The purpose of this study was to examine the associations of social support and self-efficacy with physical Activity (PA) and the mediating effect of self-efficacy on the relationship between social support and PA in Chinese adolescents. Participants included a total of 2341 Chinese adolescents (aged 12.75 ± 1.46 years). Self-reported instruments, including the physical activity questionnaire for adolescents, the social support revalued scale and the exercise self-efficacy scale, were used to measure physical activity, social support and exercise self-efficacy. Results showed that social support (r = 0.29, p < 0.05) and exercise self-efficacy (r = 0.43, p < 0.05) were significant and positive predictors of PA among Chinese adolescents, and exercise self-efficacy was a significant mediator in the relationship between social support and PA (standardized effect size = 0.15, p < 0.001). Such findings were evident with similar patterns in both male and female adolescents. The findings of this study have indicated the importance of social support and exercise self-efficacy on PA promotion in adolescents, which will aid the development of effective interventions in this population.

Purpose: The novel coronavirus disease (COVID-19) pandemic and associated restrictive measures have implications for depressive symptoms (henceforth depression) of young people and risk may be associated with their reduced physical activity (PA) level. Therefore, we aimed to examine the association between depressive symptoms and PA among college students with different gender and gender role (masculinity traits and femininity traits) during the COVID-19 pandemic. Participants and Methods: Cross-sectional study included 628 healthy college students from nineteen different locations. The Center for Epidemiological Studies Depression Scales (CES-D), the International Physical Activity Questionnaire - Short Form (IPAQ-SF), and the 50-item Chinese Sex-Role Inventory (CSRI-50) were used to measure depressive symptoms, PA continuous (weekly metabolic equivalent minutes, MET-minutes/week) and categorical indicators (activity level category) and gender role, respectively. The statistical analyses were used in partial correlation analysis, t-test, one-way ANOVA, moderation model tests, and linear regression model tests. Results: Total of 34.72% participants had clinically relevant depression (16, CES-D scale). Total of 58.6% participants were classified as a “low” activity level for spending less time on PA. Depression significantly negatively correlated with MET-minutes/week in moderate-intensity PA but not vigorous and walking scores. Of note, the depression-PA association was only moderated by the “low” activity level group in terms of categorical scores across gender groups. Participants with higher masculinity traits were less likely to have depression among all participants. Moreover, more recovered cases and fewer deaths could also predict the lower depression risk in the “high” activity level group. Conclusion: Moderate-intensity PA is beneficial for reducing depression risk among college students at a low activity level. College students with fewer masculinity traits (regardless of gender) are highly vulnerable to depression during the outbreak of COVID-19. Effective control of the COVID-19 pandemic seems critical to alleviating the burden of mental disorders of the public including depression.

Skeletal muscle mass and function tend to decline with increasing age. Insulin-like growth factor 1 (IGF-1) plays a key role in promoting skeletal muscle growth. Exercise improves skeletal muscle mass and function via the activation of IGF-1 signaling. The aim of this study was to investigate whether different types of exercise can promote muscle hypertrophy, exercise and metabolic capacities, and activate IGF-1 signaling during early aging in mice. We randomly assigned 12 month old male C57/BL6 mice into five groups: control, aerobic exercise, resistance exercise, whole-body vibration and electrical stimulation group. Gastrocnemius muscle mass, myofiber size, levels of IGF-1 signaling, oxidative stress, protein synthesis and degradation, and apoptosis were detected. C2C12 cells were used to explore the mechanism by which exercise exerts its effects. We confirmed that the four modes of exercise increased skeletal muscle mass, exercise capacity, indicators of metabolism and protein synthesis, and inhibited oxidative stress and apoptosis via activation of the IGF-1 pathway. The most effective intervention was resistance exercise. Whole-body vibration promoted muscle hypertrophy better than aerobic exercise. Furthermore, in the in vitro experiment, the importance of IGF-1/IGF-1R–PI3K/Akt signaling for maintaining skeletal muscle mass was confirmed. Aerobic exercise, resistance exercise, whole-body vibration and electrical stimulation increased skeletal muscle mass, exercise capacity, protein synthesis and metabolic enzyme activity, and inhibited protein degradation and apoptosis in mice undergoing early aging via activation of IGF-1 signaling. Of these, whole-body vibration has been shown to be significantly effective and is similar to conventional exercise in promoting muscle hypertrophy.

Background: The coronavirus disease (COVID‐19) and universal mitigation strategies have fundamentally affected peoples’ lives worldwide, particularly during the first two years of the pandemic. Reductions in physical activity (PA) and increased mental health (MH) problems among children and youth have been observed. This systematic review and meta-analysis investigated the relationship between physical activity (PA) and mental health (MH) among children and youth during the COVID‐19 pandemic. Methods: Four electronic databases (EMBASE, PsycINFO, PubMed, and Web of Science) were systematically searched to identify studies that (1) examined the relationship between PA and MH among children and youth (aged 2–24 years old) and (2) were published in peer-reviewed journals in English between January 2020 and December 2021. Relationships between PA and two MH aspects (i.e., negative and positive psychological responses) among children and youth at different age ranges and those with disabilities or chronic conditions (DCC) were synthesized. Meta-analyses were also performed for eligible studies to determine the pooled effect size. Results: A total of 58 studies were eventually included for variable categorization, with 32 eligible for meta-analyses. Our synthesis results showed that greater PA participation was strongly related to lower negative psychological responses (i.e., anxiety, depression, stress, insomnia, fatigue, and mental health problems) and higher positive psychological responses (i.e., general well-being and vigor) in children and youth during COVID-19. The pattern and strength of relations between PA and MH outcomes varied across age ranges and health conditions, with preschoolers and those with DCC receiving less attention in the existing research. Meta-analysis results showed that the magnitude of associations of PA with negative (Fisher’s z = − 0.198, p < 0.001) and positive (Fisher’s z = 0.170, p < 0.001) psychological responses among children and youth was weak. These results were linked to age of participants, study quality, and reporting of PA-related information. Conclusions: PA participation and MH among children and youth deteriorated during the COVID-19 pandemic and were closely associated with each other. For the post-COVID-19 era, additional research on age- and health condition-specific relationships between PA and MH outcomes from a comprehensive perspective is warranted. (Word count: 344 words).