Objective: To examine the association between moderate-to-vigorous physical activity (MVPA) and weight adjusted waist index (WWI) with psychological sub health in middle school students,so as to provide a basis for mental health intervention and promotion. Methods: From September to November 2023, a stratified cluster random sampling method was used to survey 47 372 middle school students aged 12-17 in Jiangsu, Xinjiang, Guangdong, Jilin and Henan provinces from eastern, western, southern, northern and central of China. MVPA, WWI, and psychological subhealth were assessed, with WWI categorized into quartiles ( Q 1- Q 4). Data were analyzed using χ 2 test, Logistic regression analysis and Logistic regression analysis of generalized linear models. Results: The overall prevalence of psychological sub health among middle school students was 21.0%, with higher rates in boys(21.4%) than girls(20.5%) ( χ 2=6.49, P <0.05). The detection rates of emotional problems, behavioral problems and social adaptation difficulties in middle school students were 27.8%, 26.9% and 17.5%, respectively. The combination of MVPA and WWI groups was used as independent variables, and the covariates were adjusted to perform Logistic regression analysis of generalized linear model;while the Q 1 group with MVPA>60 min/d was used as the reference group, the Q 4 group with MVPA<30 min/d had the highest risk of psychological sub health detection( OR =1.58, 95% CI =1.38-1.81),and the detection risks of psychological sub health among middle school students in Q 1- Q 3 groups were 1.34(1.17-1.53), 1.30(1.13-1.49) and 1.42(1.24- 1.62 )( P <0.01). Conclusions MVPA and WWI are significantly associated with psychological sub health in middle school students. Lower MVPA and higher WWI in middle school students correlate with increased sub health risks. Interventions should aim to enhance MVPA levels and reduce WWI to improve mental well being in middle school students.

Objective: To understand physical fitness and physiological function level of children and adolescents with different nutritional status in Beijing Tianjin Hebei Region, and to provide reference for physical health promotion and intervention of children and adolescents. Methods: From September to December 2019, 4 424 children and adolescents aged 7-18 years old in Beijing Tianjin Hebei Region were tested for different nutritional status, physical fitness and physiological function by using stratified cluster sampling method. Results: The detection rates of malnutrition, normal, overweight and obesity were 7.93%, 67.36% and 24.71%, respectively.There were differences in heart rate, systolic blood pressure, diastolic blood pressure, vital capacity body mass index, grip strength body mass index, oblique pull up/pull up, standing long jump, 50 m running, 1 000 m running, and BMI in boys with different nutritional status statistical significance ( Z =9.6, 55.2, 118.6, 332.5, 122.8, 15.6, 49.5, 47.5, 12.6, 113.5, P <0.01); There were differences in heart rate, systolic blood pressure, diastolic blood pressure, vital capacity body mass index, grip strength body mass index, sit up for 1 minute, standing long jump, 50 m running, 800 m running and physical fitness index in girls with different nutritional status statistical significance ( Z =33.9, 24.5, 46.5, 262.5, 102.6, 32.5, 27.5, 33.6, 27.6, 51.6, P <0.01). Correlation analysis showed that the nutritional status of boys was positively correlated with systolic blood pressure, diastolic blood pressure, 50 m running, and 1 000 m running ( r =0.27, 0.31, 0.14, 0.16, P <0.05), and was correlated with heart rate, vital capacity, body mass index, grip strength body mass index, oblique pull up/pull up, standing long jump, and BMI were negatively correlated ( r =-0.07, -0.62, -0.41, -0.21, -0.35, -0.29, P ＜0.05); nutritional status of girls it was positively correlated with systolic blood pressure, diastolic blood pressure, and 800 m running ( r =0.21, 0.27, 0.22, P <0.05), and negatively correlated with heart rate, vital capacity BMI, grip strength BMI, and BMI ( r =-0.12, -0.49, -0.32, -0.18, P <0.05). Conclusion The nutritional status of children and adolescents in Beijing Tianjin Hebei Region is related to physical fitness and physiological function. Overweight and obese child have lower physical fitness and physiological function. In the future, childhood overweight and obesity should be effectively controlled to better promote the development of physical fitness and physiological function.