Objective: To test the reliability and validity of International Physical Activity Questionnaires (long self-administrated format) (IPAQ), Chinese version on women of 12 - 44 years old, in Chengdu city.
Methods: Clustered sampling was used, according to the age distribution of investigated population. One community, one university and two middle schools (including one high school and one junior high school) in Chengdu were selected. The reliability study was conducted in a 28-day period. Participants were contacted three times within 28 days (on the 1(st), the 8(th) and the 28(th) day respectively). In the validity study, participants completed the same questionnaire and Bouchard physical activity diary (PA diary) each day for seven days between visit 1 and visit 2 before comparing the IPAQ's result with Bouchard physical activity diary's for validity study. Pearson or Spearman' correlation coefficients were calculated for validity and interclass correlation coefficients for reliability according to date distribution.
Results: (1) One hundred and eighty six participants were recruited for the reliability study. All of them completed the first questionnaire with 143 (76.88%) and 172 (92.50%) finished the second and third questionnaires. One hundred and fifty eight participants were recruited in the validity study. Qualified questionnaire accounted for 90.59% (143). (2) Results from the test-retest reliability of the Chinese version of long self-administrated format (IPAQ) showed: the ICC after one week ranged from 0.7373 to 0.972 (mean: 0.870) which were higher than those interval's reliability [ICC = 0.472 - 0.948 for three weeks interval (mean: 0.721), and 0.473 - 0.925 for four weeks interval (mean: 0.696)]. The ICCs of three weeks interval and four weeks interval were not significantly different. ICCs for vigorous physical activity and leisure time physical activity were the best. (3) The validity for different intensity, total physical activity and sitting time showed the correlation coefficients between IPAQ and PA diary ranged from 0.445 to 0.696, with correlation for vigorous physical activity the best (r = 0.696).
Conclusion: IPAQ-C seemed a reliable and validated measure of physical activity for 12 - 44 year-old women in Chengdu city.