Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | Faculty of Health and Social Sciences | en_US |
| dc.contributor.advisor | Tsang, Sharon (RS) | en_US |
| dc.contributor.advisor | Kwong, Patrick (RS) | en_US |
| dc.contributor.advisor | Cheing, Gladys (RS) | en_US |
| dc.creator | Chan, Suk Ping | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/14186 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | en_US |
| dc.rights | All rights reserved | en_US |
| dc.title | Biomechanical characteristics of compensatory reactive step responding to the simulated trip perturbation while walking in community-dwelling people with stroke | en_US |
| dcterms.abstract | Background and Purpose | en_US |
| dcterms.abstract | The prevalence of falls following stroke is high, particularly among community-dwelling patients who are discharged home and encounter challenges with a higher functional demand. The previous literature provides useful information and identify the relevant biomechanical characteristics associated with fall risk in stroke survivors. Existing evidence has investigated stance perturbation in individuals with stroke and reported that various biomechanical characteristics contribute to falls. However, it falls short of providing clear and clinically meaningful distinctions in reactive control during gait trip perturbations in stroke individuals. To address this gap, the research proposed and studied in this work aimed to investigate the specific full-body biomechanics by utilizing the simulated trip perturbation implemented during walking, amongst community-dwelling participants with stroke. This approach would provide a more comprehensive and specific knowledge for identification of unique patterns of biomechanics responses that potentially differentiates between participants with stroke and individuals of healthy control. Findings of this study would help inform the refinement of the clinical evaluation and rehabilitation that target to minimize the risk of falls in stroke survivors when they reintegrated themselves to their daily functional activities in the real-world scenarios and the associated demands and challenges to their postural balance and coordination system. | en_US |
| dcterms.abstract | Reactive stepping impairment is a prevalent problem for individuals with ambulatory stroke. The ability to execute effective reactive recovery step is crucial for coping with unexpected gait perturbations and maintaining safe locomotion. Providing effective fall prevention measures must be given top priority in order to facilitate the successful social reintegration of participants with stroke and improve their capacity to resume regular social activities, while decreasing the danger of falls, a better understanding of the biomechanical characteristics contributing to falls, through assessment of the high-risk group of independent walkers among community-dwelling stroke patients is therefore necessary. In addition, the significance of biomechanical characteristics displayed by the participants with stroke at specific phases expressed in the corresponding joint angular time profile such as trunk, shoulder and ankle angles or ankle moment for example, were crucial for understanding the multi-joint movement dynamics and identifying potential contributors to functional impairments, such as the risk of falls in participants with stroke. The identification of certain critical phases of the reactive step cycle might correspond to critical and timely control of the body system to maintain stability and balance upon perturbations. Examining the joint angular profiles at specific phases could also help identify these phase-specific compensatory strategies or movement patterns that displayed as the coping strategies developed to overcome the impairments associated with the stroke. Analyzing the joint angular time profiles could provide crucial information on the timing and coordination of joint contributions, which might be disrupted in patients with stroke and contribute to increase in fall risk. It could also help refining the evaluation of these compensatory strategies by pinpointing the specific phases where impaired joint moment take place. Specific phases of the decreasing moment during reactive step might lead to instability, or increased risk of falls if such deficits compromise the efficacy of the balance control of the individuals. By examining the biomechanical characteristics at specified phases of the joint angular time profile, researchers and clinicians could gain valuable insights into the control strategies and movement patterns of participants with stroke. This information could then be applied clinically to develop the more sensitive and specific stratification for fall risk screening, as well as individualized training for rehabilitation of the community-dwelling patients with stroke which aimed to improve their functional capacity and reduce the risk of falls. | en_US |
