Old religions used to teach you to sit or kneel and always rock, gently but definitely rock. When you rock, you swing from prevertebral to postvertebral muscle. You'd see the same thing with sailors in the more active days of the ward. You'd go down the street and you'd see a man in uniform, but you'd know without checking the uniform whether that man was a seaman or a landman. The landman went down the street boomp boomp boomp; the seaman went down rolling - from the prevertebral to the postvertebral, the prevertebral to the postvertebral, He may not have had what we would call a really balanced gait, but he did use that alternation which kept the whole body at its peak. And they do this in many religious rituals, So much of ritual, if you look at it in the light of what you know of physiology, can be seen as a form of preventive medicine.