Objective. Explore the effects of self-affirmation and message framing on increasing physical activity (PA) in female students, in line with WHO PA recommendations.
Design. A mixed-methods study using online survey data triangulated with semi-structured interviews.
Methods. 213 female students completed an online questionnaire examining the interaction effect of self-affirmation and message framing (prescriptive vs proscriptive) on reactance and cognitive outcomes, from Ajzen’s (1991) extended Theory of Planned Behaviour (TPB). Six female students participated in semi-structured interviews, to explore barriers and facilitators to engaging in regular PA, alongside their perception of proscriptive vs prescriptive-framed health messages focused around physical inactivity. Data was analysed using a series of ANCOVAs, and qualitative data using Braun & Clarke’s (2021) inductive thematic analysis.
Results. Proscriptive-framed messages elicited higher levels of anticipated negative affect and lower intentions towards engaging with WHO PA recommendations. Self-affirmation mitigated feelings of anticipated negative affect following exposure to both health messages. Qualitative data found prioritising competing demands, fear of judgement and limited
accessibility impacted PA engagement. Social support and sense of belonging could facilitate exercise behaviour. Female students perceived both framed health messages to be threatening and demotivating. Therefore, effectiveness of message framing on increasing PA remains inconclusive.
Conclusion. Prescriptive messages and self-affirmation could benefit female students’ adherence to WHO PA recommendations. Further research should explore what mediates female students fear of judgement towards engaging in PA and how social support impacts health-related behaviour change. Findings could support universities and health professionals to tailor interventions towards female students, promoting PA.

Keywords: Self-affirmation, message framing, prescriptive and proscriptive
injunctions, physical activity, qualitative research.