Abstract
This article examines the scientific and methodological foundations for assessing and improving the level of physical fitness of 15-year-old secondary school students. During the study, pedagogical assessment tools aimed at determining physical fitness indicators were applied, and the obtained results were subjected to statistical analysis. The research data were processed using descriptive statistical methods, and mean values and standard deviations were determined. The statistical analysis allowed for the assessment of the reliability and validity of the test indicators, as well as an objective characterization of the students' level of physical fitness. The results of the study demonstrated a positive dynamic in the development of motor abilities among 15-year-old students, according to initial and final testing data. The use of pedagogical tests at the beginning and end of the academic period statistically confirmed an improvement in the quality of physical fitness, indicating a scientifically grounded and age-appropriate approach to organizing physical education lessons.