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Núñez-Lisboa M, Echeverría K, Willems PA, Ivanenko Y, Lacquaniti F, Dewolf AH. Understanding gait alterations: trunk flexion and its effects on walking neuromechanics. J Exp Biol 2024; 227:jeb249307. [PMID: 39212034 DOI: 10.1242/jeb.249307] [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: 07/19/2024] [Accepted: 08/22/2024] [Indexed: 09/04/2024]
Abstract
Evolutionary and functional adaptations of morphology and postural tone of the spine and trunk are intrinsically shaped by the field of gravity in which humans move. Gravity also significantly impacts the timing and levels of neuromuscular activation, particularly in foot-support interactions. During step-to-step transitions, the centre of mass velocity must be redirected from downwards to upwards. When walking upright, this redirection is initiated by the trailing leg, propelling the body forward and upward before foot contact of the leading leg, defined as an anticipated transition. In this study, we investigated the neuromechanical adjustments when walking with a bent posture. Twenty adults walked on an instrumented treadmill at 4 km h-1 under normal (upright) conditions and with varying degrees of anterior trunk flexion (10, 20, 30 and 40 deg). We recorded lower-limb kinematics, ground reaction forces under each foot, and the electromyography activity of five lower-limb muscles. Our findings indicate that with increasing trunk flexion, there is a lack of these anticipatory step-to-step transitions, and the leading limb performs the redirection after the ground collision. Surprisingly, attenuating distal extensor muscle activity at the end of stance is one of the main impacts of trunk flexion. Our observations may help us to understand the physiological mechanisms and biomechanical regulations underlying our tendency towards an upright posture, as well as possible motor control disturbances in some diseases associated with trunk orientation problems.
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Affiliation(s)
- M Núñez-Lisboa
- Laboratory of Biomechanics and Physiology of Locomotion, Institute of NeuroScience, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
- Exercise Science Laboratory, School of Kinesiology, Faculty of Medicine, Universidad Finis Terrae, Santiago 7501014, Chile
| | - K Echeverría
- Exercise Science Laboratory, School of Kinesiology, Faculty of Medicine, Universidad Finis Terrae, Santiago 7501014, Chile
| | - P A Willems
- Laboratory of Biomechanics and Physiology of Locomotion, Institute of NeuroScience, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Y Ivanenko
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, 00179 Rome, Italy
| | - F Lacquaniti
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, 00179 Rome, Italy
- Department of Systems Medicine and Center of Space Biomedicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - A H Dewolf
- Laboratory of Biomechanics and Physiology of Locomotion, Institute of NeuroScience, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
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Campoi HG, Campoi EG, Moraes R. Occlusion of the lower visual field when wearing a facial mask does not compromise gait control when stepping into a hole in older adults. Hum Mov Sci 2023; 88:103063. [PMID: 36696831 DOI: 10.1016/j.humov.2023.103063] [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: 11/15/2022] [Revised: 12/29/2022] [Accepted: 01/16/2023] [Indexed: 01/25/2023]
Abstract
Visual exproprioception obtained from the lower visual field (LVF) is used to control locomotion on uneven terrain. Wearing a facial mask obstructs the LVF and can compromise gait control. Therefore, this study aimed to investigate the effect of occluding the LVF when wearing a facial mask on gait control while walking and stepping into a hole in older adults. Fifteen older adults walked along a wooden walkway under two different surface conditions (without and with a hole [60 cm wide and long, with a depth of 9.5 cm] and three visual conditions (control, mask, and basketball goggles with an occluded LVF). We found that occlusion of the LVF with masks or goggles did not affect the adaptations necessary to step into a hole. Neither behavioral (gait speed, margin of stability, foot landing position) nor neuromuscular (EMG activation and co-activation) parameters were affected by either visual manipulation. Older adults used a downward head pitch strategy to compensate for visual obstruction and plan the anticipatory adjustments to step into the hole. The absence of lower limb visual exproprioception due to wearing a mask did not affect locomotion control when stepping into a hole in older adults. Older adults compensated for the obstruction of the LVF through head downward tilt, which allowed them to obtain visual information about the hole two steps ahead to make anticipatory locomotor adjustments.
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Affiliation(s)
- Henrique G Campoi
- Biomechanics and Motor Control Lab, School of Physical Education and Sport of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil; Graduate Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Eduardo G Campoi
- Biomechanics and Motor Control Lab, School of Physical Education and Sport of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil; Graduate Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Renato Moraes
- Biomechanics and Motor Control Lab, School of Physical Education and Sport of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil; Graduate Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.
