THE STUDY ON THE STANDING POSTURE

-THE LATENT TINE OF THE POSTURAL CONTROL-

Abstract

The purpose of this study is to elucidate the postural controlling mechanism in terms of the postural reflex.
The subjects standing upright on the “shift board” apparatus were subjected to an unexpected postural disturbance. The latent time of the neuromuscular activities was analyzed by the method of the EMG and the changes of the joint angles were analyzed by the electrogoniometer.
The following results were obtained,
1. The change of an ankle joint appeared just at the same time with the onset of the “shift board” movement, and the EMG activity of the tibialis anterior muscle appeared in the process of the extension of the ankle joint and “shift board” movement.
2. The change of the knee joint appeared after about 40 msec following the ankle joint. The change of the hip joint and the neck joint appeared thereafter but, the neuro-muscular activities of f he various parts of the body were activated by the “shift board” stimulus at the range of about 70-90 msec latency.
3. The postural controlling mechanism was discussed in relation to the theory of “simultanious combination”.
4. The trigger of the simultanious discharge of the EMGs was discussed.