The Science of Yoga

of yoga’s biggest names, giving it disciplinary cachet. Even Iyengar got involved. Moreover, the stars often made their recommendations in the literature of yoga rather than medicine, meaning the advice tended to receive wide readership among everyday practitioners.
    The Headstand became an early target. In general, teachers advised students to unburden theneck. But they seldom mentioned that such easing contradicted Iyengar. “The whole weight of the body,” the guru wrote in Light on Yoga, “should be borne on the head alone and not on the forearms and hands.”
    Richard Rosen—a teacher in Oakland, California, who had studied at the Iyengar Institute in San Francisco—called for exactly the reverse, with the complete elimination of weight from the head and neck. The idea was to suspend the head off the floor by pressing the forearms down. “If everything feels relatively comfortable,” he wrote in Yoga World, “slowly lower your crown to the floor until it just barely touches. Keep 95 percent of your weight on the forearms and shoulders.” His recommendations seemed to require a level of gymnastic skill and strength that many beginning and intermediate students would find daunting. As for the risks, Rosen never mentioned any specifically by name but simply called the Headstand “dangerous if not practiced intelligently.”
    Robin had us do Headstands in which we transferred body weight from the neck and head to the arms. With practice, it was fairly easy to do. “At this point in the game,” he remarked as we practiced the redesigned pose, “you want a maximum amount of weight on your arms—and a minimum on your head.” Someone asked how much weight should be transferred. “Seventy-two point three percent,” he replied, eliciting howls of laughter.
    Timothy McCall, a physician who became the medical editor of Yoga Journal , advocated a more drastic approach. He called the Headstand too dangerous for general yoga classes unless a teacher had a proven ability to avoid trouble. His warning was based partly on his own injury. Through trial and error, he had found that doing the Headstand had led to a condition known as thoracic outlet syndrome, which arises from the compression of nerves passing from the neck into the arms. As a result, he felt unusual tingling in his right hand as well as sporadic numbness. McCall stopped doing the pose and his symptoms went away. Later, in recommending that general yoga classes avoid the Headstand, he noted how the inversion could produce other injuries, including degenerative arthritis of the cervical spine and retinal tears because the Headstand raises eye pressure. “Unfortunately,” McCall concluded, “the negative effects of Headstand can be insidious.”
    Today, a number of schools avoid teaching the inversion or ban it outright. The cautious stylesinclude Kripalu, Bikram, Viniyoga, and Kundalini. If, as Iyengar claims, the Headstand is “the king of all asanas,” its kingdom has undergone much contraction.
    Other postures that have suffered banishment in some circles include the Full Lotus—one of yoga’s most venerable poses. “Knees are hinge joints, meant only to bend and straighten, not twist,” Dawn Mcenter1ear, a yoga teacher in Washington, DC, told the readers of Health magazine.
    One of the most prolific reformers is Roger Cole, an Iyengar teacher with degrees from Stanford and the University of California who specializes in yoga anatomy and safety. He writes extensively for Yoga Journal and has spoken on yoga safety to the American College of Sports Medicine. Notably, Cole has drawn consistently on science to document the risky aspects of yoga postures and recommend safe practices.
    In one column, he discussed how to reduce neck bending in the Shoulder Stand by lifting the shoulders on a stack of folded blankets and letting the head fall below that level, as we had practiced in Robin’s class. In theory, that could increase the angle between the head and the torso from 90 degrees to perhaps 110 degrees. Cole also voiced rare criticism of Iyengar. He said the guru in Light on Yoga may have “inadvertently contributed” to neck injuries by calling for a perfectly vertical Shoulder Stand. Instead, Cole wrote, teachers should instruct students “to rest their weight toward the back of their shoulders and jackknife the body enough to take pressure off the neck.”
    Cole ticked off the dangers of doing the Shoulder Stand without such