In an airless, low-lit room on Second Avenue that’s painted in purple and turquoise, Sharon Gannon snakes her way among the closely parked, partly pierced, mostly beautiful, all-white young people contorting their bodies in impossible-seeming ways. More than once during the one-hour-35-minute session, she reminds them that this is something “normal people” don’t do.

“Shift your identity toward the immortal,” she urges softly. “We’re tuning in to the cosmic station.” Jangly Indian music gives way to Van Morrison. Communal sweat fogs the windows. At one point, as 30 people exhale slowly in unison, it feels like Darth Vader has joined us. By the end, Gannon, who appears to have perfected the jet-black-hair-dark-eye-shadow-gold-nose-stud look, has me lying down in the dark, joining in the meditation mantras. She is rubbing what smells suspiciously like Vicks VapoRub on the back of my neck, and I am thinking: They could do with a bit more space around here.

Space -- 9,000 square feet of it -- is exactly what the Jivamukti Yoga Center is getting when it moves next week to new digs on Lafayette Street. Gannon and her co-director, David Life, describe it as the biggest yoga studio in America, an interdisciplinary, interfaith gathering place where one can take classes in Sanskrit and the Bhagavad-Gita as well as yoga, or see dance performances, all in one building replete with an entrance-hall waterfall, a meditation room, and a huge studio.

Jivamukti’s new downstairs neighbor happens to be Crunch, which, like most other fitness centers, has begun offering its own yoga classes. Nevertheless, Gannon and Life appear to have turned the holistic-health-care bandwagon to their advantage. Several Jivamukti teachers already give classes elsewhere -- including at Crunch, whose CEO, Doug Levine, is himself a student of Gannon and Life’s and has welcomed them despite a lease that allows him to bar competing businesses from the building.

The real battle for minds and muscle is taking place within several yoga subcultures setting up ever-bigger shops around town. Now that the practice has reached a critical and spiritual -- not to mention celebrity -- mass, yoga has become big business for those very people who practice disconnection from the material world. People like Yoga Zone founder Alan Finger, a 51-year-old South African whose two Manhattan studios together equal Jivamukti’s new center. He, too, plans to open a big new space, in midtown, this year.

Tutored by his father, Kavi Yogiraj Mani Finger, Finger left Johannesburg in 1976 to start his own studios in the States, first in Washington, D.C., then in Los Angeles, where twelve years ago he opened up Yoga Works, teaching Barbra Streisand, Robin Williams, Bob Dylan, and other celebrities. But having sown the seeds of L.A.’s yoga boom, Finger packed up and moved east in 1988 because of his students’ relentless fixation on who was showing up to stretch. “Your merit as a teacher in L.A. is judged by who’s in your class,” he says. “In New York, there was less glamour. Yoga is the star, not these people.”

Of the handful of credible yoga centers in the city, each fills its own niche. Sivananda, which set up shop here in the early sixties, is perhaps the most respected of the old-guard studios, with ashrams around the world. Patanjali is the place for ashtanga purists, who practice a highly aerobic form sometimes referred to as power yoga. Iyengar, the first to develop the use of belts and blocks, has been dubbed furniture yoga.

The most commercialized contenders -- Jivamukti and Yoga Zone -- are amalgams of styles and cater to distinct clientele, as reflected by their locations and, to a lesser extent, their prices (they both charge more than most gyms). Jivamukti, whose fees recently jumped from $750 to $1,200 a year, regards itself as a youthful, downtown beacon for seekers (more than 300 a day, which may well double at the new center) of the light. Yoga Zone’s midtown mothership attracts a higher quotient of stressed-out suits (Finger refuses to discuss numbers). The school even operates a “yoga at work” program, offering sessions in your own office. Membership runs to $1,480 a year.

Jivamukti and Yoga Zone both lay claim to the title of top studio in New York -- even as they vehemently decry any suggestion that they might actually be in competition with each other. The very notion of rivalry, I am told emphatically, is essentially non-yogic (the word yoga does, after all, mean “union”); both add that they make a point of encouraging their students and teachers to seek out other schools. “We don’t want them to be kept in the dark,” Gannon says. “That doesn’t promote yoga; that promotes fear, and we don’t have anything to be afraid of.”