Filimonov A.V. 
The Russian University of Sport «GTSOLIFK», Moscow 

Grigoryev V.A. 
The Russian University of Sport «GTSOLIFK», Moscow

Keywords: libero, visual information images, expert assessment method.

Introduction. In modern volleyball, the role of the libero player is of leading importance, as his actions directly affect the success of the team in defense. One of the key factors influencing libero's effectiveness in the game is the ability to perceive and interpret information. An analysis of scientific and methodological literature indicates that volleyball players make decisions faster using visual-imaginative thinking rather than analytical.
The purpose of the study is to determine the optimal visual and informational images for libero players in defense, based on the actions of the opponent.
Methodology and organization of research. 12 coaches of student volleyball teams took part in the experiment. Their task was to evaluate the significance of the 16 images we identified in the opponent's attack actions on a 7-point scale, then the data was processed using the IBM Statistics program to determine the consistency of the coaches' opinions.
The results of the study and their discussion. The conducted survey of respondents by the method of expert assessments showed that the proposed visual signs have different meanings and contributions to the information field of the libero player. So, when an opponent touches the ball for the first time, the most significant signs, according to the respondents, are the trajectory of the ball to the connecting player (5.83/7 points). During the second transfer of the ball (during the development of the attack), the position of the hands during the transfer of the ball (6.5 points) and the trajectory of the ball after the transfer (5 points) are in the actions of the connecting player. In the next stage, experts recommend highlighting the initial position of the attacking players (5.66 points) and the run-up of the opposing attacking team (6.83 points). According to experts, the striking movement of the striking hand (7 points) and the trajectory of the ball after impact (7 points) are used in the actions of the attacking player at this stage.
Comparing the obtained X*2 value with the tabular value (p=0.01), which shows 79.9>16.81. This is the concordance coefficient found equal to 0.89. It can be concluded that the selected experts and their opinions have no differences, which gives the right to use these images in the libero information field.
Conclusions. The conducted research has identified the most significant visual and informational images to increase the effectiveness of the competitive activity of the libero player in defense. Learning to recognize and interpret such images will significantly improve the success rate of receiving the ball, reduce the number of errors, and increase the reaction speed to a blow.

References

1. Bulykin, L. V., Guba, V. P., Kostyukov, V. V., & Rodina, A. V. (Eds.). (2024). Volleyball and its varieties: Textbook. Soviet Sport.
2. Polivanova, I. I. (1974). On some functional and structural features of problem solving components. Voprosy Psikhologii, 4, 41-51.