Objectives. Social support for physical activity is reliably associated with regular physical activity, however the social cognitive processes, particularly post-intentional processes, that can explain this link have not been well characterized. In this study, we examined the extent to which the relationship between social support for physical activity and subsequent physical activity can be accounted for by planning processes.
Design and method. The design was prospective observational and the sample consisted of 903 university students. Participants completed standard theory of planned behaviour, planning, and physical activity measures at 2 time points, approximately 7 weeks apart. A gender stratified multiple mediation model was conducted to test the study hypotheses.
Results. A significant interaction between social support and gender was observed. This indicated that lower levels of social support for physical activity were associated with lower levels of physical activity at Time 2, for women only. In multiple mediation analysis, this was partly explained by the indirect effects of social support through perceived behavioural control and coping planning.
Conclusion. These findings highlight the importance of interpersonal processes in understanding the post-intentional social cognitive determinants of regular physical activity. It is likely that planning processes relating to physical activity are often influenced by those in the ongoing immediate social environment who support this behaviour. Future development of theory and interventions should take account of the socially interactive nature of planning processes.