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Strong physique is the basis and premise of all action abilities. However, the lack of physical activity of adolescents is a serious challenge facing the world. In China, the phenomenon of insufficient physical activity and physical decline of teenagers is very serious. A study found that in 2016, about 80% of school teenagers in the world spent less than 1 hour of medium and high-intensity physical activity every day, which did not meet the amount of exercise recommended by the World Health Organization, and about 84% of teenagers in China were lack of physical activity. In fact, physical exercise can not only strengthen the physical quality of teenagers, but also improve their cognitive ability and academic performance through the following mechanisms: 1) in terms of neurophysiological mechanism, physical exercise can enhance the nerve growth, gene expression, antioxidant capacity and activation level of brain tissue related to cognition and memory; 2) In terms of cognitive mechanism, sports can improve teenagers' executive function and attention, and make them show adaptive and goal-oriented behavior, so that they can not only effectively plan, manage and implement multiple tasks, but also enhance their adaptability to the social environment and abide by social norms; 3) In terms of psychological mechanism, sports have a positive effect on individual self-concept and self-efficacy, can significantly improve the physical and mental health level of teenagers, and help shape 内容过长，仅展示头部和尾部部分文字预览，全文请查看图片预览。 nvest in their children's cognitive ability and academic performance, and the average level of their children's cognitive ability and academic performance is low. Therefore, the marginal income of cognitive ability and academic performance brought by extracurricular physical exercise may be higher.

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