Psychometric properties of the 7-Day Physical Activity Recall questionnaire in individuals with severe mental illness.

Few self-report measures of physical activity have been validated in individuals with severe mental illness. The purpose of this study was to examine the validity and reliability of a 7-day recall measure (7DR: [Blair, S. N. (1984). How to assess exercise habits and physical fitness. In J. D. Matarazzo, N. E. Miller, & S. M. Weiss, (Eds.), Behavioural health: A handbook of health enhancement and disease prevention (pp. 424-447). New York: Wiley.]) through comparison with RT3 triaxial accelerometry data. Fourteen individuals took part in the study. Validity was considered by Kendall's tau correlation and (Bland, J. M., & Altman, D. G. (1986). Statistical-methods for assessing agreement between 2 methods of clinical measurement. Lancet, 1(8476), 307-310) limits of agreement and test-retest reliability was measured by ICC. The only significant correlation between measures was total energy expenditure (tau = 0.43). The 7-DR over reported moderate physical activity by 16.9 +/- 52.3 min/day, but under reported vigorous physical activity by -10.4 +/- 24.3 min/day. Test retest ICC was significant for all outcome measures. Overall, the 7-DR was reliable but exhibited questionable validity. The use of self-report questionnaires such as the 7-DR may inaccurately estimate the levels of physical activity in this population, and may not be sensitive to monitoring intervention-related changes in physical activity.