Despite having an advanced asana practice, which is supposed to help prepare the body for meditation, Grilley found himself uncomfortable when he began to attempt long, seated meditations. Yin Yoga directly addresses the demands that sitting still in one position for a long time places on the body by focusing on stretching connective tissue instead of muscle. Sarah Powers, who studied with Paul Grilley, is another well-known teacher in this field.

Yin and Yang
In Chinese philosophy, the yin yang symbolizes the duality and interdependency of the natural world. Things that are yang are moving, changing, and vigorous. In contrast, things that are yin are still, static, and calm.

The majority of western yoga practices have evolved into being very yang- lots of movement, with an emphasis on stretching the muscles. Muscles are yang, while connective tissues like tendons and ligaments are yin. Sitting for meditation is more yin, and therefore requires a practice that adresses this use of the body. While joints like the knees and ankles are fragile and easily over stretched, the body also contains joints in the pelvis, hips and lower spine that are naturally much less flexible. It is these joints that yin yoga primarily addresses.

Yin Poses
Yin poses are derived from traditional yoga poses, though they have been renamed to distinguish them. Thus, cobbler's pose becomes butterfly, plow pose becomes snail, and pigeon pose becomes sleeping swan.

Yin vs Restorative
Though Yin yoga and restorative yoga are similar in that poses are held for long periods, they have fundamentally different purposes. It is possible to get yin benefits from doing restorative poses, but the goal is not relaxation. Restorative poses are typically much more supported using props. In yin poses, gravity helps intensify the stretch. Some poses, such as dragon (a version of lizard pose ), would not work as restorative poses, which are typically done in a supine or prone position.