Mattocks Calum, Ness Andy, Leary Sam, Tilling Kate, Blair Stephen N, Shield Julian, Deere Kevin, Saunders Joanne, Kirkby Joanne, Smith George Davey, Wells Jonathan, Wareham Nicholas, Reilly John, Riddoch Chris
Dept of Social Medicine, University of Bristol, UK.
J Phys Act Health. 2008;5 Suppl 1:S98-111. doi: 10.1123/jpah.5.s1.s98.
Objective methods can improve accuracy of physical activity measurement in field studies but uncertainties remain about their use.
Children age 11 years from the Avon Longitudinal Study of Parents and Children (ALSPAC), were asked to wear a uni-axial accelerometer (MTI Actigraph) for 7 days.
Of 7159 children who attended for assessment, 5595 (78%) provided valid measures. The reliability coefficient for 3 days of recording was .7 and the power to detect a difference of 0.07 SDs (P<or=.05) was > 90%. Measures tended to be higher on the first day of recording (17 counts/min; 95% CI, 10-24) and if children wore the monitor for fewer days, but these differences were small. The children who provided valid measures of activity were different from those who did not, but the differences were modest.
Objective measures of physical activity can be incorporated into large longitudinal studies of children.
在现场研究中，客观方法可以提高身体活动测量的准确性，但在其应用方面仍存在不确定性。
来自埃文亲子纵向研究（ALSPAC）的11岁儿童被要求佩戴单轴加速度计（MTI Actigraph）7天。
在7159名参加评估的儿童中，5595名（78%）提供了有效的测量数据。3天记录的可靠性系数为0.7，检测0.07标准差差异（P≤0.05）的效能>90%。测量值在记录的第一天往往较高（17次/分钟；95%可信区间，10 - 24），并且如果儿童佩戴监测器的天数较少，但这些差异很小。提供有效活动测量值的儿童与未提供的儿童不同，但差异不大。
身体活动的客观测量可纳入大型儿童纵向研究。