| dcterms.abstract | Findings from this study would provide valuable insights that can ultimately lead to the development of more accurate and clinically useful fall risk assessment tools. This knowledge could potentially contribute to the refinement of the current interventions to further mitigate the risk of falls and support the stroke survivors' safe participation in their communities and daily activities with greater efficacy. The aim of the present study was to compare the biomechanical characteristics in reactive step during the simulated trip gait perturbation implemented on the affected side (side of the participants with stroke with paralysis) of the leg for community-dwelling participants with stroke and non-dominant side of the leg for healthy control when regular walking at their self-selected usual walking speed on the side-split treadmill system. There were three objectives under examination in this cross-sectional comparative study, which included 1) to compare the biomechanical characteristics in reactive step during the simulated trip perturbation while walking for community-dwelling participants with stroke and age- and gender-matched healthy controls; 2) to determine the correlation between Berg Balance Scale (BBS) and biomechanical characteristics of reactive step during a trip simulating gait perturbation for the relevance to fall risk in the community-dwelling participants with stroke; 3) to determine the difference in the joint angular time profiles between community-dwelling participants with stroke and healthy controls. | en_US |
| dcterms.abstract | Methods | en_US |
| dcterms.abstract | Fourteen community-dwelling participants with an age range equals to or greater than 18 and younger than 60 years old and diagnosis of stroke were recruited. Convenient sampling of ten age- and gender-matched healthy participants as control group were also recruited. | en_US |
| dcterms.abstract | The spinal and limb kinetics and kinematics parameters in response to unexpected trip simulating perturbation and reactive stepping were obtained by a 16-camera Vicon Nexus 2 system (Vicon Motion Systems Limited, USA). Thirty-nine passive reflective markers were positioned on the specified body landmarks for model reconstruction. Biomechanical parameters were calculated by the Vicon Plug-in-Gait full-body model (Vicon Nexus 2 Version). The trip reactive step simulation protocol was administered using the SBT (Bertec Corporation, USA) with side-split dual belt. | en_US |
| dcterms.abstract | The biomechanical responses of the whole-body system to the simulated trip perturbation implemented over the affected side (side of the participants with stroke with paralysis) or non-dominant limbs' side for participants in the healthy control group respectively, using the standard acceleration protocol with a former study well-defined in and same used procedure among the participants while walking at their self-selected usual walking speed on the split belt treadmill (SBT). The trip like perturbation was conducted with referencing the acceleration of the treadmill belt protocol of the previous research in stance perturbation on a motorized conventional treadmill for individuals with stroke and healthy controls. The participants were subjected to a familiarization trip as warm up trial with aiming with experiencing the participant to a trip simulating perturbation at individual self-selected usual walking speed plus the speed of protocol of 0.67 m/s and with an acceleration of 16.75 m/s². This would have been followed by everyone receiving a true perturbation testing trial at a mild increased intensity of 0.77 m/s with an acceleration of 19.24 m/s² in addition to their self-selected usual walking speed. A two-fold measures were applied to ensure the safe implementation of the testing procedure. An overhead suspension harness was used to secure the safety for the participants while preventing the knees of the participant from landing onto the treadmill belt in case of losing balance during the walking trials as well as during the trip simulation as the safety measure. In addition, an emergency stop that was placed at the front handrail within the reachable distance of the participants to reinforce the safety measure of the testing procedure. Participants were instructed to press the emergency stop button to initiate the immediate halting of the treadmill if they experienced problem to regain balance during the reactive step triggered by the simulated trip perturbation trials. Biomechanical parameters of the trunk, bilateral legs and arms relating to the reactive step of the participants for the simulated trip perturbation were compared between participants with stroke and the age- and gender-matched healthy controls. Other outcome measures of BBS and The National Institutes of Health Stroke Scale (NIHSS) were also captured. The comparative analyses of the balance score and biomechanics of the reactive step were determined. Correlation between BBS score and biomechanics characteristics of reactive step during the simulated trip perturbation while walking in community-dwelling participants with stroke for examining the fall risk related biomechanical characteristics of community-dwelling participants with stroke were determined. Biomechanics variables with significant difference during the initial contact of the reaction step between groups analysis were selected for Statistical Parametric Mapping One-dimensional (SPM1D) further analysis. The differences in joint angular time profiles during the reactive step were compared between the groups. The joint angle trajectories and moment of the specified segments, from onset of trip perturbation to foot contact were determined and compared between stroke and control group. | en_US |
| dcterms.abstract | Results | en_US |
| dcterms.abstract | Twenty-five participants were screened for their eligibility to take part in this research with reference to inclusion and exclusion criteria. Fourteen participants with stroke and ten healthy controls were finally recruited and completed the testing procedures. The groups of stroke and healthy control had comparable age (stroke 53.07 ± 9.00 versus control 46.50 ± 18.22), height (stroke 161.51 ± 8.18 cm versus control 166.96 ± 8.26 cm) and weight (stroke 64.34 ± 16.61 kg versus control 60.99 ± 8.32 kg) (p > 0.05). The history of stroke was 45.29 ± 73.05 months. The lesion involves in the location of the intracranial (14.3%), Basal Ganglia (14.3%), Thalamic (14.3%) and others or non-specific (57.1%). MFAC was category VII as an outdoor walker for both groups of stroke and control. | en_US |
