eng Science and Education Publishing Journal of Physical Activity Research 2574-4437 2026-02-25 11 1 10 20 10.12691/jpar-11-1-2 JPAR20261112 article Gordon B. Spence gordon.spence@sydney.edu.au 1 Ryan E. Rhodes 2 Coaching Psychology Unit, University of Sydney, Sydney, Australia School of Exercise Science, Physical and Health Education, University of Victoria, Canada Many adults understand the health benefits of physical activity (PA) yet struggle to translate intentions into sustained behaviour. Narrative-based approaches may support this process by reactivating affective and identity-related mechanisms linked to past PA experiences. Guided Autobiography (GAB) is a structured, non-directive small-group method designed to facilitate meaning-making through reflective writing and sharing, but it has not previously been applied in a PA context. This proof-of-concept study examined the feasibility, acceptability, and preliminary psychological impact of a brief PA-themed GAB intervention and explored whether it showed sufficient promise to warrant further testing. Seventeen mature-aged adults participated in a PA-themed GAB intervention, ¡°My Physically Active Life¡±, involving completion of a 25-year PA timeline, autobiographical writing, and shared reflection. A mixed-methods pre¨Cpost design was used, with quantitative measures of PA-related attitudes (instrumental and affective), identity, and behavioural intentions collected at baseline, with a 7-day follow-up. Qualitative data were analysed thematically to examine participants¡¯ experiences of reflection and narrative reframing. Participants reported high acceptability and described GAB as a meaningful prompt for reconnecting with positive early-life PA experiences and active identities. Instrumental attitudes were high at baseline and unchanged, functioning as a control indicator. In contrast, small-to-moderate positive effects were observed for affective attitudes (enjoyment, pleasantness) and PA-related identity, with a modest increase in behavioural intention. Qualitative findings supported these patterns, highlighting shifts in affective meaning, and self-concept. This ORBIT Phase IIa proof-of-concept study provides initial evidence that PA-themed GAB is feasible, acceptable, and engages theoretically relevant psychological mechanisms. Further refinement and controlled testing are warranted to examine its role as a preparatory intervention supporting intention¨Cbehaviour translation. https://pubs.sciepub.com/jpar/11/1/2/jpar-11-1-2.pdf guided autobiography physical activity identity affective attitudes narrative reflection behaviour change proof-of-concept