NEW YORK - Yoga is going hip-hop part of a rampant commercialization of the ancient exercise in America, where it is being marketed to new inner city audiences at Starbucks-like chains.

Yoga, the 5,000-year-old Indian discipline of exercise, diet and meditation, has exploded into a US$3 billion industry in the United States, with urban entertainment impresario Russell Simmons the newest figure to join in.

Simmons, the founder of Def Jam Records, has released a video series titled, "Yoga Live", with instructions set to 72 tracks of original hip-hop music - sounds that might have jarred the yogis of bygone days.

Simmons said he tried to distil the spiritual from the physical in his tapes. "We packaged it intentionally in a way for people to digest the physical practice," he told Reuters. "It's not meant to get them worried about religion or spirituality."

In another commercial move into yoga, entrepreneurs Rob Wrubel and George Lichter who teamed up to lead online search tool Ask Jeeves, have launched Yoga Works, a chain of yoga studios that aims to grow from its current 14 sites to an average of 10 studios in the largest US cities.

Interest in yoga has exploded.

A Harris survey of a sampling of 4,700 people across the country commissioned by Yoga Journal showed that 16.5 million people were practicing yoga, or 7.5 per cent of US adults.

Other offshoots of the ancient art that have found popularity include yoga spinning and combining the practice with indoor cycling and heat training. There is also a new California hybrid called budokon, Japanese for "way of the spiritual warrior," that mixes martial arts, yoga, meditation and optimal nutrition.

Some practitioners are concerned about the marketing of yoga.

"The commercial opportunities lead to less genuine forms of yoga," said Swami Ramananda, 51, head of Integral Yoga Institute's two New York City centres.

Ramananda said he worried about exercise fads co-opting yoga in a superficial way. "If someone's intention is to make money, he is not offering yoga with students in mind," he said.

Yoga Journal spokesperson Dayna Macy illustrated yoga's striking rise in popularity by her magazine's rapid growth in circulation -- from 90,000 in 1998, to 170,000 in 2000, to a current 325,000.

"Yoga is a very powerful practice and survives because its teachings are very adaptable to the culture where it lands," she said.

Many in the US yoga establishment agree.

Garrett Sarley, head of the Kripalu Centre for Yoga and Health in Lenox, Massachusetts, said, "The premise of Kripalu yoga embraces the idea that more is better. In the end all yogas lead to one great yoga."

Now turf wars have sprung up over the right to copyright and trademark specific yoga programs.

A legal battle in California is ongoing over whether Beverly Hills maestro Bikram Choudhury has ownership rights over his "Bikram Yoga" program - a specific sequence of 26 postures and breathing exercises performed in a heated room.

Luke Cammack, 32, co-director of a Bikram Yoga studio in New York, said he tried various styles of yoga before settling on this.

"You have to be calm because it's really intense," said Cammack. "We don't teach philosophy. There's no chanting."