There are a number of tensions at play in Kate Churchill’s documentary about the proliferation of yoga as both spiritual path and commercial workout culture, and the vigor with which the believers will try to convert the skeptics. What’s frustrating about this otherwise friendly, lightweight look at the diverse world of yoga practitioners is that its director winds up focusing on the least interesting and most predictable tension: that which arises between herself and her hand-picked, inflexible star. Churchill, a lithe, centered believer, recruits Nick Rosen, a bland, atheistic young journalist, to help her prove the dubious but documentary-ready premise that yoga can “transform” anyone. Churchill creates a yoga-tasting menu for Nick, guiding him through various schools, and touching (too lightly) on one of the phenomenon’s ironies: enlightenment for sale. The duo travels to India and, after several months, Churchill grows impatient for her subject’s big breakthrough. When a modest version of that breakthrough arrives, you get the feeling the director wants to tell her godless charge not to choke on it.