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Van den Borre I, Peiffer M, Huysentruyt R, Huyghe M, Vervelghe J, Pizurica A, Audenaert EA, Burssens A. Development and validation of a fully automated tool to quantify 3D foot and ankle alignment using weight-bearing CT. Gait Posture 2024; 113:67-74. [PMID: 38850852 DOI: 10.1016/j.gaitpost.2024.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 05/08/2024] [Accepted: 05/27/2024] [Indexed: 06/10/2024]
Abstract
INTRODUCTION Foot and ankle alignment plays a pivotal role in human gait and posture. Traditional assessment methods, relying on 2D standing radiographs, present limitations in capturing the dynamic 3D nature of foot alignment during weight-bearing and are prone to observer error. This study aims to integrate weight-bearing CT (WBCT) imaging and advanced deep learning (DL) techniques to automate and enhance quantification of the 3D foot and ankle alignment. METHODS Thirty-two patients who underwent a WBCT of the foot and ankle were retrospectively included. After training and validation of a 3D nnU-Net model on 45 cases to automate the segmentation into bony models, 35 clinically relevant 3D measurements were automatically computed using a custom-made tool. Automated measurements were assessed for accuracy against manual measurements, while the latter were analyzed for inter-observer reliability. RESULTS DL-segmentation results showed a mean dice coefficient of 0.95 and mean Hausdorff distance of 1.41 mm. A good to excellent reliability and mean prediction error of under 2 degrees was found for all angles except the talonavicular coverage angle and distal metatarsal articular angle. CONCLUSION In summary, this study introduces a fully automated framework for quantifying foot and ankle alignment, showcasing reliability comparable to current clinical practice measurements. This operator-friendly and time-efficient tool holds promise for implementation in clinical settings, benefiting both radiologists and surgeons. Future studies are encouraged to assess the tool's impact on streamlining image assessment workflows in a clinical environment.
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Affiliation(s)
- Ide Van den Borre
- Department of Telecommunications and Information Processing, Group for Artificial Intelligence and Sparse Modelling (GAIM), Ghent University, St-Pietersnieuwstraat 41, Gent, OVL B-9000, Belgium
| | - Matthias Peiffer
- Department of Orthopaedics, Ghent University Hospital, Corneel Heymanslaan 10, Gent, OVL 9000, Belgium; Foot and Ankle Research and Innovation Lab (FARIL), Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, USA
| | - Roel Huysentruyt
- Department of Orthopaedics, Ghent University Hospital, Corneel Heymanslaan 10, Gent, OVL 9000, Belgium
| | - Manu Huyghe
- Department of Orthopaedics, Ghent University Hospital, Corneel Heymanslaan 10, Gent, OVL 9000, Belgium
| | - Jean Vervelghe
- Department of Orthopaedics, Ghent University Hospital, Corneel Heymanslaan 10, Gent, OVL 9000, Belgium
| | - Aleksandra Pizurica
- Department of Telecommunications and Information Processing, Group for Artificial Intelligence and Sparse Modelling (GAIM), Ghent University, St-Pietersnieuwstraat 41, Gent, OVL B-9000, Belgium
| | - Emmanuel A Audenaert
- Department of Orthopaedics, Ghent University Hospital, Corneel Heymanslaan 10, Gent, OVL 9000, Belgium
| | - Arne Burssens
- Department of Orthopaedics, Ghent University Hospital, Corneel Heymanslaan 10, Gent, OVL 9000, Belgium.
