Navas León, SergioTajadura Jiménez, AnaMorales Márquez, LuisBorda Mas, María de las MercedesAvargues Navarro, María LuisaSánchez Martín, Milagrosa2025-11-032025-11-032025Navas León, S., Tajadura Jiménez, A., Morales Márquez, L., Borda Mas, M.d.l.M., Avargues Navarro, M.L. y Sánchez Martín, M. (2025). Exploring the mediating role of motivational regulations in the relationship between body image and physical activity by sex: A structural equation modelling approach. BMC Psychology, 13 (1), 1189.https://doi.org/10.1186/s40359-025-03476-4.2050-7283https://hdl.handle.net/11441/178528Background: This study investigates how motivational regulation mediates the relationship between body image satisfaction and physical activity participation, considering sex differences. Methods: The study used a cross-sectional design and involved 1012 participants stratified by sex of the Spanish adult population. Body image satisfaction was assessed using the Multidimensional Body Self-Relations Questionnaire (MBSRQ), motivational regulation using the Behavioural Regulation Exercise Questionnaire (BREQ-3), and total weekly minutes of moderate-vigorous PA with the International Physical Activity Questionnaire Short Form (IPAQ-SF). Structural equation modelling was used to test the hypothesised relationships. Results: The findings showed that satisfaction with physical appearance and physical shape had both direct and indirect associations with moderate-vigorous PA and motivational regulation. The relationship between body image satisfaction and moderate-vigorous PA was mainly mediated by intrinsic, integrated, and introjected regulations for men and integrated, identified, and amotivated regulations for women. Conclusion: These findings suggest that motivational regulation may play a crucial role in the relationship between body image satisfaction and PA participation. Promoting intrinsic and integrated motivation in men and women, respectively, rather than appearance-based goals, may foster more sustainable PA. The findings can provide valuable insights for policymakers and practitioners seeking to promote healthy PA behaviour.21 p.engAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Body imageexercise psychologymotivational theoryphysical inactivityself-determination theorystructural equation modellinginfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccesshttps://doi.org/10.1186/s40359-025-03476-4