The eight limbs of yoga represent different values.

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Although it may seem like you need eight arms and legs to do some of the more advanced yoga postures, that's not what the term "limbs of yoga" refers to. The eight limbs of yoga is actually a set of guidelines on how to live, practice and worship, laid out in Patanjali's Yoga Sutra text in the second century BCE.

In Sanskrit, the ancient language of the Yoga Sutra, the word ashtanga means "eight-limbed." (This is where Ashtanga Yoga, a type of yoga characterized by its specific flow of postures and an emphasis on breath and gaze, gets its name.) According to the text, the ashtanga, or eight-fold path, is what yogis should use to make ethical and moral decisions, to achieve a meaningful life, and to incorporate spirituality into their practice.

Only a few of these limbs involve yoga as you might typically think of it -- on a mat, during a structured class, breathing and stretching, says Brigitte Bourdeau, a certified health counselor and yoga instructor in New York City. "Some of the limbs are ways of conducting your life -- how you treat others, the environment, society," she says. "Others are about how you treat yourself -- in terms of cleanliness, how you use your energy and your personal values. Basically, they're things you'll find in any religion or any major philosophy on life."

The limbs are usually presented in a specific order, because it's traditionally believed that one should gain experience with the first limbs -- those that deal with the physical parts of yoga -- before they can move on and truly achieve the emotional and spiritual benefits of meditation and enlightenment. And it's true that someone who takes yoga once or twice a week at a local gym may never get a taste of all eight limbs -- no matter how good they get at Downward Dog.

"Some people may only ever do the asanas; while other people may only ever try meditation, and others only study the scriptures and learn Sanskrit," says Bourdeau. Still, for a true practitioner of the full ashtanga yoga philosophy, one limb is not generally considered more important than another; ideally, they all work together to help one realize true peace and happiness.