scholarly journals Persons post-stroke improve step length symmetry by walking asymmetrically

2020 ◽  
Author(s):  
Purnima Padmanabhan ◽  
Keerthana Sreekanth ◽  
Shivam Gulhar ◽  
Kendra M. Cherry-Allen ◽  
Kristan A. Leech ◽  
...  
Keyword(s):  
Center Of Mass ◽  
Metabolic Cost ◽  
Step Length ◽  
Gait Pattern ◽  
Future Research ◽  
Cost Of Transport ◽  
Post Stroke ◽  
Paretic Limb ◽  
Gait Parameters ◽  
The Many

Abstract Background Restoration of step length symmetry is a common rehabilitation goal after stroke. Persons post-stroke often retain the ability to walk with symmetric step lengths ("symmetric steps") at an elevated metabolic cost relative to healthy adults. Two key questions with direct implications for rehabilitation have emerged: 1) how do persons post-stroke generate symmetric steps, and 2) why do symmetric steps remain so effortful? Here, we aimed to understand how persons post-stroke generate symmetric steps and explored how the resulting gait pattern may relate to the metabolic cost of transport. Methods We recorded kinematic, kinetic, and metabolic data as nine persons post-stroke walked on an instrumented treadmill under two conditions: preferred walking and symmetric stepping (using visual feedback). Results Gait kinematics and kinetics remained markedly asymmetric even when persons post-stroke improved step length symmetry. Impaired paretic propulsion and abnormal movement of the center of mass were evident during both preferred walking and symmetric stepping. These deficits contributed to diminished positive work performed by the paretic limb on the center of mass in both conditions. Within each condition, decreased positive paretic work correlated with increased metabolic cost of transport and decreased walking speed across participants. Conclusions It is critical to consider the mechanics used to restore symmetric steps when designing interventions to improve walking after stroke. Future research should consider the many dimensions of asymmetry in post-stroke gait, and additional within-participant manipulations of gait parameters are needed to improve our understanding of the elevated metabolic cost of walking after stroke.

scholarly journals Persons post-stroke improve step length symmetry by walking asymmetrically

2020 ◽  
Author(s):  
Purnima Padmanabhan ◽  
Keerthana Sreekanth ◽  
Shivam Gulhar ◽  
Kendra M. Cherry-Allen ◽  
Kristan A. Leech ◽  
...  
Keyword(s):  
Center Of Mass ◽  
Metabolic Cost ◽  
Step Length ◽  
Gait Pattern ◽  
Future Research ◽  
Cost Of Transport ◽  
Post Stroke ◽  
Paretic Limb ◽  
Gait Parameters ◽  
The Many

Abstract Background Restoration of step length symmetry is a common rehabilitation goal after stroke. Persons post-stroke often retain the ability to walk with symmetric step lengths ("symmetric steps"); however, the resulting walking pattern remains effortful. Two key questions with direct implications for rehabilitation have emerged: 1) how do persons post-stroke generate symmetric steps, and 2) why do symmetric steps remain so effortful? Here, we aimed to understand how persons post-stroke generate symmetric steps and explored how the resulting gait pattern may relate to the metabolic cost of transport. Methods We recorded kinematic, kinetic, and metabolic data as nine persons post-stroke walked on an instrumented treadmill under two conditions: preferred walking and symmetric stepping (using visual feedback). Results Gait kinematics and kinetics remained markedly asymmetric even when persons post-stroke improved step length symmetry. Impaired paretic propulsion and aberrant movement of the center of mass were evident during both preferred walking and symmetric stepping. These deficits contributed to diminished positive work performed by the paretic limb on the center of mass in both conditions. Within each condition, decreased positive paretic work correlated with increased metabolic cost of transport and decreased walking speed across participants. Conclusions It is critical to consider the mechanics used to restore symmetric steps when designing interventions to improve walking after stroke. Future research should consider the many dimensions of asymmetry in post-stroke gait, and additional within-participant manipulations of gait parameters are needed to improve our understanding of the elevated metabolic cost of walking after stroke.

scholarly journals Persons post-stroke restore step length symmetry by walking asymmetrically

