Component Analysis Of Plantar COP During Human Standing Balance

Plantar center of pressure (COP) during standing is the only force resource for human to maintain balance, this study suggests that the nervous system control the muscles activity to control the movement of COP, and, ultimately, to maintain balance. Therefore, the different neuromuscular control components can be reflected in the trajectory of COP. As the posture control system is hierarchical, so the components can be extracted according to the hierarchical levels. In order to accomplish this research purposes, this thesis captured the muscle activity, center of pressure, and the kinematics of body segments during standing synchronically.By processing these digital signals, this research design a new set of analytical methods to discover the relations between COP and other variables.The results are as follows, the component of COP under 0.3Hz demonstrate no significant relations with the muscles activity. The component between 0.3Hz and 5Hz have significant relations with soleus muscle activity. Those between 0.3Hz to 2Hz may reflect a high hierarchical level control of human posture. Those between 2Hz to 5Hz body may contain signal related with short-cycle feedback postural control such as the one synaptic reflex muscle contraction. Those between 5 to 10 Hz shows strong correlations with muscle stiffness and tonic contraction. However, no significant results has yet been found of the components with frequency above 10 Hz.The direction of this research could help develop new assessment system of human balance. It may also provide an alternative methods to evaluate the degree and sorts of fatigue of human body.