University of Southern Denmark, Institute of Sports Science and Clinical Biomechanics, Centre of Research in Childhood Health, Campusvej, Odense M, Denmark.
Int J Behav Nutr Phys Act. 2012 Sep 12;9:113. doi: 10.1186/1479-5868-9-113.
More studies include multiple generations of the Actigraph activity monitor. So far no studies have compared the output including the newest generation and investigated the impact on the output of the activity monitor when enabling the low frequency extension (LFE) option. The aims were to study the responses of four generations (AM7164, GT1M, GT3X and GT3X+) of the Actigraph activity monitor in a mechanical setup and a free living environment with and without enabling the LFE option.
The monitors were oscillated in a mechanical setup using two radii in the frequency range 0.25-3.0 Hz. Following the mechanical study a convenience sample (N = 20) wore three monitors (one AM7164 and two GT3X) for 24 hours.
The AM7164 differed from the newer generations across frequencies (p < 0.05) in the mechanical setup. The AM7164 produced a higher output at the lower and at the highest intensities, whereas the output was lower at the middle intensities in the mid-range compared to the newer generations. The LFE option decreased the differences at the lower frequencies, but increased differences at the higher. In free living, the mean physical activity level (PA) of the GT3X was 18 counts per minute (CPM) (8%) lower compared to the AM7164 (p < 0.001). Time spent in sedentary intensity was 26.6 minutes (95% CI 15.6 to 35.3) higher when assessed by the GT3X compared to the AM7164 (p < 0.001). Time spend in light and vigorous PA were 23.3 minutes (95% CI 31.8 to 14.8) and 11.7 minutes (95% CI 2.8 to 0.7) lower when assessed by the GT3X compared to the AM7164 (p < 0.05). When enabling the LFE the differences in the sedentary and light PA intensity (<333 counts*10 sec-1) were attenuated (p > 0.05 for differences between generations) thus attenuated the difference in mean PA (p > 0.05) when the LFE option was enabled. However, it did not attenuate the difference in time spend in vigorous PA and it introduced a difference in time spend in moderate PA (+ 3.0 min (95% CI 0.4 to 5.6)) between the generations.
We observed significant differences between the AM7164 and the newer Actigraph GT-generations (GT1M, GT3X and GT3X+) in a mechanical setup and in free-living. Enabling the LFE option attenuated the differences in mean PA completely, but induced a bias in the moderate PA intensities.
越来越多的研究包括了 Actigraph 活动监测器的多代产品。到目前为止，还没有研究比较包括最新一代产品的输出情况，并调查在启用低频扩展 (LFE) 选项时对活动监测器输出的影响。目的是在机械设置和自由生活环境中研究四代 (AM7164、GT1M、GT3X 和 GT3X+) Actigraph 活动监测器的反应，同时启用和不启用 LFE 选项。
使用两种半径在 0.25-3.0 Hz 的频率范围内，在机械设置中对监测器进行振荡。机械研究后，方便样本 (N=20) 佩戴三个监测器 (一个 AM7164 和两个 GT3X) 24 小时。
在机械设置中，AM7164 在各个频率上与新一代产品不同 (p<0.05)。在较低和最高强度下，AM7164 的输出较高，而在中强度下，与新一代产品相比，中程输出较低。LFE 选项降低了低频下的差异，但增加了高频下的差异。在自由生活中，与 AM7164 相比，GT3X 的平均身体活动水平 (PA) 低 18 个计数/分钟 (CPM) (p<0.001)。当使用 GT3X 评估时，久坐强度的时间增加了 26.6 分钟 (95%CI 15.6 至 35.3) (p<0.001)。与 AM7164 相比，使用 GT3X 评估时，轻强度和剧烈强度的 PA 时间分别减少了 23.3 分钟 (95%CI 31.8 至 14.8) 和 11.7 分钟 (95%CI 2.8 至 0.7) (p<0.05)。启用 LFE 后，久坐和轻强度 PA 强度 (<333 计数*10 sec-1) 的差异减弱 (p>0.05 为两代产品之间的差异)，从而减弱了启用 LFE 选项时平均 PA 的差异 (p>0.05)。然而，它并没有减弱剧烈 PA 时间花费的差异，并且在两代之间引入了中度 PA 时间花费的差异 (+3.0 分钟 (95%CI 0.4 至 5.6))。
我们在机械设置和自由生活中观察到 AM7164 与新一代 Actigraph GT 代产品 (GT1M、GT3X 和 GT3X+) 之间存在显著差异。启用 LFE 选项完全减弱了平均 PA 的差异，但在中度 PA 强度上引入了偏差。
