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Shin S, Simpkins C, Ahn J, Yang F. Impact of standing perturbation intensities on fall and stability outcomes in healthy young adults. J Biomech 2024; 168:112123. [PMID: 38696984 DOI: 10.1016/j.jbiomech.2024.112123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 03/14/2024] [Accepted: 04/24/2024] [Indexed: 05/04/2024]
Abstract
Motorized treadmills have been extensively used in investigating reactive balance control and developing perturbation-based interventions for fall prevention. However, the relationship between perturbation intensity and its outcome has not been quantified. The primary purpose of this study was to quantitatively analyze how the treadmill belt's peak velocity affects the perturbation outcome and other metrics related to the reactive balance in young adults while the total belt displacement is controlled at 0.36 m. Thirty-one healthy young adults were randomly assigned into three groups with different peak belt speeds: low (0.9 m/s), medium (1.2 m/s), and high (1.8 m/s). Protected by a safety harness, participants were exposed to a forward support surface translation while standing at an unexpected timing on an ActiveStep treadmill. The primary (perturbation outcome: fall vs. recovery) and secondary (dynamic stability, hip descent, belt distance at liftoff, and recovery step latency) outcome measures were compared among groups. Results revealed that a higher perturbation intensity is correlated with a greater faller rate (p < 0.001). Compared to the low- and medium-intensity groups, the high-intensity group was less stable (p < 0.001) with a larger hip descent (p < 0.001) and a longer belt distance (p < 0.001) at the recovery step liftoff. The results suggest that the increased perturbation intensity raises the risk of falling with larger instability and poorer reactive performance after a support surface translation-induced perturbation in healthy young adults. The findings could furnish preliminary guidance for us to design and select the optimal perturbation intensity that can maximize the effects of perturbation-based training protocols.
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Affiliation(s)
- Sangwon Shin
- Department of Biomechanics, University of Nebraska at Omaha, Omaha, NE 68182, USA
| | - Caroline Simpkins
- Department of Kinesiology and Health, Georgia State University, Atlanta, GA 30303, USA
| | - Jiyun Ahn
- Department of Kinesiology and Health, Georgia State University, Atlanta, GA 30303, USA
| | - Feng Yang
- Department of Kinesiology and Health, Georgia State University, Atlanta, GA 30303, USA.
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Purohit R, Varas-Diaz G, Bhatt T. Functional electrical stimulation to enhance reactive balance among people with hemiparetic stroke. Exp Brain Res 2024; 242:559-570. [PMID: 38214733 DOI: 10.1007/s00221-023-06729-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 10/23/2023] [Indexed: 01/13/2024]
Abstract
BACKGROUND Individuals with stroke demonstrate a twofold higher fall incidence compared to healthy counterparts, potentially associated with deficits in reactive balance control, which is crucial for regaining balance from unpredictable perturbations to the body. Moreover, people with higher stroke-related motor impairment exhibit greater falls and cannot recover balance during higher perturbation intensities. Thus, they might need supplemental agents for fall prevention or even to be included in a perturbation-based protocol. Functional electrical stimulation is a widely used clinical modality for improving gait performance; however, it remains unknown whether it can enhance or interfere with reactive balance control. METHODS We recruited twelve ambulatory participants with hemiparetic stroke (61.48 ± 6.77 years) and moderate-to-high motor impairment (Chedoke-McMaster Stroke Leg Assessment ≤ 4/7). Each participant experienced 4 unpredicted paretic gait-slips, with and without functional electrical stimulation (provided 50-500 ms after perturbation) in random order. The paretic quadriceps muscle group was chosen to receive electrical stimulation, considering the role of support limb knee extensors for preventing limb-collapse. Outcomes including primary (laboratory falls), secondary (reactive stability, vertical limb support) and tertiary (compensatory step length, step initiation, execution time) measures were compared between the two conditions. RESULTS Participants demonstrated fewer falls, higher reactive stability, and higher vertical limb support (p < 0.05) following gait-slips with functional electrical stimulation compared to those without. This was accompanied by reduced step initiation time and a longer compensatory step (p < 0.05). CONCLUSION The application of functional electrical stimulation to paretic quadriceps following gait-slips reduced laboratory fall incidence with enhanced reactive balance outcomes among people with higher stroke-related motor impairment. Our results lay the preliminary groundwork for understanding the instantaneous neuromodulatory effect of functional electrical stimulation in preventing gait-slip falls, future studies could test its therapeutic effect on reactive balance. Clinical registry number: NCT04957355.
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Affiliation(s)
- Rudri Purohit
- Department of Physical Therapy, College of Applied Health Sciences, University of Illinois at Chicago, 1919 W Taylor Street, Chicago, IL, 60612, USA
- Ph.D. Program in Rehabilitation Sciences, College of Applied Health Sciences, University of Illinois at Chicago, 1919 W Taylor Street, Chicago, IL, 60612, USA
| | - Gonzalo Varas-Diaz
- Carrera de Kinesiología, Departamento Ciencias de la Salud, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Tanvi Bhatt
- Department of Physical Therapy, College of Applied Health Sciences, University of Illinois at Chicago, 1919 W Taylor Street, Chicago, IL, 60612, USA.