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Abd El-Tawab AE, Farhana A. Three dimensional analysis of hip joint reaction force using Q Hip Force (AQHF) software: Implication as a diagnostic tool. PLoS One 2022; 17:e0273159. [PMID: 36155640 PMCID: PMC9512223 DOI: 10.1371/journal.pone.0273159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 08/03/2022] [Indexed: 11/18/2022] Open
Abstract
Assessment of hip joint reaction force (JRF) is one of the analytical methods that can enable an understanding of the healthy walking index and the propensity towards disease. In this study, we have designed software, Analysis Q Hip Force (AQHF), to analyze the data retrieved from the mathematical equations for calculating the JRF and ground reaction force (GRF) that act on the hip joint during the early part of the stance phase. The stance phase is considered the least stable sub-phase during walking on level ground, and the gait stability is sequentially minimized during walking on elevated ramps. We have calculated the JRF and GRF values of walking stances on varied inclinations. The data obtained from these calculations during walking on elevated ramps were exported from mathematical equations to Q Hip Force software as two separate values, namely the JRF data and GRF data of the hip joint. The Q Hip Force software stores the two reaction force data in a text file, which allows the import and easy readability of the analyzed data with the AQHF application. The input and output data from the AQHF software were used to investigate the effect of different walking ramps on the magnitude of the hip JRF and GRF. The result of this study demonstrates a significant correlation between the JRF/GRF values and healthy walking indices till a ramp elevation of 70°. The software is designed to calculate and extrapolate data to analyze the possibility of stress in the hip joint. The framework developed in this study shows promise for preclinical and clinical applications. Studies are underway to use the results of JRF and GRF values as a diagnostic and prognostic tools in different diseases.
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Affiliation(s)
- Amany Eid Abd El-Tawab
- Department of Physical Therapy and Health Rehabilitation, College of Applied Medical Science, Jouf University, Aljouf, Saudi Arabia
- Faculty of Physical Therapy, Biomechanics Department, Cairo University, Cairo, Egypt
| | - Aisha Farhana
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Aljouf, Saudi Arabia
- * E-mail:
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dos Santos LO, Batistela RA, Moraes R. Gait control to step into a lowered surface with one limb with different demands for accuracy in younger and older adults. Exp Gerontol 2022; 161:111716. [DOI: 10.1016/j.exger.2022.111716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 10/11/2021] [Accepted: 01/25/2022] [Indexed: 11/29/2022]
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Modulation of sagittal-plane center of pressure and force vector direction in human standing on sloped surfaces. J Biomech 2021; 119:110288. [PMID: 33636461 DOI: 10.1016/j.jbiomech.2021.110288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 01/04/2021] [Accepted: 01/23/2021] [Indexed: 11/20/2022]
Abstract
The multi-joint coordination responsible for maintaining upright posture in the standing human manifests in the pattern of variation of the support-surface force (F). Assessment of both the translational and rotational kinematics in the sagittal-plane requires understanding the critical relationship between the direction and location of F. Prior work demonstrated that band-pass filtered F direction and center-of-pressure (CoP) covary in time such that the F vector lines-of-action pass near a fixed point called an intersection point (IP). The height of that IP (IPz) varies systematically with the frequency of the pass band. From F measurements in able-bodied humans (n = 17) standing on various pitched surfaces, the present study also found the emergent property of an IP, with IPz located above the center of mass (CoM) at frequencies <1.75 Hz and below the CoM for higher frequencies. This property aids in maintaining upright posture for various perturbation modes within a single control structure. From purely mechanical effects, standing on a pitched surface should not change IPz, however these measurements of F show that IPz is generally closer to CoM height. This characterization of quiet standing provides simple means of assessing the complex multi-joint coordination of standing and relates directly to the physical demands of controlling the translational and rotational aspects of body posture.
