Strengths and Limitations
MYOPIA, CYCLOPLEGIA
To our knowledge, this study is the first RCT to assess the effect of a 2-hour extracurricular physical activity program on academic performance in Chinese children over 1 academic year. Other strengths of the trial included a large sample size, high retention rate, and refraction tests after full cycloplegia to evaluate myopia status.This trial also has several limitations. First, it was difficult to unify the type and intensity of physical activity and equip all participating children with wearable devices for objective, real-time testing due to the unevenness of school facilities and the large sample size. Second, only mathematics test scores were used to evaluate the academic performance; further studies of the effect of physical activity on performance in other academic disciplines are needed. Third, only a questionnaire-based well-being index of children was assessed; more comprehensive mental health assessments after physical activity program intervention are needed in the future. Fourth, as this study focused on children in grades 3 and 4 in a single country, the generalizability of the findings to children in other countries with other ethnicities and age groups is limited, and caution should be taken when generalizing the results.