Physical activity, sedentary behaviour and physical self-perceptions in adolescent girls: A mediation analysis

Abstract

ObjectiveFew studies have examined the relationship between sedentary behaviour (SB) and mental well-being. This study assessed whether SB is associated with physical self-perceptions, independent of participation in moderate-to-vigorous physical activity (MVPA). Previous studies in this area simultaneously entered measures of SB and MVPA as predictors in regression models. In a novel approach, this study used mediation analyses to avoid problems of collinearity between SB and MVPA. DesignCross-sectional. SettingSchool-based. MethodAdolescent females (N = 238) used validated instruments to self-report time spent in SB and MVPA on the previous day, and to provide ratings for physical self-perceptions. Where a self-perception variable was associated with SB, Baron and Kenny's method was used to test if the relationship was mediated by MVPA. ResultsThere were small direct associations between SB and two self-perceptions, which were not mediated by MVPA: ‘sports competence’ (−.022) and ‘physical conditioning’ (−.023). There was also a negative association between SB and perceived ‘physical strength’, which, by contrast, was mediated by MVPA. ConclusionResults for selected self-perceptions indicate that SB may be important to aspects of mental well-being independent of MVPA engagement. Future studies should use longitudinal and prospective designs to (a) assess the causality and direction of associations between SB and self-perceptions; (b) explore how individual SBs relate to self-perceptions; and (c) establish if the magnitude of these associations is clinically relevant.