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AminiAghdam S, Blickhan R, Karamanidis K. The influence of sagittal trunk lean on uneven running mechanics. J Exp Biol 2021; 224:jeb228288. [PMID: 33257431 DOI: 10.1242/jeb.228288] [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: 05/08/2020] [Accepted: 11/19/2020] [Indexed: 11/20/2022]
Abstract
The role of trunk orientation during uneven running is not well understood. This study compared the running mechanics during the approach step to and the step down for a 10 cm expected drop, positioned halfway through a 15 m runway, with that of the level step in 12 participants at a speed of 3.5 m s-1 while maintaining self-selected (17.7±4.2 deg; mean±s.d.), posterior (1.8±7.4 deg) and anterior (26.6±5.6 deg) trunk leans from the vertical. Our findings reveal that the global (i.e. the spring-mass model dynamics and centre-of-mass height) and local (i.e. knee and ankle kinematics and kinetics) biomechanical adjustments during uneven running are specific to the step nature and trunk posture. Unlike the anterior-leaning posture, running with a posterior trunk lean is characterized by increases in leg angle, leg compression, knee flexion angle and moment, resulting in a stiffer knee and a more compliant spring-leg compared with the self-selected condition. In the approach step versus the level step, reductions in leg length and stiffness through the ankle stiffness yield lower leg force and centre-of-mass position. Contrariwise, significant increases in leg length, angle and force, and ankle moment, reflect in a higher centre-of-mass position during the step down. Plus, ankle stiffness significantly decreases, owing to a substantially increased leg compression. Overall, the step down appears to be dominated by centre-of-mass height changes, regardless of having a trunk lean. Observed adjustments during uneven running can be attributed to anticipation of changes to running posture and height. These findings highlight the role of trunk posture in human perturbed locomotion relevant for the design and development of exoskeleton or humanoid bipedal robots.
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Affiliation(s)
- Soran AminiAghdam
- Sport and Exercise Science Research Centre, School of Applied Sciences, London South Bank University, London SE1 0AA, UK
| | - Reinhard Blickhan
- Department of Motion Science, Institute of Sport Sciences, Friedrich Schiller University Jena, Seidelstraße 20, 07740 Jena, Germany
| | - Kiros Karamanidis
- Sport and Exercise Science Research Centre, School of Applied Sciences, London South Bank University, London SE1 0AA, UK
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Li J, Wang P, Huang HJ. Dry Epidermal Electrodes Can Provide Long-Term High Fidelity Electromyography for Limited Dynamic Lower Limb Movements. SENSORS (BASEL, SWITZERLAND) 2020; 20:E4848. [PMID: 32867264 PMCID: PMC7506900 DOI: 10.3390/s20174848] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/19/2020] [Accepted: 08/24/2020] [Indexed: 01/22/2023]
Abstract
Due to the limitations of standard wet Silver/Silver Chloride (Ag/AgCl) hydrogel electrodes and the growing demand for long-term high fidelity surface electromyography (EMG) recording, dry epidermal electrodes are of great interest. Evaluating the usability and signal fidelity of dry epidermal electrodes could help determine the extent of potential applications using EMG electrodes. We collected EMG signals over eight days from the right rectus femoris of seven subjects using single-use dry epidermal electrodes and traditional Ag/AgCl electrodes while covered and uncovered during dynamic movements (leg extension, sit-to-stand, and treadmill walking at 0.75 m/s and 1.30 m/s). We quantified signal fidelity using signal-to-noise ratio (SNR); signal-to-motion ratio (SMR); and a metric we previously developed, the Signal Quality Index, which considers that better EMG signal quality requires both good signal-to-noise ratio and good signal-to-motion ratio. Wear patterns over the eight days degraded EMG signal quality. Uncovered epidermal electrodes that remained intact and maintained good adhesion to the skin had signal-to-noise ratios, signal-to-motion ratios, and Signal Quality Index values that were above the acceptable thresholds for limited dynamic lower limb movements (leg extension and sit-to-stand). This indicated that dry epidermal electrodes could provide good signal quality across all subjects for five days for these movements. For walking, the signal-to-noise ratios of the uncovered epidermal electrodes were still above the acceptable threshold, but signal-to-motion ratios and the Signal Quality Index values were far below the acceptable thresholds. The signal quality of the epidermal electrodes that showed no visible wear was stable over five days. As expected, covering the epidermal electrodes improved signal quality, but only for limited dynamic lower limb movements. Overall, single-use dry epidermal electrodes were able to maintain high signal quality for long-term EMG recording during limited dynamic lower limb movements, but further improvement is needed to reduce motion artifacts for whole body dynamic movements such as walking.
