When she’s not teaching Cambridge middle-schoolers, Marilyn Rottersman, 63, works up a sweat at her gym and ushers at a local theater. Would she join a senior organization?

“Why should I?’’ she asks. “I do boxing, with gloves and [punching] bags. When I think about senior groups, I think they’re for old people. That’s not an option.’’

Jack Murray, 70, balked when friends invited him to visit the Franklin senior center some years back. “I have no interest,’’ he said. Murray, who works part time as an insurance broker, prefers downhill skiing in the White Mountains.

Campaigns to attract younger members to “senior centers’’ and organizations aimed at older adultsare often uphill slogs, meeting stubborn resistance from boomers who avoid activities and labelsthat might suggest they’re getting old. Few turn away senior bus or movie discounts. But many would prefer to bike, play electric guitar, or go on an African safari than join any group with the word “senior’’ in its name.

The truth is, baby boomers like Murray and Rottersman may not like the idea, but they are prized recruitment targets for senior associations and nonprofits seeking to rejuvenate themselves as their membership ages. Senior centers across Massachusetts are wooing them with offers of wine tastings and martial arts classes, while a bevy of “village’’ groups want them as volunteers and younger companions to older seniors living in their homes.

“We need to refresh ourselves, to bring in new talent and energy,’’ said Laura Connors, who will retire this spring as executive director of Beacon Hill Village in Boston.

But the target demographic will need a little convincing.

“We think we can be immortal and still be rock ’n’ rolling,’’ said Jane O’Connor, 66, a business coach in the Berkshires who specializes in the over-55 market and cites the Bob Dylan ballad “Forever Young’’ as a motto for her generation. “It’s all about the next adventure.’’

Marc Cendron, 64, of Newburyport, a doctor at Boston Children’s Hospital, said he’s in the “absolutely not’’ camp when it comes to joining the senior club. “All my friends are in their 60s and early 70s,’’ he said. “They go fishing, they go hiking. A lot of us are still racing cars.’’

Car racing may be a stretch, but organizations catering to the over-50 set say they want to be driven by their members’ interests. Their goal, they say, is to reinvent themselves to meet the needs of a new generation.

“I’m 57, so I think about what would entice me,’’ said Teresa Arnold, who took over 15 months ago as executive director of the Salem Council on Aging.

She came on board in time for September’s opening of the city’s new senior center — rebranded, like many in the state, as a “community life center.’’ It offers a cafe, a weight room, daytime fitness classes, and evening programs featuring healthy cooking classes and “paint and sip’’ gatherings that combine sketching with drinking chardonnay.

Beacon Hill Village burst onto the scene in 2002 as a pioneering community providing programs and services for residents “aging in place’’ in their homes and neighborhood. Volunteers shuttled neighbors to medical appointments, delivered meals from nearby restaurants, and accompanied members on museum visits. It quickly became the prototype for a global “village’’ movement, spawning imitators from California to South Korea.

Seventeen years later, the median age of village members is 78. Some original stalwarts have died or moved, and the group is looking for ways to recruit boomers. Its activities range from chamber music salons and lectures at King’s Chapel Parish House to book groups and male-only outings to a local tavern. Boomers make up less than 20 percent of the 380 members.

The village has expanded its recruitment area to other downtown neighborhoods, such as the Back Bay and the South End, and has members from Cambridge and Brookline. While its plan to draw new members is still taking shape, it’s already reaching out to local boomers on Facebook, “getting real about social media,’’ Connors said.

“It’s a matter of sustainability,’’ she said. “The village won’t be here in 15 years if boomers aren’t a part of it.’’

At an afternoon book group last month, five women, ranging in age from 64 to 84, sat around a conference table at Beacon Hill Village’s office on Joy Street, dissecting Tara Westover’s memoir “Educated.’’ They also reviewed the club’s three inviolable rules: that members read the books, don’t say at the start of the discussion whether they liked it, and show up for meetings on time. (All five women arrived at least 15 minutes early.)

Their analysis of the book was the kind of serious literary discussion you’d be more likely to hear in a university classroom than a senior coffee klatch. “The mountain almost becomes another character,’’ said retired teacher Diana Crane, 71, who led the discussion. “It represents strength and beauty.’’

Marcia Rothenberg, 64, the youngest member of the monthly book group, admitted that she sometimes felt like she’d like to come and listen even if she hadn’t read the book. “This has become a support group and a friendship group,’’ she said. “And it would be really hard to not see people for two months.’’

Creating that intergenerational vibe is also the aim at senior centers.

“We want to be a hub,’’ said Arnold at the Salem Council on Aging. “Going to a senior center is still a stigma for a lot of people. But this place spans three generations — there’s people in their 50s, 70s, and 90s — and there are wonderful activities for everyone.’’

One is an enhanced fitness class, where about three dozen men and women — including a contingent of boomers — were limbering up on a recent morning. For the next hour, two instructors from the YMCA of the North Shore put them through their drills, marching, swinging their arms, and shouting “toes up, heels down’’ to pop rock classics.

Afterward, a winded Altagracia Gomez, 65, a retired assistant teacher, said she goes to the 20,000-square-foot center three times a week to exercise with the seniors.

“People say you got to be old to be here,’’ Gomez said. “But you’ll never be old if you start doing these exercises.’’

Robert Weisman can be reached at robert.weisman@globe.com. Follow him on Twitter @GlobeRobW.