Comparing normal walking and compensated walking: Their stability and perturbation resistance. A simulation study

2009 ◽  
Vol 224 (7) ◽  
pp. 891-901 ◽  
Author(s):  
W Yu ◽  
Y Ikemoto ◽  
R Acharya ◽  
J Unoue
Keyword(s):  
Joint Stiffness ◽  
Human Walking ◽  
Compensatory Mechanism ◽  
Normal Walking ◽  
Specific Muscle ◽  
Falling Risk ◽  
Muscle Groups ◽  
The Stability ◽  
Pes Equinus ◽  
Spastic Gait

People usually develop different kinds of compensated gait in response to local function deficits, such as muscle weakness, spasticity in specific muscle groups, or joint stiffness, in order to overcome the falling risk factors. Compensated walking has been analysed empirically in the impaired gait analysis area. However, the compensation could be identified spatially and temporally. The stability and perturbation resistance of compensated walking have not been analysed quantitatively. In this research, a biomimetic human walking simulator was employed to model one individual paraplegic subject with plantarflexor spasticity. The pes equinus was expressed by biasing the outputs of plantarflexor neurons corresponding to the spastic muscles. Then, the compensatory mechanism was explored by adjusting the outputs of the other muscles. It was shown that this approach can be used for quantitative analysis of the spastic gait and compensated walking. Thus, this research can improve the understanding of the behaviour of compensated walking, bringing insights not only for building useful walking assist systems with high safety but also for designing effective rehabilitation interventions.

Simulate and sense force exertions during virtual patient transfer tasks

2020 ◽  
Vol 64 (1) ◽  
pp. 2092-2096
Author(s):  
Ken Chen ◽  
Rebecca Widmayer ◽  
Karen B. Chen
Keyword(s):  
Muscle Activity ◽  
Fine Tuning ◽  
Activity Levels ◽  
Patient Lifting ◽  
Perceived Workload ◽  
Specific Muscle ◽  
Muscle Groups ◽  
Forceful Exertion ◽  
Lifting Task ◽  
Transfer Tasks

Virtual reality (VR) is commonplace for training, yet simulated physical activities in VR do not require trainees to engage and contract the muscle groups normally engaged in physical lifting. This paper presents a muscle activity-driven interface to elicit the sensation of forceful, physical exertions when lifting virtual objects. Users contracted and attained predefined muscle activity levels that were calibrated to user-specific muscle activity when lifting the physical counterpart. The overarching goal is to engage the appropriate muscles, and thereby encourage and elicit behaviors normally seen in the physical environment. Activities of 12 key muscles were monitored using electromyography (EMG) sensors while they performed a three-part patient lifting task in a Cave Automatic Virtual Environment. Participants reported higher task mental loads and less physical loads for the virtual lift than the physical lift. Findings suggest the potential to elicit sensation of forceful exertion via EMG feedback but needed fine-tuning to offset perceived workload.

Semi-Rigid Connection in Timber Structure: Stiffness Reduction and Instability Interaction

2020 ◽  
Vol 20 (07) ◽  
pp. 2050072 ◽  
Author(s):  
A. Manuello
Keyword(s):  
Joint Stiffness ◽  
Structural Response ◽  
Actual Condition ◽  
Space Structures ◽  
Beam Elements ◽  
Stiffness Reduction ◽  
Rigid Connection ◽  
Geometrical Imperfections ◽  
The Stability ◽  
Rigid Joints

Latticed shells and domes usually consist of hundreds, sometimes thousands, beam elements connected by rigid or semi-rigid joints. These connecting elements result, generally, very sophisticated, made with different materials and constituted by disparate connection systems. Recently, the stiffness connections were studied, numerically and experimentally, as one of the most important factors influencing significantly the structural response of space structures and domes. Very often, in the design process, the joints are assumed to be hinged or clamped. This assumption may result significantly far from the actual condition of in-service structure and components, leading to not understanding or not being able to prevent sudden catastrophic collapses (buckling, snap-through). Thus, the inclusion of joint stiffness reduction in the numerical model is necessary, more and more also due to the types of external loads, such as overloads that occur during the life of the structure or, especially, seismic solicitations. In this paper, the stability of an existent timber dome has been studied increasing the yieldingness of the connecting nodes according to an original approach. In addition, sensitivity of this kind of structure to the amplitude and the geometrical imperfections shape have been also considered. Numerical analyses have been conducted with local displacement controls, to take into account the geometric nonlinearity effects. Results evidenced that the dome is affected by instability interaction for particular slenderness and stiffness reduction of the connections.