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Molitor SL, Neptune RR. Lower-limb joint quasi-stiffness in the frontal and sagittal planes during walking at different step widths. J Biomech 2024; 162:111897. [PMID: 38103312 DOI: 10.1016/j.jbiomech.2023.111897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 11/28/2023] [Accepted: 12/04/2023] [Indexed: 12/19/2023]
Abstract
Quasi-stiffness describes the intersegmental joint moment-angle relationship throughout the progression of a task. Previous work has explored sagittal-plane ankle quasi-stiffness and its application for the development of powered lower-limb assistive devices. However, frontal-plane quasi-stiffness remains largely unexplored but has important implications for the development of exoskeletons since clinical populations often walk with wider steps and rely on frontal-plane balance recovery strategies at the hip and ankle. This study aimed to characterize frontal-plane hip and ankle quasi-stiffness during walking and determine how step width affects quasi-stiffness in both the frontal and sagittal planes. Kinematic and kinetic data were collected and quasi-stiffness values computed for healthy young adults (n = 15) during treadmill walking across a range of step widths. We identified specific subphases of the gait cycle that exhibit linear and quadratic frontal-plane quasi-stiffness approximations for the hip and ankle, respectively. In addition, we found that at wider step widths, sagittal-plane ankle quasi-stiffness increased during early stance (∼12-35% gait cycle), sagittal-plane hip quasi-stiffness decreased in late stance (∼40-55% gait cycle) and frontal-plane hip quasi-stiffness decreased during terminal stance (∼48-65% gait cycle). These results provide a framework for further exploration of frontal-plane quasi-stiffness, lend insight into how quasi-stiffness may relate to balance control at various step widths, and motivate the development of stiffness-modulating assistive devices to improve balance related outcomes.
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Affiliation(s)
- Stephanie L Molitor
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Richard R Neptune
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, USA.
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van Duijnhoven E, van der Veen M, Koopman FS, Nollet F, Bruijn SM, Brehm MA. Gait stability and the relationship with energy cost of walking in polio survivors with unilateral plantarflexor weakness. Gait Posture 2024; 107:104-111. [PMID: 37801868 DOI: 10.1016/j.gaitpost.2023.09.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 09/13/2023] [Accepted: 09/28/2023] [Indexed: 10/08/2023]
Abstract
BACKGROUND Polio survivors often exhibit plantarflexor weakness, which impairs gait stability, and increases energy cost of walking. Quantifying gait stability could provide insights in the control mechanisms polio survivors use to maintain gait stability and in whether impaired gait stability is related to the increased energy cost of walking. RESEARCH QUESTION Is gait stability impaired in polio survivors with plantarflexor weakness compared to able-bodied individuals, and does gait stability relate to energy cost of walking? METHODS We retrospectively analyzed barefoot biomechanical gait data of 31 polio survivors with unilateral plantarflexor weakness and of 24 able-bodied individuals. We estimated gait stability by calculating variability (SD) of step width, step length, double support time, and stance time, and by the mean and variability (SD) of the mediolateral and anteroposterior margin of stability (MoSML and MoSAP). In addition, energy cost of walking (polio survivors only) at comfortable speed was analyzed. RESULTS Comfortable speed was 31% lower in polio survivors compared to able-bodied individuals (p < 0.001). Corrected for speed differences, step width variability was significantly larger in polio survivors (+41%), double support time variability was significantly smaller (-27%), MoSML (affected leg) was significantly larger (+80%), and MoSAP was significantly smaller (affected leg:-17% and non-affected leg:-15%). Step width and step length variability (affected leg) were positively correlated with energy cost of walking (r = 0.502 and r = 0.552). MoSAP (non-affected leg) was negatively correlated with energy cost of walking (r = -0.530). SIGNIFICANCE Polio survivors with unilateral plantarflexor weakness demonstrated an impaired gait stability. Increased step width and step length variability and lower MoSAP could be factors related to the elevated energy cost of walking in polio survivors. These findings increase our understanding of stability problems due to plantarflexor weakness, which could be used for the improvement of (orthotic) interventions to enhance gait stability and reduce energy cost in polio survivors.
