scholarly journals Quantifying the Dynamic Stability of Gait Patterns in People with Hallux Valgus

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Chaneun Park ◽  
Nyeonju Kang ◽  
KyoungKyu Jeon ◽  
Kiwon Park
Keyword(s):  
Hallux Valgus ◽  
Dynamic Stability ◽  
Lower Limb ◽  
The Other ◽  
Knee Joints ◽  
Maximum Lyapunov Exponent ◽  
Joint Movement ◽  
Gait Patterns ◽  
Gait Dynamics ◽  
Gait Stability

Hallux valgus (HV), which is mainly caused by the wearing of narrow-width and high-heeled shoes, disrupts gait behavior because it deforms lower limb joints. There is limited information regarding the relationship between the foot disease HV and lower limb joints. Previous studies evaluating abnormal gait patterns caused by deformity used spatiotemporal parameters; however, they failed to characterize the overall gait dynamics. To address this issue, this study is aimed at characterizing the gait stability of patients with HV and examining the joints that are critically affected by HV. To assess complex gait dynamics, we quantified the potential changes in gait stability by using the maximum Lyapunov exponent (MLE). Angular displacements of the ankle, knee, and hip in the sagittal plane during walking were investigated to calculate the MLE for gait stability based on foot conditions (i.e., barefoot, flat shoes, and high heels). During walking, a large MLE ( P < 0.05 ) was noted for the knee joints of subjects with HV, relative to the other lower limb joints. HV appears to have the most critical effect on the knee joints during walking. Ankle movement exhibited higher dynamic stability than the other joint movements of the lower limb ( P < 0.05 ). The type of shoe used in the experiment showed no significant dependence with gait stability and joint movement ( P > 0.05 ). Quantitative assessments of dynamic stability using the MLE may help clinicians assess the overall gait dynamics of HV patients and other people suffering from gait disturbances.

scholarly journals Lower Limb Kinematics in Individuals with Hip Osteoarthritis during Gait: A Focus on Adaptative Strategies and Interlimb Symmetry

2021 ◽  
Vol 8 (4) ◽  
pp. 47
Author(s):  
Micaela Porta ◽  
Massimiliano Pau ◽  
Bruno Leban ◽  
Michela Deidda ◽  
Marco Sorrentino ◽  
...  
Keyword(s):  
Lower Limb ◽  
Functional Limitations ◽  
Hip Osteoarthritis ◽  
Movement Analysis ◽  
Human Movement ◽  
Point Of View ◽  
Negative Effects ◽  
Gait Patterns ◽  
Limb Kinematics

Among the functional limitations associated with hip osteoarthritis (OA), the alteration of gait capabilities represents one of the most invalidating as it may seriously compromise the quality of life of the affected individual. The use of quantitative techniques for human movement analysis has been found valuable in providing accurate and objective measures of kinematics and kinetics of gait in individuals with hip OA, but few studies have reported in-depth analyses of lower limb joint kinematics during gait and, in particular, there is a scarcity of data on interlimb symmetry. Such aspects were investigated in the present study which tested 11 individuals with hip OA (mean age 68.3 years) and 11 healthy controls age- and sex-matched, using 3D computerized gait analysis to perform point-by-point comparisons of the joint angle trends of hip, knee, and ankle. Angle-angle diagrams (cyclograms) were also built to compute several parameters (i.e., cyclogram area and orientation and Trend Symmetry) from which to assess the degree of interlimb symmetry. The results show that individuals with hip OA exhibit peculiar gait patterns characterized by severe modifications of the physiologic trend at hip level even in the unaffected limb (especially during the stance phase), as well as minor (although significant) alterations at knee and ankle level. The symmetry analysis also revealed that the effect of the disease in terms of interlimb coordination is present at knee joint as well as hip, while the ankle joint appears relatively preserved from specific negative effects from this point of view. The availability of data on such kinematic adaptations may be useful in supporting the design of specific rehabilitative strategies during both preoperative and postoperative periods.

Dynamic Stability of Ni FCC Crystal under Isotropic Tension

2013 ◽  
Vol 592-593 ◽  
pp. 47-50
Author(s):  
Petr Řehák ◽  
Miroslav Černý
Keyword(s):  
Dynamic Stability ◽  
Wave Vector ◽  
First Principles ◽  
Lattice Dynamics ◽  
Harmonic Approximation ◽  
Tensile Loading ◽  
The Other ◽  
Other Hand ◽  
Critical Strains

Lattice dynamics and stability of fcc crystal of Ni under isotropic (hydrostatic) tensile loading are studied from first principles using supercell method and a harmonic approximation. According to the results, strength of the crystal is determined by occurrence of an instability related to soft phonons with finite wave vector. On the other hand, the critical strains and stresses associated with such instabilities are only slightly lower than those related to the volumetric instability.

