Turning point

TYNGSBOROUGH -- ''Step-step. Rock-step."

Kathy Coughlin is putting her ballroom dance students through their paces.

Wearing a white sweatshirt and black tights, Coughlin stands in the middle of the 12 couples with members ranging in age from teens to elders. ''Remember, you have to feel the music," she says and cues up a salsa tune.

Out in the hallway, a few budding ballerinas dawdle after an earlier class. And as Steven and Bridget L'Ecuyer of Tyngsborough wait for their class to begin, they watch through a picture window from a hallway and begin mimicking the steps in the studio.

Inspired by the TV show ''Dancing With the Stars," the middle-aged couple has been taking ballroom dance classes from Coughlin for three weeks and they are impressed with her easygoing teaching style.

''The dancers all have different skill levels, and she has patience, no matter how good or bad you are," said Bridget.

''She makes you want to dance."

Friday is ballroom dance night at Centerstage Dance Academy in Tyngsborough. On other days, there's ballet, modern, tap -- even hip-hop.

Coughlin has been teaching dance for 34 years, and in that time, her business has grown to more than 200 students, representing the changing face of Tyngsborough.

Before 1958, when the new Route 3 cut an asphalt swath through town and it became simply an exit on the Middlesex Turnpike to many, Tyngsborough was proclaimed the ''Gateway to the White Mountains" to motorists driving north from Boston.

The town had a large summer population of working-class residents attracted by its lakes and ponds and the short drive from Boston.

Though the town's population has increased by only about 800 since the 2000 Census and now stands at 11,849, the working-class community of small cottages and trailer parks has been giving way to condos and housing developments.

The honky-tonks, bait shops, and businesses such as Frenchy's Cement Ornaments and Matthew's strip club are being swept aside by strip malls, big-box stores, and upscale restaurants that appeal to newer residents commuting to Boston and the high-tech businesses along routes 3 and 128.

Coughlin helped advance the evolution of Tyngsborough last November, when she moved her Centerstage Dance Academy across the street into a larger space in an industrial park off Westford Road.

The move enabled Coughlin and her six instructors to carry on three classes at the same time.

The facility has two studios, one with a divider that enables it to be separated into two rooms. Both studios have ''sprung flooring," soft layers of foam and other material under the surface that adds bounce to a dancer's step.

Business was booming on a recent Saturday morning. SUVs lined up in front of the building and disgorged elfin passengers in tights. Inside, mothers sat sipping cups of coffee, chatting on cellphones, and kibitzing as their children participated in elementary dance classes on the other side of the picture window. One woman read a newspaper under a picture of a ballerina.

Dozens of shoes and sneakers of various colors were piled outside the studio doors, where they had been exchanged for dance shoes. A half-dozen young dancers raced through the corridor, while others were inside the studio, dancing to Barry Manilow's ''Bandstand."

''Dream, Create . . . Dance," says the sign on the wall.

In the far studio, the theme from the movie ''2001: A Space Odyssey" segues into a Strauss waltz, and 20 teens with outstretched arms swirl around the studio to form a human pinwheel.

Coughlin, preparing the Centerstage Dancers for a competition, leaves a trio of older students in charge and returns to her office to speak to a visitor.

''We don't just teach them how to dance but how to present themselves," she says. ''It gives these kids confidence."

Coughlin said she's a fan of dance history and enjoys sharing her knowledge with her students -- for instance, how the dance steps Buffalo Shuffle and the Lindy Hop got their names. ''They learn the history and get excited," she said.

When it's pointed out that there is not a single male in sight -- neither student nor parent -- Coughlin explains that she had seven boy students last year, but only one this year. ''They get to a certain age, and their friends begin making fun of them,'' she said.

A young student comes in to model the red-and-white striped vest she intends to wear in a competition, to make sure it meets with Coughlin's approval.

''I love them all," Coughlin says. ''I feel like I'm their mom."

Coughlin and her staff teach students as young as preschoolers. She estimates she has taught thousands of students over her career and says some of them have become members of the Alvin Ailey, Brenda Buffalino, and Mark Morris dance companies.

''I started teaching part time, and it turned into this," she said sweeping her hand over the pile of hula hoops she uses to make the classes fun for preschoolers.

A Lowell native who now lives in Tyngsborough, Coughlin said she has been dancing since she was 5. Her first teacher was E. Virginia Bowser. '' I thought she was God."

When Coughlin got to Boston State College, she found out how much she didn't know. She began visiting New York City to take master classes, staying in boarding houses for a week or two at a time. One of her instructors was Bob Fosse.

She said she still takes master classes and keeps up to date with the latest teaching techniques at workshops conducted by the Dance Teachers Club of Boston.

''The kids demand quality."

Justyn Thoren has been an instructor with Coughlin for 10 years. ''Teaching here is fun," she said. ''Kathy instills in all of her students a joy in movement."

And among those experiencing that joy are the L'Ecuyers.

''It's fun, but it's not easy," says Bridget L'Ecuyer, ''because the man has to lead, and that's something that modern women aren't used to."