Validation of an instrument for measurement of physical activity in youth

This study assessed the reliability and validity of the Previous Day Physical Activity Recall (PDPAR), a self-report instrument designed to measure physical activity in youth. Subjects were randomly selected students in grades 7-12. Test-retest reliability was reported as the correlation between estimated relative energy expenditures determined from two PDPAR administrations completed within 1 h. Interrater reliability was determined by two observers using the scoring protocol. Validity was assessed using footstrikes (pedometer), Caltrac activity counts, and heart rate monitoring as criterion measures. Interrater and test-retest reliability was 0.99 and 0.98, respectively (P 50% HRR sustained for 20 min and the number of 30-min blocks with a relative energy expenditure of at least four metabolic equivalent tasks (MET) was 0.63 (P < 0.01). The PDPAR provides valid and reliable estimates of physical activity and also accurately identifies bouts of moderate to vigorous activity.