Correction: An earlier version of this column misstates the date of the opening of the Go Figure fitness studio in Potomac. The opening is set for Friday, Nov. 11, 2011, not Thursday. This version has been corrected.

From left, Alyssa Adams, Reina Offutt Pratt and Mary Farber at Potomac Pilates’s barre. (Mark Gail/THE WASHINGTON POST)

Ever heard the one about the woman who walks into a barre? If not, that’s about to change as the city’s fitness scene makes room for ballet-inspired exercise classes.

That doesn’t mean it’s time to dust off your old tutu. These lessons aren’t designed to land you a starring role in “The Nutcracker,” but rather to help you look like you could by borrowing dancers’ strengthening and stretching techniques — while using their favorite prop.

The idea was originally developed 60 years ago in London by Lotte Berk. A student brought her method to New York in the 1970s, and it’s taken off over the past decade as more than a dozen barre fitness systems have been developed and marketed across the country.

Folks have been barre-hopping in other cities for years, and now it’s the District’s turn. ZenGo, a combo cycling/barre gym in Bethesda, launched last month. Friday marks the opening of Go Figure in Potomac — the brand’s first location outside the New York suburbs. By the end of November, Barre3 plans to offer classes at its studio in Georgetown. (Its big selling point: The creator is Madonna’s trainer.)

“There’s so much barre buzz now,” says Linda Bachrack, who brought the format to the District in the summer of 2006, when she started teaching Pure Barre at a yoga studio on U Street. She’d been a fan of a Pure Barre studio when she lived in Michigan, and thought there’d be a demand for it in Washington.

“I’m not surprised it caught on. But I was surprised we were the only show in town for so long. I kept thinking, anytime now,” Bachrack says.

If you’re wondering what it is about pulsing up and down in a plie that creates such an addiction, it seems to be that it works. “I can’t get anything else to tone my butt, but I’ve noticed a difference since doing this,” says Katie Schrier, 36, who’s taken classes at the Bar Methoddowntown and is now a regular at Xtend Barre classes at Fuel Pilates in Georgetown.

Fuel owner Kelly Griffith started the program a year ago as a complement to Pilates training. It’s similarly focused on strengthening the core, but there’s more of a cardio component thanks to a constant flow from one move to the next and exercises that work multiple muscles simultaneously. When she’s cueing, “Down an inch, up an inch,” that doesn’t sound particularly challenging, but just watch the sweat dripping down students’ faces. “You’re getting at these tiny muscles you don’t with anything else,” she says. “When’s the last time you lifted your leg by squeezing your butt?”

And when was the last time your legs shook uncontrollably as you tried to hold a particular position? That quake sensation happens in just about every barre class — one of the many common denominators. Each style has its own hallmarks. Some are on wood floors, others are on padded carpeting. Some require students to wear socks, others demand bare feet. Most claim to be better than the competition because they focus more on safety. But the exercises are fairly consistent.

Usually you’ll start with marching leg lifts to warm up the body. Then it’s time to grab light weights (typically three pounds or less) for a series of arm exercises that require keeping your limbs up for an extended period without a break. You’ll move to the barre to work thighs and “seat” (the barre word for butt) with movements that often involve standing on one leg, being on your toes or both. From there, you’ll likely sit on the ground and hold the barre above your head to attack those abs by lifting your legs. Between each section, you stretch.

Not that every class is the same. Within this framework, there are endless variations, particularly when you bring in props other than the barre. Slightly squishy balls that often get squeezed between students’ thighs are common. One that’s not is the glide board, a slippery surface designed to let users do a side-to-side ice skating motion. You’ll only find that at BeyondBarre, which is offered at Potomac Pilates.

Determined to add barre to her schedule, Potomac Pilates owner Reina Offutt Pratt and some of her staff members took seven different classes in 24 hours in New York in January. After experimenting with developing her own program, Pratt brought in BeyondBarre this summer, and she’s been amazed by the range of ages it attracts. It brings in the typical 25- to 45-year-old crowd, but also students who are much older.

You’ll often find 40-year-old Molly Hamilton taking BeyondBarre classes with her mom, who’s in her 70s. That’s because this kind of exercise doesn’t require running, jumping or other jarring movements that often limit seniors in fitness classes. But being kinder to your body can end up being a more effective work out, says Go Figure’s Julie Wender, who’s had clients into their 80s. “Just because there’s no impact in one sense of the word doesn’t mean it doesn’t have impact,” she says.

There’s no better advertisement for the benefits of barre as you mature than Bachrack. The 59-year-old grandmother of six has a better body than most women a third of her age — and the beginnings of a barre empire. Shortly after she moved her popular classes to her studio on 14th Street four years ago, Bachrack and lead teacher Amy Barnes developed their own style, B.Fit.

They’ve trained the barre instructors at Capitol Hill’s Red Bow, which Bachrack considers its “sister studio.” Richmond Barre, which launched this fall, is also using the B.Fit method. And Bachrack’s considering opening another location in Northern Virginia.

Talk about raising the barre.

More online Follow @postmisfits on Twitter, and read more fitness coverage at .