Aim: This study aims to find and evaluate an experimental approach to developing the strength of 14–15-year-olds in extracurricular fitness and health classes at the gym. Materials & Methods: Classes are based on a circle training form, they are held three times a week, taking into account the students' age-specific strength development and performing complex strength exercises using How to use equipment to simulate and exercise with local and regional exercise exercises. The randomized method is used to select a group of students aged 14-15 years (60 people) to participate in experimental classes in the school's physical education system (supplemental). Research Results: The positive influence of the experimental program on the training and development of strength competencies (dynamic, static) of students (male) aged 14-15 in the context of supplementary physical education at school has been being established. By the end of the trial period, the number of students with "average" and "above average" physical health increased and the number of young men with "low" strength development levels decreased. The proposed test method increases the student's fitness level, as evidenced by the increase in the motor test score values. The value of the elastic index of young men increases by 20%, the speed is 12.48%, the endurance is 10.26%, and the speed-strength increases by 7.75%. The number of young men with "average" and "high" levels of the value of the motor test indicators increases. Conclusion: Proposing experimental methods to develop the physical capabilities of 14-15-year-old students in school gymnastics is highly effective and can be encouraged to improve the fitness and physical capacity of the student.