[Role of extrapolation and dynamic stereotype in the mechanisms of the formation and improvement of adequate motor coordinations].

Hardness (tonus), viscosity, bioelectric potentials, force and endurance of human muscles were studied. All these properties are subject to considerable alterations in conditions of fluctuations of muscle temperature, oxygen provision. They change permanently also in the process of dynamic work or static efforts (25, 50 and 75% of maximal strength). This is not in accordance with the mechanism of dynamic stereotype. The latter is conformed only to the succession of phases during standard movement performance. The intrinsic structure of motor activity, corresponding to the complex of active motor units, is permanently altered not only during work but in the restitution period as well. The nervous system due to its plasticity, has a high extrapolation capacity. It reacts adequately to new tasks arising with changes in the external or internal environment. Training improves extrapolation but after its cessation extrapolation becomes worse.