2019 ◽  
Author(s):  
Purnima Padmanabhan ◽  
Keerthana Sreekanth Rao ◽  
Shivam Gulhar ◽  
Kendra M. Cherry-Allen ◽  
Kristan A. Leech ◽  
...  
Keyword(s):  
Center Of Mass ◽  
Metabolic Cost ◽  
Step Length ◽  
Gait Pattern ◽  
Vertical Movement ◽  
Cost Of Transport ◽  
Post Stroke ◽  
Paretic Limb ◽  
Rehabilitation Goal ◽  
Limb Kinematics

ABSTRACTBackgroundRestoration of step length symmetry is a common rehabilitation goal after stroke. Persons post-stroke often retain the capacity to walk with symmetric step lengths (“symmetric steps”); however, the resulting walking pattern remains effortful. Two key questions with direct implications for rehabilitation have emerged: 1) how do persons post-stroke generate symmetric steps, and 2) why do symmetric steps remain so effortful?ObjectiveTo understand how persons post-stroke generate symmetric steps and how the resulting gait pattern relates to the metabolic cost of transport.MethodsTen persons post-stroke walked on an instrumented treadmill under two conditions: preferred walking and symmetric stepping (using visual feedback). We recorded kinematic, kinetic, and metabolic data during both conditions.ResultsPersons post-stroke restored step length symmetry using energetically expensive, asymmetric patterns. Impaired paretic propulsion and abnormal vertical movement of the center of mass were evident during both preferred walking and symmetric stepping. These deficits contributed to diminished positive work performed by the paretic limb on the center of mass in both conditions. Decreased positive paretic work correlated with increased metabolic cost of transport, decreased self-selected walking speed, and increased asymmetry in limb kinematics.ConclusionsIt is important to consider the mechanics used to restore symmetric steps when designing interventions to improve walking after stroke. Facilitating symmetric steps via increased paretic propulsion or enabling paretic limb advancement without excessive vertical movement may enable persons post-stroke to walk with a less effortful, more symmetric gait pattern.

scholarly journals Persons post-stroke restore step length symmetry by walking asymmetrically

2020 ◽  
Author(s):  
Purnima Padmanabhan ◽  
Keerthana Sreekanth ◽  
Shivam Gulhar ◽  
Kendra M. Cherry-Allen ◽  
Kristan A. Leech ◽  
...  
Keyword(s):  
Center Of Mass ◽  
Metabolic Cost ◽  
Step Length ◽  
Gait Pattern ◽  
Vertical Movement ◽  
Cost Of Transport ◽  
Post Stroke ◽  
Paretic Limb ◽  
Rehabilitation Goal ◽  
Limb Kinematics

Abstract Background: Restoration of step length symmetry is a common rehabilitation goal after stroke. Persons post-stroke often retain the ability to walk with symmetric step lengths (“symmetric steps”); however, the resulting walking pattern remains effortful. Two key questions with direct implications for rehabilitation have emerged: 1) how do persons post-stroke generate symmetric steps, and 2) why do symmetric steps remain so effortful? The objective of this study was to understand how persons post-stroke generate symmetric steps and how the resulting gait pattern relates to the metabolic cost of transport. Methods: We recorded kinematic, kinetic, and metabolic data as ten persons post-stroke walked on an instrumented treadmill under two conditions: preferred walking and symmetric stepping (using visual feedback).Results: Persons post-stroke restored step length symmetry using energetically costly, asymmetric patterns. Impaired paretic propulsion and abnormal vertical movement of the center of mass were evident during both preferred walking and symmetric stepping. These deficits contributed to diminished positive work performed by the paretic limb on the center of mass in both conditions. Decreased positive paretic work correlated with increased metabolic cost of transport, decreased self-selected walking speed, and increased asymmetry in limb kinematics.Conclusions: It is critical to consider the mechanics used to restore symmetric steps when designing interventions to improve walking after stroke. Facilitating symmetric steps via increased paretic propulsion or enabling paretic limb advancement without excessive vertical movement may enable persons post-stroke to walk with a less effortful gait pattern.

scholarly journals Individual differences in locomotor function predict the capacity to reduce asymmetry and modify the energetic cost of walking post-stroke

