Physiological Studies on Functional Development of Body Equilibrium

To clarify the mechanism of the development of equilibrium skills, a study was done of subjects standing on a freely movable balance-board who practiced maintaining their balance while moving freely in a left-right direction. Swayings of the head and of the body's center of gravity (BCG), activities of both soleus muscles and the inclination of the balance-board before and after training were recorded with a polygraph and analyzed with the use of a 5-dimensional feedback model.We observed acquisition, maintenance and transfer gained by training. (1) Acquisition was manifested by the effects of training on four healthy adults using a balance-board for 30 minutes daily for two months. (2) Maintenance was mani-fested in two of the subjects by grades of acquisition after a rest period of a month. (3) Transfer was manifested by the effects of training in two separate healthy adults standing on one foot for 20 minutes daily for two months instead of using a balance-board.Results : (1) Acquisition training using a balance-board led to regular swayings of the head and BCG, and steady activities of both soleus muscles without burst discharge, with subsequent horizontal maintainability of the balance-board. Swa-yings of the head and BCG and muscle activity corresponded to the movement of the balance-board. Muscle activity, especially, showed high power and fine control up to a high frequency. (2) Maintenance acquired balance-board training effects were decreased, but maintained. (3) Transfer : the ability to maintain balance acquired by training in standing on one foot to some degree equalled that acquired by using a balance-board.We noted that maintenance of a steady standing posture was possible because labyrinthine and proprioceptive postural regulations became precise with pre-dominant improvement in spinal proprioceptive reflexes.