The orgins of yoga reach all the way back to the Hindu religion, before Christ was even born. But many faithful churchgoers are chanting phrases from the Bible when they do their Downward Dog, and it's causing yoga purists to lose their cool.
Susan Bordenkircher teaches a Monday night Christian yoga class called "Outstretched in Faith."
"I approach each class as a way to share with people something great about their faith," she said.
But which faith? Traditional yoga, with it's roots in the Hindu religion, predates Christianity.
Its original goal was to develop self-awareness and find divinity within oneself.
Those Hindu ideals offend some Christians. Pope Benedict XVI has warned that yoga "can degenerate into a cult of the body."
When Bordenkricher, a devout Methodist, was first exposed to Yoga, she loved the exercise, but was turned off by some of the Hindu-based chanting.
"It made me feel uncomfortable," she said. "It made me feel as if those were elements that I certainly did not want to participate in."
So Susan joined a growing trend, modifying traditional yoga, replacing many of the Hindu chants with biblical phrases, or Christian themes.
There are clear physical benefits to this kind of activity. It stretches the muscles and relaxes the body. But Yoga purists say that Yoga without Hinduism, isn't Yoga at all.
"If you take a tree an chop off it's roots, then you don't have a tree, do you?" said Professor Subhas Tiwari, a professor of Yoga philosophy at Hindu University.
Tiwaris says yoga is not something that can be edited with the Hindu parts cut out.
"Yoga is mind body spirit," he said. "You want to make those separations then you live in a schizophrenic world."
Bordenkircher bristles at this charge.
"There is no way that you can take a posture that is from a body that God created and say this can only be used for the Hindu faith," she said.
It is a peaceful debate about the body and soul.
ABC News' John Berman filed this report for "World News Tonight."