Through dropping the tail bone when doing Taiji or standing meditation, the lower back relaxes. Especially when the head is pointed vertically to the sky or ceiling, the gravity will naturally pull the vetebrate straight and relax the muscles around the whole backbone all the way to the neck. The shoulders will then follow to relax. When the tensions are gone, more Qi flow and better blood circulation can reach the brain, and the brain will function at its peak. Doses of endorphin will then be secreted to comfort the whole body, and getting rid of stress and pain. Isn't that wonderful?
Wingchuntaiji