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Affiliation(s)
- Elza van Duijnhoven
- Amsterdam UMC location University of Amsterdam, Department of Rehabilitation Medicine, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Movement Sciences, Rehabilitation & Development, Amsterdam, the Netherlands.
| | - Marit van der Veen
- Amsterdam UMC location University of Amsterdam, Department of Rehabilitation Medicine, Meibergdreef 9, Amsterdam, the Netherlands
| | - Fieke S Koopman
- Amsterdam UMC location University of Amsterdam, Department of Rehabilitation Medicine, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Movement Sciences, Rehabilitation & Development, Amsterdam, the Netherlands
| | - Frans Nollet
- Amsterdam UMC location University of Amsterdam, Department of Rehabilitation Medicine, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Movement Sciences, Rehabilitation & Development, Amsterdam, the Netherlands
| | - Sjoerd M Bruijn
- Amsterdam Movement Sciences, Rehabilitation & Development, Amsterdam, the Netherlands; Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Merel-Anne Brehm
- Amsterdam UMC location University of Amsterdam, Department of Rehabilitation Medicine, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Movement Sciences, Rehabilitation & Development, Amsterdam, the Netherlands
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Brough LG, Neptune RR. Individual muscle responses to mediolateral foot placement perturbations during walking. J Biomech 2022; 141:111201. [PMID: 35764014 DOI: 10.1016/j.jbiomech.2022.111201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 05/18/2022] [Accepted: 06/13/2022] [Indexed: 10/18/2022]
Abstract
Walking requires active control of frontal plane balance through adjustments to mediolateral foot placement and ground reaction forces. Previous work on mediolateral balance perturbations and control of foot placement has often focused on the bilateral gluteus medius muscles. However, additional leg and trunk muscles can influence foot placement by transferring power to the foot and pelvis during swing. Thus, the purpose of this study was to determine individual muscle contributions to balance control following medial and lateral foot placement perturbations. Ten participants performed treadmill walking trials which included perturbations immediately before randomized heel strikes. Muscle contributions to foot placement, ground reaction forces, trunk power and frontal plane external moments during representative perturbed and unperturbed gait cycles were estimated using musculoskeletal modeling and simulation. Net muscle contributions to foot placement were 61 ± 50% more medial during the first recovery step following lateral perturbations and 28 ± 14% less medial in the second recovery step following medial perturbations. Following lateral perturbations, the swing gluteus medius performed 57 ± 50% more lateral work and the stance gluteus medius performed 61 ± 50% more medial work on the foot. Following medial perturbations, the erector spinae performed 39 ± 33% less lateral work on the foot. Changes in net muscle work on the foot were inconsistent with changes in step width, suggesting that changes in step width were not due to active muscle control but rather the mechanical effect of the perturbation. These outcomes provide a foundation for future studies analyzing balance control in populations at risk of falling.
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Affiliation(s)
- Lydia G Brough
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, USA.
| | - Richard R Neptune
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, USA
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Muscle contributions to pre-swing biomechanical tasks influence swing leg mechanics in individuals post-stroke during walking. J Neuroeng Rehabil 2022; 19:55. [PMID: 35659252 PMCID: PMC9166530 DOI: 10.1186/s12984-022-01029-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 05/18/2022] [Indexed: 11/16/2022] Open
Abstract
Background Successful walking requires the execution of the pre-swing biomechanical tasks of body propulsion and leg swing initiation, which are often impaired post-stroke. While excess rectus femoris activity during swing is often associated with low knee flexion, previous work has suggested that deficits in propulsion and leg swing initiation may also contribute. The purpose of this study was to determine underlying causes of propulsion, leg swing initiation and knee flexion deficits in pre-swing and their link to stiff knee gait in individuals post-stroke. Methods Musculoskeletal models and forward dynamic simulations were developed for individuals post-stroke (n = 15) and healthy participants (n = 5). Linear regressions were used to evaluate the relationships between peak knee flexion, braking and propulsion symmetry, and individual muscle contributions to braking, propulsion, knee flexion in pre-swing, and leg swing initiation. Results Four out of fifteen of individuals post-stroke had higher plantarflexor contributions to propulsion and seven out of fifteen had higher vasti contributions to braking on their paretic leg relative to their nonparetic leg. Higher gastrocnemius contributions to propulsion predicted paretic propulsion symmetry (p = 0.005) while soleus contributions did not. Higher vasti