Echevarría-Polo Marcos, Marín Pedro J, Pueyo Esther, Ramos Maqueda Javier, Garatachea Nuria
EXER-GENUD "Growth, Exercise, NUtrition and Development" Research Group, University of Zaragoza, 50009 Zaragoza, Spain.
Faculty of Health and Sports Sciences, University of Zaragoza, 22001 Huesca, Spain.
Sensors (Basel). 2025 Apr 15;25(8):2480. doi: 10.3390/s25082480.
This study aimed to evaluate the intra- and inter-instrument variability and reliability of the Axivity AX6 accelerometer under controlled technical conditions and human motion scenarios. In the first experiment, 12 accelerometers were affixed to a vibration platform and tested at four frequencies (2.2, 3.2, 6.5, and 9.4 Hz) along three axes to assess frequency- and axis-dependent variability. In the second experiment, four AX6 accelerometers were simultaneously placed on a subject's wrist and tested under four human motion conditions (walking at 4 km·h and 6 km·h and running at 8 km·h and 10 km·h). Results demonstrated low intra- and inter-instrument variability (CVintra: 3.3-4.5%; CVinter: 6.3-7.7%) with high reliability (ICC = 0.98). Similar results were observed in human motion conditions (CVintra: 5.3-8.8%; CVinter: 7.1-10.4%), with ICC values of 0.98 for combined devices, and 0.99 for each device individually. Despite statistically significant differences ( < 0.05) between devices in human motion all conditions, the variations remained below the minimal clinically significant difference threshold. These findings indicate that under technical conditions on a vibrating platform, and within the range of typical human accelerations, the Axivity AX6 is a reliable tool for measuring accelerations representative of physical activity. However, further research is necessary to validate its performance under free-living conditions.
本研究旨在评估在受控技术条件和人体运动场景下，Axivity AX6加速度计的仪器内和仪器间变异性及可靠性。在第一个实验中，将12个加速度计固定在振动平台上，并沿三个轴在四个频率（2.2、3.2、6.5和9.4Hz）下进行测试，以评估频率和轴相关的变异性。在第二个实验中，将四个AX6加速度计同时放置在受试者的手腕上，并在四种人体运动条件下（以4km·h和6km·h的速度行走以及以8km·h和10km·h的速度跑步）进行测试。结果表明，仪器内和仪器间变异性较低（仪器内变异系数CVintra：3.3 - 4.5%；仪器间变异系数CVinter：6.3 - 7.7%），可靠性较高（组内相关系数ICC = 0.98）。在人体运动条件下也观察到了类似结果（仪器内变异系数CVintra：5.3 - 8.8%；仪器间变异系数CVinter：7.1 - 10.4%），组合设备的ICC值为0.98，每个设备单独的ICC值为0.99。尽管在所有人体运动条件下不同设备之间存在统计学显著差异（P < 0.05），但变化仍低于最小临床显著差异阈值。这些发现表明，在振动平台的技术条件下以及典型人体加速度范围内，Axivity AX6是测量代表身体活动的加速度的可靠工具。然而，需要进一步研究以验证其在自由生活条件下的性能。
