Screening

The criteria for inclusion and exclusion are set out in Table ​Table1.1. Studies could address PA as a component of a broader public health initiative such as obesity prevention, provided they addressed PA as a discrete component of the intervention or analysis.

Inclusion and exclusion criteria

• English language

• Peer-reviewed papers with available full text, including conceptual or theoretical papers and papers that synthesized existing literature

• Explicitly identify as using systems approaches or methods, or describe an application of systems approaches to PA

• Application of systems approaches to PA as a discrete component of the intervention or analysis

• Conference abstracts, dissertations, grey literature, book chapters

• Application of systems approaches:

- for sport injury, athletes or professional sport

- to reduce road injury

- to model pedestrian movements in crowded contexts

- for physiological studies

- for social justice purposes (e.g. sport for development and peace)

- for transport (unless they addressed active transportation, i.e. public transport, walking and cycling)

We adopted a conservative approach, and papers were retained for full-text screening if it was unclear from the title and abstract whether inclusion criteria were met. A subset of 200 papers were screened independently by two authors (TN and AB), with an inter-rater agreement of 94.5%. Conflicts were resolved by discussion and agreement between TN and AB. A further 83 papers were screened jointly to achieve consensus on decision criteria, and then each paper was screened by one reviewer. The full-text versions of the papers were screened by one reviewer (TN), with any uncertainties resolved by discussion with other authors (WB and AB). Papers that related to the same study (e.g. the WHO STOPS trial [15–17]) or related to the same overarching initiative (e.g. the Healthy Kids, Healthy Communities [HKHC] projects funded by the Robert Wood Johnson Foundation) [18–22] were included and classified separately according to the stage of systems approach and method used.