Department of Physical Therapy, University of British Columbia, Vancouver, BC, Canada.
School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.
PLoS One. 2024 May 16;19(5):e0293691. doi: 10.1371/journal.pone.0293691. eCollection 2024.
Capturing human locomotion in nearly any environment or context is becoming increasingly feasible with wearable sensors, giving access to commonly encountered walking conditions. While important in expanding our understanding of locomotor biomechanics, these more variable environments present challenges to identify changes in data due to person-level factors among the varying environment-level factors. Our study examined foot-specific biomechanics while walking on terrain commonly encountered with the goal of understanding the extent to which these variables change due to terrain. We recruited healthy adults to walk at self-selected speeds on stairs, flat ground, and both shallow and steep sloped terrain. A pair of inertial measurement units were embedded in both shoes to capture foot biomechanics while walking. Foot orientation was calculated using a strapdown procedure and foot trajectory was determined by double integrating the linear acceleration. Stance time, swing time, cadence, sagittal and frontal orientations, stride length and width were extracted as discrete variables. These data were compared within-participant and across terrain conditions. The physical constraints of the stairs resulted in shorter stride lengths, less time spent in swing, toe-first foot contact, and higher variability during stair ascent specifically (p<0.05). Stride lengths increased when ascending compared to descending slopes, and the sagittal foot angle at initial contact was greatest in the steep slope descent condition (p<0.05). No differences were found between conditions for horizontal foot angle in midstance (p≥0.067). Our results show that walking on slopes creates differential changes in foot biomechanics depending on whether one is descending or ascending, and stairs require different biomechanics and gait timing than slopes or flat ground. This may be an important factor to consider when making comparisons of real-world walking bouts, as greater proportions of one terrain feature in a data set could create bias in the outcomes. Classifying terrain in unsupervised walking datasets would be helpful to avoid comparing metrics from different walking terrain scenarios.
利用可穿戴传感器在几乎任何环境或背景下捕捉人类运动变得越来越可行，从而可以获得常见的步行条件。虽然这对于扩展我们对运动生物力学的理解很重要，但这些更具变化性的环境给识别由于环境水平因素之外的个体水平因素导致的数据变化带来了挑战。我们的研究在常见地形上行走时检查了足部特定的生物力学，目的是了解由于地形而导致这些变量变化的程度。我们招募了健康的成年人以自选择的速度在楼梯、平地以及浅和陡峭的倾斜地形上行走。在每只鞋子中嵌入一对惯性测量单元以在行走时捕捉足部生物力学。使用捷联程序计算足部方向，通过对线性加速度进行二次积分确定足部轨迹。提取站立时间、摆动时间、步频、矢状面和额状面方向、步长和步宽作为离散变量。在个体内和地形条件之间比较这些数据。楼梯的物理限制导致步长更短、摆动时间更短、脚趾先接触以及在上楼梯时的变异性更高（p<0.05）。与下坡相比，在上坡时步长增加，在陡峭的下坡接触条件下初始接触时的矢状足角最大（p<0.05）。在中间站立时，水平足角在条件之间没有差异（p≥0.067）。我们的结果表明，在上坡和下坡时，在斜坡上行走会导致足部生物力学发生不同的变化，而楼梯需要与斜坡或平地不同的生物力学和步态时间。这在比较真实世界的行走回合时可能是一个重要因素，因为数据集内一种地形特征的比例更大可能会导致结果产生偏差。在无监督的行走数据集中对地形进行分类将有助于避免比较来自不同行走地形场景的指标。
