A yin yoga class usually consists of a series of long-held, passive floor poses that mainly work the lower part of the body: the hips, pelvis, inner thighs, lower spine. These areas are especially rich in connective tissues, while expanding flexibility and invigorating the energy centers of the body (nadis), blockages are released and your energy flow increases. Yin yoga focuses on static movement, pranayama (breathing exercises) and meditation. The primary differences between yin yoga and many others forms of yoga is that you are encouraged not to use your muscles and passive poses are held for up to 5 minutes, sometime longer. This flow of energy through the body in chinese medicine is referred to as chi and in Yin yoga philosophy as prana. This energy travels through pathways in the body referred to as meridians. It is thought in yin yoga the chi runs through the connective tissue in the body (meridians/pathway).