Not so young. Not so serious.

Not so fast.

Sure, they’re getting up there. Most are baby boomers, and a couple have already retired. But don’t let their name fool you. The members of the Not So Buff exercise club are pretty buff.

“The idea is overall healthiness,” says 62-year-old Martin Howell, co-founder of the not-so-hardcore club.

But there’s more to it than lifting weights.

“We do the exercises, but we do as much laughing,” Howell says. “We tease each other ruthlessly.”

Members poke fun at one another’s paunches, love handles and “man boobs” as they pump iron, do aerobics and even learn new yoga poses. They’ve also been known to break into song on occasion.

But all that goofing around doesn’t mean they slack off. When it comes to exercising, these jokesters mean business.

The 14 men of Not So Buff have been working out twice a week at the Yakima Family YMCA for 10 years now.

They pitch in to pay a personal trainer, who pushes them through a series of strength-training, aerobic and yoga exercises one night a week. The other night, a group member leads the session — part exercise class, part support group, part men’s club.

“You’d think you’re in a pub,” Howell says. “This is like the show ‘Cheers’ for an exercise group,” except there’s no Carla or Diane. “It is boys’ night.”

Jokes abound in the Not So Buff brotherhood. But there’s also a serious side to this fraternity.

“We’re 55, 60 years old,” Howell says. “We’re sitting at a point where the worst of your health issues are hitting in — the high cholesterol, the high blood pressure. Every time I turn around there’s something that’s not working like it did when I was 25.”

Members range in age from 50 to 78, except for one 33-year-old, a Gen X-er who’s new and brings down the median age. He’s the baby of the bunch. Most members are nearing retirement. And they’re easy to spot at the Y, sporting yellow, green and gray “Not So Buff” — “NSB” for short — T-shirts.

“Good-looking bunch, huh?” says their personal trainer, 31-year-old Beau Braun, before leading them through a set of bicep curls.

The men meet in a designated “Not So Buff Room,” located down a first-floor hall next to the racquetball courts. Plaques on the wall commemorate the group’s fundraising to make Y programs available to children whose families might otherwise not be able to afford it.

Below the awards, there’s a target heart-rate chart and sign warning: “There will be a $5 charge for whining.”

That doesn’t stop them, of course. They joke about being allergic to exercise, pretend to hit each other with yoga mats and applaud when they’ve finished a set.

“We laugh at each other and ourselves,” says 66-year-old Tom Froula, who’s been Not So Buff for four years.

It’s one of the unwritten rules: You have to have a sense of humor — dry, wry and witty is best — as well as a thick skin. You have to be able to take it if you’re gonna dish it out — and you’re expected to dish it out. That’s part of the fun. What’s the point of sweating if you’re not having any?

Get caught taking the elevator or otherwise taking it easy, and you’ll get stuck wearing a pink T-shirt proclaiming: “Girlie Man of the Month.”

“There’s nothing politically correct” about the club, Howell says. “We’re not P.C.”

They tone it down for yoga, though. Their trainer, Howell says, “would like us not to crack jokes during yoga so we’ve learned to be quiet” — at least while doing downward dog or practicing the child’s or warrior poses.

Braun reminds them to focus: “Take your time. Focus on yourself. Stay centered. Nice and tall,” he encourages.

“That’s good stuff right there. Love it. Exhale.”

Froula wobbles a bit and strives to keep his balance.

“Timber!” he calls, but he doesn’t fall.

“I think the group dynamic is motivation because it makes it fun,” he says. “It’s much easier than trying to do it by myself or on my own.”

Howell and a friend — Yakima dentist Tom Holbrook, 56 — formed the group in 2000. They’ve been going strong, and growing stronger, ever since.

“We started out with two,” Howell says. “For six or eight months, there were three of us. Then it went to five.”

Now, more than a dozen men — including fruit industry folks, businessmen and a stockbroker — regularly come to workouts.

“We buy into the idea that personal training makes a difference,” says Howell, who collects about $15 per month per person for the Tuesday-night trainer.

Holbrook frequently leads the Thursday night workouts.

Dennis Murphy has been going since 2005. The 66-year-old retired Air Force lieutenant colonel laughingly recalls how Howell recruited him, saying something like, “‘I don’t know you but you’re fat and old. You need in our group.’”

“I’ve been there ever since,” he says. “It’s the highlight of my week, every Tuesday and Thursday.”

The pink T-shirt tradition was his idea. He got stuck wearing it in December when fellow Not So Buff-ers caught him using the elevator after a workout. But the same guys helped him lose 22 pounds, enough to get him back into his old uniform, which he wore to a recent military ball.

NSB members, he says, strengthen each other’s resolve long after New Year’s resolutions wear off.

“Our likelihood for exercise as individuals is probably 100-fold greater because we have the group,” Howell agrees. “You need a group of people that will hold you accountable. You don’t let anybody in our group give up.”

Once a month, the group goes to dinner at the Olive Garden for post-workout pasta. Sometimes, they stop at Bob’s Keg and Cork for a beer or two after exercising. And if one of them lands in the hospital — it’s happened a few times in the past 10 years — members all go to visit.

“I feel very fortunate to be part of the group,” says 78-year-old Dwight Berghoff, a retired orchardist and the oldest member of Not So Buff. “We have a lot of fun joshing.”

The tight-knit fraternity doesn’t have room for new members at the moment. But Howell encourages friends or colleagues to start similar groups — or keep together teams from the recent Yakima vs. Yuma Weight Loss Challenge — for the New Year and all its resolutions.

“It’s a very simple message to anybody,” he says. “Yes, you can do this.”