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

摘要： 目的 本研究使用加速度计对儿童的日常体力活动进行评估,建立北京市5~6岁儿童不同体力活动强度的分界值。方法 在北京市幼儿园及小学选取5~6岁儿童60名(男30名,女30名)。受试儿童依次完成看动画、慢走、快走、跑步以及自由活动等项目,使用Actigraph GT9X加速度计以及Polar H6心率带记录儿童测试过程中的加速度值以及心率,通过ROC曲线对分界值进行校准,并使用儿童活动评级量表(CARS)对自由活动进行编码,对结果进行验证。结果 1)共60名受试儿童参加测试,最终得到56例有效数据。平均年龄为(6.1±0.6)岁,BMI的中位数(四分位数)为15.2(14.4,16.0)kg/m²。2)体力活动静态、轻、中、剧烈强度分界值分别为0~116、117~780、781~1 005和≥1 006 次/15 s;3)使用ROC曲线分析在强度水平的灵敏度分别为100.0%、85.4%、和98.2%,特异度分别为100.0%、86.5%和98.0%;4)与CARS观察法的编码结果进行一致性检验,κ值=0.71。结论 本研究建立的5~6岁儿童体力活动强度加速度分界值,操作简单易行,为5~6岁儿童的日常体力活动进行检测和评估提供了一种新的手段。

关键词: 体力活动, 分界值, 加速度, 儿童