What do pedometer counts represent? A comparison between pedometer data and data from four different questionnaires

Objectives: To compare physical activity (PA) reported through pedometer registrations (step counts) with PA reported in four different questionnaires; to compare step count thresholds (7500, 10000 and 12500 steps/d) with the PA guideline of 30 min of moderate to vigorous PA (MVPA) per day. Subjects: A sample of 310 healthy adults, mean age 38.7 (sty 11.9) years, volunteered to participate. Forty-seven per cent was male and 93% of the sample was employed. Methods: PA was assessed by interview (Minnesota Leisure Time Physical Activity Questionnaire (MLTPAQ)), three self-administered questionnaires (long version and short version of the International Physical Activity Questionnaire (long-form IPAQ, short-form IPAQ), Baecke questionnaire) and seven consecutive days of pedometer registration. Results: Step counts correlated positively with questionnaire-based PA. The strongest correlations were found between step counts and total PA reported in the long-form IPAQ (r(s) = 0.37), moderate PA reported in the short-form IPAQ (r(s) = 0.33), total and moderate PA reported in the MLTPAQ (r(s) = 0.32), and the total and leisure-tithe PA indices (excluding sport) reported in the Baecke questionnaire (r(s) = 0.44). According to step counts, 22.6% of the participants were somewhat active, 18.7% active and 39.4% highly active. As assessed by the long-form IPAQ, short-forth IPAQ and MLTPAQ, the guideline of 30 min MVPA/d was reached by respectively 85.4%, 84.8% and 68.0% of participants. Conclusion: Pedometer-based data offer adequate information to discriminate between levels of PA. Caution is needed when comparing active samples based on different PA recommendations.