High prevalence of physical inactivity and obesity in children and adolescents has become a global problem. This systematic review aimed to examine the existing literature regarding the factors that influence participation in physical activity (PA) in children and adolescents with reference to the social ecological model (SEM) proposed by McLeroy et al. (1988). The SEM provides a framework under which the influencing factors are categorized into five levels: intrapersonal, interpersonal, organizational, community, and public policy. A systematic search of relevant literature published before July 2020 was conducted through Ebsco, ProQuest, PubMed Central, Scopus, and Web of Science. A total of fourteen studies met the inclusion criteria. The selected articles were all of high quality as assessed using the Mixed Methods Appraisal Tool (2018). The results indicated that gender, age, ethnicity, and self-concept were the most common influencing factors at the intrapersonal level. At the interpersonal and organization levels, supports from friends, parents, and teachers were positive predictors of students’ PA participation. Accessibility of facilities and safe neighborhoods was a crucial factor that influenced children and adolescents’ participation in PA at the community level. Future studies on the effective types of policies or practices that could successfully promote facilities’ accessibility and improve neighborhood safety are required. The outcomes of this systematic review are expected to inform practice and support the development and implementation of sound policies for the promotion of PA participation in children or adolescents from a comprehensive social ecological viewpoint.

Objective: This study aims to validate previous structural models of factors influencing dietary behavior changes and construct the knowledge, attitude, and behavioral models of youth school football players. Methods: 279 school football players aged 12–17 years in Grades 7–12 in Hunan Province, China, completed a questionnaire to collect data on sports nutrition knowledge, attitudes, and behavior. A structural equation model (SEM) was built based on the knowledge-attitude-behavior (KAB) model and the theory of planned behavior (TPB) model to introduce nutritional knowledge directly or by altering attitudes into the dietary behavior path of players. Four factors affecting dietary behaviors were involved in the hypothetical structure, which consists of the following hypotheses: (1) nutrition knowledge affects the attitude towards sports nutrition (H1); (2) nutrition knowledge affects dietary behaviors (H2); (3) nutrition knowledge affects subjective norms (H3); (4) nutrition knowledge affects perceived behavioral control (H4); (5) subjective norms affect dietary behaviors (H5); and 6) perceived behavioral control affects dietary behaviors (H6). Results: Confirmatory factor analysis (CFA) revealed that the reliability, convergent validity, and discriminant validity of the built SEM conformed to the measured relationships in each dimension. In the final structural model, it was found that nutrition knowledge had a direct impact on the attitudes of players and affected their dietary behaviors in a direct manner or through their subjective norms and perceived behavioral control. Conclusions: The results are in agreement with the TPB-based KAB chain and support the KAB theory for youth school football players in Hunan Province, China.

Objective: This study investigates the impact of physical activity on cognitive function in Chinese middle-aged and older adult individuals, examining the relationship between different intensities of physical activity and cognitive function, as well as the effect of physical activity on various types of cognitive function.Method: A total of 27,529 samples were selected from the China Health and Retirement Longitudinal Study (CHARLS) data from 2011 to 2018 for regression analysis. Multidimensional fixed effects estimation was used to validate the impact of physical activity on cognitive function in middle-aged and older adults, analyzing differences in the intensity of physical activity and types of cognitive function. The empirical results were further tested using methods such as propensity score matching (PSM). Additionally, this paper conducted heterogeneity analyses by gender, place of residence, presence of children, and marital status.Results: Physical activity had a positive impact on cognitive function among middle-aged and older adults in China by improving their cardiovascular health, and this result held true regardless of gender, rural or urban residence, presence of children, or marital status. This conclusion was supported by both alternative explanatory variables and results from propensity score matching. Further research found that physical activity improves immediate memory and delayed recall among middle-aged and older adults. Moderate physical activity enhances the health of the older adult population, whereas excessive physical activity may impair cognitive function in middle-aged and older adults.Conclusion: Our study found that PA can effectively promote the improvement of cognitive function in middle-aged and older adults, with this conclusion still holding true in older populations. Such physical activity should be moderate, because vigorous physical activity may impair cognitive function in middle-aged and older people. The study conclusions play a significant role in promoting physical activity, delaying cognitive decline, achieving active aging, and reducing the burden of informal caregiving.