There are a large number of 6.97 million left-behind children in China at the end of August 2018. Left-behind children exhibit many psychologically unhealthy behavioural disorders. This study aimed to compare the differences in scientific fitness literacy (SFL) between rural left-behind and general minors, and to analyze the factors affecting the SFL of left-behind minors in the family environment. A random stratified sampling was conducted among minors aged 3–18 in rural areas of China, and 2239 valid samples were obtained. The questionnaire is based on the SFL part and the family environment part of the China National Fitness Activity Status Survey, except for the SFL part of the children’s questionnaire does not contain the attitude dimension, the questionnaires of several other age groups contain three dimensions: attitude, skills, and habits. The SFL of general children and adolescents was higher than that of left-behind children and adolescents, and in the sub-dimensions, children’s attitudes and adolescents’ skills and habits differed greatly, with the general minors having better performance. The SFL showed a significant increasing trend with age in the general minors but the difference between children and adolescents in the left-behind minors was not significant. The scores of habituation in left-behind minors increased with age group, and the scores of the general minors group did not vary much between age groups. In the multiple regression analysis for the left-behind minors, it was found that left-behind young children were less influenced by family environment on SFL score, and children’s SFL was more influenced by family environment. A separate analysis of the 7–9 and 10–12-year-old groups revealed that factors such as parental support and encouragement influenced SFL with different weights, and the importance of parents rotated, while the number of sporting goods in the family was important in all four age models. For the left-behind minors with a large amount in China, the role of the family environment in their SFL cannot be ignored, and the promotion of this literacy should be carried out in a targeted manner.

Children's and adolescents' participation in soccer is low in all regions of China. To achieve coordinated development of soccer in all regions and contribute to a strong sports nation, this study aims to identify the factors that influence the participation of children and adolescents in soccer programs through a cross-sectional analysis of the "soccer population" of children and adolescents aged 7–18. A total of 38,258 children and adolescents aged 7–18 completed a questionnaire; children in the 7–9 age group were helped by their primary guardians. The questions concerned the family level, school level, community level, and individual level. The results showed that the area of the region and the average annual precipitation were correlated with the participation of children and adolescents in soccer programs. In addition, the percentage of children and adolescents participating in soccer programs was higher than the percentage of those who liked it and were proficient in it. Parental encouragement and support, as well as easy access, availability, and safety of sports facilities, are likely to promote children's and adolescents' participation in soccer programs.

COVID-19-associated lockdown has been implemented worldwide, potentially causing unfavorable changes in lifestyle and psychological health. Physical literacy, healthy diets, and lifestyles play important roles in mitigating the adverse effects. Therefore, this study aimed to enable individuals to understand their fitness literacy and establish a personalized exercise plan. In this study, 903 adults aged 19－59 were surveyed based on the concept of scientific fitness literacy and the influencing factors in the context of the effective containment of COVID-19 before (2019) and during (2020) the pandemic. This study screened four factors from four dimensions–cognition, attitude, ability and skills, and behavior and habits–that can influence adults' scientific fitness literacy. Confirmatory factor analysis (CFA) and AMOS software were used to construct an evaluation index system of scientific fitness literacy for adults. The model consisting 10 items with 4 factors to evaluation index system has good overall fitness, reliability, convergent validity, differential validity, and model stability and was able to analyze the factors that affect the scientific fitness literacy of individuals from different perspectives. This allowed individuals at different stages to have a deeper understanding of scientific fitness literacy.

Soccer participation among children and adolescents is low in China. To achieve a coordinated development of soccer in all regions and to promote the physical health of children and adolescents, this study aims to identify the influencing factors regarding the participation of children and adolescents in soccer programs through a cross-sectional analysis of the “soccer population” of children and adolescents. A total of 38,258 children and adolescents aged 7–18 years were included in this study. In addition, the analysis was conducted by dividing the regions where the children and adolescents live into three parts according to socioeconomic status, and by incorporating five dimensions, including environment, family, school, community, and individual levels to find the influencing factors of children and adolescents’ participation in soccer. Chi-square test, Pearson’s correlation, and one-way logistic regression analyses were used. The results showed that the area (r = 0.487) and the average annual precipitation (r = −0.367) were associated with the participation of children and adolescents in soccer programs. Moreover, the percentage of children and adolescents who participated in soccer programs (24.5%) was higher than those who liked soccer or were proficient in it (14.4%). Meanwhile, parental encouragement and support (OR = 0.627; 95% CI, 1.102–3.179), as well as the accessibility (OR = 0.558; 95% CI, 1.418–2.155), availability (OR = 1.419; 95% CI, 1.179–1.707), and safety of sports facilities (OR = 0.316; 95% CI, 0.614–0.865), influence children and adolescents’ participation in soccer programs.

Background: Obesity is a worldwide health problem with many disadvantages for children and adolescents, especially for the sexual development of boys. Exercise and caloric restriction are effective in improving obesity; however, the factors influencing these improvements should be studied in detail. We conducted a randomized controlled study of factors affecting changes in body composition and physical capacity in males aged 13-15 years. Methods: Subjects were divided into three groups based on body fat percentage (BFP), and randomly divided into control and intervention groups. The experimental conditions of this study were based on an exercise camp with a 12-week closed training period. The intervention group received a combination of aerobic exercise, resistance exercise, and caloric restriction. All subjects were uniformly housed and had a standard time for diet and rest, whereas the control group performed their coursework during the exercise intervention time and had no dietary restrictions. The subjects were tested for body composition and physical capacity before and after the intervention. Results: The effect of exercise training and energy-restricted diets on fat loss and physical capacity was limited to relatively lower extremity explosive strength and cardiorespiratory endurance, with a significant effect on body composition. Fat mass reduction was influenced by obesity with a high level of individual variability, with higher levels of obesity resulting in greater reductions in fat mass. The reduction in BFP was not affected by the level of obesity, and there was a mild causal relationship with salivary testosterone (ST) in the intervention group but not in the control group. ST was predictive of future BFP in exercisers; individuals with high ST had a greater reduction in BFP under conditions of prolonged exercise and caloric restriction. Conclusions: More obese male adolescents can obtain greater fat mass reduction with the intervention, but fat-free mass and exercise quality are minimally affected by the level of obesity. Adolescent males with higher ST ground tend to gain improvements in body composition, and ST can be predictive of future BFP but needs to be in the context of an exercise intervention.