Yin Yoga is slow-paced style of yoga (as exercise), incorporating principles of traditional Chinese medicine, with asanas (postures) that are held for longer periods of time than in other yoga styles. Advanced practitioners may stay in one asana for five minutes or more. As conceptualized in the Taoist and Dharmic traditions, the sequences of postures are meant to stimulate the channels of the subtle body, known as meridians in Chinese medicine and as nadis in Hatha yoga.
https://en.wikipedia.org/wiki/Yin_Yoga