Validity and Reliability of 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.