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Mehdizadeh S, Glazier PS. Effect of simulated sensorimotor noise on kinematic variability and stability of a biped walking model. Comput Methods Biomech Biomed Engin 2021; 24:1097-1103. [PMID: 33426927 DOI: 10.1080/10255842.2020.1867852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Whether higher variability in older adults' walking is an indication of increased instability has been challenged recently. We performed a computer simulation to investigate the effect of sensorimotor noise on the kinematic variability and stability in a biped walking model. Stochastic differential equations of the system with additive Gaussian white noise was constructed and solved. Sensorimotor noise mainly resulted in higher kinematic variability but its influence on gait stability is minimal. This implies that kinematic variability evident in walking gaits of older adults could be the result of internal sensorimotor noise and not an indication of instability.
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Affiliation(s)
- Sina Mehdizadeh
- KITE-Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada
| | - Paul S Glazier
- National Sports Institute of Malaysia, Kuala Lumpur, Malaysia
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Fettrow T, Reimann H, Grenet D, Crenshaw J, Higginson J, Jeka J. Walking Cadence Affects the Recruitment of the Medial-Lateral Balance Mechanisms. Front Sports Act Living 2019; 1:40. [PMID: 33344963 PMCID: PMC7739695 DOI: 10.3389/fspor.2019.00040] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 09/16/2019] [Indexed: 12/04/2022] Open
Abstract
We have previously identified three balance mechanisms that young healthy adults use to maintain balance while walking. The three mechanisms are: (1) The lateral ankle mechanism, an active modulation of ankle inversion/eversion in stance; (2) The foot placement mechanism, an active shift of the swing foot placement; and (3) The push-off mechanism, an active modulation of the ankle plantarflexion angle during double stance. Here we seek to determine whether there are changes in neural control of balance when walking at different cadences and speeds. Twenty-one healthy young adults walked on a self-paced treadmill while immersed in a 3D virtual reality cave, and periodically received balance perturbations (bipolar galvanic vestibular stimulation) eliciting a perceived fall to the side. Subjects were instructed to match two cadences specified by a metronome, 110 bpm (High) and 80 bpm (Low), which in this experiment, led to faster and slower gait speeds, respectively. The results indicate that subjects altered the use of the balance mechanisms at different cadences. The lateral ankle mechanism was used more in the Low condition, while the foot placement mechanism was used more in the High condition. There was no difference in the use of the push-off mechanism between cadence conditions. These results suggest that neural control of balance is altered when gait characteristics, such as cadence change, suggesting a flexible balance response that is sensitive to the constraints of the gait cycle. We speculate that the use of the balance mechanisms may be a factor resulting in well-known characteristics of gait in populations with compromised balance control, such as slower gait speed in older adults or higher cadence in people with Parkinson's disease.
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Affiliation(s)
- Tyler Fettrow
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States
| | - Hendrik Reimann
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States
| | - David Grenet
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States
| | - Jeremy Crenshaw
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States
| | - Jill Higginson
- Department of Mechanical Engineering, University of Delaware, Newark, DE, United States
| | - John Jeka
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States
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Hsieh KL, Sheehan RC, Wilken JM, Dingwell JB. Healthy individuals are more maneuverable when walking slower while navigating a virtual obstacle course. Gait Posture 2018; 61:466-472. [PMID: 29494819 PMCID: PMC5866787 DOI: 10.1016/j.gaitpost.2018.02.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 01/27/2018] [Accepted: 02/13/2018] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Maintaining stability, especially in the mediolateral direction, is important for successful walking. Navigating in the community, however, may require people to reduce stability to make quick lateral transitions, creating a tradeoff between stability and maneuverability. Walking slower can improve stability during steady state walking, but there remains a need to better understand how walking speed influences maneuverability. This study investigated how walking at different speeds influenced how individuals modulate both stability and maneuverability in a virtual obstacle course. METHODS Fifteen healthy adults walked on a treadmill in a virtual environment for 6 trials each at typical and slower speed. Participants made repeated transitions between virtual sets of arches displayed in any of 4 lanes. Participants were instructed to walk under the arches and hit as few arches as possible. To quantify stability, mean step width and mean lateral margin of stability (Mean MOS) were calculated and averaged for ipsilateral and contralateral steps. To quantify maneuverability, the number of arches hit when entering or exiting each arch set was calculated and averaged for each condition. RESULTS Participants exhibited high levels of variability in their stepping patterns. Mean MOS and mean step width were significantly greater for the typical speed than slower speed for the ipsilateral steps (p < 0.001). Participants hit more arches during the typical speed than during the slow speed (p = 0.039). CONCLUSION When walking at the slower speed, healthy individuals exhibited decreased stability of ipsilateral steps, but increased maneuverability and better transition performance.
