Spatial-Temporal Structure Features of Muscle Synergies during Profiling Elements Implementation in Rhythmic Gymnastics

Abstract

The article presents an analysis of the muscle synergies involved in making ball throws in different directions and from different starting positions. The study involved 6 highly qualified athletes engaged in rhythmic gymnastics. Electromyograms of the superficial muscles of the upper extremities and trunk were recorded synchronously during the movements, as well as video capture of the movements of body segments. Synergy parameters were extracted from the recorded signals using factor analysis using the principal component method. It has been established that individuals who have mastered a complex motor skill can demonstrate similar motor control strategies. This is manifested in the structuring of intermuscular interaction in the form of two general modules, the degree of involvement of muscles in which is highly similar in the implementation of different motor tasks. The first muscle module implements active movement of the upper limb by jointly activating the muscles of the forearm, shoulder and upper shoulder girdle, and also provides stabilization of the position of the trunk by synchronizing the activity of the muscles of the back and abdomen. The second muscle module is specific and is mainly associated with high involvement in the synergy of the muscles of the upper shoulder girdle and forearm for the implementation of exercises performed without visual control, or from starting positions that limit the mobility of certain parts of the body. Thus, the solution to the problem of coordination of many elements of the motor system may consist not only in reducing the number of executive organs—muscles involved in control, but also in organizing control variables in the form of modules at the kinematic level and their stabilization through muscle synergies.