MECHANISM OF VARIABILITY REDUCTION IN THE SYSTEM OF SKELETAL MUSCLE MANAGEMENT IN ATHLETES ACCORDING TO THE PRINCIPLE OF FUNCTIONAL SYNERGY FORMATION
The question of physiological function variability is of great theoretical interest, since it is a part of the theory of human voluntary movement control. The skeletal muscle control system should probably have a mechanism to reduce or limit the range of its possible variations. Presumably, the organization of the motor system elements according to the principle of muscular synergy is of such a nature. The objective of the work is to study variations and signs of the coordinated bioelectric activity of skeletal muscles in one of the resulting archery phases. Materials and Methods. The study enrolled 5 highly qualified sportsmen (Master of Sport, International Master of Sport). Archers shot 10 series of 3 shots, target distance 18 m, indoors. Simultaneous recording of electrical activity of 12 skeletal muscles of the upper limb girdle and a 3D video sequence was made. The authors analyzed indicators of distribution, descriptive and variation statistics for grouped data. Multiple regression analysis was used to identify signs of consistent muscle activity. Results. Variability magnitudes, characterized by statistical parameters, established for the turn-off-peak characteristics of various muscles, did not have an explicit dependence. Muscles with relatively high scattering parameters in terms of the EMG average amplitude could have a small variation in the average number of EMG turns. The radial flexor of the left hand wrist was a part of muscular synergy in 90 % of cases, the anterior part of the left limb deltoid muscle - in 80 % of cases, the lower and upper beams of the right and left cowl muscle - in 70 % of cases. Other muscles under consideration were their part in less than 60 % of cases. Conclusion. The system of skeletal muscles that are actively involved in the resulting phases of precision movement can be controlled according to the mechanism of functional synergy formation, which probably helps to reduce the range of possible variations in the parameters of muscle electroactivity.