“I oughta be doing that with you,” the moderately overweight mom who was watching her son yelled.

“We’re starting a class in April,” Polly Eslinger yelled back. “You’re welcome to join us.”

Eslinger’s response seemed to surprise the woman: We were on Cary’s Middle Creek Park Playground at the time, six grown-ups mixed among  kids cavorting on the equipment. A class in what, the woman probably wondered — playing on a playground?

Well, yes. More precisely, a class in how parents can take advantage of playground time to get in a workout while their kids wear themselves out being kids.

The idea for her Playground Boot Camp came to Eslinger when her two sons were younger. She’d take them to the playground and wonder why all the kids were playing and all the parents were sitting on benches talking, drinking coffee, reading the paper. Why aren’t they taking advantage of all this great exercise equipment? she wondered. Like the ultimate chin-up bar, the jungle gym. Or that monster abs machine, the swingset? Or that all-body workout, the slide?

You’ll get a good feel for the class by watching the accompanying video, in which Eslinger demonstrates a few of her favorite playground moves.

Those whys led Eslinger, a fitness trainer, to create Playground Boot Camp, a class designed to show parents that playground time can be mommy-and-daddy-getting-buff time.

“I’m very concerned about our youth and what they’re learning from their parents,” says Eslinger. “They see their parents being sedentary, it sends a message.”

So Eslinger took the boot camp class she teaches in local gyms and tweaked it for playground use. The monkey bars make a great strength training device, working from a plank position with your feet in the swingset’s seat makes for a killer abs workout, and climbing up a slide (“Don’t do what mommy does”) is a surprisingly good full-body workout that demands all your muscles chip in for a successful summit.

Eslinger’s boot camp runs 8 weeks (it begins April 9) and eases parents (and grandparents) into the playground-as-gym concept. The first two weeks (Phase 1) is a light mix of cardio and strength training. Phase 2 -weeks 3, 4 and 5 incorporates the playground equipment in a fast-paced circuit-training regimen that involves minute-long stretches of exercise divided by 15 second rest/recovery periods. Phase 3 -weeks 6, 7 and 8 puts parents through an obstacle course and doing team exercises. Each class runs 45 minutes. Parents are encouraged to bring their kids so the little ones will get used to the idea of mommy or daddy working out while they play.

Eslinger hopes the exercises parents learn during Playground Boot Camp will carry over to their regular visits to the playground.

Adds Eslinger: “A lot of parents say, ‘I just don’t have time to exercise.’ They’re bringing their kids to the playground anyway, now they have time.”

Playground Boot Camp
Where: Middle Creek Park Playground, 151 Middle Creek Park Ave., Cary. Here’s a map.
When: Friday mornings, 9:30-10:15, April 9-May 28.
Cost: $44 for Cary residents, $57 nonresidents.
To register: Call the Middle Creek Community Center at 771-1295, or visit www.townofcary.org.