contributions to braking in pre-swing predicted lower knee flexion (p = 0.022). The rectus femoris had minimal contributions to lower knee flexion acceleration in pre-swing compared to contributions from the vasti. However, for some individuals with low knee flexion, during pre-swing the rectus femoris absorbed more power and the iliopsoas contributed less power to the paretic leg. Total musculotendon work done on the paretic leg in pre-swing did not predict knee flexion during swing. Conclusions These results emphasize the multiple causes of propulsion asymmetry in individuals post-stroke, including low plantarflexor contributions to propulsion, increased vasti contributions to braking and reliance on compensatory mechanisms. The results also show that the rectus femoris is not a major contributor to knee flexion in pre-swing, but absorbs more power from the paretic leg in pre-swing in some individuals with stiff knee gait. These results highlight the need to identify individual causes of propulsion and knee flexion deficits to design more effective rehabilitation strategies. Supplementary Information The online version contains supplementary material available at 10.1186/s12984-022-01029-z.
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Task-prioritization and balance recovery strategies used by young healthy adults during dual-task walking. Gait Posture 2022; 95:115-120. [PMID: 35472735 DOI: 10.1016/j.gaitpost.2022.04.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 03/30/2022] [Accepted: 04/13/2022] [Indexed: 02/02/2023]
Abstract
BACKGROUND Maintaining dynamic balance is an essential task during walking, with foot-placement playing a critical role. Dual-task studies analyzing steady-state walking with cognitive loads have found healthy adults prioritize cognitive task performance at the expense of maintaining control of their balance. However, few studies have focused on the influence of cognitive loads on more difficult motor tasks, such as walking with unexpected foot-placement perturbations. Individuals often recover from a loss of balance using an ankle or hip strategy; however, how cognitive loads affect these balance recovery strategies remains unknown. RESEARCH QUESTION How do individuals prioritize cognitive resources and does the balance recovery strategy used change following mediolateral foot-placement perturbations during steady-state walking when performing cognitive tasks of increasing difficulty? METHODS Fifteen young healthy adults walked during unperturbed and perturbed conditions with increasing cognitive loads (no cognitive load, attentive listening, spelling short words backwards and spelling long words backwards). No specific task-prioritization instructions were given. Medial and lateral foot-placement perturbations were applied prior to heel-strike during random steps. RESULTS Cognitive performance decreased between the unperturbed and perturbed conditions. While balance control decreased during perturbed relative to unperturbed walking, the additional cognitive load had little effect on balance control during the perturbations. Lastly, the balance recovery strategy used, as measured by peak joint moments at the ankle and hip, was unaffected by the additional cognitive loads. SIGNIFICANCE Individuals appear to prioritize their balance control over cognitive performance when experiencing foot-placement perturbations and do not change their balance recovery strategy with the addition of a cognitive load. These results highlight the flexibility of task-prioritization in young adults and provide a foundation for future studies analyzing neurologically impaired populations.
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Differences in Muscle Demand and Joint Contact Forces Between Running and Skipping. J Appl Biomech 2022; 38:382-390. [DOI: 10.1123/jab.2022-0011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 06/28/2022] [Accepted: 08/19/2022] [Indexed: 11/15/2022]
Abstract
Skipping has been proposed as a viable cross-training exercise to running due to its lower knee contact forces and higher whole-body energy expenditure. However, how individual muscle forces, energy expenditure, and joint loading are affected by differences in running and skipping mechanics remains unclear. The purpose of this study was to compare individual muscle forces, energy expenditure, and lower extremity joint contact forces between running and skipping using musculoskeletal modeling and simulations of young adults (n = 5) performing running and skipping at 2.5 m·s−1 on an instrumented treadmill. In agreement with previous work, running had greater knee and patella contact forces than skipping which was accompanied by greater knee extensor energetic demand. Conversely, skipping had greater ankle contact forces and required greater energetic demand from the uniarticular ankle plantarflexors. There were no differences in hip contact forces between gaits. These findings further support skipping as a viable alternative to running if the primary goal is to reduce joint loading at the commonly injured patellofemoral joint. However, for those with ankle injuries, skipping may not be a viable alternative due to the increased ankle loads. These findings may help clinicians prescribe activities most appropriate for a patient’s individual training or rehabilitation goals.
