Faculty of Health Science, Department of Biomedical Sciences, University of León, Spain.
Int J Sports Med. 2013 Nov;34(11):975-82. doi: 10.1055/s-0033-1337945. Epub 2013 May 22.
The aims of this study were: to compare energy expenditure (EE) estimated from the existing GT3X accelerometer equations and EE measured with indirect calorimetry; to define new equations for EE estimation with the GT3X in youth, adults and older people; and to define GT3X vector magnitude (VM) cut points allowing to classify PA intensity in the aforementioned age-groups. The study comprised 31 youth, 31 adults and 35 older people. Participants wore the GT3X (setup: 1-s epoch) over their right hip during 6 conditions of 10-min duration each: resting, treadmill walking/running at 3, 5, 7, and 9 km · h⁻¹, and repeated sit-stands (30 times · min⁻¹). The GT3X proved to be a good tool to predict EE in youth and adults (able to discriminate between the aforementioned conditions), but not in the elderly. We defined the following equations: for all age-groups combined, EE (METs)=2.7406+0.00056 · VM activity counts (counts · min⁻¹)-0.008542 · age (years)-0.01380 · body mass (kg); for youth, METs=1.546618+0.000658 · VM activity counts (counts · min⁻¹); for adults, METs=2.8323+0.00054 · VM activity counts (counts · min⁻¹)-0.059123 · body mass (kg)+1.4410 · gender (women=1, men=2); and for the elderly, METs=2.5878+0.00047 · VM activity counts (counts · min⁻¹)-0.6453 · gender (women=1, men=2). Activity counts derived from the VM yielded a more accurate EE estimation than those derived from the Y-axis. The GT3X represents a step forward in triaxial technology estimating EE. However, age-specific equations must be used to ensure the correct use of this device.
比较现有的 GT3X 加速度计方程估算的能量消耗 (EE) 和间接测热法测量的 EE；为年轻人、成年人和老年人制定新的 GT3X 估计 EE 方程；定义 GT3X 矢量幅度 (VM) 切点，以分类上述年龄组的 PA 强度。研究包括 31 名年轻人、31 名成年人和 35 名老年人。参与者在右侧臀部佩戴 GT3X（设置：1 秒时窗），进行 6 种 10 分钟持续时间的测试：休息、跑步机行走/跑步速度为 3、5、7 和 9 km·h⁻¹、以及重复坐站（30 次·min⁻¹）。GT3X 被证明是一种很好的工具，可以预测年轻人和成年人的 EE（能够区分上述条件），但不适用于老年人。我们定义了以下方程：对于所有年龄组，EE（METs）=2.7406+0.00056·VM 活动计数（计数·min⁻¹）-0.008542·年龄（岁）-0.01380·体重（kg）；对于年轻人，METs=1.546618+0.000658·VM 活动计数（计数·min⁻¹）；对于成年人，METs=2.8323+0.00054·VM 活动计数（计数·min⁻¹）-0.059123·体重（kg）+1.4410·性别（女性=1，男性=2）；对于老年人，METs=2.5878+0.00047·VM 活动计数（计数·min⁻¹）-0.6453·性别（女性=1，男性=2）。从 VM 获得的活动计数比从 Y 轴获得的活动计数产生更准确的 EE 估计。GT3X 是三轴技术估计 EE 的一个进步。然而，必须使用特定年龄的方程来确保正确使用该设备。
