Blood flow change in the lower extremities of volleyball players during functional tests

Features of cardiodynamics and systemic hemodynamics of athletes have been well documented, while the study and evaluation of the regional blood flow is not enough. The study of the physiological mechanisms of adaptation of blood supply to the muscles in selected sports is crucial for experimental and clinical practice. Currently, there are reports on the state of the muscle blood flow of athletes in cyclic and acyclic, mainly power, sports. Typically, peripheral blood flow studies are conducted in relative rest, but to rate adaptations of skilled athletes becomes possible only under the additional use of functional tests. It is the nature of the reaction to physical stress that allows assessing the functional status of the various systems of the body. With this in mind, we performed the present study, the aim of which was to study the reaction of peripheral blood flow in the lower extremities of volleyball players on performing step-load. Volleyball is a situational sport requiring complex manifestations of the physical characteristics and motor skills in variable modes of muscle activity. The structure of training is dominated by dynamic loads of aerobic nature (80%). The variable power of such loads allows to largely satisfy the oxygen need when exercising. This predetermines the high "readiness" of regional lower limb vessels blood supply to rapidly respond to the load, compared to the untrained, as evidenced by an increase of rheographic indicators - the maximum amplitude of arterial components, rheographic index, amplitude-frequency component. After performing step-load the tone of arteries of small and medium caliber in all groups did not change significantly, while the tone of arteries of large caliber increased. According to the research led by V. Karpman (1994), the rigidity of the walls of the arteries determines the efficiency of the acceleration of blood flow in these vessels to a very large extent. The venous outflow of the untrained people increased by 1.4 times, while in the group of athletes it did not change. Training and competition dynamic loads of volleyball players help to increase the extensibility of the veins and reduce their tone, which reduces the rate of venous blood flow while maintaining good blood outflow. The proposed step-load for athletes is insignificant to identify the adaptive changes of the venous bed. Peripheral vascular resistance at the level of pre- and post-capillaries increased in the group of athletes when performing step-load. Thus, the volleyball players showed the following changes in the peripheral blood flow when performing step-load (the right thigh segment): a statistically significant increase in all indicators of blood supply, an increase of arterial caliber, a constant level of venous outflow, an increased peripheral vascular resistance at the level of pre- and post-capillaries. This indicates a high "level of readiness" of regional blood vessels of the lower limbs to provide rapid response to the load.

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