Chu Eva Y W, McManus Alison M, Yu Clare C W
Institute of Human Performance, University of Hong Kong, Hong Kong.
Med Sci Sports Exerc. 2007 Nov;39(11):2085-91. doi: 10.1249/mss.0b013e318148436c.
The purpose of this study was to provide RT3 accelerometer thresholds to distinguish nonambulation from ambulation, as well as distinguish between low, moderate, and vigorous intensity ambulation in Chinese children.
Thirty-five 8- to 12-yr-olds completed a laboratory-based experiment to calibrate the RT3 device across a range of intensities. Oxygen uptake during sedentary tasks and ambulation was aligned, with corresponding RT3 output, to one of four intensity categories (sedentary, < 2 METs; low, > or = 2 but < 3 METs; moderate, > or = 3 but < 6; and vigorous, > or = 6). Threshold values were derived using receiver operator curves to distinguish the sedentary from low intensity, low from moderate intensity, and moderate from vigorous intensity. These were confirmed in an independent sample of 46 similarly aged children.
RT3 movement counts increased in a linear manner with scaled oxygen uptake from stationary to vigorous movement (r(2) = 0.83). The ROC-derived thresholds showed a good ability to discriminate between nonambulatory and ambulatory tasks, as well as distinguish between low, moderate, and vigorous ambulation (sensitivity values of 87-100% and specificity values of 97-100%). ROC analyses in the independent sample showed sensitivity and specificity values ranging from 72 to 98%, indicating that the thresholds provided an accurate distinction between the four intensity categories. A Cohen's kappa of kappa = 0.92 confirmed that the lower threshold had near-perfect agreement with the independent sample, whereas the moderate-intensity and vigorous-intensity thresholds showed good agreement with the independent sample (kappa = 0.63 and 0.65, respectively).
The RT3 accelerometer provides an acceptable marker of both sedentary and ambulatory behavior in Chinese children.
本研究旨在提供RT3加速度计阈值，以区分中国儿童的非行走状态与行走状态，以及区分低强度、中等强度和高强度行走。
35名8至12岁儿童完成了一项基于实验室的实验，以在一系列强度下校准RT3设备。将久坐任务和行走过程中的摄氧量与相应的RT3输出进行匹配，分为四个强度类别之一（久坐，<2梅脱；低强度，≥2但<3梅脱；中等强度，≥3但<6；高强度，≥6）。使用受试者工作特征曲线得出阈值，以区分久坐与低强度、低强度与中等强度、中等强度与高强度。这些阈值在46名年龄相仿的儿童独立样本中得到了验证。
从静止到剧烈运动，RT3运动计数随标化摄氧量呈线性增加（r² = 0.83）。通过受试者工作特征曲线得出的阈值显示出良好的能力，能够区分非行走任务和行走任务，以及区分低强度、中等强度和高强度行走（敏感度值为87 - 100%，特异度值为97 - 100%）。独立样本中的受试者工作特征曲线分析显示，敏感度和特异度值在72%至98%之间，表明这些阈值能够准确区分四个强度类别。Cohen's kappa系数κ = 0.92证实，较低阈值与独立样本几乎完全一致，而中等强度和高强度阈值与独立样本显示出良好的一致性（κ分别为0.63和0.65）。
RT3加速度计为中国儿童的久坐行为和行走行为提供了一个可接受的指标。