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The immediate effect of foot orthoses on gluteal and lower limb muscle activity during overground walking in healthy young adults. Gait Posture 2021; 89:102-108. [PMID: 34265525 DOI: 10.1016/j.gaitpost.2021.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 06/21/2021] [Accepted: 07/04/2021] [Indexed: 02/02/2023]
Abstract
BACKGROUND Although foot orthoses are often used in the management of lower limb musculoskeletal conditions, their effects on muscle activation is unclear, especially in more proximal segments of the lower limb. RESEARCH QUESTION Primary aim: Is there an immediate effect of foot orthoses on gluteal muscle activity during overground walking in healthy young adults? Secondary aim: Is there an immediate effect of foot orthoses on the activity of hamstring, quadriceps and calf muscles? METHODS In eighteen healthy young adults, muscle activity was recorded using fine wire electrodes for gluteus minimus (GMin; anterior, posterior) and gluteus medius (GMed; anterior, middle, posterior); and surface electrodes for gluteus maximus (GMax), hamstring, quadriceps and calf muscles. Participants completed six walking trials for two conditions; shoe and shoe with prefabricated foot orthoses. Muscle activity was normalised to the peak activity of the shoe condition and analysed using one-dimensional statistical non-parametric mapping to identify differences across the gait cycle. RESULTS Activity of GMed (anterior, middle, posterior) and GMin (posterior) was reduced in early stance phase when the orthosis was worn in the shoe (p < 0.05). GMin (anterior) activity was significantly reduced during swing (p < 0.05). Muscle activity was also significantly reduced during the orthoses condition for the lateral hamstrings and calf muscles (p < 0.05). SIGNIFICANCE Using foot orthoses may provide a strategy to reduce demand on GMin, GMed, lateral hamstring and calf muscles while walking.
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Parker CJ, Guerin H, Buchanan B, Lewek MD. Targeted verbal cues can immediately alter gait following stroke. Top Stroke Rehabil 2021; 29:382-391. [PMID: 34027831 DOI: 10.1080/10749357.2021.1928840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Background: Physical therapists use verbal cueing extensively during gait rehabilitation. Nevertheless, little is known about the ability of individuals post-stroke to make immediate changes to targeted spatiotemporal gait parameters from verbal commands. Additionally, adequate muscle strength may be necessary to promote positive alterations in gait.Objectives: To determine the influence of targeted verbal cues on spatiotemporal gait parameters for individuals with chronic stroke. Further, we assessed the potential of a relationship between cue-induced gait modifications and paretic lower limb strength.Methods: Using a within-subjects design, twenty-seven adults with chronic stroke walked over a pressure mat with verbal cues to walk at (1) comfortable and (2) fast speeds, with increased (3) arm swing, (4) foot height, (5) step length, (6) push off, and (7) cadence. We also assessed lower extremity strength using a hand-held dynamometer. We measured gait speed, step length, stance time, and cadence for comparisons between conditions and performed correlational analyses to assess the influence of strength on gait alterations.Results: Specific cues elicited increased walking speed, cadence, step lengths and paretic limb stance time. Only greater paretic hip and knee flexion strength was related to the ability to increase cadence when cued to do so (r > 0.41).Conclusion: With targeted verbal cueing, clinicians can improve step length, gait speed, stance time and cadence for individuals with chronic stroke. Lower extremity strength does not appear to be related to the ability to alter gait with verbal cueing in individuals with chronic stroke.
