Fitness empress Michelle Austin has become a minor international celebrity in recent years. In her television infomercial broadcast on four continents, Ms. Austin promises that her ballet bar workout, “Fluidity,” will give you a dancer’s body in as few as two, 30-minute sessions a week.

Anyone who has ever taken a class with Ms. Austin knows she is not shy, and she has been known to approach women on the street — and, in one case, at an Upper West Side Starbucks — to tell them how Fluidity could transform their respective figures. Those encounters, while potentially ego-bruising for the women, have ultimately created Fluidity devotees, some of whom appear on the half-hour infomercial.

In addition to pitching the $199 freestanding bar on television — Ms. Austin says she has sold more than 100,000 this year — the chatty blonde is one of several instructors who teach Fluidity group classes at four New York gyms.

THE BASICS

According to Ms. Austin, the goal of Fluidity is not to isolate muscle groups, but to integrate them so that a single movement is working, say, the hip, thigh, calf, and rear. To sculpt a body that is lean and proportionate — not bulky — “all of the muscles need to do a little kumbaya, and work together,” she said.

Most of the exercises and the stretches are to be done standing, while holding or resting one foot on the adjustable bar. Signature moves include the “fold-over seat work,” during which the hands are grasping the bar in a wide V-shape, the torso is angled forward, and one foot is lifted back and off the ground for a series of small, precise motions. Another staple exercise resembles a set of pull-ups, done while positioned — back facing the bar, legs and torso aligned, feet resting on the mat —about 45 degrees off the floor.

The best part of these exercises, Ms. Austin contends, is that they strengthen and stretch the front and backside of the body in equal measure. Before one of her students began taking the class, Ms. Austin, not one to mince words, told the woman that “from the front, you look 20, and from the back, you look 70.”

THE WORKOUT

Over the weekend, I took Ms. Austin’s amusing, 70-minute class alongside about 30 other women of all shapes and sizes at New York Health & Racquet Club in Chelsea. The session began with a series of standing, lower body exercises that recalled Callan Pinckney’s “Callanetics” stretching workout video, which my stepmother and I liked to do in the late 1980s. The obvious difference here was that instead of stabilizing myself with a dining room chair, I was using a sturdy ballet bar, fixed at hip height.

As some of the lower body exercises neared completion, my muscles were only beginning to burn. At times I felt as if I could have done another 25 repetitions. The upper body workout, however, parts of which made use of a resistance band fastened to the bar, was arduous from the get-go. So too was the abdominal work, which was the least inspired portion of the regimen.

During the class, Ms. Austin worked out alongside her students. As she glided through the movements, she talked almost non-stop, relating stories about her college days (she often skipped classes) and her family (she lets her nephew beat her at checkers). And she peppered the one-way conversation with physiology factoids: Did you know that the human body contains 630 muscles? Her wide-ranging monologues were the perfect distraction to a mostly challenging workout, which I felt the next day in shoulder muscles I never knew I had.

Fluidity classes at Bally Total Fitness, 350 W. 50th St., between Eighth and Ninth avenues, 212-265-9400; at New York Health & Racquet Club, 60 W. 23rd St. at Sixth Avenue, 212-989-2300; the JCC in Manhattan, 334 Amsterdam Ave. at 76th Street, 646-505-5716, and Printing House Fitness & Squash Club, 421 Hudson St. at Leroy Street, 212-243-7600. For more information, visit fluidity.com.