Walking with wider steps changes foot placement control, increases kinematic variability and does not improve linear stability
Walking humans respond to pulls or pushes on their upper body by changing where they place their foot on the next step. Usually, they place their foot further along the direction of the upper body perturbation. Here, we examine how this foot placement response is affected by the average step width d...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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The Royal Society
2017-01-01
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| Series: | Royal Society Open Science |
| Subjects: | |
| Online Access: | https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.160627 |
| _version_ | 1811323352186355712 |
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| author | Jennifer A. Perry Manoj Srinivasan |
| author_facet | Jennifer A. Perry Manoj Srinivasan |
| author_sort | Jennifer A. Perry |
| collection | DOAJ |
| description | Walking humans respond to pulls or pushes on their upper body by changing where they place their foot on the next step. Usually, they place their foot further along the direction of the upper body perturbation. Here, we examine how this foot placement response is affected by the average step width during walking. We performed experiments with humans walking on a treadmill, both normally and at five different prescribed step widths. We prescribed step widths by requiring subjects to step on lines drawn on the treadmill belt. We inferred a linear model between the torso marker state at mid-stance and the next foot position. The coefficients in this linear model (which are analogous to feedback gains for foot placement) changed with increasing step width as follows. The sideways foot placement response to a given sideways torso deviation decreased. The fore–aft foot placement response to a given fore–aft torso deviation also decreased. Coupling between fore–aft foot placement and sideways torso deviations increased. These changes in foot placement feedback gains did not significantly affect walking stability as quantified by Floquet multipliers (which estimate how quickly the system corrects a small perturbation), despite increasing foot placement variance and upper body motion variance (kinematic variability). |
| first_indexed | 2024-04-13T13:53:48Z |
| format | Article |
| id | doaj.art-b6b1bdf822524058b31eacd4868e577d |
| institution | Directory Open Access Journal |
| issn | 2054-5703 |
| language | English |
| last_indexed | 2024-04-13T13:53:48Z |
| publishDate | 2017-01-01 |
| publisher | The Royal Society |
| record_format | Article |
| series | Royal Society Open Science |
| spelling | doaj.art-b6b1bdf822524058b31eacd4868e577d2022-12-22T02:44:17ZengThe Royal SocietyRoyal Society Open Science2054-57032017-01-014910.1098/rsos.160627160627Walking with wider steps changes foot placement control, increases kinematic variability and does not improve linear stabilityJennifer A. PerryManoj SrinivasanWalking humans respond to pulls or pushes on their upper body by changing where they place their foot on the next step. Usually, they place their foot further along the direction of the upper body perturbation. Here, we examine how this foot placement response is affected by the average step width during walking. We performed experiments with humans walking on a treadmill, both normally and at five different prescribed step widths. We prescribed step widths by requiring subjects to step on lines drawn on the treadmill belt. We inferred a linear model between the torso marker state at mid-stance and the next foot position. The coefficients in this linear model (which are analogous to feedback gains for foot placement) changed with increasing step width as follows. The sideways foot placement response to a given sideways torso deviation decreased. The fore–aft foot placement response to a given fore–aft torso deviation also decreased. Coupling between fore–aft foot placement and sideways torso deviations increased. These changes in foot placement feedback gains did not significantly affect walking stability as quantified by Floquet multipliers (which estimate how quickly the system corrects a small perturbation), despite increasing foot placement variance and upper body motion variance (kinematic variability).https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.160627walkingstabilityfoot placementfeedback controlstep width |
| spellingShingle | Jennifer A. Perry Manoj Srinivasan Walking with wider steps changes foot placement control, increases kinematic variability and does not improve linear stability Royal Society Open Science walking stability foot placement feedback control step width |
| title | Walking with wider steps changes foot placement control, increases kinematic variability and does not improve linear stability |
| title_full | Walking with wider steps changes foot placement control, increases kinematic variability and does not improve linear stability |
| title_fullStr | Walking with wider steps changes foot placement control, increases kinematic variability and does not improve linear stability |
| title_full_unstemmed | Walking with wider steps changes foot placement control, increases kinematic variability and does not improve linear stability |
| title_short | Walking with wider steps changes foot placement control, increases kinematic variability and does not improve linear stability |
| title_sort | walking with wider steps changes foot placement control increases kinematic variability and does not improve linear stability |
| topic | walking stability foot placement feedback control step width |
| url | https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.160627 |
| work_keys_str_mv | AT jenniferaperry walkingwithwiderstepschangesfootplacementcontrolincreaseskinematicvariabilityanddoesnotimprovelinearstability AT manojsrinivasan walkingwithwiderstepschangesfootplacementcontrolincreaseskinematicvariabilityanddoesnotimprovelinearstability |