Message framing has been used as a strategy for promoting physical activity (PA) in university students, but the effectiveness of gain-framed (GF), or loss-framed (LF) messages is variable. This study aims to investigate the effects on motivation and PA behaviour of framed messaging on social media in university students. Gain- and loss-framed messages communicated the mental health outcomes of PA. A three-arm feasibility study (n = 148) collected pre-post intervention online questionnaire responses to assess motivation for PA, exercise, active travel, and PA levels, in response to the messaging intervention on Facebook. Both GF and LF messages effectively increased average motivation for PA in comparison to controls (GF by 0.3 (on a 7-point Likert scale), 9% [95% CI: 3-17%], p = 0.007, LF by 0.3, 10% [CI: 3-18%], p = 0.005). Average motivation for exercise increased in comparison to controls (GF by 0.6, 16% [95% CI: 6-26%], p = 0.001, LF by 0.5, 14.6% [95% CI: 5-26%], p < 0.001). Average motivation for active travel increased in comparison to controls (GF by 0.7, 18% [95% CI: 8-29%], p < 0.001, LF by 0.6, 19% [95% CI: 8-30%], p < 0.001). No meaningful differences between GF or LF messages were observed. Framed messages regarding mental health outcomes of PA delivered via social media could be effective for increasing PA motivation in university students. However, based on our results there is no gain- or loss-framed advantage.
Keywords: health promotion; mental health; message framing; physical activity; social media.