2017 ◽  
Author(s):  
Natalia Sánchez ◽  
James M. Finley
Keyword(s):  
Individual Differences ◽  
Visual Feedback ◽  
Metabolic Cost ◽  
Step Length ◽  
Energetic Cost ◽  
Stroke Survivors ◽  
Locomotor Function ◽  
Post Stroke ◽  
Paretic Limb ◽  
Over Ground Walking

AbstractChanges in the control of the lower extremities post-stroke lead to persistent biomechanical asymmetries during walking. These asymmetries are associated with an increase in energetic cost, leading to the possibility that reduction of asymmetry can improve economy. However, the influence of asymmetry on economy may depend on the direction and cause of asymmetry. For example, impairments with paretic limb advancement may result in shorter paretic steps while deficits in paretic support or propulsion result in shorter non-paretic steps. Given differences in the underlying impairments responsible for each type of step length asymmetry, the capacity to reduce asymmetry, and the associated changes in energetic cost may not be consistent across this population. Here, we identified factors explaining individual differences in the capacity to voluntarily reduce step length asymmetry and modify energetic cost during walking. Twenty-four individuals post-stroke walked on a treadmill with visual feedback of their step lengths to aid explicit modification of asymmetry. We found that individuals who naturally took longer paretic steps had a greater capacity to reduce asymmetry, and were better able to transfer the effects of training to over-ground walking. In addition, baseline energetic cost was negatively correlated with reductions in cost, such that participants with a more economical gait were more likely to reduce energetic cost by improving symmetry. These results demonstrate that many stroke survivors retain the capacity to voluntarily walk more symmetrically on a treadmill and over-ground. However, whether reductions in asymmetry reduce metabolic cost depends on individual differences in impairments affecting locomotor function.

scholarly journals Individual Differences in Locomotor Function Predict the Capacity to Reduce Asymmetry and Modify the Energetic Cost of Walking Poststroke

2018 ◽  
Vol 32 (8) ◽  
pp. 701-713 ◽  
Author(s):  
Natalia Sánchez ◽  
James M. Finley
Keyword(s):  
Individual Differences ◽  
Metabolic Cost ◽  
Step Length ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
Locomotor Function ◽  
Paretic Limb ◽  
Residual Capacity ◽  
Walking Economy ◽  
Baseline Cost

Changes in the control of the lower extremities poststroke lead to persistent biomechanical asymmetries during walking. These asymmetries are associated with an increase in energetic cost, leading to the possibility that reducing asymmetry can improve walking economy. However, the influence of asymmetry on economy may depend on the direction and cause of asymmetry. For example, impairments with paretic limb advancement may result in shorter paretic steps, whereas deficits in paretic support or propulsion result in shorter nonparetic steps. Given differences in the underlying impairments responsible for step length asymmetry, the capacity to reduce asymmetry and the associated changes in energetic cost may not be consistent across this population. Here, we identified factors explaining individual differences in the capacity to voluntarily reduce step length asymmetry and modify energetic cost during walking. A total of 24 individuals poststroke walked on a treadmill, with visual feedback of their step lengths to aid explicit modification of asymmetry. We found that individuals who took longer paretic steps had a greater capacity to reduce asymmetry and were better able to transfer the effects of practice to overground walking than individuals who took shorter paretic steps. In addition, changes in metabolic cost depended on the direction of asymmetry, baseline cost of transport, and reductions in specific features of spatiotemporal asymmetry. These results demonstrate that many stroke survivors retain the residual capacity to voluntarily walk more symmetrically on a treadmill and overground. However, whether reductions in asymmetry reduce metabolic cost depends on individual differences in impairments affecting locomotor function.

