[Proprioceptive regulation of standing in the human. An electromyography study]

Electromyographic experiments, undertaken in connection with action of standing, are here described. A short, sharp push given in an anterior or posterior direction caused an abrupt upsetting of balance, whereby adaptive reactions of the relevant muscles were found to occur after an interval of 60 to 90 msecs. These reactions, although having become automatic as a result of the early-acquired upright posture, are in fact of a voluntary nature and fully controllable by the will. It is demonstrated that these reactions are very probably due to stimulation of deep mechano- and joint-receptors. They do not have anything to do with a functional stretchreflex mechanism.