[Validity study of the "Physical Activity Checklist" in children].

OBJECTIVE To assess the validity and operational equivalence of the "Physical Activity Checklist" in children. METHODS This study complements the cross-cultural adaptation of the Physical Activity Checklist Interview, conducted with 118 school children aged between seven and ten years old, enrolled from the second to the fifth grades of primary education in the city of Sao Paulo, SP, Southeastern Brazil, in 2009. The questionnaire enables the quantification of time spent in moderate and vigorous physical activities and sedentary activities and the total and weighted metabolic costs. The accelerometer was adopted as a criterion measure of physical activity. The variables total physical activity (counts/min) and time spent in moderate to vigorous physical activity were quantified. The concurrent validity was assessed by Pearson's correlation coefficient while the operational equivalence was assessed by data concerning the duration and evaluation of the interview. RESULTS The values for the correlation coefficient between the results from the questionnaire and the accelerometer ranged from 0.34 to 0.40. It was found that LAF overestimates time spent doing moderate and vigorous physical activity when compared to the accelerometer. The average duration of the interviews was 24 minutes (minimum = 13 min, maximum = 41 min, sd = 5 min). The interview item showing the poorest result was the children's ability to estimate time (poor or fair in 24.8% of interviews). CONCLUSIONS In relation to the original version, the questionnaire "Physical Activity Checklist" presents similar indices of concurrent validity and operational equivalence, confirming the appropriateness of the cross-cultural adaptation.