Background: An understanding of physical activity through mediators of behaviour change is important to evaluate the efficacy of interventions. The purpose of this review is to update prior reviews with meta-analysis in order to evaluate the state of physical activity interventions that include proposed mediators of behaviour change. Methods: Literature was identified through searching of five key databases. Studies were eligible if they described a published experimental or quasi-experimental trial in English examining the effect of an intervention on physical activity behaviour and mediators in non-clinical adult populations with the necessary statistical information to be included in the meta-analytic structural equation modelling analysis. Results: Fifty-one articles (49 samples) met the eligibility criteria. Small overall effects were identified for mediation paths a (r = .16; 95% CI = .10 to .22), b (r = .21; 95% CI .16 to .27), and c (r = .24; 95% CI .12 to .35), c' (r = .05 to .19) and ab (r = .02 to .07) that showed similar findings by theory and construct. Conclusion: The effect sizes seen in physical activity interventions are mediated by our current theories, but the effects are very small and no one construct/theory appears to be a critical driver of the mediated effect compared to any other. Innovation and increased fidelity of interventions is needed.

Sweden has adopted a somewhat different approach to handle the corona pandemic, which has been widely debated both on national and international levels. The Swedish model involves more individual responsibility and reliance on voluntary civic liability than law enforcement, while common measures in other countries are based on more controlling strategies, such as restrictive lockdowns, quarantines, closed borders, and mandatory behavior constraints. This commentary aims to give a brief overview of the foundations of the Swedish model as well as a discussion on how and why it has been adopted in the Swedish society based on Swedish legislations, culture, and traditions. Finally, perspectives on how the Swedish model could be connected to the tenets of self-determination theory will be discussed.

Aims Self-determined motivation has been found to be an important predictor of exercise behavior. Findings on gender and age differences are however mixed and previous research has called for studies to examine gender and age as potential moderating factors as they might influence how motivation quality affects exercise behavior. Methods Embedded in a controlled trial of a digital intervention aiming to promote exercise motivation, this study examined specific (longitudinal) pathways related to motivation quality, psychological need satisfaction and exercise behavior within the self-determination theory (SDT) process model in a sample of 318 adult employees. The participants completed web-based versions of Basic Psychological Needs in Exercise Scale, Behavioural Regulations in Exercise Questionnaire-2, and Leisure Time Exercise Questionnaire three times during a six weeks period. Results Moderation analyses revealed significant gender and age differences in the associations of motivation quality, basic psychological needs and exercise behavior over time. Several paths in the SDT-process model, linking psychological needs and motivation quality to exercise behavior, were moderated by gender and age. The stipulated mechanisms between exercise, motivation and psychological need satisfaction in the SDT-process model revealed to be stronger for women than for men, and stronger for older adults than for younger and middle-aged adults. The effect of amotivation on exercise was also significantly moderated by age in the full sample, by positively predicting light exercise for younger adults. Conclusions Future recommendations are related to the examination of potential differences in opportunities of autonomy support in the social context based on factors such as gender and age, and also to further examine these factors as potential moderators instead of statistically controlling them as default.

Objective: The objective of the present study was to investigate (a) if daily physical activity at the within-person level is related to four different core affects the same evening, (b) if core affects in the evening predict physical activity the following day, and (c) if physical activity predicts core affects the following day. Design: A total of 166 university students were asked to complete the affect and physical activity measures once a day (in the evening), for seven days. Bivariate unconditional latent curve model analyses with structured residuals were performed to investigate the relations within days and across days between the core affects and physical activity. Main outcome measures: Core affects and physical activity. Results: Physical activity had positive within-day associations with pleasant-activated and pleasant-deactivated core affects and a negative within-day association with unpleasant-deactivated affective responses. There were, however, no statistically significant relations between core affects and physical activity across days. Conclusion: These results highlight that the measurement interval might be an important factor that influences the association between core affects and physical activity behaviors.

human behaviour and how to tailor successful interventions, programs and policies would be to study motivational aspects and self-determination theory [6-8] is a promising framework in this area of research [9,10]. The core message in self-determination theory is that motivation quality and satisfaction of basic psychological needs will fuel the direction of human behaviour and psychological wellbeing [7,8]. According to self-determination theory, psychological need satisfaction will be promoted to the extent that the social environment is autonomy supportive, i.e. when fundamental human needs for autonomy (volition and feelings of choice), competence (feeling efficient and capable) and relatedness (feeling connected to and cared for by others) are nourished. It is also suggested that motivation quality matters more than mere motivation magnitude and that motivation quality is suggested to vary on a continuum ranging from completely self-determined (intrinsic) motivation, via various degrees of controlled behavioural regulations (extrinsic motivation) to amotivation (lack of motivation) at the other end. It is suggested that more self-determined forms of motivation will facilitate behaviour adoption and maintenance as well as psychological well-being. Psychological need satisfaction will also promote internalization of motivational regulations into more self-determined forms of motivation [7,8]. Recent research have suggested that a given behaviour can be fuelled by a combination of different motivational regulations simultaneously [11], also called