@article{ref1,
title="Human walking in the real world: interactions between terrain type, gait parameters, and energy expenditure",
journal="PLoS one",
year="2021",
author="Kuo, Arthur D. and Adamczyk, Peter G. and Ojeda, Lauro V. and Rebula, John R. and Kowalsky, Daniel B.",
volume="16",
number="1",
pages="e0228682-e0228682",
abstract="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 R2 = 0.52, 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.<p /> <p>Language: en</p>",
language="en",
issn="1932-6203",
doi="10.1371/journal.pone.0228682",
url="http://dx.doi.org/10.1371/journal.pone.0228682"
}