The effect of stride length on lower extremity joint kinetics at various gait speeds.

Robot-assisted training is a promising tool under development for improving walking function based on repetitive goal-oriented task practice. The challenges in developing the controllers for gait training devices that promote desired changes in gait is complicated by the limited understanding of the...

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Main Authors: Robert L McGrath, Melissa L Ziegler, Margaret Pires-Fernandes, Brian A Knarr, Jill S Higginson, Fabrizio Sergi
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2019-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0200862
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author Robert L McGrath
Melissa L Ziegler
Margaret Pires-Fernandes
Brian A Knarr
Jill S Higginson
Fabrizio Sergi
author_facet Robert L McGrath
Melissa L Ziegler
Margaret Pires-Fernandes
Brian A Knarr
Jill S Higginson
Fabrizio Sergi
author_sort Robert L McGrath
collection DOAJ
description Robot-assisted training is a promising tool under development for improving walking function based on repetitive goal-oriented task practice. The challenges in developing the controllers for gait training devices that promote desired changes in gait is complicated by the limited understanding of the human response to robotic input. A possible method of controller formulation can be based on the principle of bio-inspiration, where a robot is controlled to apply the change in joint moment applied by human subjects when they achieve a gait feature of interest. However, it is currently unclear how lower extremity joint moments are modulated by even basic gait spatio-temporal parameters. In this study, we investigated how sagittal plane joint moments are affected by a factorial modulation of two important gait parameters: gait speed and stride length. We present the findings obtained from 20 healthy control subjects walking at various treadmill-imposed speeds and instructed to modulate stride length utilizing real-time visual feedback. Implementing a continuum analysis of inverse-dynamics derived joint moment profiles, we extracted the effects of gait speed and stride length on joint moment throughout the gait cycle. Moreover, we utilized a torque pulse approximation analysis to determine the timing and amplitude of torque pulses that approximate the difference in joint moment profiles between stride length conditions, at all gait speed conditions. Our results show that gait speed has a significant effect on the moment profiles in all joints considered, while stride length has more localized effects, with the main effect observed on the knee moment during stance, and smaller effects observed for the hip joint moment during swing and ankle moment during the loading response. Moreover, our study demonstrated that trailing limb angle, a parameter of interest in programs targeting propulsion at push-off, was significantly correlated with stride length. As such, our study has generated assistance strategies based on pulses of torque suitable for implementation via a wearable exoskeleton with the objective of modulating stride length, and other correlated variables such as trailing limb angle.
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spelling doaj.art-9068308f5019419399185038216c1ce72022-12-21T19:56:32ZengPublic Library of Science (PLoS)PLoS ONE1932-62032019-01-01142e020086210.1371/journal.pone.0200862The effect of stride length on lower extremity joint kinetics at various gait speeds.Robert L McGrathMelissa L ZieglerMargaret Pires-FernandesBrian A KnarrJill S HigginsonFabrizio SergiRobot-assisted training is a promising tool under development for improving walking function based on repetitive goal-oriented task practice. The challenges in developing the controllers for gait training devices that promote desired changes in gait is complicated by the limited understanding of the human response to robotic input. A possible method of controller formulation can be based on the principle of bio-inspiration, where a robot is controlled to apply the change in joint moment applied by human subjects when they achieve a gait feature of interest. However, it is currently unclear how lower extremity joint moments are modulated by even basic gait spatio-temporal parameters. In this study, we investigated how sagittal plane joint moments are affected by a factorial modulation of two important gait parameters: gait speed and stride length. We present the findings obtained from 20 healthy control subjects walking at various treadmill-imposed speeds and instructed to modulate stride length utilizing real-time visual feedback. Implementing a continuum analysis of inverse-dynamics derived joint moment profiles, we extracted the effects of gait speed and stride length on joint moment throughout the gait cycle. Moreover, we utilized a torque pulse approximation analysis to determine the timing and amplitude of torque pulses that approximate the difference in joint moment profiles between stride length conditions, at all gait speed conditions. Our results show that gait speed has a significant effect on the moment profiles in all joints considered, while stride length has more localized effects, with the main effect observed on the knee moment during stance, and smaller effects observed for the hip joint moment during swing and ankle moment during the loading response. Moreover, our study demonstrated that trailing limb angle, a parameter of interest in programs targeting propulsion at push-off, was significantly correlated with stride length. As such, our study has generated assistance strategies based on pulses of torque suitable for implementation via a wearable exoskeleton with the objective of modulating stride length, and other correlated variables such as trailing limb angle.https://doi.org/10.1371/journal.pone.0200862
spellingShingle Robert L McGrath
Melissa L Ziegler
Margaret Pires-Fernandes
Brian A Knarr
Jill S Higginson
Fabrizio Sergi
The effect of stride length on lower extremity joint kinetics at various gait speeds.
PLoS ONE
title The effect of stride length on lower extremity joint kinetics at various gait speeds.
title_full The effect of stride length on lower extremity joint kinetics at various gait speeds.
title_fullStr The effect of stride length on lower extremity joint kinetics at various gait speeds.
title_full_unstemmed The effect of stride length on lower extremity joint kinetics at various gait speeds.
title_short The effect of stride length on lower extremity joint kinetics at various gait speeds.
title_sort effect of stride length on lower extremity joint kinetics at various gait speeds
url https://doi.org/10.1371/journal.pone.0200862
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