Evidence-Based and Theoretically-Driven Behaviour Change Interventions for Physical Activity to Enhance Health and Wellbeing

There are high rates of inactivity in UK adults, which can lead to a range of health problems. The main aims of this thesis were: first to review existing behaviour change intervention design, delivery, evaluation, and reporting frameworks to gauge the most effective process and/or combination; second to review the existing literature on physical activity and sedentary behaviour interventions, to see whether they work, what techniques might be effective, and how well they were reported; third to review theories of behaviour (change) in terms of completeness and suitability for physical activity and sedentary behaviour; fourth to test the chosen theory (COM-B model) in terms of the relevant components of the three constructs (Capability, Opportunity, Motivation) and how well they predicted moderate-to-vigorous physical activity (MVPA) and sedentary behaviour (in comparison to the Theory of Planned Behaviour); last to design, implement, and evaluate (including from the deliverers’ perspective) a community physical activity programme, with the techniques highlighted in the review included in the content and the behavioural drivers from the theory analysis as secondary outcomes. The exploration of behaviour change intervention design frameworks concluded by summarising a nine-step process covering the most important elements from needs assessment to dissemination. The systematic review showed physical activity interventions to be effective at changing behaviour and maintaining those changes, and pointed towards behaviour change techniques that were associated with effectiveness. The theory review concluded that the COM-B contained the most comprehensive range of behavioural determinants and was ideally situated within the Behaviour Change Wheel for designing interventions. The COM-B analysis showed a strong prediction of MVPA and highlighted Psychological Capability and Reflective Motivation as important drivers. Sedentary behaviour was also predicted relatively strongly with Psychological Capability the most important driver. The Active Herts programme was then detailed and evaluated, showing improvements in physical activity, health, life satisfaction, and wellbeing at 3 and 6 months. COM-B measures predicted MVPA more strongly after intervention at 3 and 6 months, than at baseline, and were better at predicting MVPA performance than change over this period. Interviews with the Get Active Specialists delivering the programme reflected positively on the training, materials, and overall programme. Key lessons to take forward were extra support at the start with supervision and engaging referrers, and limiting the length and complexity of outcomes measures. The discussion explored the need to measure long-term outcomes of behaviour change, difficulties in measuring the constructs of the COM-B, the balance between standardisation and tailoring of interventions, and adopting a transdisciplinary approach to programme design.