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Affiliation(s)
- Chelsea J Parker
- Human Movement Science Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Hailey Guerin
- Division of Physical Therapy, Department of Allied Health Sciences, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Ben Buchanan
- Division of Physical Therapy, Department of Allied Health Sciences, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Michael D Lewek
- Human Movement Science Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Division of Physical Therapy, Department of Allied Health Sciences, University of North Carolina at Chapel Hill, Chapel Hill, United States
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Dragunas AC, Cornwell T, Lopez-Rosado R, Gordon KE. Post-Stroke Adaptation of Lateral Foot Placement Coordination in Variable Environments. IEEE Trans Neural Syst Rehabil Eng 2021; 29:731-739. [PMID: 33835919 PMCID: PMC8115208 DOI: 10.1109/tnsre.2021.3072252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Individuals with stroke often have difficulty modulating their lateral foot placement during gait, a primary strategy for maintaining lateral stability. Our purpose was to understand how individuals with and without stroke adapt their lateral foot placement when walking in an environment that alters center of mass (COM) dynamics and the mechanical requirement to maintain lateral stability. The treadmill walking environments included: 1) a Null Field – where no forces were applied, and 2) a Damping Field – where external forces opposed lateral COM velocity. To evaluate the response to the changes in environment, we quantified the correlation between lateral COM state and lateral foot placement (FP), as well as step width mean and variability. We hypothesized the Damping Field would produce a stabilizing effect and reduce both the COM-FP correlation strength and step width compared to the Null Field. We also hypothesized that individuals with stroke would have a significantly weaker COM-FP correlation than individuals without stroke. Surprisingly, we found no differences in COM-FP correlations between the Damping and Null Fields. We also found that compared to individuals without stroke in the Null Field, individuals with stroke had weaker COM-FP correlations (Paretic < Control: p = 0.001, Non-Paretic < Control: p = 0.007) and wider step widths (p = 0.001). Our results suggest that there is a post-stroke shift towards a non-specific lateral stabilization strategy that relies on wide steps that are less correlated to COM dynamics than in individuals without stroke.
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Biomechanical response to mediolateral foot-placement perturbations during walking. J Biomech 2020; 116:110213. [PMID: 33465580 DOI: 10.1016/j.jbiomech.2020.110213] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 09/14/2020] [Accepted: 12/11/2020] [Indexed: 11/20/2022]
Abstract
Dynamic balance in the frontal plane requires active control, which is accomplished largely through control of mediolateral foot placement. Individuals without mobility impairments have the ability to compensate for variability in foot-placement to maintain their balance; however, it is unknown how individuals respond to unexpected mediolateral perturbations to their foot placement that alter their balance control. The purpose of this study was to identify the biomechanical responses of individuals without mobility impairments to medial and lateral foot-placement perturbations during walking. Three-dimensional body segment kinematic and ground reaction force data were collected from 15 participants at 1.0 m/s and their self-selected speed on an instrumented treadmill. Dynamic balance was assessed by analyzing whole-body angular momentum in the frontal plane. We hypothesized that participants would respond to the perturbations with a combination of a lateral ankle strategy, hip adduction strategy and/or ankle push-off strategy to restore their balance. Overall, the medial perturbations adversely affected dynamic balance while lateral perturbations had little effect. Individuals responded to medial (lateral) perturbations with an increased (decreased) ankle inversion moment, which correlated to lateral (medial) shifts in their foot center of pressure. In addition, individuals responded to medial (lateral) perturbations with a decreased (slightly decreased) hip abduction moment. Contrary to our hypothesis, we did not observe an ankle push-off moment response but rather, a small response in the opposite direction. These results highlight the response of individuals without mobility impairments to unexpected foot-placement perturbations and provide a basis of comparison for those with impaired balance control.
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