Yin poses are typically held for at least 3 to 5 minutes, though some can last for much longer than that. This longer holding time puts minor strain on the connective tissues surrounding the spine and joints. When the muscles, tendons, and ligaments are stressed in this manner, they will stretch if they are relaxed, allowing for greater flexibility and range of motion. Because these connective tissues cannot stretch if a joint is tense, these poses must be done in a relaxed state and position or they will not be effective. The movement of these tissues and the increased flow of oxygen through them also enhances the blood flow and circulation to various parts of the body.