Human walking in the real world: interactions between terrain type, gait parameters, and energy expenditure

Humans often traverse real-world environments with a variety of surface irregularities and inconsistencies, which can disrupt steady gait and require additional effort. Such effects have, however, scarcely been demonstrated quantitatively, because few laboratory biomechanical measures apply outdoors. Walking can nevertheless be quantified by other means. In particular, the foot’s trajectory in space can be reconstructed from foot-mounted inertial measurement units (IMUs), to yield measures of stride and associated variabilities. But it remains unknown whether such measures are related to metabolic energy expenditure. We therefore quantified the effect of five different outdoor terrains on foot motion (from IMUs) and net metabolic rate (from oxygen consumption) in healthy adults (N = 10; walking at 1.25 m/s). Energy expenditure increased significantly (P < 0.05) in the order Sidewalk, Dirt, Gravel, Grass, and Woodchips, with Woodchips about 27% costlier than Sidewalk. Terrain type also affected measures, particularly stride variability and virtual foot clearance (swing foot’s lowest height above consecutive footfalls). In combination, such measures can also roughly predict metabolic cost (adjusted , partial least squares regression), and even discriminate between terrain types (10% reclassification error). Body-worn sensors can characterize how uneven terrain affects gait, gait variability, and metabolic cost in the real world.

人类在真实环境中行进时，常会遭遇各类地表不平整与不一致性，这些因素会干扰稳定步态，并额外增加行进能耗。然而此类效应鲜有定量研究证实，原因是实验室生物力学测量方法鲜有能应用于户外场景。不过，步行行为可通过其他手段实现量化。具体而言，可通过足部搭载的惯性测量单元（IMU）重构足部在空间中的运动轨迹，以此获取步幅及其相关变异性等指标。但目前尚不清楚此类指标是否与代谢能耗存在关联。为此，我们针对10名健康成年人（以1.25 m/s的速度步行），量化了5种不同户外地形对足部运动（由IMU采集数据）与净代谢率（由耗氧量计算得到）的影响。研究结果显示，能耗支出按人行道、土路、碎石路、草地、木屑路的顺序显著升高（P < 0.05），其中木屑路的能耗比人行道高出约27%。地形类型同时也会对相关指标产生影响，尤其体现在步幅变异性与虚拟足部间隙（即摆动脚在连续落脚时的最低高度）方面。结合此类指标，还可通过校正后的偏最小二乘回归粗略预测代谢能耗，甚至能对地形类型进行分类（重分类误差为10%）。综上，可穿戴传感器可用于表征真实环境中不平整地形对步态、步态变异性以及代谢成本的影响。

搜集汇总

背景与挑战

背景概述

该数据集研究了人类在真实世界行走时地形类型对步态参数和能量消耗的影响，基于10名健康成年人在五种不同户外地形上的实验数据，使用脚戴惯性测量单元和代谢率测量。研究发现地形类型显著影响能量消耗和步态变异性，例如木屑地形比人行道增加约27%的能量消耗，且步态指标可用于预测代谢成本和区分地形类型。