| dcterms.abstract | Participants with stroke exhibited slower walking speeds and deviations in joint angles. The stepping strategy used with usual walking speeds selected by participants with stroke of 0.27 ± 0.10 m/s and healthy control of 0.72 ± 0.16 m/s. Independent-Samples t-test results revealed the trunk flexion angle of participants with stroke was greater than control at initial contact (stroke 16.40 ± 9.36 degree versus healthy control 3.43 ± 2.48 degree, p ≤ 0.05). The ankle dorsiflexion angle over the trip side was greater in stroke group (stroke 14.41 ± 6.11 degree versus healthy control 7.49 ± 5.47 degree (p = 0.009). The ankle dorsiflexion moment over the trip side limb normalized by body weight was smaller in stroke group (stroke 0.27 ± 0.27 Nm/kg versus healthy control 0.68 ± 0.37 Nm/kg (p ≤ 0.05). Shoulder abduction angle over the reactive step side significantly different between groups at initial contact of reactive step (stroke 25.22 ± 10.54 degree versus healthy control 14.35 ± 6.39 degree (p = 0.008). Shoulder external rotation angle over the trip side at initial contact of reactive step (stroke 33.09 ± 19.94 degree versus healthy control 14.10 ± 10.78 degree (p = 0.012) was greater in participants with stroke. It highlighted distinct upper limb kinematic strategies employed by stroke participants during reactive stepping. The increased shoulder abduction angle and altered shoulder movements observed in stroke patients suggest that they rely on arm abduction and adjustments in shoulder positioning to enhance postural control and maintain stability. These compensatory mechanisms might contribute to the redistribution of forces throughout the body, ultimately promoting postural stability and reducing the risk of falls. | en_US |
| dcterms.abstract | The performance of balance in the stroke group was significantly poorer compared to the control group. BBS showed significantly different score between group with lower score in stroke (stroke 51.14 ± 4.22 versus normal control 56.00 ± 0.00 (p ≤ 0.05). This finding highlighted the significant impact of stroke on an individual's balance ability. The higher BBS scores observed in the control group indicate that these individuals exhibited superior balance compared to the stroke participants. This was likely attributable to the neurological and functional impairments commonly experienced by individuals after a stroke. The lower BBS scores in the stroke group had important implications for increasing risk of falls and the overall functional independence of these individuals. Impaired balance were well-established risk factors for falls, which could lead to serious injuries, decreased mobility, and a reduced quality of life for stroke survivors. The findings also revealed deficiencies in reactive step balance control as indicated by the two tiers to assess the balance performance in this study, first by the clinical score of BBS and second by the specified cluster of biomechanical characteristics using advanced technology measurements of motion capturing. | en_US |
| dcterms.abstract | The study found a moderate association between BBS scores and some biomechanical characteristics. Some associations between BBS and knee flexion angle (ρ = -0.682, p ≤ 0.05), and adduction angle (ρ = -0.578, p ≤ 0.05) over the reactive step side of the unaffected limb (limb without paralysis) at initial contact; ankle dorsiflexion (ρ = -0.741, p ≤ 0.05), adduction (ρ = -0.769, p ≤ 0.05), and external rotation (ρ = -0.805, p ≤ 0.05) angles over the trip side of the affected limb (limb with paralysis) were determined by Spearman's rho correlation in the sample of community-dwelling participants with stroke. Participants with stroke exhibited impaired balance control which addresses the concept of center of mass state in which it is the velocity and position relative to base of support during walking and tended to walk at slower speeds compared to the control group. | en_US |
| dcterms.abstract | By analyzing the joint angular profiles throughout the entire reactive step sequence, the researchers were able to gain valuable insights into the neuromuscular control strategies employed by participants with stroke in response to these external perturbations. This information was crucial for understanding the underlying mechanisms that contributed to balance impairments and increased fall risk in individuals after a stroke. The comprehensive assessment of the joint movement patterns during the reactive step excursion provided the researchers with a detailed characterization of the biomechanical adjustments made by stroke patients to maintain balance and prevent a fall. This level of detail was essential for identifying specific deficits in motor control and joint coordination that might be targeted through tailored rehabilitation interventions. | en_US |
