Long term effects of self-determination theory and motivational interviewing in a web-based physical activity intervention: randomized controlled trial

Background: Our main objective in the current study was to evaluate the long-term effectiveness (12 months from baseline) of I Move (a web-based computer tailored physical activity intervention, based on self-determination theory and motivational interviewing). To this end, we compared I Move to a web-based computer tailored physical activity intervention based on traditional health behavior theories (Active Plus), and to a no-intervention control group. As a secondary objective, the present study aimed to identify participant characteristics that moderate the long term effects of I Move and Active Plus. Methods: A randomized controlled trial was conducted, comparing three research conditions: 1) the I Move condition, participants in this condition received I Move; 2) the Active Plus condition, participants in this condition received Active Plus; 3) the control condition; participants in this condition received no intervention and were placed on a waiting list. Main outcome measures were weekly minutes of moderate to vigorous physical activity and weekly days with minimal 30 min of physical activity. All measurements were taken by web-based questionnaires via the study website. Intervention effects were analyzed using multilevel linear regression analyses. Results: At 12 months from baseline, I Move was found to be effective in increasing weekly minutes of moderate to vigorous physical activity (ES = .13), while Active Plus was not. In contrast, Active Plus was found to be effective in increasing weekly days with >= 30 min PA at 12 months (ES = .11), while I Move was not. No moderators of the effects of I Move were found. Conclusions: The results suggest that web-based computer tailored physical activity interventions might best include elements based on both self-determination theory/motivational interviewing and traditional health behavioral theories. To be more precise, it is arguable that the focus of the theoretical foundations, used in new web-based PA interventions should depend on the intended program outcome. In order to draw firm conclusions, however, more research on the effects of self-determination theory and motivational interviewing in web-based physical activity promotion is needed

Physical Activity and Physical Self-Concept in Youth: Systematic Review and Meta-Analysis

Background: Evidence suggests that physical self-concept is associated with physical activity in children and adolescents, but no systematic review of this literature has been conducted. Objective: The primary aim of this systematic review and meta-analysis was to determine the strength of associations between physical activity and physical self-concept (general and sub-domains) in children and adolescents. The secondary aim was to examine potential moderators of the association between physical activity and physical self-concept. Methods: A systematic search of six electronic databases (MEDLINE, CINAHL, SPORTDiscus, ERIC, Web of Science and Scopus) with no date restrictions was conducted. Random effects meta-analyses with correction for measurement were employed. The associations between physical activity and general physical self-concept and sub-domains were explored. A risk of bias assessment was conducted by two reviewers. Results: The search identified 64 studies to be included in the meta-analysis. Thirty-three studies addressed multiple outcomes of general physical self-concept: 28 studies examined general physical self-concept, 59 examined perceived competence, 25 examined perceived fitness, and 55 examined perceived appearance. Perceived competence was most strongly associated with physical activity (r = 0.30, 95 % CI 0.24–0.35, p < 0.001), followed by perceived fitness (r = 0.26, 95 % CI 0.20–0.32, p < 0.001), general physical self-concept (r = 0.25, 95 % CI 0.16–0.34, p < 0.001) and perceived physical appearance (r = 0.12, 95 % CI 0.08–0.16, p < 0.001). Sex was a significant moderator for general physical self-concept (p < 0.05), and age was a significant moderator for perceived appearance (p ≤ 0.01) and perceived competence (p < 0.05). No significant moderators were found for perceived fitness. Conclusion: 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