scholarly journals How accuracy of foot-placement is affected by the size of the base of support and crutch support in stroke survivors and healthy adults

2020 ◽  
Vol 76 ◽  
pp. 224-230 ◽  
Author(s):  
Susanne M. van der Veen ◽  
Ulrike Hammerbeck ◽  
Kristen L. Hollands
Keyword(s):  
Healthy Adults ◽  
Stroke Survivors ◽  
Foot Placement ◽  
Base Of Support

scholarly journals Foot-placement accuracy during planned and reactive target stepping during walking in stroke survivors and healthy adults

2020 ◽  
Vol 81 ◽  
pp. 261-267
Author(s):  
Susanne M. van der Veen ◽  
Ulrike Hammerbeck ◽  
Kristen L. Hollands
Keyword(s):  
Healthy Adults ◽  
Stroke Survivors ◽  
Foot Placement ◽  
Placement Accuracy

scholarly journals Associations Between Foot Placement Asymmetries and Metabolic Cost of Transport in Hemiparetic Gait

2016 ◽  
Vol 31 (2) ◽  
pp. 168-177 ◽  
Author(s):  
James M. Finley ◽  
Amy J. Bastian
Keyword(s):  
Walking Speed ◽  
Metabolic Cost ◽  
Positive Association ◽  
Stroke Survivor ◽  
Gas Analysis ◽  
Stroke Survivors ◽  
Cost Of Transport ◽  
Foot Placement ◽  
Hemiparetic Gait ◽  
All Speeds

Stroke survivors often have a slow, asymmetric walking pattern. They also walk with a higher metabolic cost than healthy, age-matched controls. It is often assumed that spatial-temporal asymmetries contribute to the increased metabolic cost of walking poststroke. However, elucidating this relationship is made challenging because of the interdependence between spatial-temporal asymmetries, walking speed, and metabolic cost. Here, we address these potential confounds by measuring speed-dependent changes in metabolic cost and implementing a recently developed approach to dissociate spatial versus temporal contributions to asymmetry in a sample of stroke survivors. We used expired gas analysis to compute the metabolic cost of transport (CoT) for each participant at 4 different walking speeds: self-selected speed, 80% and 120% of their self-selected speed, and their fastest comfortable speed. We also computed CoT for a sample of age- and gender-matched control participants who walked at the same speeds as their matched stroke survivor. Kinematic data were used to compute the magnitude of a number of variables characterizing spatial-temporal asymmetries. Across all speeds, stroke survivors had a higher CoT than controls. We also found that our sample of stroke survivors did not choose a self-selected speed that minimized CoT, contrary to typical observations in healthy controls. Multiple regression analyses revealed negative associations between speed and CoT and a positive association between asymmetries in foot placement relative to the trunk and CoT. These findings suggest that interventions designed to increase self-selected walking speed and reduce foot-placement asymmetries may be ideal for improving walking economy poststroke.

scholarly journals Measurement of passive ankle stiffness in subjects with chronic hemiparesis using a novel ankle robot

2011 ◽  
Vol 105 (5) ◽  
pp. 2132-2149 ◽  
Author(s):  
Anindo Roy ◽  
Hermano I. Krebs ◽  
Christopher T. Bever ◽  
Larry W. Forrester ◽  
Richard F. Macko ◽  
...  
Keyword(s):  
Ankle Joint ◽  
Frontal Plane ◽  
Chronic Stroke ◽  
Healthy Adults ◽  
Stroke Survivors ◽  
Passive Stiffness ◽  
Mechanical Stiffness ◽  
Treatment Protocols ◽  
Ankle Stiffness ◽  
Hemiparetic Stroke

Our objective in this study was to assess passive mechanical stiffness in the ankle of chronic hemiparetic stroke survivors and to compare it with those of healthy young and older (age-matched) individuals. Given the importance of the ankle during locomotion, an accurate estimate of passive ankle stiffness would be valuable for locomotor rehabilitation, potentially providing a measure of recovery and a quantitative basis to design treatment protocols. Using a novel ankle robot, we characterized passive ankle stiffness both in sagittal and in frontal planes by applying perturbations to the ankle joint over the entire range of motion with subjects in a relaxed state. We found that passive stiffness of the affected ankle joint was significantly higher in chronic stroke survivors than in healthy adults of a similar cohort, both in the sagittal as well as frontal plane of movement, in three out of four directions tested with indistinguishable stiffness values in plantarflexion direction. Our findings are comparable to the literature, thus indicating its plausibility, and, to our knowledge, report for the first time passive stiffness in the frontal plane for persons with chronic stroke and older healthy adults.

