Evaluation of the complexity of the motor task from the point of view of muscle activation

Abstract

Today, many specialists from various fields, such as physiology, biology, rehabilitation, traumatology and others, are actively researching the functioning of the musculoskeletal system and its relationship with the central nervous system. This is a very relevant topic in today's world, as various factors such as traumatic injury, chronic or hereditary disease, neurological impairment and the aging process have a direct impact on the state of the musculoskeletal system, muscle function and movement coordination. One of our goals is to study the dynamics of two-joint equilibrium muscle contraction in order to determine the final forces created by the right upper limb of a person in the horizontal plane. We are conducting a study in which the electromyographic (EMG) activity of the muscles of the shoulder and shoulder girdle, as well as the spatial and force parameters of movements that occur during free two-joint efforts, are studied. The purpose of this study is the process and mechanism of central coordination of motor commands sent to the muscles of the shoulder and shoulder girdle during bicondylar movements, especially when performing targeted efforts with the hand, in the presence of visual control. Synchronization and coordination of the muscles of the shoulder and shoulder girdle during the performance of two-joint movements were studied in an experiment with experimental subjects. By recording the electromyographic activity of 8 muscles and calculating the moments of forces generated by the muscles, it was found that muscle synchronization was more pronounced during elbow flexion, and muscle coordination - during shoulder extension. The findings of the study indicate that the muscles of the shoulder and shoulder girdle work in a synchronous and coordinated mode during two-joint movements. Muscle synchronization and coordination appeared to be important for precise movement control, with elbow flexion and shoulder extension showing greater accuracy compared to other movements.