| dcterms.abstract | Statistical analysis using SPM1D revealed significant differences in multiple aspects of the parameter series studied at particular phases during the comparisons. These differences included trunk flexion angle and shoulder abduction over the contralateral side of the tripped foot, as well as shoulder external rotation angle, ankle dorsiflexion angle and moment over the ipsilateral side of the tripped foot. These findings suggested that the observed time series of joint angles and ankle moment were not randomly derived but exhibited deterministic patterns. The results indicated distinct biomechanical characteristics associated with stroke during the reactive step, involving altered joint movements and coordination. In particular, participants who had experienced a stroke presented an increased trunk flexion angle (t = 2.625, p = 0.038) at the end phase of cycle, suggesting an altered strategy to regain balance and prevent a fall post-perturbation. Additionally, dichotomous patterns were also discernible in the ankle joint dorsiflexion moment, with significant differences being evident toward the end phase of the cycle, occurring during approximately 70% to 100% of the cycle. Correspondingly, the trunk flexion angle and ankle dorsiflexion angle displayed significant between-group differences in the latter phases of the reactive step, indicating a delayed, compensatory mechanism in the stroke group. Notably, there was a reduction in the moment of ankle dorsiflexion over the affected side among the stroke participants (t = 3.299, p < 0.001), implying a potential weakness or coordination deficit that could contribute to fall risk. | en_US |
| dcterms.abstract | Similarly, the shoulder abduction angle over the contralateral side (t = 3.175, p = 0.016), and the shoulder external rotation angle over the ipsilateral side (t = 2.891, p = 0.042), indicated a significant recruitment of upper body strategies to counterbalance the disruption in stability at early stage of reactive step. Both groups exhibited shoulder abduction over the reactive side throughout the entire reactive step excursion. A similar trend was found for shoulder external rotation over the trip side, with significant differences occurring in the middle phase of the reactive step cycle and persisting until approximately 60% of the cycle. Additionally, the ankle angle on the ipsilateral side also exhibited significant discrepancies (t = 3.218, p = 0.05). | en_US |
| dcterms.abstract | The study successfully captured the joint movement patterns throughout the entire reactive step excursion during a trip simulation perturbation while walking. This approach allowed the researchers to comprehensively examine the biomechanics characteristics of the reactive step response in stroke patients. The study demonstrated that the method of using a SBT to simulate trip perturbation while walking was a safe and feasible way to assess the reactive step biomechanics in the stroke population. The SBT system was able to induce unexpected trips during walking, triggering the participants to take a reactive step to regain stability. | en_US |
| dcterms.abstract | The successful implementation of this SBT-based perturbation protocol in the stroke population demonstrated its potential as a reliable and safe research tool for the evaluation of reactive step responses. This approach allowed for the controlled elicitation and systematic analysis of balance recovery strategies, which could inform the development of evidence-based fall prevention strategies for participants with stroke. | en_US |
| dcterms.abstract | Discussion | en_US |
| dcterms.abstract | Participants with stroke demonstrated slower walking speeds and deviations in joint angles, indicating the use of compensatory mechanisms to maintain balance and stability. Significant between-group differences were observed in several biomechanical characteristics which included trunk flexion angle, ankle dorsiflexion angle and moment, shoulder external rotation angle of the trip side, and shoulder abduction angle of the reactive step side during the simulated trip perturbation. | en_US |
| dcterms.abstract | By addressing these specific areas of difference, it may be possible to enhance postural control and stability in stroke patients during reactive stepping. The observed altered biomechanical characteristics in these joints reflect an adaptive response to the postural disturbance caused by the simulated trip perturbation while walking, with the aim of minimizing the risk of falling. According to the findings, some potential future interventions that can be considered specifically address the deficits observed in reactive stepping. | en_US |
| dcterms.abstract | A poorer balance performance was demonstrated in patients with stroke as indicated by significantly lower score of BBS when compared to healthy control. This finding is consistent with previous research highlighting the impact of stroke on balance control and stability. Within the stroke group, the BBS scores were found to be correlated with specific biomechanics characteristics. Higher BBS scores were associated with some favorable joint angles related to knee and ankle movements during the first reactive step. These findings suggest that better balance performance in stroke participants is associated to more optimal joint angles suggesting enhanced control and stability when responding to trip perturbations. | en_US |
| dcterms.abstract | SPM1D results provided valuable insights into the joint movement patterns and biomechanical characteristics at particular phases associated with stroke during the reactive step following the simulated trip perturbation while walking. Five variables under investigation showed statistically significant differences. This included trunk flexion angle and shoulder abduction on the contralateral side of the tripped foot, as well as shoulder external rotation angle and ankle dorsiflexion angle and moment on the ipsilateral side of the tripped foot. | en_US |