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Affiliation(s)
- Katherine L. Hsieh
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD,Military Performance Lab, Center for the Intrepid, JBSA Ft. Sam Houston, TX, USA
| | - Riley C. Sheehan
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD,Military Performance Lab, Center for the Intrepid, JBSA Ft. Sam Houston, TX, USA,Department of Kinesiology & Health Education, The University of Texas at Austin, Austin, TX, USA
| | - Jason M. Wilken
- Military Performance Lab, Center for the Intrepid, JBSA Ft. Sam Houston, TX, USA,DoD-VA Extremity Trauma and Amputation Center of Excellence (EACE)
| | - Jonathan B. Dingwell
- Department of Kinesiology & Health Education, The University of Texas at Austin, Austin, TX, USA,Please address all correspondence to: Jonathan B. Dingwell, Ph.D. Department of Kinesiology, Pennsylvania State University, 276 Recreation Building, University Park, PA 16802, Phone: 814 – 865 – 7761, , Web: http://biomechanics.psu.edu/
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Kaminski E, Hoff M, Rjosk V, Steele CJ, Gundlach C, Sehm B, Villringer A, Ragert P. Anodal Transcranial Direct Current Stimulation Does Not Facilitate Dynamic Balance Task Learning in Healthy Old Adults. Front Hum Neurosci 2017; 11:16. [PMID: 28197085 PMCID: PMC5281631 DOI: 10.3389/fnhum.2017.00016] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 01/09/2017] [Indexed: 11/27/2022] Open
Abstract
Older adults frequently experience a decrease in balance control that leads to increased numbers of falls, injuries and hospitalization. Therefore, evaluating older adults’ ability to maintain balance and examining new approaches to counteract age-related decline in balance control is of great importance for fall prevention and healthy aging. Non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) have been shown to beneficially influence motor behavior and motor learning. In the present study, we investigated the influence of tDCS applied over the leg area of the primary motor cortex (M1) on balance task learning of healthy elderly in a dynamic balance task (DBT). In total, 30 older adults were enrolled in a cross-sectional, randomized design including two consecutive DBT training sessions. Only during the first DBT session, either 20 min of anodal tDCS (a-tDCS) or sham tDCS (s-tDCS) were applied and learning improvement was compared between the two groups. Our data showed that both groups successfully learned to perform the DBT on both training sessions. Interestingly, between-group analyses revealed no difference between the a-tDCS and the s-tDCS group regarding their level of task learning. These results indicate that the concurrent application of tDCS over M1 leg area did not elicit DBT learning enhancement in our study cohort. However, a regression analysis revealed that DBT performance can be predicted by the kinematic profile of the movement, a finding that may provide new insights for individualized approaches of treating balance and gait disorders.
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Affiliation(s)
- Elisabeth Kaminski
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany
| | - Maike Hoff
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany
| | - Viola Rjosk
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany
| | - Christopher J Steele
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain SciencesLeipzig, Germany; Department of Psychiatry, Cerebral Imaging Centre, Douglas Mental Health Institute, McGill UniversityMontreal, QC, Canada
| | - Christopher Gundlach
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain SciencesLeipzig, Germany; Faculty of Psychology, Department of Experimental Psychology and Methods, University of LeipzigLeipzig, Germany
| | - Bernhard Sehm
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany
| | - Arno Villringer
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain SciencesLeipzig, Germany; Mind and Brain Institute, Charité and Humboldt UniversityBerlin, Germany
| | - Patrick Ragert
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain SciencesLeipzig, Germany; Faculty of Sport Science, Institute for General Kinesiology and Exercise Science, University of LeipzigLeipzig, Germany
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Russell DM, Apatoczky DT. Walking at the preferred stride frequency minimizes muscle activity. Gait Posture 2016; 45:181-6. [PMID: 26979903 DOI: 10.1016/j.gaitpost.2016.01.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Revised: 08/29/2015] [Accepted: 01/28/2016] [Indexed: 02/02/2023]
Abstract
This study determined whether walking at the preferred stride frequency minimizes muscle activity compared with other cadences at the same speed. Anthropometric measurements were recorded from 10 subjects and used to estimate their predicted resonant stride frequency. The preferred walking speed and stride frequency were determined from freely adopted walking on a treadmill. For the experimental trials the treadmill was set at each individual's preferred walking speed. Participants walked for 6 min at eight cadences prescribed by an auditory metronome: preferred stride frequency and -35, -25, -15, 0, +15, +25, +35% of predicted resonant stride frequency. Oxygen consumption was measured via gas analysis. Muscle activity of the right leg gastrocnemius (GA), tibialis anterior (TA), biceps femoris (BF) and rectus femoris (RF) muscles was recorded via electromyography (EMG). On average, participants preferred to walk with a stride frequency .07 Hz lower than their predicted resonant stride frequency, however a strong positive correlation was observed between these variables. Stride frequency had a significant and large quadratic effect on VO2 (RLR(2)=.76), and activity of the GA (RLR(2)=.66), TA (RLR(2)=.83), BF (RLR(2)=.70) and RF (RLR(2)=.78) muscles. VO2, GA and TA activity were all minimal at the preferred stride frequency and increased for faster or slower cadences. BF and RF activity were minimal across a broad range of slow frequencies including the preferred stride frequency and increased for faster frequencies. The preferred stride frequency that humans readily adopt during walking minimizes the activation of the GA, TA, BF and RF muscles, which in turn minimizes the overall metabolic cost.
