Part of the problem, say many teachers and practitioners, is a scarcity of instructors capable of guiding students into a more-advanced practice. These days, they say, many master teachers travel around the world giving workshops, another result of the profitable explosion in yoga's popularity. Americans spend $5.7 billion a year on yoga classes, products, equipment, clothing and media, up 87 percent from 2004, the Yoga Journal study found.
While it is hard to accurately tell how many people have advanced practices, especially given the range of what constitutes "advanced," a survey by the chain Yoga Works this year showed that 10 percent of its students self-identified as advanced. Further, the Yoga Journal study estimated that almost 12 percent of those practicing yoga have been doing so for 10 years or more, which at least demonstrates a strong commitment.
There are some generally accepted markers for what makes a student advanced. Barring injury, they are comfortable holding a headstand (considered an advanced beginner's pose) for several minutes or more. They work on free-standing handstands, and attempt deep backbends, forward bends, twists and other arm balances. If they're truly advanced, they don't radiate smugness as they practice difficult postures.