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Affiliation(s)
- Jinfeng Li
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA;
| | - Pulin Wang
- Stretch Med, Inc., Austin, TX 78750, USA;
| | - Helen J. Huang
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA;
- Bionic Materials, Implants, and Interfaces (BiionixTM) Cluster, University of Central Florida, Orlando, FL 32816, USA
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AminiAghdam S, Vielemeyer J, Abel R, Müller R. Reactive gait and postural adjustments following the first exposures to (un)expected stepdown. J Biomech 2019; 94:130-137. [PMID: 31399205 DOI: 10.1016/j.jbiomech.2019.07.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/04/2019] [Accepted: 07/21/2019] [Indexed: 10/26/2022]
Abstract
This study evaluated the reactive biomechanical strategies associated with both upper- and lower-body (lead and trail limbs) following the first exposures to (un)expected stepdown at comfortable (1.22 ± 0.08 m/s) and fast (1.71 ± 0.11 m/s) walking velocities. Eleven healthy adults completed 34 trails per walking velocity over an 8-m, custom-built track with two forceplates embedded in its center. For the expected stepdown, the track was lowered by 0-, -10- and -20-cm from the site of the second forceplate, whereas the unexpected stepdown was created by camouflaging the second forceplate (-10-cm). Two-way repeated-measurement ANOVAs detected no velocity-related effects of stepdown on kinematic and kinetic parameters during lead limb stance-phase, and on the trail limb stepping kinematics. However, analyses of significant interactions revealed greater peak flexion angles across the trunk and the trail limb joints (hip, knee and ankle) in unexpected versus expected stepdown conditions at a faster walking velocity. The -10-cm unexpected stepdown (main effect) had a greater influence on locomotor behavior compared to expected conditions due mainly to the absence of predictive adjustments, reflected by a significant decrease in peak knee flexion, contact time and vertical impulse during stance-phase. Walking faster (main effect) was associated with an increase in hip peak flexion and net anteroposterior impulse, and a decrease in contact time and vertical impulse during stepdown. The trail limb, in response, swung forward faster, generating a larger and faster recovery step. However, such reactive stepping following unexpected stepdown was yet a sparse compensation for an unstable body configuration, assessed by significantly smaller step width and anteroposterior margin-of-stability at foot-contact in the first-recovery-step compared with expected conditions. These findings depict the impact of the expectedness of stepdown onset on modulation of global dynamic postural control for a successful accommodation of (un)expected surface elevation changes in young, healthy adults.
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Affiliation(s)
- Soran AminiAghdam
- Department of Orthopedic Surgery, Bayreuth Hospital, Bayreuth, Bavaria, Germany; Department of Neurology, Bayreuth Hospital, Bayreuth, Bavaria, Germany; Sport and Exercise Science Research Centre, School of Applied Sciences, London South Bank University, London, United Kingdom.
| | - Johanna Vielemeyer
- Department of Orthopedic Surgery, Bayreuth Hospital, Bayreuth, Bavaria, Germany; Department of Neurology, Bayreuth Hospital, Bayreuth, Bavaria, Germany
| | - Rainer Abel
- Department of Orthopedic Surgery, Bayreuth Hospital, Bayreuth, Bavaria, Germany
| | - Roy Müller
- Department of Orthopedic Surgery, Bayreuth Hospital, Bayreuth, Bavaria, Germany; Department of Neurology, Bayreuth Hospital, Bayreuth, Bavaria, Germany
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AminiAghdam S, Griessbach E, Vielemeyer J, Müller R. Dynamic postural control during (in)visible curb descent at fast versus comfortable walking velocity. Gait Posture 2019; 71:38-43. [PMID: 31005853 DOI: 10.1016/j.gaitpost.2019.04.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 03/27/2019] [Accepted: 04/11/2019] [Indexed: 02/02/2023]
Abstract
BACKGROUND The unexpectedness of ground-contact onset in stepping down due, e.g., to a camouflaged curb during ongoing gait may impose potential postural control challenges, which might be deteriorated when walking faster. RESEARCH QUESTION Does traversing camouflaged versus visible curbs, at a fast walking velocity, induce more unstable body configurations, assessed by a smaller anteroposterior "margin of stability" (MoS)? METHODS For twelve healthy participants, we investigated MoS at foot touchdown in descent and in the first recovery step from 0- and 10-cm visible and camouflaged curbs at comfortable (1.22 ± 0.08 m/s) and fast (1.71 ± 0.11 m/s) walking velocities. Three-way (velocity, elevation, visibility) and two-way (velocity, visibility) repeated-measurement ANOVAs were performed to determine their interactions on MoS, and its determining parameters, during curb negotiation and recovery step, respectively. RESULTS No greater postural instability when traversing a camouflaged versus visible curb at a faster walking velocity during curb descent, indicated by no three-way interaction effects on MoS. However, an elevation-by-visibility interaction showed a dramatic decrease of MoS when descending a 10-cm camouflaged versus visible curb. This was because of a farther anterior displacement of center-of-mass with a larger velocity. Furthermore, the walking velocity was independently associated with a smaller MoS and a more anteriorly-shifted center-of-mass with a higher velocity. In the recovery step, participants demonstrated a reduced stability of the body configuration when walking faster or recovering from a camouflaged than from a visible curb. The mentioned result implies that the potential to increase the base-of-support to compensate for an increased center-of-mass velocity, induced by an increased walking velocity, is limited. SIGNIFICANCE Despite a significant independent main effect of walking velocity, a more unstable postural control observed during traversing of camouflaged versus visible curbs was found not to be walking velocity-related in young individuals. Further research, including elderly may shed more light on these results.