scholarly journals 1. Importance of Physical Exercise in Living Arrangements Artist

2016 ◽  
Vol 11 (1) ◽  
pp. 133-138
Author(s):  
Ana-Cristina Leşe
Keyword(s):  
Physical Exercise ◽  
Living Arrangements ◽  
Screening Method ◽  
Musical Instrument ◽  
Modern Technology ◽  
School Screening ◽  
Physical Exercises ◽  
Specific Muscle ◽  
Muscle Groups ◽  
Timely Warning

AbstractIncreased occurrence of spine deviation is the result not only of modern technology hazards (for example, sitting in front of the computer for long hours) or lack of physical exercise, but also of specific posture related to the study of a musical instrument. The aim of this paper is the timely warning of children who choose to study a musical instrument about the spine deviations that can occur in time, also to refer them to a specialist and to encourage them to take up exercises meant to tone specific muscle groups. The study was conducted on two groups of students from the department of Musical interpretations, 1st and 2nd year, and two groups of students from the department of Painting and Photography and video, 1st year, at the “George Enescu” Arts University of Iaşi. The school screening method was used with the help of four MA students at the department of Kinetotherapy. The data were tabulated. We recommended that subjects be referred to specialised examinaton by doctors at the Pediatric Orthopedics clinic and have special sets of physical exercises.

scholarly journals Diagnostic Value of Muscle Ultrasound for Myopathies and Myositis

2020 ◽  
Vol 22 (11) ◽  
Author(s):  
Jemima Albayda ◽  
Nens van Alfen
Keyword(s):  
Imaging Modality ◽  
Neuromuscular Disorders ◽  
Diagnostic Value ◽  
Inflammatory Myopathies ◽  
Muscle Disorders ◽  
Muscle Edema ◽  
Specific Muscle ◽  
Muscle Groups ◽  
Muscle Ultrasound ◽  
Screening And Diagnosis

Abstract Purpose of Review The purpose of this review is to critically discuss the use of ultrasound in the evaluation of muscle disorders with a particular focus on the emerging use in inflammatory myopathies. Recent Findings In myopathies, pathologic muscle shows an increase in echogenicity. Muscle echogenicity can be assessed visually, semi-quantitatively, or quantitatively using grayscale analysis. The involvement of specific muscle groups and the pattern of increase in echogenicity can further point to specific diseases. In pediatric neuromuscular disorders, the value of muscle ultrasound for screening and diagnosis is well-established. It has also been found to be a responsive measure of disease change in muscular dystrophies. In chronic forms of myositis like inclusion body myositis, ultrasound is very suitable for detecting markedly increased echogenicity and atrophy in affected muscles. Acute cases of muscle edema show only a mild increase in echogenicity, which can also reverse with successful treatment. Summary Muscle ultrasound is an important imaging modality that is highly adaptable to study various muscle conditions. Although its diagnostic value for neuromuscular disorders is high, the evidence in myositis has only begun to accrue in earnest. Further systematic studies are needed, especially in its role for detecting muscle edema.

Physiotherapy of the scapulohumeral joint in dogs with osteochondritis dissecans – literature review

2017 ◽  
Vol XXII (128) ◽  
pp. 80-98
Author(s):  
Luís Guilherme de Faria ◽  
Patrícia Popak ◽  
Luciane dos Reis Mesquita ◽  
Gabriela Rodrigues Sampaio ◽  
Bruno Watanabe Minto ◽  
...  
Keyword(s):  
Osteochondritis Dissecans ◽  
Humeral Head ◽  
Endochondral Ossification ◽  
Clinical Symptoms ◽  
Physical Activities ◽  
Relieve Pain ◽  
Specific Muscle ◽  
Muscle Groups ◽  
Surgical Treatments ◽  
Passive Movements

Physiotherapy in veterinary medicine can be used to strengthen specific muscle groups, which is particularly interesting in the conservative treatment of osteochondritis dissecans (OCD) of the humeral head. OCD is endochondral ossification disorder and is characterized by an injury to the joint cartilage. There are conservative and surgical treatments for the disease that aim to restore limb functionality and relieve pain. Building the musculature through physical rehabilitation strengthens the periarticular muscles and decreases the progression of osteoarthrosis, reducing clinical symptoms. Some of the main physical activities used in the treatment of dogs with OCD of the humeral head include active and passive movements, hydrotherapy, massage and cryotherapy.

