# Evaluation of Lower Extremities Power, Movement, Position and Effectiveness in Volleyball
## 1 Introduction
The libero is responsible for the defensive play and for receiving the serve [19]. In their research, [PERSON] et al. showed that players playing in different positions have significant differences in body height and range with one hand and with both hands in attack and block. In the middle, as opposed to the opposite hitters, they have a higher level of blocking and attacking characteristics (they are younger, taller, have a lower BMI and have a greater range in attack and block). Setter and libero players are shorter, lighter and older, which can favor better performance in setting the ball, receiving a serve or defending [17]. Determining a single proper level of strength and power in volleyball players is very difficult or even impossible. It is related to the variability of these parameters in the individual phases of volleyball players' training and their long-term development. However, in the process of training the players, it is important to recognize those parameters that may be useful in the analysis of the technique and effectiveness of the game. Based on these results, the training process can be optimized to eliminate the constraints and increase the performance of players. When analyzing whether the power of a volleyball player's lower limbs has an impact on their game effectiveness, it is essential to clarify the concept of power. Power is expressed by the formula \(P=W/t\), where \(P\) represents Power, \(W\) represents Work, and \(t\) represents time. Additionally, velocity (V) can be determined using the formula \(V=s/t\), which measures the speed of completing a specific task. In essence, power refers to the ability of the nervous and muscular systems to overcome resistance with the greatest possible speed of muscle contraction. Regarding power as a trait, it is one of the factors that allow us to determine a person's physical capabilities. The main goal of the presented work was to verify the relationship between the different parameters of the lower extremities and the effectiveness in the game, as well as the possibility of playing in a given position. The aim of this study was not only to identify differences in lower limb power levels among players in various positions but also to examine how these differences may affect the technical efficiency of players and the team's performance. Understanding whether players with greater lower limb power are more effective in key aspects of the game, such as attack, block, and reception, allows for the optimization of training strategies, which can directly contribute to improved match results. In this research, the authors tried to assess the importance of lower limb power, jump height, time in the air, step width, and contact time with the ground in the context of effectiveness factors. An attempt was made to answer the question of whether the parameters of lower extremities have an impact on the effectiveness of technical activities performed by players at specific positions on the court. The authors looked for an explanation of the issues related to the influence of lower limbs on the effectiveness of the serve, attack, and reception and set on the occurrence of differences related to highly variable characteristics of the game in given volleyball positions. The link between the parameters of the lower extremities and the effectiveness in volleyball will help determine the influence on the effectiveness of technical elements in volleyball, which is directly related to the quality of the game and, therefore, to the final result of the match.