On a cold Saturday in early 2009, Glenn Black, a yoga teacher of nearly four decades, whose devoted clientele includes a number of celebrities and prominent gurus, was giving a master class at Sankalpah Yoga in Manhattan. Black is, in many ways, a classic yogi: he studied in Pune, India, at the institute founded by the legendary B. K. S. Iyengar, and spent years in solitude and meditation. He now lives in Rhinebeck, N.Y., and often teaches at the nearby Omega Institute, a New Age emporium spread over nearly 200 acres of woods and gardens. He is known for his rigor and his down-to-earth style. But this was not why I sought him out: Black, I’d been told, was the person to speak with if you wanted to know not about the virtues of yoga but rather about the damage it could do. Many of his regular clients came to him for bodywork or rehabilitation following yoga injuries. This was the situation I found myself in. In my 30s, I had somehow managed to rupture a disk in my lower back and found I could prevent bouts of pain with a selection of yoga postures and abdominal exercises. Then, in 2007, while doing the extended-side-angle pose, a posture hailed as a cure for many diseases, my back gave way. With it went my belief, naïve in retrospect, that yoga was a source only of healing and never harm.
At Sankalpah Yoga, the room was packed; roughly half the students were said to be teachers themselves. Black walked around the room, joking and talking. “Is this yoga?” he asked as we sweated through a pose that seemed to demand superhuman endurance. “It is if you’re paying attention.” His approach was almost free-form: he made us hold poses for a long time but taught no inversions and few classical postures. Throughout the class, he urged us to pay attention to the thresholds of pain. “I make it as hard as possible,” he told the group. “It’s up to you to make it easy on yourself.” He drove his point home with a cautionary tale. In India, he recalled, a yogi came to study at Iyengar’s school and threw himself into a spinal twist. Black said he watched in disbelief as three of the man’s ribs gave way — pop, pop, pop.
After class, I asked Black about his approach to teaching yoga — the emphasis on holding only a few simple poses, the absence of common inversions like headstands and shoulder stands. He gave me the kind of answer you’d expect from any yoga teacher: that awareness is more important than rushing through a series of postures just to say you’d done them. But then he said something more radical. Black has come to believe that “the vast majority of people” should give up yoga altogether. It’s simply too likely to cause harm.
Not just students but celebrated teachers too, Black said, injure themselves in droves because most have underlying physical weaknesses or problems that make serious injury all but inevitable. Instead of doing yoga, “they need to be doing a specific range of motions for articulation, for organ condition,” he said, to strengthen weak parts of the body. “Yoga is for people in good physical condition. Or it can be used therapeutically. It’s controversial to say, but it really shouldn’t be used for a general class.” ...