scholarly journals Development of Postural Stability Index to Distinguish Different Stability States

Entropy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 314 ◽  
Author(s):  
Nurul Nurwulan ◽  
Bernard Jiang ◽  
Vera Novak
Keyword(s):  
Postural Stability ◽  
Stability Index ◽  
Ensemble Empirical Mode Decomposition ◽  
Normal Walking ◽  
Healthy Older Adults ◽  
Acceleration Signal ◽  
Mode Decomposition ◽  
Key Factor ◽  
The Stability ◽  
Wearable Accelerometers

A key factor for fall prevention involves understanding the pathophysiology of stability. This study proposes the postural stability index (PSI), which is a novel measure to quantify different stability states on healthy subjects. The results of the x-, y-, and z-axes of the acceleration signals were analyzed from 10 healthy young adults and 10 healthy older adults under three conditions as follows: Normal walking, walking with obstacles, and fall-like motions. The ensemble empirical mode decomposition (EEMD) was used to reconstruct the acceleration signal data. Wearable accelerometers were located on the ankles and knees of the subjects. The PSI indicated a decreasing trend of its values from normal walking to the fall-like motions. Free-walking data were used to determine the stability based on the PSI. The segmented free-walking data indicated changes in the stability states that suggested that the PSI is potentially helpful in quantifying gait stability.

scholarly journals Modeling and simulating the neuromuscular mechanisms regulating ankle and knee joint stiffness during human locomotion

2015 ◽  
Vol 114 (4) ◽  
pp. 2509-2527 ◽  
Author(s):  
Massimo Sartori ◽  
Marco Maculan ◽  
Claudio Pizzolato ◽  
Monica Reggiani ◽  
Dario Farina
Keyword(s):  
Muscle Activation ◽  
Joint Stiffness ◽  
Human Locomotion ◽  
Biological Tissues ◽  
Musculoskeletal Model ◽  
Theoretical Description ◽  
Knee Joints ◽  
Dynamic Simulations ◽  
Muscle Groups ◽  
The Individual

This work presents an electrophysiologically and dynamically consistent musculoskeletal model to predict stiffness in the human ankle and knee joints as derived from the joints constituent biological tissues (i.e., the spanning musculotendon units). The modeling method we propose uses electromyography (EMG) recordings from 13 muscle groups to drive forward dynamic simulations of the human leg in five healthy subjects during overground walking and running. The EMG-driven musculoskeletal model estimates musculotendon and resulting joint stiffness that is consistent with experimental EMG data as well as with the experimental joint moments. This provides a framework that allows for the first time observing 1) the elastic interplay between the knee and ankle joints, 2) the individual muscle contribution to joint stiffness, and 3) the underlying co-contraction strategies. It provides a theoretical description of how stiffness modulates as a function of muscle activation, fiber contraction, and interacting tendon dynamics. Furthermore, it describes how this differs from currently available stiffness definitions, including quasi-stiffness and short-range stiffness. This work offers a theoretical and computational basis for describing and investigating the neuromuscular mechanisms underlying human locomotion.

Finite Element Stability Analysis of a Glulam Dome

1992 ◽  
Vol 7 (4) ◽  
pp. 353-361 ◽  
Author(s):  
S.M. Holzer ◽  
C.H. Wu ◽  
J. Tissaoui
Keyword(s):  
Finite Element ◽  
Joint Stiffness ◽  
Buckling Load ◽  
Nonlinear Method ◽  
Beam Elements ◽  
Eigenvalue Method ◽  
Straight Beam ◽  
Glued Laminated Timber ◽  
The Status ◽  
The Stability

The paper centres on stability investigations of a glued-laminated timber (glulam) dome under several snow load conditions. The dome consists of a triangulated network of curved glulam beams, a decking supported by curved purlins, and a steel tension ring. The dome is represented by two different models. The first model is a rigid-jointed space frame composed of curved beam elements. The second model consists of straight beam elements, with rigid or flexible joints, and a bracing to simulate the lateral support of the beams provided by the decking. Two finite element methods are presented and used in the analyses: A nonlinear method that computes the buckling load and a combined nonlinear/linear eigenvalue method that provides estimates of the buckling load. The results presented include buckling pressures, buckling modes, effects of joint stiffness and bracing on the stability of the dome, and the status of the material prior to buckling.

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