Concentric muscle contraction regulation in athletes, adapted to various types of motor activity

All the previous studies on mechanisms and patterns of the human body adaptation to different types of motor activities describe evolution of specific parameters characterizing the state of certain functional systems of athletes’ body. However, there is a lack of studies focused on variation of the coordination structure of repetitive motor actions in athletes practicing favored sports. The research purpose was to study the regulation mechanisms of repetitive concentric muscle contractions in athletes adapted to the different types of muscle activity. Three groups of athletes aged 18 - 24 years took part in our research: 8 basketball players, 8 sprinters and 8 stayers with high sport qualification. The test group performed concentric muscle contractions (plantar flexion of foot) to failure. The concentric muscle contraction was carried out in three sets with determined period and amplitude with 90% of the individual maximum effort. The amplitude and frequency of the turns of the electrical muscle activity (EMG) of m. gastrocnemius and m. tibialis anterior was registered. Sprinter athletes showed the highest average EMG amplitude of m. gastrocnemius registered throughout the 3 sets period of training to failure, which was equal to 627,4 µV. Revealed regulation features of repetitive concentric muscle contractions in athletes of all three groups are related to the specifics of their training and competitive activities. Adaptation to specific training and competitive loads leads to the evolution of regulation mechanisms of repetitive concentric muscle contractions, which is reflected in the modification of motor commands used by athletes for its implementation. It was found that electrical activity of m. gastrocnemius of sprinters increases at the end of the each set. This fact probably reflects the implementation of motor command providing for activation of high-threshold rapid motor units.

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