Findings indicate a prominent role for non-conscious processes in determining health behavior and inclusion of past behavior in RAA tests is important to yield precise estimates of model effects.

ObjectivePhysical activity (PA) is associated with a decreased incidence of dementia, but much of the evidence comes from short follow-ups prone to reverse causation. This meta-analysis investigates the effect of study length on the association.DesignA systematic review and meta-analysis. Pooled effect sizes, dose–response analysis and funnel plots were used to synthesise the results.Data sourcesCINAHL (last search 19 October 2021), PsycInfo, Scopus, PubMed, Web of Science (21 October 2021) and SPORTDiscus (26 October 2021).Eligibility criteriaStudies of adults with a prospective follow-up of at least 1 year, a valid cognitive measure or cohort in mid-life at baseline and an estimate of the association between baseline PA and follow-up all-cause dementia, Alzheimer’s disease or vascular dementia were included (n=58).ResultsPA was associated with a decreased risk of all-cause dementia (pooled relative risk 0.80, 95% CI 0.77 to 0.84, n=257 983), Alzheimer’s disease (0.86, 95% CI 0.80 to 0.93, n=128 261) and vascular dementia (0.79, 95% CI 0.66 to 0.95, n=33 870), even in longer follow-ups (≥20 years) for all-cause dementia and Alzheimer’s disease. Neither baseline age, follow-up length nor study quality significantly moderated the associations. Dose–response meta-analyses revealed significant linear, spline and quadratic trends within estimates for all-cause dementia incidence, but only a significant spline trend for Alzheimer’s disease. Funnel plots showed possible publication bias for all-cause dementia and Alzheimer’s disease.ConclusionPA was associated with lower incidence of all-cause dementia and Alzheimer’s disease, even in longer follow-ups, supporting PA as a modifiable protective lifestyle factor, even after reducing the effects of reverse causation.

BackgroundGiven the documented decline in levels of physical activity in early adolescence, promoting physical activity in young people is a priority for health promotion. School physical education (PE) is an important existing network in which participation in physical activity beyond school can be promoted to the captive young people. The objective of current article is to present the protocol for a PE teacher-delivered theory-based trial to promote secondary school students’ participation in physical activity out-of-school contexts. The intervention will be guided by the trans-contextual model explaining the processes by which PE teachers’ support for autonomous motivation in the classroom promotes students’ motivation to engage in out-of-school physical activity. We hypothesize that school students receiving the teacher-delivered intervention to promote autonomous motivation toward physical activity will exhibit greater participation in physical activities outside of school, relative to students receiving a control intervention.MethodsThe trial will adopt a waitlist-control design with cluster-randomization by school. PE teachers assigned to the intervention condition will receive a two-week, 12-h training program comprising basic information on how to promote out-of-school physical activity and theory-based training on strategies to promote students’ autonomous motivation toward physical activity. Teachers assigned to the waitlist control condition will receive an alternative training on how to monitor physical functional capacity in children with special needs. PE teachers (n = 29) from eleven schools will apply the intervention program to students (n = 502) in PE classes for one month. Physical activity participation, the primary outcome variable, and psychological mediators from the trans-contextual model will be measured at pre-trial, post-trial, and at one-, three- and six-months post-trial. We will also assess teachers’ autonomy-supportive techniques and behaviours by observation.DiscussionThe study will make a unique contribution to the literature by testing a theory-based intervention delivered by PE teachers to promote school students’ participation in out-of-school physical activity. Information will be useful for educators, community stakeholders and policy makers interested in developing programs to promote students’ out-of-school physical activity.Trial registrationISRCTN39374060. Registered 19.7.2018.Electronic supplementary materialThe online version of this article (10.1186/s12889-019-6478-x) contains supplementary material, which is available to authorized users.

Background: We examined effects of trait self-control, constructs from social cognition theories, and intentions on health behaviours. Trait self-control was expected to predict health behaviour indirectly through theory constructs and intentions. Trait self-control was also predicted to moderate the intention-behaviour relationship. Methods: Proposed effects were tested in six datasets for ten health-related behaviours from studies adopting prospective designs. Participants (N = 3,249) completed measures of constructs from social cognition theories and self-control at an initial time point and self-reported their behaviour at followup. Results: Results revealed indirect effects of self-control on behaviour through social cognition constructs and intentions for eight behaviours: eating fruit and vegetables, avoiding fast food, dietary restrictions, binge drinking, physical activity, walking, out-of-school physical activity, and pre-drinking. Self-control moderated the intention-behaviour relationship in four behaviours: dietary restriction, and alcohol-related behaviours. Conclusions: Mediation effects suggest that individuals with high self-control are more likely to hold beliefs and intentions to participate in future health behaviour, and more likely to act. Moderation effects indicate that individuals with high self-control are more likely to enact healthy intentions and inhibit unhealthy intentions, but findings were restricted to few behaviours. Training self-control and managing contingencies that derail goaldirected action may be effective intervention strategies.

Background Inadequate physical activity in young people is associated with several physical and mental health concerns. Physical education (PE) is a potentially viable existing network for promoting physical activity in this population. However, little research has been conducted on whether PE teachers can influence students’ engagement in leisure-time physical activity. The present study therefore examined the efficacy of an intervention aimed at increasing PE teachers’ autonomy support on students’ leisure-time physical activity (the PETALS trial). The intervention was guided by the trans-contextual model (TCM) explaining the processes by which PE teachers’ provision of autonomy support during PE promotes students’ motivation and engagement in physical activity in their leisure time. Methods The study adopted a cluster-randomized, waitlist control intervention design with randomization by school. Participants were PE teachers (N = 29, 44.83%female; M age = 42.83, SD = 9.53 yrs) and their lower secondary school students (N = 502, 43.82%female; M age = 14.52, SD = 0.71 yrs). We measured TCM constructs, including perceived autonomy support, autonomous motivation in PE and leisure time, beliefs and intentions towards leisure-time physical activity, and physical activity behavior at baseline, post-intervention, and at one-, three-, and six-months. Study hypotheses were tested through a series of ANOVAs and structural equation models using post-intervention and one-month follow-up data. Results We found no changes in TCM constructs or physical activity behavior in either group at post-intervention or at 1 month. Path analyses supported two propositions of the TCM as change variables: perceived autonomy support had a significant effect on autonomous motivation in PE and autonomous motivation in PE had a significant effect on autonomous motivation in leisure time. Although we found a direct effect of autonomous motivation in leisure time on physical activity, we did not find support for the third premise of the TCM that autonomous motivation in leisure time indirectly affects physical activity through beliefs and intentions. Conclusions Current findings did not support the efficacy of the PETALS intervention at changing physical activity behavior and TCM constructs. More research is required to determine whether the TCM predictive validity is supported when other model variables are manipulated through experimental and intervention studies. Trial registration ISRCTN, ISRCTN39374060. Registered 19 July 2018. Prospectively registered.