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Affiliation(s)
- Daniel M Russell
- School of Physical Therapy and Athletic Training, Old Dominion University, USA.
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MEI QICHANG, FENG NENG, REN XUEJUN, LAKE MAK, GU YAODONG. FOOT LOADING PATTERNS WITH DIFFERENT UNSTABLE SOLES STRUCTURE. J MECH MED BIOL 2015. [DOI: 10.1142/s0219519415500141] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Foot loading patterns can be changed by using different unstable sole structures, detailed quantification of which is of great significance for research and technological development in falling prevention and lower limb disorders rehabilitation. In this study, unstable soles constructions are adjusted through unstable elements in heel and medial, neutral and lateral forefoot and the foot loading patterns are comparatively studied. A total of 22 healthy male subjects participated in this test. Subjects are asked to walk over a 12 m walkway with control shoes and experimental shoes in self-adapted speed. Significant peak pressure, contact area and pressure-time integral differences in middle foot are found between control shoes and experimental shoes. In addition, peak pressure and pressure-time integral are found to increase significantly with unstable elements adding to center forefoot. The results showed that adjusting the unstable elements in coronal plane of forefoot could effectively alter the distribution of plantar pressure, this could potentially offer a mechanism for preventing falling of elderly and rehabilitation of lower extremity malfunctions. This study also demonstrates a novel concept that unstable element could be effectively adjusted in terms of position to meet different functional requirement.
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Affiliation(s)
- QICHANG MEI
- Faculty of Sport Science, Ningbo University, Zhejiang 315211, P. R. China
| | - NENG FENG
- Rehabilitation Center, Ningbo Ninth Hospital, Zhejiang 315020, P. R. China
| | - XUEJUN REN
- School of Engineering, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - MAK LAKE
- School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 2ET, UK
| | - YAODONG GU
- Faculty of Sport Science, Ningbo University, Zhejiang 315211, P. R. China
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Mehdizadeh S, Arshi AR, Davids K. Constraints on dynamic stability during forward, backward and lateral locomotion in skilled football players. Eur J Sport Sci 2015; 16:190-8. [DOI: 10.1080/17461391.2014.995233] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Walking at the preferred stride frequency maximizes local dynamic stability of knee motion. J Biomech 2014; 47:102-8. [DOI: 10.1016/j.jbiomech.2013.10.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 09/17/2013] [Accepted: 10/05/2013] [Indexed: 11/23/2022]
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Roos PE, Dingwell JB. Using dynamic walking models to identify factors that contribute to increased risk of falling in older adults. Hum Mov Sci 2013; 32:984-96. [PMID: 24120280 DOI: 10.1016/j.humov.2013.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 06/05/2013] [Accepted: 07/03/2013] [Indexed: 10/26/2022]
Abstract
Falls are common in older adults. The most common cause of falls is tripping while walking. Simulation studies demonstrated that older adults may be restricted by lower limb strength and movement speed to regain balance after a trip. This review examines how modeling approaches can be used to determine how different measures predict actual fall risk and what some of the causal mechanisms of fall risk are. Although increased gait variability predicts increased fall risk experimentally, it is not clear which variability measures could best be used, or what magnitude of change corresponded with increased fall risk. With a simulation study we showed that the increase in fall risk with a certain increase in gait variability was greatly influenced by the initial level of variability. Gait variability can therefore not easily be used to predict fall risk. We therefore explored other measures that may be related to fall risk and investigated the relationship between stability measures such as Floquet multipliers and local divergence exponents and actual fall risk in a dynamic walking model. We demonstrated that short-term local divergence exponents were a good early predictor for fall risk. Neuronal noise increases with age. It has however not been fully understood if increased neuronal noise would cause an increased fall risk. With our dynamic walking model we showed that increased neuronal noise caused increased fall risk. Although people who are at increased risk of falling reduce their walking speed it had been questioned whether this slower speed would actually cause a reduced fall risk. With our model we demonstrated that a reduced walking speed caused a reduction in fall risk. This may be due to the decreased kinematic variability as a result of the reduced signal-dependent noise of the smaller muscle forces that are required for slower. These insights may be used in the development of fall prevention programs in order to better identify those at increased risk of falling and to target those factors that influence fall risk most.
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Affiliation(s)
- Paulien E Roos
- Arthritis Research UK Biomechanics and Bioengineering Centre, Division School of Healthcare Studies, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.
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