Background
LENS
Physical activity (PA) is key to the maintenance of physical [Self-determination theory (SDT) proposes that motivation that fulfils fundamental human needs, determines behaviour [Qualitative research increases our understanding of an intervention’s mechanisms of behaviour change [One value of longitudinal qualitative research has been to determine how motivation may be internalised and its impact on behavioural maintenance [Motivators of behaviour change are likely to change over the life course. A range of studies highlight that older adults differ from younger adults in how they engage with PA interventions [Our qualitative longitudinal study explored motivations for PA and ongoing engagement among participants in a 12-month PA and behavioural maintenance programme. The perspectives of session leaders and service managers delivering the programme were also explored. Through the lens of SDT, the study provides an in-depth evaluation of the impact of the proposed mechanisms of action of the intervention in the context of a large-scale, multi-site trial.