Translating a walking intervention for health professional delivery within primary care: A mixed-methods treatment fidelity assessment.

High levels of fidelity of delivery were demonstrated. However, patient-, provider-, and component-level factors impacted on treatment delivery and receipt. We recommend that methods for the enhancement and assessment of treatment fidelity are consistently implemented to enhance the rigour of physical activity intervention research. Statement of contribution What is already known on this subject? Physical activity interventions delivered within primary care by health professionals have so far demonstrated limited impact on behaviour change initiation and maintenance. Treatment fidelity enhancement and assessment strategies can support the successful translation of behaviour change interventions into real-life settings. Few studies have examined treatment fidelity within the context of physical activity interventions, particularly within clinical settings, and existing fidelity studies are limited by methodological quality and rigour. What does this study add? High levels of fidelity were found for a physical activity intervention delivered in primary care. Patient-, provider-, and component-level factors may impact on treatment delivery and receipt. The implementation of best practice fidelity recommendations can support near-optimal fidelity.