| dcterms.abstract | Participants with stroke exhibited distinct deviations in joint angles, which included the increase in trunk flexion, ankle dorsiflexion angle over the ipsilateral side of the tripped foot and altered upper body movement strategies over distinct phases of reactive step. The trunk flexion angle and ankle dorsiflexion angle displayed differences in the end phase of the reactive step, indicating a delayed, compensatory mechanism in the stroke group. The shoulder abduction angle over the contralateral side of the tripped foot during the initial phase of the trip simulation, indicated a significant recruitment of upper body strategies to counterbalance the disruption in stability at early stage during reactive step. A similar trend was found for shoulder external rotation over the ipsilateral side of the tripped foot, with significant differences occurring in the middle phase of the reactive step cycle and persisting until approximately 80% of the cycle. They also showed reduced ankle moment over the ipsilateral side of the tripped foot, indicating potential muscle strength or motor control impairments especially at the end phase of reactive cycle. | en_US |
| dcterms.abstract | The results revealed distinct upper limb biomechanics strategies in participants with stroke during the reactive step following a perturbation, particularly in the shoulder region. These compensatory mechanisms might contribute to the redistribution of forces throughout the body, ultimately promoting postural stability and reducing the risk of falls. Understanding and investigating the upper limb strategies employed by stroke patients during balance control has significant implications for rehabilitation interventions. Targeting therapies that focus on improving upper limb coordination, strength, and control can potentially enhance balance recovery and functional mobility in stroke patients. Incorporating upper limb movements into balance training exercises can facilitate the integration of upper body control with lower body movements, ultimately promoting overall postural stability. | en_US |
| dcterms.abstract | These findings highlight the importance of addressing these biomechanics characteristics or compensatory mechanism at particular phases in rehabilitation and fall prevention strategies. Understanding these biomechanical characteristics can contribute to target interventions for improving balance and reducing fall risks in individuals with stroke. | en_US |
| dcterms.abstract | Conclusion | en_US |
| dcterms.abstract | The current study provided an understanding of the movement patterns and identified biomechanical characteristics associated with stroke during the reactive step over the affected side (side of the participants with stroke with paralysis) following the simulated trip perturbation while walking on SBT. There was difference in biomechanical characteristics of reactive stepping during the simulated trip perturbation while walking on the SBT between participants of stroke and healthy controls. The findings also revealed deficiencies in reactive step balance control, compromised trunk control, and reduced stability in participants with stroke compared to healthy controls. The study also highlighted distinct upper limb kinematic strategies employed by stroke participants during reactive stepping. The increased shoulder abduction angle and altered shoulder movements observed in stroke patients suggest that they rely on arm abduction and adjustments in shoulder positioning to enhance postural control and maintain stability. These compensatory mechanisms might contribute to the redistribution of forces throughout the body, ultimately promoting postural stability and reducing the risk of falls. The study also revealed moderate correlation between balance assessment score and the biomechanical characteristics of reactive stepping in participants with stroke to identify fall risk-related factors. Among those identified biomechanics characteristics, participants with stroke exhibited distinct deviations in joint angles and moment at particular phases of majority the identified biomechanics characteristics, indicating altered motor control and coordination or compensation strategies compared to healthy controls at particular phases in SPM1D analysis. These deviations might be attributed to tactical requirements, particularly the need for more vigorous movements during the simulated trip perturbation while walking. Setting accurate rehabilitation goals in biomechanical perspective including specific joints, specific movement strategy and specific phase of reactive step training over the particular joints are of major importance during stroke, as was understanding the underlying biomechanical characteristics of balance control in individuals with stroke and can guide the development of specific interventions to enhance fall prevention and management in the specific target group. | en_US |
| dcterms.extent | 1 volume (various pagings) : color illustrations | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2025 | en_US |
| dcterms.educationalLevel | DHSc | en_US |
| dcterms.educationalLevel | All Doctorate | en_US |
| dcterms.accessRights | restricted access | en_US |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 8642.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 2.32 MB | Adobe PDF | View/Open |
Copyright Undertaking
As a bona fide Library user, I declare that:
- I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
- I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
- I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.
Please use this identifier to cite or link to this item:
https://theses.lib.polyu.edu.hk/handle/200/14186