Dynamic and Reactive Walking for Humanoid Robots Based on Foot Placement Control

2016 ◽  
Vol 13 (02) ◽  
pp. 1550041 ◽  
Author(s):  
Juan Alejandro Castano ◽  
Zhibin Li ◽  
Chengxu Zhou ◽  
Nikos Tsagarakis ◽  
Darwin Caldwell
Keyword(s):  
Center Of Mass ◽  
Humanoid Robots ◽  
Gait Pattern ◽  
Gait Patterns ◽  
Foot Placement ◽  
Inverted Pendulum Model ◽  
Gait Parameters ◽  
Pendulum Model ◽  
Single Mass ◽  
Walking Velocity

This paper presents a novel online walking control that replans the gait pattern based on our proposed foot placement control using the actual center of mass (COM) state feedback. The analytic solution of foot placement is formulated based on the linear inverted pendulum model (LIPM) to recover the walking velocity and to reject external disturbances. The foot placement control predicts where and when to place the foothold in order to modulate the gait given the desired gait parameters. The zero moment point (ZMP) references and foot trajectories are replanned online according to the updated foothold prediction. Hence, only desired gait parameters are required instead of predefined or fixed gait patterns. Given the new ZMP references, the extended prediction self-adaptive control (EPSAC) approach to model predictive control (MPC) is used to minimize the ZMP response errors considering the acceleration constraints. Furthermore, to ensure smooth gait transitions, the conditions for the gait initiation and termination are also presented. The effectiveness of the presented gait control is validated by extensive disturbance rejection studies ranging from single mass simulation to a full body humanoid robot COMAN in a physics based simulator. The versatility is demonstrated by the control of reactive gaits as well as reactive stepping from standing posture. We present the data of the applied disturbances, the prediction of sagittal/lateral foot placements, the replanning of the foot/ZMP trajectories, and the COM responses.

scholarly journals Disentangling the energetic costs of step time asymmetry and step length asymmetry in human walking

2021 ◽  
Author(s):  
Jan Stenum ◽  
Julia T. Choi
Keyword(s):  
Energy Cost ◽  
Metabolic Cost ◽  
Step Length ◽  
Human Walking ◽  
Metabolic Power ◽  
Healthy Human ◽  
Time Asymmetry ◽  
Double Support ◽  
Post Stroke ◽  
The Cost

The metabolic cost of walking in healthy individuals increases with spatiotemporal gait asymmetries. Pathological gait, such as post-stroke, often has asymmetry in step lengths and step times which may contribute to an increased energy cost. But paradoxically, enforcing step length symmetry does not reduce metabolic cost of post-stroke walking. The isolated and interacting costs of asymmetry in step times and step lengths remain unclear, because previous studies did not simultaneously enforce spatial and temporal gait asymmetries. Here, we delineate isolated costs of asymmetry in step times and step lengths in healthy human walking. We first show that the cost of step length asymmetry is predicted by the cost of taking two non-preferred step lengths (one short and one long), but that step time asymmetry adds an extra cost beyond the cost of non-preferred step times. The metabolic power of step time asymmetry is about 2.5 times greater than the cost of step length asymmetry. Furthermore, the costs are not additive when walking with asymmetric step times and step lengths: metabolic power of concurrent asymmetry in step lengths and step times is driven by the cost of step time asymmetry alone. The metabolic power of asymmetry is explained by positive mechanical power produced during single support phases to compensate for a net loss of center of mass power incurred during double support phases. These data may explain why metabolic cost remains invariant to step length asymmetry in post-stroke walking and suggests how effects of asymmetry on energy cost can be attenuated.

scholarly journals A Dual-Learning Paradigm Simultaneously Improves Multiple Features of Gait Post-Stroke

2018 ◽  
Vol 32 (9) ◽  
pp. 810-820 ◽  
Author(s):  
Kendra M. Cherry-Allen ◽  
Matthew A. Statton ◽  
Pablo A. Celnik ◽  
Amy J. Bastian
Keyword(s):  
Knee Flexion ◽  
Joint Angle ◽  
Step Length ◽  
Learning Task ◽  
Gait Pattern ◽  
Learning Paradigm ◽  
Post Stroke ◽  
Learning Conditions ◽  
Hip Flexion ◽  
Gait Impairments

