 8 to 12. “I want to play with them, I want to jump on the trampoline, I want to swim.”