Investigation of physiological and kinematic parameters during 5-5 narrow field games played in different field sizes in football players in the U13-U14 age category

The aim of this research is to investigate the effects and changes of physiological and kinematic parameters during 5-5 narrow field games played on different field sizes in 13-14 age group football players. A total of 30 football players aged 13-14 participated in the research. Participants' physical measurements, Yo-yo intermittent recovery test scores, Perceived Difficulty Level (PLD) and performance levels were measured with a GPS athlete tracking device. Football players were randomly divided into 3 groups according to the Yo-yo test results. Three different field sizes (30x20m, 40x30m and 50x40m) were used for small field games. Measurements were taken of the participants' height, body weight, heart rate, perceived difficulty level as physiological parameters, and training load, metabolic power, displacement speed and distance traveled as kinematic parameters. The analysis of the data obtained was evaluated with the SPSS 22.0 statistical package program. One-way analysis of variance test was used for comparison of more than two independent groups. The significance level of the findings was taken as p<0.05. When heart rate, training load values, displacement speed, metabolic power were compared between the research groups at three different field sizes, no statistically significant difference was found between them. p>0.05 Distance covered and perceived difficulty level (AZD) at three different field sizes between the research groups. When the values were compared, a statistically significant difference was detected between them, p <0.05 The most important result of this research is that field dimensions have an impact not only on physical and kinematic variables but also on the football players' experiences and perceptions during the game. It was determined that in larger fields, the time the ball stays on the field increases and the flow of the game becomes more continuous. This shows that pitch dimensions have a significant impact on the duration and flow of the game.