The study is to find anh evalute an experimental approach to developing the strenght capactiy 15-16 year-olds during extracurricular physical education and health classes in the gym.Materials and methods. The randomized method is used to select a group of students aged 15-16 years (30 people) to participate in classes using the experimental method in the school physical education system (supplement).Classes are based on circle training form, they are held three times a week, taking into account the age characteristics of students' strength ability development and performing complex strength exercises using Use simulation and workout equipment with local and regional fitness exercises. Research results. The positive influence of the experimental program on the training and development of strength abilities (dynamic, static) of students (male) aged 15-16 in the context of supplementary physical education at school has is established. By the end of the trial, 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 increased motor test index values. The value of the elasticity index of young males increased by 20%, speed 12.48%, endurance 10.26%, and speed endurance increased by 7.75%. The number of young men with "average" and "high" levels of the value of the motor test indicators increases. Conclude. Proposed experimental methodology to develop 15- 16-year-old students' physical competencies in supplementary physical education at school has been shown to be highly effective and can be encouraged to improve their fitness and proficiency student's physical fitness.