درخت حوزه‌های تخصصی

The purpose of this study is to compare the performance indicators between different football positions using the Global Positioning System (GPS) in Iranian Premier League football players. This is quasi-experimental study. To conduct this research, 18 football players who are members of a club in the Iranian Premier League were selected as the available sample, and the players were divided into 6 groups based on the game post. Then the data related to the players' performance (total distance, distance traveled with maximum speed, duration of maximum speed, maximum speed, sprints, number of accelerations, and number of decelerations) in 6 consecutive matches Collected using Global Positioning System (GPS). Also, one-way ANOVA analysis and SPSS software were used for data analysis at a significant level (α = 0.05). Based on the findings of the present study, between different football positions for the variables of total distance (P≤0.00), distance traveled at maximum speed (P≤0.00), duration of maximum speed (P≤0.00), maximum speed (P≤0.00), sprints (P≤0.00), number of accelerations (P≤0.00) and number of decelerations (P≤0.00) there are significant differences. There are many fundamental differences between the performance indicators of different football positions with each other it is necessary to recognize these differences and it is necessary to consider special exercises according to the physiological needs of each post.

Introduction: This research was conducted to determine whether professional athletes with Chronic Ankle Instability (CAI) exhibit differences in maintaining balance under conditions of with and without visual informationMaterials and Methods: Forty-five elite players with CAI were classified into soccer, volleyball, and basketball groups (n=15 each). All participants performed a static single-leg balance test in conditions wherein visual information was provided and withheld. Also, their center of pressure (CoP) oscillation parameters was measured. The data were examined through an analysis of variance (ANOVA) and the Tukey test.Results: A significant difference was found between the soccer and volleyball players (P=0.034) in anteroposterior CoP displacement. Furthermore, there was a significant difference between soccer compared with volleyball (P=0.001) and basketball (P=0.02) groups regarding mediolateral sway and sway area (P=0.003 and P=0.03, respectively) when they performed the test with their eyes open. A significant difference occurred between the soccer and volleyball players concerning anteroposterior and mediolateral sway (P=0.002 and P=0.04, respectively) and sway area (P=0.004) when they performed the test with their eyes closed.Conclusion: Given the necessity of maintaining a good balance in sports, volleyball coaches should design practices that reduce players’ reliance on visual information. These practices should strengthen their proprioceptive abilities through an increased challenge to their proprioceptive senses.