[Reliability and validity of a 7-day physical activity questionnaire for elementary students].
OBJECTIVE
To evaluate the use of a 7-day physical activity questionnaire in epidemiologic studies on 4-6th grades children.


METHODS
Focus group discussion, observation and expert consultation were used to develop 7-day physical activity questionnaire. The reliability and validity of questionnaire were determined in a sample of 92 children in 4-6th grades who were randomly selected from four schools in urban Beijing. A two-week test-retest reliability was determined. The questionnaire was validated against experts' evaluation and Caltrac motion sensor.


RESULTS
For different measures of activity, the agreement was good between the test and retest. Kappa values ranged from 0.46 to 0.79, and the Spearman correlations ranged from 0.66 to 0.87 in boys and 0.57 to 0.82 in girls, with significant difference (P < 0.01). The face validity and content validity were good by experts' evaluation. There was no significant difference between questionnaire results and Caltrac motion sensor for both boys and girls, and the questionnaire correlated significantly (r = 0.46, 0.38 for different measures of activity) with Caltrac motion sensor for boys.


CONCLUSIONS
These data provided evidence that the 7-day physical activity questionnaire yield a reliable estimate of past week physical activity for 4 - 6-grade children and provided valid estimation of past week physical activity for boys.
Liu
Ai-Ling
AL
Department of School Nutrition, Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
Ma
Guan-Sheng
GS
Zhang
Qian
Q
Ma
Wen-Jing
WJ
D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity; D011795:Surveys and Questionnaires