Yin yoga classes are less about breaking a sweat and more about relaxing into poses that allow for a deep fascia stretch. Fascia is a connection of fibers throughout the body that helps hold things together. Research shows your fascia requires holding a pose longer than what your muscles might need.
Muscle can effectively stretch after holding a pose for 30 seconds. Fascia, on the other hand, requires at least 5 minutes – sometimes – to effectively target, activate, and release. Therefore, yin yoga classes are typically an hour or 90 minutes and you only hold 7 or so yoga poses.
Because you’re holding a pose for a minimum of 5 minutes – poses in yin classes are passive, not active. They do not require you to tense then hold muscles in a contracted state. Rather, you’re put into a pose that requires no muscle tension and encouraged to close your eyes, breath, and actively relax every muscle.
Example of poses in a yin class are sharshankasana (child’s pose), mandukasana (frog pose), and supta baddha konasana (reclining bound angle pose).