Validity and reliability question 8 of the Paffenbarger Physical Activity Questionnaire among healthy adults.

Background: Little information exists regarding the psychometric properties of question 8 (Q8) of the Paffenbarger Physical Activity Questionnaire (PPAQ) to assess exercise. Thus, we conducted 2 studies to assess the validity and test-retest reliability of Q8 among adults.

Methods: Study 1 participants (n = 419) were 44.1 ± 16.1 years of age. Validity was determined by comparing self-reported hr·d-1 in sedentary, light, moderate, and vigorous intensity physical activity (PA) and MET-hr·wk-1 on Q8 at baseline to accelerometer and health/fitness measurements using Spearman rank-order correlations. Study 2 participants (n = 217) were 44.7 ± 16.3 years of age and completed Q8 at baseline, 3 months, and 6 months. Test-retest reliability was determined using repeated measures analysis of covariance, intraclass correlations (ICCs), and standard error of the measurement (SEM).

Results: Q8 displayed good criterion validity compared with accelerometer measurements (r = .102 to .200, P < .05) and predictive validity compared with health/fitness measurements (r = -.272 to .203, P < .05). No differences were observed in self-reported hr·d-1 in any of the PA categories at baseline, 3 months, and 6 months (ICC: 0.49 to 0.68; SEM: 1.0 to 2.0; P > .05), indicating good reliability.

Conclusion: Q8 demonstrates adequate criterion validity, acceptable predictive validity, and satisfactory test-retest reliability and can be used in conjunction with other components of the PPAQ to provide a complete representation of exercise.