MECHANISM OF MUSCULAR STABILIZATION PROCESS IN JOINTS

This paper defines the process of muscular stabilization acknowledging that it requires putting active muscular constraints on redundant degrees of freedom in the human motion act and in the stabilization of excessive mobility of external systems. It also subjects the process to identification using a procedure which is based on the step function coercion method. As a result of the identification, two models were formulated: the functional model of the wrist joint as the object of regulation and the regulation model of muscular stabilization process. In the first, a linear lumped-parameter second-order system with a time-dependent stiffness was considered. The other case discussed a regulation system with two signal pathways, one of which includes the delays equalling the mean time of a motor reaction in man. Against the background of physiological principles, the interpretation of these two formalisms was used to establish the functional role of tissue stiffness in the process of muscular stabilization of joints. It also led us to propose a mechanism governing this process, which explains a considerable loss of the resultant muscular force when it is exerted on unstable external objects.