A physical activity screening measure for use with adolescents in primary care

Objective: To develop a reliable and valid physical activity screening measure for use with adolescents in primary care settings. Study Design: We conducted 2 studies to evaluate the test-retest reliability and concurrent validity of 6 single-item and 3 composite measures of physical activity. Modifications were based on the findings of the 2 studios, and a best measure was evaluated in study 3. Accelerometer data served as the criterion standard for tests of validity. Results: In study 1 (N=250; mean age, 15 years; 56% female, 36% white), reports on the composite measures were most reliable. In study 2 (N=57, mean age, 14 years; 65%;, female; 37%;, white), 6 of the a screening measures correlated significantly with accelerometer data. Subjects, however, had great difficult) reporting bouts of activity and distinguishing between intensity levels. Instead, we developed a single measure assessing accumulation of 60 minutes of moderate to vigorous physical activity. Evaluated in study 3 (N=148; mean age, 12 years; 65% female; 27% white), the measure was reliable (intraclass correlation, 0.77) and correlated significantly (r=0.40, P < .001) with accelerometer data. Correct clas sification (63%), sensitivity (71%), and false-positive rates (40%) were reasonable. Conclusion: The moderate to vigorous physical activity screening measure is recommended for clinical practice with adolescents.