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Affiliation(s)
- Soran AminiAghdam
- Department of Motion Science, Institute of Sport Science, Friedrich-Schiller-University Jena, Jena, Thuringia, Germany; Department of Neurology/Department of Orthopedic Surgery, Bayreuth Hospital, Bayreuth, Bavaria, Germany.
| | - Eric Griessbach
- Department for the Psychology of Human Movement and Sport, Institute of Sport Science, Friedrich-Schiller-University Jena, Thuringia, Germany
| | - Johanna Vielemeyer
- Department of Neurology/Department of Orthopedic Surgery, Bayreuth Hospital, Bayreuth, Bavaria, Germany
| | - Roy Müller
- Department of Motion Science, Institute of Sport Science, Friedrich-Schiller-University Jena, Jena, Thuringia, Germany; Department of Neurology/Department of Orthopedic Surgery, Bayreuth Hospital, Bayreuth, Bavaria, Germany
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AminiAghdam S, Müller R, Blickhan R. Locomotor stability in able-bodied trunk-flexed gait across uneven ground. Hum Mov Sci 2018; 62:176-183. [DOI: 10.1016/j.humov.2018.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/24/2018] [Accepted: 10/25/2018] [Indexed: 11/16/2022]
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Liew BXW, Del Vecchio A, Falla D. The influence of musculoskeletal pain disorders on muscle synergies-A systematic review. PLoS One 2018; 13:e0206885. [PMID: 30395599 PMCID: PMC6218076 DOI: 10.1371/journal.pone.0206885] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 10/22/2018] [Indexed: 11/21/2022] Open
Abstract
Background Musculoskeletal (MSK) pain disorders represent a group of highly prevalent and often disabling conditions. Investigating the structure of motor variability in response to pain may reveal novel motor impairment mechanisms that may lead to enhanced management of motor dysfunction associated with MSK pain disorders. This review aims to systematically synthesize the evidence on the influence of MSK pain disorders on muscle synergies. Methods Nine electronic databases were searched using Medical Subject Headings and keywords describing pain, electromyography and synergies. Relevant characteristics of included studies were extracted and assessed for generalizability and risk of bias. Due to the significant heterogeneity, a qualitative synthesis of the results was performed. Results The search resulted in a total of 1312 hits, of which seven articles were deemed eligible. There was unclear consistency that pain reduced the number of muscle synergies. There were low consistencies of evidence that the synergy vector (W weights) and activation coefficient (C weights) differed in painful compared to asymptomatic conditions. There was a high consistency that muscle synergies were dissimilar between painful and asymptomatic conditions. Conclusions MSK pain alters the structure of variability in muscle control, although its specific nature remains unclear. Greater consistency in muscle synergy analysis may be achieved with appropriate selection of muscles assessed and ensuring consistent achievement of motor task outcomes. Synergy analysis is a promising method to reveal novel understandings of altered motor control, which may facilitate the assessment and treatment of MSK pain disorders.
