The Science of Yoga

longer needed surgery and expressed bewilderment at how little science understood the mechanics of the arm.
    At his own office, Fishman led an investigation into how the Headstand had achieved the cure. His main tool was the electromyograph—the heir to Jacobson’s methods for tracking muscle activity. It let Fishman and his aides zero in on rotator activation. The team took measurements as he stood upright and on his head. The readings showed that two other rotator muscles had joined the action—the subscapularis and the rhomboid major. They engaged most when Fishman inverted his posture and proceeded to raise his shoulders—a key feature of the Iyengar Headstand. Iyengar taught that, once students were upside down, they should widen and raise their shoulders as far from the floor as possible. That extra lift turned out to be the main factor that produced the healing benefits.
    Fishman concluded that the Headstand taught the other rotators to assume new roles. “It’s training yourself to use a different muscle,” he said, smiling, talking amile a minute. By another name, it was muscle substitution—avoiding an existing problem by using other muscles.
    Pleased with the results, Fishman decided to see if the benefits could extend to others. He asked the next patients with torn rotator cuffs if they would like to try the Headstand cure. Sure, ten answered. He and his assistants taught them an easy form of the inversion that they could do with the help of a folding chair.
    Fishman’s prescription? Do it once a day for thirty seconds. Nothing more. At the end of six weeks, he and his team checked the patients. To Fishman’s delight, nine of the ten found they could move their arms like a person with a healthy shoulder. All decided to forgo surgery.
    Sharon Williams, a development director at Dance Theater of Harlem, had come to Fishman with chronic pain in her right shoulder. It had ached for a month, and examination revealed a partly torn rotator cuff. After she started the Headstands, the pain went away and she found that her arm could once again move through its usual range of motion. It was a huge relief.
    The results were surprising. Fishman and his aides published them so other health professionals could learn the trick.
    I asked where else yoga could heal.
    Fishman said it excelled in such things as osteoporosis—the disease of the bone that removes minerals and leads to increased risk of fracture. It often strikes older women and, without pain or symptoms or diagnosis, lies behind millions of fractures of the hip, spine, and wrist. Yoga stretching, he said, worked beautifully to stimulate the rebuilding of the bone. It happened at a molecular level. Stress on a bone prompted it to grow denser and stronger in the way that best counteracted the stress. Fishman said that for three years he had been conducting a study to find out which poses worked best to stimulate the rejuvenation.
    “It’s a big thing,” he said of the disease. “Two hundred million women in the world have it and most can’t afford the drugs,” some of which produce serious side effects. By contrast, Fishman enthused, “Yoga is free” and completely natural.
    “There are bad things in yoga,” he volunteered. But not enough to outweigh the benefits.
    Fishman knew the dark side in detail, it turned out. He told me about an injury survey thathe and his colleagues were doing—the one based at the Columbia College of Physicians and Surgeons that documented hundreds of yoga injuries, including strokes.
    On the plus side, Fishman said, yoga excelled at fighting the stiffness of arthritis. The inflammation and tight joints restrict movement, and yoga worked to increase the range of motion. As was his habit, Fishman had written a book about it, Yoga for Arthritis.
    How often do you prescribe yoga for your patients?
    Twice this morning, Fishman replied.
    A woman in her late thirties had severe osteoporosis. The loss of bone mineral had weakened her frame and she had broken her foot four times doing exercises. Fishman prescribed a series of yoga stretches to be done flat on her back, lessening the chance of spinal fracture and providing a stimulus to help bring back the minerals.
    Another woman, in her early forties, had severe neck pain. She also suffered from degeneration of the macula—the highly sensitive part of the retina responsible for central vision. Fishman suspected that her poor eyesight had caused her, a stock trader, to