Validating Determinants for an Alternate Foot Placement Selection Algorithm During Human Locomotion in Cluttered Terrain

2007 ◽  
Vol 98 (4) ◽  
pp. 1928-1940 ◽  
Author(s):  
Renato Moraes ◽  
Fran Allard ◽  
Aftab E. Patla
Keyword(s):  
Dynamic Stability ◽  
Center Of Mass ◽  
Frontal Plane ◽  
Human Locomotion ◽  
The Body ◽  
Selection Algorithm ◽  
Foot Placement ◽  
Double Support ◽  
One Step ◽  
Base Of Support

The goal of this study was to validate dynamic stability and forward progression determinants for the alternate foot placement selection algorithm. Participants were asked to walk on level ground and avoid stepping, when present, on a virtual white planar obstacle. They had a one-step duration to select an alternate foot placement, with the task performed under two conditions: free (participants chose the alternate foot placement that was appropriate) and forced (a green arrow projected over the white planar obstacle cued the alternate foot placement). To validate the dynamic stability determinant, the distance between the extrapolated center of mass (COM) position, which incorporates the dynamics of the body, and the limits of the base of support was calculated in both anteroposterior (AP) and mediolateral (ML) directions in the double support phase. To address the second determinant, COM deviation from straight ahead was measured between adaptive and subsequent steps. The results of this study showed that long and lateral choices were dominant in the free condition, and these adjustments did not compromise stability in both adaptive and subsequent steps compared with the short and medial adjustments, which were infrequent and adversely affected stability. Therefore stability is critical when selecting an alternate foot placement in a cluttered terrain. In addition, changes in the plane of progression resulted in small deviations of COM from the endpoint goal. Forward progression of COM was maintained even for foot placement changes in the frontal plane, validating this determinant as part of the selection algorithm.

scholarly journals The critical phase for visual control of human walking over complex terrain

2017 ◽  
Vol 114 (32) ◽  
pp. E6720-E6729 ◽  
Author(s):  
Jonathan Samir Matthis ◽  
Sean L. Barton ◽  
Brett R. Fajen
Keyword(s):  
Complex Terrain ◽  
Visual Information ◽  
Center Of Mass ◽  
Ground Surface ◽  
The Body ◽  
Foot Placement ◽  
Preceding Step ◽  
Control Work ◽  
Base Of Support ◽  
Target Visibility

To walk efficiently over complex terrain, humans must use vision to tailor their gait to the upcoming ground surface without interfering with the exploitation of passive mechanical forces. We propose that walkers use visual information to initialize the mechanical state of the body before the beginning of each step so the resulting ballistic trajectory of the walker’s center-of-mass will facilitate stepping on target footholds. Using a precision stepping task and synchronizing target visibility to the gait cycle, we empirically validated two predictions derived from this strategy: (1) Walkers must have information about upcoming footholds during the second half of the preceding step, and (2) foot placement is guided by information about the position of the target foothold relative to the preceding base of support. We conclude that active and passive modes of control work synergistically to allow walkers to negotiate complex terrain with efficiency, stability, and precision.

scholarly journals A novel Movement Amplification environment reveals effects of controlling lateral centre of mass motion on gait stability and metabolic cost

2020 ◽  
Vol 7 (1) ◽  
pp. 190889
Author(s):  
Mengnan/Mary Wu ◽  
Geoffrey L. Brown ◽  
Jane L. Woodward ◽  
Sjoerd M. Bruijn ◽  
Keith E. Gordon
Keyword(s):  
Metabolic Cost ◽  
Mass Motion ◽  
Step Width ◽  
Centre Of Mass ◽  
Cost Of Transport ◽  
Gait Patterns ◽  
Gait Stability ◽  
Foot Placement ◽  
Base Of Support ◽  
Healthy Participants

During human walking, the centre of mass (COM) laterally oscillates, regularly transitioning its position above the two alternating support limbs. To maintain upright forward-directed walking, lateral COM excursion should remain within the base of support, on average. As necessary, humans can modify COM motion through various methods, including foot placement. How the nervous system controls these oscillations and the costs associated with control are not fully understood. To examine how lateral COM motions are controlled, healthy participants walked in a ‘Movement Amplification’ force field that increased lateral COM momentum in a manner dependent on the participant's own motion (forces were applied to the pelvis proportional to and in the same direction as lateral COM velocity). We hypothesized that metabolic cost to control lateral COM motion would increase with the gain of the field. In the Movement Amplification field, participants were significantly less stable than during baseline walking. Stability significantly decreased as the field gain increased. Participants also modified gait patterns, including increasing step width, which increased the metabolic cost of transport as the field gain increased. These results support previous research suggesting that humans modulate foot placement to control lateral COM motion, incurring a metabolic cost.

Investigating Center-of-Pressure Based Parameters to Quantify Athlete and Non-Athlete Balance

2016 ◽  
Author(s):  
Lara A. Thompson ◽  
Mehdi Badache
Keyword(s):  
Time Series ◽  
Visual Cues ◽  
Center Of Pressure ◽  
Standing Balance ◽  
Body Sway ◽  
Foot Placement ◽  
Eyes Closed ◽  
Position Time Series ◽  
Eyes Open ◽  
Base Of Support

Through ground reaction (foot) forceplate-based, center-of-pressure (COP) parameters, we aimed to investigate differences in standing balance for young, healthy individuals from both athlete (soccer) and non-athlete subject populations. We investigated five, COP displacement and velocity parameters derived from the COP position time series. Soccer athlete and non-athlete subjects performed standing balance for postural tasks of increasing difficulty levels, by varying visual cues (eyes-open/eyes-closed) and base of support (wide/tandem foot placement), leading to four test conditions: 1) wide/eyes-open, 2) wide/eyes-closed, 3) tandem/eyes-open, 4) tandem/eyes-closed. By investigating position and velocity characteristics of the COP position time series, we observed that the soccer athletes had generally lower COP displacement and velocity parameters (meaning they were more stable and perhaps better able to control their body sway) than the non-athletes. This study lends new insights as to how parameters derived from the COP position can be utilized to determine differences in balance between normal subject populations (e.g., athletes versus non-athletes).

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