Sources of autonomy support, subjective vitality and physical activity behaviour associated with participation in a lunchtime walking intervention for physically inactive adults

Objectives: Based on Basic Needs Theory (BNT: Deci & Ryan, 1985), this study examined longitudinal relationships between autonomy support from two sources, psychological need satisfaction, subjective vitality and self-reported physical activity during a walking intervention for physically inactive adults. We proposed that autonomy support provided via a walk leader and the overall programme would independently predict change in subjective vitality and physical activity from baseline to week 16 (post-intervention) and at four month follow-up. Further, we proposed that direct relationships among sources of autonomy support and outcomes would be mediated by autonomy, relatedness, and competence need satisfaction. Design: A longitudinal examination. Methods: Participants (N=69; n=63 females, n=6 males) from a 16-week walking programme completed a multi-section questionnaire measuring the aforementioned variables at three time points, including a four month post-intervention follow-up. Results: Both hypotheses were partly supported. Autonomy support from the walk leader positively predicted changes in subjective vitality from baseline to week 16 and in physical activity from baseline to follow-up. Autonomy support from the programme positively predicted changes in subjective vitality from baseline to week 16. Finally, autonomy gained from the walk leader mediated the relationship between autonomy support and subjective vitality, and between perceived autonomy support and physical activity. Conclusions: Findings indicate that autonomy support from both a walk leader and wider programme can predict psychological need satisfaction, subjective vitality and physical activity. Clinicians and researchers implementing future walking interventions may increase physical activity and subjective vitality by facilitating psychological need satisfaction through autonomy support from both sources.