Background. Gait impairments after stroke arise from dysfunction of one or several features of the walking pattern. Traditional rehabilitation practice focuses on improving one component at a time, which may leave certain features unaddressed or prolong rehabilitation time. Recent work shows that neurologically intact adults can learn multiple movement components simultaneously. Objective. To determine whether a dual-learning paradigm, incorporating 2 distinct motor tasks, can simultaneously improve 2 impaired components of the gait pattern in people posttroke. Methods. Twelve individuals with stroke participated. Participants completed 2 sessions during which they received visual feedback reflecting paretic knee flexion during walking. During the learning phase of the experiment, an unseen offset was applied to this feedback, promoting increased paretic knee flexion. During the first session, this task was performed while walking on a split-belt treadmill intended to improve step length asymmetry. During the second session, it was performed during tied-belt walking. Results. The dual-learning task simultaneously increased paretic knee flexion and decreased step length asymmetry in the majority of people post-stroke. Split-belt treadmill walking did not significantly interfere with joint-angle learning: participants had similar rates and magnitudes of joint-angle learning during both single and dual-learning conditions. Participants also had significant changes in the amount of paretic hip flexion in both single and dual-learning conditions. Conclusions. People with stroke can perform a dual-learning paradigm and change 2 clinically relevant gait impairments in a single session. Long-term studies are needed to determine if this strategy can be used to efficiently and permanently alter multiple gait impairments.

Terrain Characterization Using Modified RANSAC Analysis of Human Gait Data

2012 ◽  
Author(s):  
Christopher Sullivan ◽  
Elizabeth A. DeBartolo ◽  
Kathleen Lamkin-Kennard
Keyword(s):  
Side Effects ◽  
Surface Profile ◽  
Lower Leg ◽  
Gait Pattern ◽  
Test Subject ◽  
Foot Drop ◽  
Human Gait ◽  
Post Stroke ◽  
The Many ◽  
Foot Orthotic

One of the many lasting side effects of a stroke can be foot drop, or an inability to dorsiflex the foot. In order to remedy this, many people wear an ankle-foot orthotic (AFO) post-stroke. One of the many troubles these individuals face is in dealing with obstacles such as stairs and ramps, because the AFO limits the plantarflexion that is natural in navigating these obstacles [1,2]. The end goal of this research is to create an active AFO that adapts to changing ground terrain, providing a more natural gait pattern. This paper presents the first part of this work: a means for identifying terrain in order to control an AFO. This has been accomplished using an infrared (IR) range sensor attached to the lower leg, used to measure the surface profile of the ground just ahead of a test subject. Using a modified RANSAC technique to fit experimental gait data, standardized gait profiles for different terrain have been quantified and shown to be reproducible, indicating the utility of the technique for terrain identification and AFO control.

scholarly journals Preferred Gait Characteristics in Young Adults in Qatar: Physiological, Perceptual, and Spatiotemporal Analysis

SAGE Open ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 215824402094572
Author(s):  
Lina Majed ◽  
Clint Hansen ◽  
Olivier Girard
Keyword(s):  
Young Adults ◽  
Perceived Exertion ◽  
Metabolic Cost ◽  
Spatiotemporal Analysis ◽  
Rating Of Perceived Exertion ◽  
Cost Of Transport ◽  
Gait Characteristics ◽  
Gait Parameters ◽  
Spatiotemporal Parameters ◽  
Support Phase

Preferred walking speed (PWS) is considered a robust measure for assessing mobility and overall health. Healthy reference data are unavailable for Qatar. The aim of this study was to investigate PWS and underlying gait parameters around PWS among healthy young adults living in Qatar. PWS was assessed for 18 Qataris (9 females) and 16 non-Qatari Arabs residing in Qatar (9 females). Within- and between-gender group comparisons were carried out using Mann–Whitney U-tests. Metabolic cost of transport, heart rate, rating of perceived exertion, and spatiotemporal parameters were compared between Qatari and non-Qatari groups of similar gender at seven speed levels relative to PWS using two-way analyses of variance (ANOVAs). Similar comparisons were done at two absolute speeds using Mann–Whitney U-tests. While PWS did not differ significantly between the female groups, it was on average 19% slower for the Qatari males as compared to non-Qatari males. At similar relative speeds, differences appeared solely in physiological parameters between female groups. Only spatiotemporal differences were revealed between the male groups where longer stride and support phase durations and slower stride frequencies characterized the Qatari male group. It is suggested that differences in PWS could be due to potential cultural factors (e.g., cultural clothing) differentiating the Qatari and non-Qatari groups. PWS values reported in this study also appear systematically lower when compared to Western references found in the literature. Findings suggest that the assessment of normative gait values needs to take both cultural habits and geographic disparity into account.

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