College of Medicine, Veterinary and Life Sciences, University of Glasgow, UK.
Int J Obes (Lond). 2011 Apr;35 Suppl 1:S98-103. doi: 10.1038/ijo.2011.40.
The impact of accelerometer-related methodological decisions relating to the assessment of physical activity and sedentary time has not been conclusively determined in young children.
To determine the effects of epoch and cutoff points on the assessment of physical activity and sedentary time and to determine the accelerometer wear time required to achieve reliable accelerometer data in children.
Children were recruited from centres at Ghent, Glasgow, Gothenburg and Zaragoza.
Physical activity was assessed for 1 week in 86 children (41 girls, 45 boys; mean age 7±2 years) by uniaxial accelerometry. The epoch was set at 15 s and reintegrated to 30 and 60 s. Time spent sedentary and in moderate and vigorous physical activity (MVPA) was assessed using a range of cutoff points. Number of days required to achieve 80% reliability was predicted using the Spearman-Brown Prophecy formula.
The Reilly cutoff points (<1100 counts per min (CPM)) indicated less sedentary time per day when comparing 15 vs 30 s and 15 vs 60 s epochs: 570±91 vs 579±93 min and 570±91 vs 579±94 min, respectively; P<0.05. Pate cutoff points (>420 counts per 15 s) reported more MVPA time per day compared with Sirard (890 counts per 15 s) and Puyau cutoff points (>3200 counts per min) using 15 s epoch: 78 (4-197) min (median (range) vs 18 (1-80) min and 24 (1-100) min, respectively; P<0.001. Compliance with guidelines of at least 60 min MVPA was 84, 78 and 73% for Pate cutoff points using 15, 30 and 60 s epochs, respectively, but 0% for Sirard and Puyau cutoff points across epochs. The number of days required to achieve 80% reliability for CPM, sedentary and MVPA time was 7.4-8.5 days.
Choice of epoch and cutoff point significantly influenced the classification of sedentary and MVPA time and observed compliance to the MVPA guidelines.
加速度计相关方法学决策对儿童身体活动和久坐时间的评估影响尚未得出明确结论。
确定时距和截止点对身体活动和久坐时间评估的影响，并确定儿童获得可靠加速度计数据所需的加速度计佩戴时间。
在根特、格拉斯哥、哥德堡和萨拉戈萨的中心招募了儿童。
通过单轴加速度计对 86 名儿童（女孩 41 名，男孩 45 名；平均年龄 7±2 岁）进行了为期 1 周的身体活动评估。时距设定为 15 s，并重新整合为 30 s 和 60 s。使用一系列截止点评估久坐时间和中高强度身体活动（MVPA）时间。使用斯皮尔曼-布朗预测公式预测达到 80%可靠性所需的天数。
当比较 15 s 与 30 s 和 15 s 与 60 s 时距时，Reilly 截止点（<1100 计数/分钟（CPM））表明每天的久坐时间更少：570±91 分钟与 579±93 分钟和 570±91 分钟与 579±94 分钟，分别；P<0.05。与 Sirard（890 计数/15 s）和 Puyau 截止点（>3200 计数/分钟）相比，Pate 截止点（>420 计数/15 s）报告的每天 MVPA 时间更多：78（4-197）分钟（中位数（范围）与 18（1-80）分钟和 24（1-100）分钟，分别；P<0.001。使用 15 s 时距，Pate 截止点达到至少 60 min MVPA 指南的依从率分别为 84%、78%和 73%，但 Sirard 和 Puyau 截止点在所有时距均为 0%。达到 CPM、久坐和 MVPA 时间 80%可靠性所需的天数为 7.4-8.5 天。
时距和截止点的选择显著影响了久坐和 MVPA 时间的分类以及对 MVPA 指南的观察依从性。
