Johnson R K, Russ J, Goran M I
Department of Nutrition and Food Sciences, University of Vermont, Burlington 05405, USA.
Int J Obes Relat Metab Disord. 1998 Nov;22(11):1046-52. doi: 10.1038/sj.ijo.0800723.
The objective of this study was to determine whether the Caltrac accelerometer was a meaningful predictor of physical activity related energy expenditure (AEE) in free-living, pre-adolescent children.
The sample consisted of 31 children (14 girls, 17 boys; 22 Caucasian, 9 Mohawk) with a mean age of 8.3 (+/- 2.0) y.
AEE was measured by subtracting postprandial resting metabolic rate (RMR), measured via indirect calorimetry, from total daily energy expenditure (TDEE), derived from the doubly labeled water (DLW) method. Average daily activity counts (AC) were measured using a Caltrac accelerometer, which was worn for three days, two weekdays and one weekend day, within the DLW dosing period.
AEE was related to gender (r = 0.42, P = 0.02), fat mass (FM, r = 0.32; P = 0.07), and fat free mass (FFM, r = 0.32; P = 0.07), but not to AC (r = -0.09; P = 0.63). After adjusting for gender, race, FM and FFM using multiple correlation regression analysis (R = 0.53), AC did not significantly increase the amount of variation explained in AEE. An estimate of the calories expended in physical activity was derived from AC using a formula developed by Sallis et al. This estimate was significantly higher than AEE (956 kcal/d vs 469 kcal/d, respectively, t = 5.9, P < 0.001).
The Caltrac was not a meaningful predictor of AEE in our sample. The caloric estimates of energy expended in physical activity derived from the Caltrac AC, were significantly higher in comparison with measured AEE in these free-living children.
本研究的目的是确定Caltrac加速度计是否是自由生活的青春期前儿童身体活动相关能量消耗（AEE）的有意义预测指标。
样本包括31名儿童（14名女孩，17名男孩；22名白种人，9名莫霍克人），平均年龄8.3（±2.0）岁。
AEE通过从双标记水（DLW）法得出的每日总能量消耗（TDEE）中减去通过间接量热法测量的餐后静息代谢率（RMR）来测量。平均每日活动计数（AC）使用Caltrac加速度计进行测量，该加速度计在DLW给药期内佩戴三天，两个工作日和一个周末日。
AEE与性别相关（r = 0.42，P = 0.02）、脂肪量（FM，r = 0.32；P = 0.07）和去脂体重（FFM，r = 0.32；P = 0.07）有关，但与AC无关（r = -0.09；P = 0.63）。使用多重相关回归分析（R = 0.53）对性别、种族、FM和FFM进行校正后，AC并未显著增加AEE中解释的变异量。使用Sallis等人开发的公式从AC得出身体活动中消耗的卡路里估计值。该估计值显著高于AEE（分别为956千卡/天和469千卡/天，t = 5.9，P < 0.001）。
在我们的样本中，Caltrac不是AEE的有意义预测指标。与这些自由生活儿童中测量的AEE相比，从Caltrac AC得出的身体活动中消耗的能量的卡路里估计值显著更高。
