Yoga is hot, and the number of practitioners is growing—even in Christian churches. Some 16.5 million Americans currently practice yoga, up 43 percent from 2002. And many of the recent converts are flexing at church. Some Christians are touting yoga's spiritual as well as physical benefits. Others fear naïve participants will be led into Eastern mysticism.

Jessica Beaubien is the instructor for SoulStretch.org, a Christian yoga ministry started at Royal Oak (Michigan) United Methodist Church. "Christ-centered yoga gives me time to 'Be still' before God," she says. "It helps me listen for his quiet voice and become aware of his awesome presence within me."

"The postures and the presence in the body can itself be a prayer," instructor Carolyn Blueml says, "whether of praise or gratitude or need."

DeAnna Smothers is co-founder of Yahweh Yoga, a Christ-based yoga studio located in Chandler, Arizona. She believes that the ancient practice can help Christians better understand Paul's ...