Features of voluntary muscle tone regulation in individuals with long-term adaptation to speed-strength loads

The maintenance of muscle tone and the coordination of active movements involve the same neural centers, with muscle tone influencing key movement characteristics such as smoothness and amplitude. Adaptive changes in muscle tone may reflect the functional state of motor centers in both the spinal cord and the brain. This study aimed to examine the effects of regular speed-strength physical activity on muscle tone parameters. The tone of the superficial flexor muscles of the right forearm in male individuals was examined, with participants divided into three groups based on their sport specialization: martial arts (MA), team sports (TS), and untrained individuals (UT). Muscle tone (myotonus, mt) was measured using the mechanical myotonometer «Metrimpex» in three states: resting tone (RT), contraction tone (CT), and relaxation tone (RLT). These measurements were used to calculate muscle tone amplitude indicators. The MA group exhibited significantly higher values of RT, CT, and RLT compared to the UT group by 8, 12, and 8 %, respectively (P<0.05). The CT in the TS group was 9 % higher than in the UT group (P<0.05). Additionally, the tone amplitude in both the MA and TS groups exceeded that of the UT group by 22–24 % (P<0.05). Across all groups, a strong positive correlation was observed between contraction tone and tone amplitude (r=0.65–0.77), while a strong negative correlation (r=–0.634) was found between relaxation tone and tone amplitude in the MA group. These findings suggest that the ability to relax muscles plays a crucial role in determining tone amplitude among martial artists. Such adaptations may be associated with the demands of rapid movements that require timely relaxation of antagonist muscles.