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Affiliation(s)
- Bernard X. W. Liew
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- * E-mail: ,
| | - Alessandro Del Vecchio
- Neuromuscular Research & Technology, Department of Bioengineering, Faculty of Engineering, Imperial College London, Kensington, London, United Kingdom
| | - Deborah Falla
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
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AminiAghdam S, Blickhan R. The effects of an expected twofold perturbation on able-bodied gait: Trunk flexion and uneven ground surface. Gait Posture 2018; 61:431-438. [PMID: 29477127 DOI: 10.1016/j.gaitpost.2018.02.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 01/31/2018] [Accepted: 02/13/2018] [Indexed: 02/02/2023]
Abstract
BACKGROUND Although alteration in trunk orientation and ground level potentially affects gait pattern individually, it is plausible to examine the interaction effects of such factors. OBJECTIVE The interaction effects between trunk-flexed gait and uneven ground on able-bodied gait pattern. METHODS For twelve able-bodied participants, we compared the adaptive mechanisms in kinematics, kinetics and spatial-temporal parameters of gait (STPG) with bent postures (30° and 50° of sagittal trunk flexion) across uneven surface (10-cm visible drop at the sight of the second ground contact) with that of upright posture on even ground surface. RESULTS Significant between-posture changes on the uneven surface included a decreased peak ankle dorsiflexion angle and vertical ground reaction force (GRF) 2nd peak as trunk flexion increased. Moreover, significant between-ground surface changes for each individual gait posture were a decreased peak ankle dorsiflexion angle and ankle range of motion irrespective of trunk posture and a reduced trailing step duration and vertical GRF 2nd peak in upright walking. The spatial parameters of gait remained unchanged across uneven surface, but at the expense of pronounced adjustments in temporal parameters, i.e., a more conservative gait strategy, indicating a distinct contribution from spatial and temporal strategies in trunk-flexed gaits. This was associated with greater peak flexion angles across lower limb joints regardless of trunk posture, alongside with an exertion of greater forces at faster rates earlier in stance and attenuated forces at lower rates at the end of the stance (i.e., early-skewed vertical GRF). When considering the main effect of posture, a more crouched gait was executed with reduced temporal parameters (except for cadence) and an early-skewed vertical GRF patterns with increasing trunk flexion. SIGNIFICANCE These results may have implications for understanding the nature of compensatory mechanisms in gait pattern of older adults and/or patients with altered trunk orientations while accommodating uneven ground.
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Affiliation(s)
- Soran AminiAghdam
- Department of Motion Science, Institute of Sport Science, Friedrich Schiller University Jena, Seidelstraße 20, 07740 Jena, Germany.
| | - Reinhard Blickhan
- Department of Motion Science, Institute of Sport Science, Friedrich Schiller University Jena, Seidelstraße 20, 07740 Jena, Germany
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Müller R, Andrada E. Skipping on uneven ground: trailing leg adjustments simplify control and enhance robustness. ROYAL SOCIETY OPEN SCIENCE 2018; 5:172114. [PMID: 29410879 PMCID: PMC5792957 DOI: 10.1098/rsos.172114] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 12/13/2017] [Indexed: 06/08/2023]
Abstract
It is known that humans intentionally choose skipping in special situations, e.g. when descending stairs or when moving in environments with lower gravity than on Earth. Although those situations involve uneven locomotion, the dynamics of human skipping on uneven ground have not yet been addressed. To find the reasons that may motivate this gait, we combined experimental data on humans with numerical simulations on a bipedal spring-loaded inverted pendulum model (BSLIP). To drive the model, the following parameters were estimated from nine subjects skipping across a single drop in ground level: leg lengths at touchdown, leg stiffness of both legs, aperture angle between legs, trailing leg angle at touchdown (leg landing first after flight phase), and trailing leg retraction speed. We found that leg adjustments in humans occur mostly in the trailing leg (low to moderate leg retraction during swing phase, reduced trailing leg stiffness, and flatter trailing leg angle at lowered touchdown). When transferring these leg adjustments to the BSLIP model, the capacity of the model to cope with sudden-drop perturbations increased.
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Affiliation(s)
- Roy Müller
- Motionscience, Institute of Sport Sciences, Friedrich Schiller University Jena, Seidelstraße 20, 07749 Jena, Germany
- Department of Neurology/ Department of Orthopaedic Surgery, Klinikum Bayreuth GmbH, Hohe Warte 8, 95445 Bayreuth, Germany
| | - Emanuel Andrada
- Institute of Systematic Zoology and Evolutionary Biology with Phyletic Museum, Friedrich Schiller University Jena, Erbertstraße 1, 07743 Jena, Germany
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