Recommended Amount Of Physical Activity For Chinese Students According To National Student Physical Fitness Standards

PURPOSE: To find out the optimal recommended amount of moderate and vigorous physical activity for adolescent students in China, with the goal achieving fair, good and excellent in National Student Physical Fitness Standards. METHODS: The data came from 4,632 adolescent students in ten provinces in eastern and western China, with an average 16.5 years old. Test items: height, weight, lung capacity, standing long jump, seating forward bending, 50-meter run, 1000-meter run (male), 800-meter run (female), sit-ups(female), and pull-ups (male). The physical fitness level of students was evaluated according to the National Physical Fitness Standard for Students: A score of 60 or above is considered as fair and 80 or above is considered as good and excellent. Physical activity was measured using Actigraph GT3X+, and counts per minute (CPM) was used to classify the intensity of physical activity. 500-3999CPM was regarded as moderate physical activity (MPA), 4000 CPM or more was regarded as vigorous physical activity (VPA). The cumulative time of MVPA was obtained by addition. MedCalc medical statistical software was used for ROC curve fitting and calculation of the optimal critical cut-off value. RESULTS: When students' fair level of physical fitness and MVPA fitted by the ROC curve, the AUC was 0.659 with the asymptotic significance of 0.000 (P < 0.05), and the maximum Youden's index (sensitivity + specificity-1) was 0.300. The model had a significant predictive value, and the corresponding critical cut-off value of MVPA was 50.207 min/d. The AUC was 0.645 with the asymptotic significance of 0.000 (P < 0.05), the maximum Youden index was 0.248, and the corresponding critical cut-off value of MVPA was 100.402 min/d after students' good or excellent level of physical fitness and MVPA fitted by the ROC curve. CONCLUSIONS: For Chinese students to maintain their physical fitness at the fair level or above, MVPA needs to be no less than 150 min per week; to maintain their physical fitness at a good level or excellent, MVPA needs to be no less than 300 min per week.