Objectives. Most studies examine associations between social-cognitive variables and self-regulated behavioural change across two or three occasions only. This study adopts an innovative perspective by analysing associations across 11 occasions, which allows examining patterns of associations both on the between- and within-person levels. Method. Thirty initially untrained participants of a running training programme completed 11 monthly questionnaires. All questionnaires assessed motivational and volitional variables and self-reported running. Additionally, net running time of marathon, or half-marathon distance at the end of programme, was available. Results. Self-efficacy turned out to be associated with intentions on the betweenand within-person levels. Individual differences in change patterns and within-person fluctuations in volitional variables, intentions, and self-efficacy turned out to be consistently associated with change patterns and within-person fluctuations in selfregulated running training over time and with successfully running marathon or halfmarathon distance. Conclusions. In contrast to examining only one facet of change, this study is the first to differentiate two components of change in health behaviour self-regulation: a systematic trend component, and a component representing within-person unsystematic fluctuations. Thus, results of the present study provide a comprehensive picture of the dynamic relations between motivational, volitional, and behavioural characteristics which occur between and within persons.