Boutaayamou Mohamed, Schwartz Cédric, Stamatakis Julien, Denoël Vincent, Maquet Didier, Forthomme Bénédicte, Croisier Jean-Louis, Macq Benoît, Verly Jacques G, Garraux Gaëtan, Brüls Olivier
Laboratory of Human Motion Analysis, University of Liège (ULg), Liège, Belgium; INTELSIG Laboratory, Department of Electrical Engineering and Computer Science, ULg, Liège, Belgium.
Laboratory of Human Motion Analysis, University of Liège (ULg), Liège, Belgium.
Med Eng Phys. 2015 Feb;37(2):226-32. doi: 10.1016/j.medengphy.2015.01.001. Epub 2015 Jan 21.
An original signal processing algorithm is presented to automatically extract, on a stride-by-stride basis, four consecutive fundamental events of walking, heel strike (HS), toe strike (TS), heel-off (HO), and toe-off (TO), from wireless accelerometers applied to the right and left foot. First, the signals recorded from heel and toe three-axis accelerometers are segmented providing heel and toe flat phases. Then, the four gait events are defined from these flat phases. The accelerometer-based event identification was validated in seven healthy volunteers and a total of 247 trials against reference data provided by a force plate, a kinematic 3D analysis system, and video camera. HS, TS, HO, and TO were detected with a temporal accuracy ± precision of 1.3 ms ± 7.2 ms, -4.2 ms ± 10.9 ms, -3.7 ms ± 14.5 ms, and -1.8 ms ± 11.8 ms, respectively, with the associated 95% confidence intervals ranging from -6.3 ms to 2.2 ms. It is concluded that the developed accelerometer-based method can accurately and precisely detect HS, TS, HO, and TO, and could thus be used for the ambulatory monitoring of gait features computed from these events when measured concurrently in both feet.
提出了一种原始信号处理算法，用于基于步幅逐次地从应用于左右脚的无线加速度计中自动提取行走的四个连续基本事件：足跟触地（HS）、足尖触地（TS）、足跟离地（HO）和足尖离地（TO）。首先，对从足跟和足尖三轴加速度计记录的信号进行分段，得到足跟和足尖的平稳阶段。然后，从这些平稳阶段定义四个步态事件。基于加速度计的事件识别在7名健康志愿者身上进行了验证，针对测力板、运动学3D分析系统和摄像机提供的参考数据，共进行了247次试验。检测到HS、TS、HO和TO的时间精度±精密度分别为1.3 ms±7.2 ms、-4.2 ms±10.9 ms、-3.7 ms±14.5 ms和-1.8 ms±11.8 ms，相关的95%置信区间为-6.3 ms至2.2 ms。得出的结论是，所开发的基于加速度计的方法能够准确、精确地检测HS、TS、HO和TO，因此可用于在双脚同时测量时对从这些事件计算出的步态特征进行动态监测。
