Sustainability of Positive Body Image Changes One Year After Exercise Interventions in Young Women: A Quasi-Experimental Study

Although some exercise interventions have demonstrated short-term benefits for women's positive body image, evidence regarding their longer-term effects-particularly under real-world conditions-remains limited. Understanding the sustainability of post-intervention outcomes is important for assessing the practical relevance of exercise programmes and their potential to improve positive body image. The aim of this study was to examine the sustainability of post-intervention outcomes related to positive body image one year after participation in non-randomised 8-week Nirvana Fitness (NF) and Functional Training (FT) interventions among young women under real-world conditions. Young women (mean age 22.79 ± 6.14) were self-selected into either the NF group (n = 16) or the FT (n = 15) group and participated in an eight-week exercise intervention. A control group (n = 17) of women did not participate in the intervention. Participants completed online questionnaires assessing body appreciation, body surveillance, functionality appreciation, body-mind connection, intrinsic exercise motivation, physical activity at baseline, immediately after the intervention, and 12 months later. Changes in outcomes over time were analysed using linear mixed-effects models with fixed effects for group, time, and their interaction, random intercepts for participants, and adjustment for age and body mass index. Analysis revealed significant group × time interactions for body appreciation, functionality appreciation, body-mind connection, and intrinsic exercise regulation, indicating differential changes over time between interventions and control groups. Body surveillance showed a significant effect of time only, whereas leisure-time exercise differed between groups but did not change over time. Overall, intervention groups demonstrated more favourable change patterns across positive body image-related outcomes compared with the control group. Conclusion: Participation in intervention programmes was associated with sustained improvements in positive body image and exercise motivation, but not with changes in body surveillance or leisure-time physical activity. Given the self-selected group allocation and small sample size, these findings should be considered exploratory. Larger randomised studies are needed to confirm the sustainability and generalisability of these findings.