The Science of Yoga

their bottoms high in the air, they keep their heads as close as possible to their knees. The movement ends with the students lowering themselves back down into the squat. Modern texts that describe that style of Frog recommend doing it anywhere from fifteen to more than one hundred times, its rhythms growing increasingly fluid and fast as the student warms up.
    The ten volunteers in the Davis study had led fairly sedentary lives. A condition for participation in the study was that they had engaged in no regular physical activity—including yoga—for the previous half year. Moreover, the researchers had the students refrain from all other forms of exercise. As with the Duke study, the researchers got around the measurement problem by performing the physiological assessments before and after the yoga training.
    Having gathered and analyzed the data, the Davis team got ready to present its findings to the world. That meant finding a reputable journal.
    Not all public representations of science are created equal. Journals range from bad to great. A minimum requirement for a good journal is that it conducts a process known as peer review—that is, it maintains panels of scientists working in the field who review any proposed article. They exercise what amounts to quality control, making sure a submission hangs together and, if weak, gets rejected or revised to address the inadequacies. Some of the world’s best journals are published by professional associations and have long histories. Science , for instance, was founded in 1880 with the financial support of Thomas Edison and is now published by the American Association for the Advancement of Science, a large professional group headquartered in Washington. The best journals—the ones most widely accepted and admired within the scientific community—achievegood names by virtue of long histories of responsible reporting, quality articles, and exhaustive peer review.
    In 2001, the Davis team laid its findings before the world. It did so not in a sports journal, not in a physiology journal, and not in a general-interest journal of good reputation, such as Science. Instead, it reported the yoga findings in Preventive Cardiology , the journal that Amsterdam had recently founded and on which he served as editor in chief.
    In theory, his editorial control did nothing to diminish the study’s credibility. The journal, after all, was peer reviewed. Amsterdam told me that the manuscript was sent to several reviewers with whom he had no relationship, making their evaluation “blind” and unbiased. Moreover, Preventive Cardiology was the official journal of the American Society for Preventive Cardiology, a professional group. Still, a situation in which the most important gatekeeper at a journal also submits his or her own work for publication can foster a perception of a conflict of interest. Did reviewers go easy on the manuscript to curry favor? Did the editor have a financial stake in the journal’s success, and thus an incentive to make bold claims that would draw wide attention, raising the journal’s readership?
    A related problem centered on the sheer magnitude of Amsterdam’s submissions. Preventive Cardiology carried so much of his own work that the journal, despite its professional affiliation, seemed less like an impartial forum than a vanity press. The same issue that featured the yoga study carried another one of his papers. In all, the quarterly journal that year published four of his articles. No other author came close. His work, except for the yoga study, focused on medical aspects of heart disease.
    That led to a final topic of procedural significance—whether Preventive Cardiology was the right place for the yoga study. The Davis team reported a range of athletic findings, not just ones related to the heart. It seems like its natural home would have been an athletic forum, perhaps the Journal of Exercise Physiology. But the authors, for whatever reason or reasons, instead chose the pages of Preventive Cardiology .
    The study came across as strong and authoritative. For instance, the Davis scientists reported that the fledgling yogis racked up solid gains in muscular strength. One test centered on knee extension—the act of straightening out the leg while raising a heavy weight. On average, the students improved 28 percent.They also showed greater flexibility. On average, they increased the amount they could bend forward (as in the Frog) by 14