关键词: 体力活动, 分界值, 加速度, 儿童

Abstract: Objective To establish accelerometer count cutoffs to categorize activity intensity of 5-to 6-year-old children and to evaluate the accelerometer as a measure of children's physical activity in preschool. Methods Sixty children aged 5~6 years completed series of activities (watching cartoons,slow walking,brisk walking,running and free activities) while wearing a accelerometer and an Polar H6 heart rate monitor to measure accelerometer counts and HR separately.Receiver Operating Characteristic (ROC) curve analyses identified count cutoffs for four intensities physical activity.Children's Activity Rating Scale(CARS)was used to verify the classification of four physical activity intensities. Results 1)Sixty children attended the test and finally valid data of 56 children were received;2) The cut-off points of different intensities of physical activity level were 0~116,117~780,781~1 005 and ≥1 006 counts/15s respectively;3) Sensitivities of the intensities were 100.0%,85.4% and 98.2%,respectively.Specificities of the intensities were 100.0%,86.5% and 90.0%,respectively;4) The consistency test for the results of CARS observation method was given(κ=0.71). Conclusion The ActiGraph count cutoffs established and validated in this study can be used to objectively categorize the time that preschool-age children spend in different intensity levels of physical activity.

Key words: physical activity, cut points, accelerometer, children