Measuring psychological, social, and environmental influences on leisure-time physical activity among adults

Many of the self-administered scales for measuring physical activity (PA) influences were originally developed for vigorous-intensity exercise, focus on only one domain of influence, and have not been evaluated for both reliability and validity using population-based samples. Objective: This study describes the factorial validity and internal reliability of scales for measuring individual-level psychological, social, and environmental influences on leisure-time PA among adults in the general population. Method: Constructs were identified from a literature review and formative research with a socio-economically diverse sample. Items were generated using previously developed scales and interview data. New items were pre-tested using reliability and principal components analyses, with data collected from a mail survey sent to a randomly selected population-based sample. Qualitative feedback was obtained from a convenience sample and expert panel. A second mail survey provided data for principal components and reliability analyses. Results: Twenty-eight scales were factorially derived and 24 had acceptable or marginally acceptable levels of internal consistency with Cronbach's alpha values ranging from 0.65 to 0.91. Conclusions and Implications: The 24 scales are suitable for researchers and practitioners interested in measuring individual-level influences on PA that are consistent with Social Cognitive Theory. More research is required to assess predictive validity, sensitivity to change and test/re-test reliability.