The domain in which physical activity occurs influences the relationship between physical activity and mental health and should, therefore, be considered when developing interventions, treatment programs, and policy guidelines.

Overall, a significant association has been consistently demonstrated between physical activity and physical self-concept and its various sub-domains in children and adolescents. Age and sex are key moderators of the association between physical activity and physical self-concept.

No abstract

The results of this meta-analysis indicate a medium effect size relationship between general physical self-concept, perceived competence and perceived fitness and physical activity in young people. • General physical self-concept, perceived competence and perceived fitness may act as both determinants and outcomes of physical activity behaviour in youth. • Strategies to enhance physical self-perceptions in children and adolescents may assist in efforts to promote physical activity.

Introduction The primary objective of this study was to examine longitudinal associations between changes in recreational screen-time and mental health outcomes during the first year of secondary school in a sample of Australian adolescents. Methods Adolescents (N = 322; 65.5% females) reported total and device specific screen-time (television, DVD, computer, and tablet/mobile phone) and mental health (physical selfconcept, psychological well-being and psychological difficulties) over a school year. Multilevel linear regression analyses were conducted and adjusted for relevant covariates. Results Changes in total recreational screen-time (B =-.003, p = .048) and tablet/mobile phone use (B =-.015, p < .001) were negatively associated with physical self-concept. Changes in total recreational screen-time (B =-.008, p = .001) and computer use (B =-.025, p = .003) were negatively associated with psychological well-being. A positive association was found with television/DVD use and psychological difficulties (B = .007, p = .015). No associations were found for non-recreational screen-time. Conclusion Changes in recreational screen-time were associated with changes in a range of mental health outcomes during the first year of secondary school, with no clear device-specific trends emerging. These findings suggest that reducing recreational screen-time among adolescents may have utility as a strategy for promoting mental health in this population.

ATLAS is an innovative school-based intervention designed to improve the health behaviors and related outcomes of adolescent males in low-income communities.

The purpose of this study was to assess the feasibility and preliminary efficacy of a high‐intensity interval training (HIIT) intervention integrated into the workplace on physical and mental health outcomes in a sample of adults. The Work‐HIIT intervention was evaluated at the University of Newcastle (March‐July 2019). University employees (18+ years) who self‐identified as predominantly sedentary at work (n = 47, 43.0 ± 10.7 years; 41 female) were recruited, screened, and randomized after baseline assessments into Work‐HIIT (n = 24) or wait‐list control (n = 23) conditions. Participants were asked to attend 2‐3 researcher‐facilitated HIIT sessions/week (weeks 1‐8). Sessions included a 2‐minute gross‐motor warm‐up, followed by various combinations of aerobic and muscular fitness exercises lasting 8 minutes (using 30:30 second work: rest intervals). Program feasibility was assessed using measures of satisfaction, compliance, adherence, fidelity, and retention. Physiological and psychological outcomes were measured at baseline and 9 weeks. Feasibility data were investigated using descriptive statistics and efficacy outcomes determined using linear mixed models and Cohen's d effect sizes. Participant ratings showed high levels of satisfaction (4.6/5); 71% of participants attended ≥2 sessions/wk and averaged 85.9% HRmax across all sessions (including rest and work intervals). Small‐to‐medium positive effects resulted for cardiorespiratory fitness [+2.9 laps, 95% CI (−4.19‐10.14); d = 0.34] and work productivity [+0.26, d = 0.47]. Large positive effects resulted for muscular fitness [push‐ups +3.5, d = 0.95; standing jump +10.1 cm, d = 1.12]; HIIT self‐efficacy [+16.53, d = 1.57]; sleep [weekday +0.76 hours, d = 1.05]; and autonomous motivation [+0.23, d = 0.76]. This study supports the feasibility and preliminary efficacy of facilitator‐led Work‐HIIT as a time‐efficient, enjoyable, and convenient workplace exercise option for adults.

ACTRN12614000163606.