Fitness for the Agelesss

Reading Job's Body by Deane Juhan provides continuing illustrations of how amazing the human body is and how its systems work together to produce the actions, feelings and stable structures that we take for granted.
With tai chi, always on my mind, every chapter reveals amazing details that can explain how tai chi works.  Chapter 7, "Muscle as a Sense Organ" is no exception.  The anatomical descriptions are so detailed that I can only refer the reader to the book rather than try to summarize.  I may try to pull out some of this detail in my review of the book on this blog, but for today, I will just mention a few of the aspects that are presented to stimulate an interest in further exploration by the reader.
Muscle tissue does not have sensory receptors as does the skin, bone or connective tissue, but it does have the mechanisms to create a kinesthetic sense.  Muscle spindle receptors detecting the slightest stretch of a muscle fiber, golgi bodies detecting stretch and pressure on the tendons, the reticular formation in the brain sensing levels of arousal, the functioning of the eyes and ears in maintaining equilibrium and other systems all work together in reflex arcs and loops to control muscle tone, spatial awareness,  perception of self and much more.  The intricate relationships between a wide variety of sensation coming from muscle activity are coordinated in the cerebellum in order for us to function.
How tai chi is learned through repetition becomes anatomically clear as the muscle sensory capacity comes to light.  Repetition as the main method of instruction becomes more that just a class mantra.  It is only through this repetition that the individual can begin to benefit from the alignment, release of tension and the sense of equilibrium that, along with an awareness of body mind centering, may be the best definition of chi or life force.  My personal preference in referring to chi is to see it not as something that is created or even generated, but rather something that is released when it is not blocked.  I am reminded of a favorite reference in "Anatomy Trains" that the ancient Greek  philosopher/physician, Paracelsus believes that "all disease is caused by blockage".  In tai chi parlance it can be said that "the generation of chi is a release of blockage".