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McCrum C, Bhatt TS, Gerards MHG, Karamanidis K, Rogers MW, Lord SR, Okubo Y. Perturbation-based balance training: Principles, mechanisms and implementation in clinical practice. Front Sports Act Living 2022; 4:1015394. [PMID: 36275443 PMCID: PMC9583884 DOI: 10.3389/fspor.2022.1015394] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 09/20/2022] [Indexed: 02/05/2023] Open
Abstract
Since the mid-2000s, perturbation-based balance training has been gaining interest as an efficient and effective way to prevent falls in older adults. It has been suggested that this task-specific training approach may present a paradigm shift in fall prevention. In this review, we discuss key concepts and common issues and questions regarding perturbation-based balance training. In doing so, we aim to provide a comprehensive synthesis of the current evidence on the mechanisms, feasibility and efficacy of perturbation-based balance training for researchers and practitioners. We address this in two sections: "Principles and Mechanisms" and "Implementation in Practice." In the first section, definitions, task-specificity, adaptation and retention mechanisms and the dose-response relationship are discussed. In the second section, issues related to safety, anxiety, evidence in clinical populations (e.g., Parkinson's disease, stroke), technology and training devices are discussed. Perturbation-based balance training is a promising approach to fall prevention. However, several fundamental and applied aspects of the approach need to be further investigated before it can be widely implemented in clinical practice.
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Affiliation(s)
- Christopher McCrum
- Department of Nutrition and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, Netherlands
- Neuromotor Rehabilitation Research Group, Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | - Tanvi S. Bhatt
- Department of Physical Therapy, College of Applied Health Sciences, University of Illinois, Chicago, IL, United States
| | - Marissa H. G. Gerards
- Department of Epidemiology, Care and Public Health Institute (CAPHRI), Maastricht University, Maastricht, Netherlands
- Department of Physiotherapy, Maastricht University Medical Center (MUMC+), Maastricht, Netherlands
| | - Kiros Karamanidis
- Sport and Exercise Science Research Centre, School of Applied Sciences, London South Bank University, London, United Kingdom
| | - Mark W. Rogers
- Department of Physical Therapy and Rehabilitation Science, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Stephen R. Lord
- Falls, Balance and Injury Research Centre, Neuroscience Research Australia, Sydney, NSW, Australia
- Faculty of Medicine and Health, University of New South Wales, Sydney, NSW, Australia
| | - Yoshiro Okubo
- Falls, Balance and Injury Research Centre, Neuroscience Research Australia, Sydney, NSW, Australia
- Faculty of Medicine and Health, University of New South Wales, Sydney, NSW, Australia
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Luna TD, Santamaria V, Ai X, Agrawal SK. Reactive Postural Control During Sit-to-Stand Motion. IEEE Robot Autom Lett 2022. [DOI: 10.1109/lra.2022.3181351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Tatiana D. Luna
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Victor Santamaria
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Xupeng Ai
- Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Sunil K. Agrawal
- Department of Mechanical Engineering, Department of Rehabilitation and Regenerative Medicine, Columbia University, New York, NY, USA
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Li J, Huang HJ. Small directional treadmill perturbations induce differential gait stability adaptation. J Neurophysiol 2022; 127:38-55. [PMID: 34851745 PMCID: PMC8721900 DOI: 10.1152/jn.00091.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Introducing unexpected perturbations to challenge gait stability is an effective
approach to investigate balance control strategies. Little is known about the
extent to which people can respond to small perturbations during walking. This
study aimed to determine how subjects adapted gait stability to multidirectional
perturbations with small magnitudes applied on a stride-by-stride basis. Ten
healthy young subjects walked on a treadmill that either briefly decelerated
belt speed (“stick”), accelerated belt speed
(“slip”), or shifted the platform medial-laterally at right leg
mid-stance. We quantified gait stability adaptation in both anterior-posterior
and medial-lateral directions using margin of stability and its components, base
of support, and extrapolated center of mass. Gait stability was disrupted upon
initially experiencing the small perturbations as margin of stability decreased
in the stick, slip, and medial shift perturbations and increased in the lateral
shift perturbation. Gait stability metrics were generally disrupted more for
perturbations in the coincident direction. Subjects employed both feedback and
feedforward strategies in response to the small perturbations, but mostly used
feedback strategies during adaptation. Subjects primarily used base of support
(foot placement) control in the lateral shift perturbation and extrapolated
center of mass control in the slip and medial shift perturbations. These
findings provide new knowledge about the extent of gait stability adaptation to
small magnitude perturbations applied on a stride-by-stride basis and reveal
potential new approaches for balance training interventions to target foot
placement and center of mass control. NEW & NOTEWORTHY Little is known about if and how humans can
adapt to small magnitude perturbations experienced on a stride-by-stride basis
during walking. Here, we show that even small perturbations disrupted gait
stability and that subjects could still adapt their reactive balance control.
Depending on the perturbation direction, subjects might prefer adjusting their
foot placement over their center of mass and vice versa. These findings could
help potentially tune balance training to target specific aspects of
balance.
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Affiliation(s)
- Jinfeng Li
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida
| | - Helen J Huang
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida.,Disability, Aging, and Technology (DAT) Cluster, University of Central Florida, Orlando, Florida.,Bionic Materials, Implants, and Interfaces (Biionix) Cluster, University of Central Florida, Orlando, Florida
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