An intervention to increase walking requires both motivational and volitional components: a replication and extension

An intervention to increase walking has previously been developed, consisting of three motivational techniques, designed to increase self-efficacy, and three volitional techniques, designed to help translate intentions into action. Previous research found large effects (d = 0.90) on the objectively measured walking behaviour of 130 English adult volunteers, mediated by self-efficacy. The present study aimed to replicate this intervention, and decompose the intervention to assess whether both motivational and volitional intervention components are necessary. A three-group experimental design was employed, with n = 35 adult volunteers randomly allocated to receive one of three interventions: (a) a "combined" intervention, containing motivational and volitional components in session at T1 and a filler task at T2, (b) a "motivation first" intervention, where the motivational components were received at T1 and the volitional components at T2, or (c) a "volition first" intervention, where the volitional components were received at T1 followed by motivational components at T2. At T2, there was a significant main effect of time, such that there was an increase in walking, but this did not differ between groups. At T3, the "combined" intervention group showed a large (d = 1.06) and significant (p = 0.036) increase in walking behaviour, in contrast to both other interventions (time × groups interaction, p = 0.003). The "combined" intervention also produced a significant increase in self-efficacy, relative to the two other interventions. This study demonstrates generalisability of previous large intervention effects and suggests that use of both motivational and volitional components is optimal in producing change in walking behaviour. Future research should explore the mechanisms by which techniques to increase self-efficacy and planning interact.