RESUMO
Objective To evaluate the validity and reliability of an item-specific physical activity scale for Chinese children and adolescents(I-PASCA). Methods Students from Grade 4-12 in Nanjing were randomly selected using a multi-stage sampling approach, 7-days physical activity (PA) level was recorded by self-reported I-PASCA and PA log and were objectively measured with accelerometers. The total moderate and vigorous PA (MVPA) time was calculated. Cronbach α was calculated to estimate the reliability of I-PASCA. Pearson correlation coefficient and Bland-Altman were used to examine I-PASCA's validity. Results There were 815 students recruited in 2013 to evaluate the reliability and validity of I-PASCA using PA log. Cronbach α for I-PASCA was 0.73 regarding moderate and vigorous PA (MVPA). The Spearman correlation coefficients of the values of PA recorded by I-PASCA and PA log were 0.59 for MVPA, and the Bland-Altman coefficient was 95.8% for MVPA. 624 students were involved to examine the reliability and validity of I-PASCA using accelerometers. Cronbach α for I-PASCA was 0.72 regarding MVPA. The Spearman correlation coefficient was 0.36 for MVPA, while the Bland-Altman coefficient was 95.5% for MVPA. Conclusions The I-PASCA, the first physical activity questionnaire specific to Chinese children and adolescents, shows acceptable reliability and validity and can be used to evaluate Chinese students' physical activity level in population-based studies.