To What Extent Does Not Wearing Shoes Affect the Local Dynamic Stability of Walking?: Effect Size and Intrasession Repeatability

2014 ◽  
Vol 30 (2) ◽  
pp. 305-309 ◽  
Author(s):  
Philippe Terrier ◽  
Fabienne Reynard
Keyword(s):  
Dynamic Stability ◽  
Effect Size ◽  
Intraclass Correlation ◽  
Clinical Findings ◽  
Local Dynamic ◽  
Gait Stability ◽  
Local Dynamic Stability ◽  
Gait Parameters ◽  
Absolute Agreement ◽  
The Stability

Local dynamic stability (stability) quantifies how a system responds to small perturbations. Several experimental and clinical findings have highlighted the association between gait stability and fall risk. Walking without shoes is known to slightly modify gait parameters. Barefoot walking may cause unusual sensory feedback to individuals accustomed to shod walking, and this may affect stability. The objective was therefore to compare the stability of shod and barefoot walking in healthy individuals and to analyze the intrasession repeatability. Forty participants traversed a 70 m indoor corridor wearing normal shoes in one trial and walking barefoot in a second trial. Trunk accelerations were recorded with a 3D-accelerometer attached to the lower back. The stability was computed using the finite-time maximal Lyapunov exponent method. Absolute agreement between the forward and backward paths was estimated with the intraclass correlation coefficient (ICC). Barefoot walking did not significantly modify the stability as compared with shod walking (average standardized effect size: +0.11). The intrasession repeatability was high (ICC: 0.73–0.81) and slightly higher in barefoot walking condition (ICC: 0.81–0.87). Therefore, it seems that barefoot walking can be used to evaluate stability without introducing a bias as compared with shod walking, and with a sufficient reliability.

Study on Wear-Preventing of Needle Valve in Fuel Injection System Mounted on DME Engine

2011 ◽  
Vol 228-229 ◽  
pp. 1057-1062
Author(s):  
Xin Rong Wen ◽  
Guang De Zhang ◽  
Wei Hua Wang ◽  
Xie Lu ◽  
Sun Jing
Keyword(s):  
Dynamic Stability ◽  
Structural Design ◽  
Fuel Injection ◽  
Dynamic Instability ◽  
Calculation Model ◽  
The Other ◽  
Injection System ◽  
Needle Valve ◽  
Fuel Injection System ◽  
Theoretical Support

The purpose of this paper is to provide theoretical support for the structural design to prevent the wear of needle. The actual wear of the orientation part of the needle in scrapped needles was researched. The presented results showed that the main reason to the wear of the orientation part of needle was the dynamic instability and the abrasives enter into the surface of orientation part which increases the wear, and that the calculation model of dynamic stability was proposed to prevent the wear of needle. This model was a pressure rod, one end of which was fixed, the other was free, and the two ends were pressed on axial force which changes with time. Besides, the classic formula of dynamic stability of pressure rod was changed rationally, so as to correspond with the calculation model. It will play a part in preventing the wear of needle.

Catastrophic Concomitant Arterial and Venous Thrombosis in a Mild COVID-19-Positive Patient

2021 ◽  
Author(s):  
Raka A. Nugraha ◽  
Hary S. Muliawan ◽  
Nyityasmono T. Nugroho ◽  
Muhammad Ikhsan ◽  
Suko Adiarto
Keyword(s):  
Critical Illness ◽  
Venous Thrombosis ◽  
Lower Limb ◽  
The Other ◽  
Ambulatory Setting ◽  
Current Evidence ◽  
Global Burden ◽  
Significant Morbidity ◽  
Ambulatory Patients ◽  
Clinical Consequences

AbstractSince its first discovery in late 2019, coronavirus disease 2019 (COVID-19) has been a global burden associated with significant morbidity and mortality. COVID-19 has been correlated with the development of hypercoagulable state that predisposes the patients to a higher risk of thromboembolism. Current evidence suggests higher incidence of thrombosis, particularly venous thrombosis, among hospitalized COVID-19 patients, mostly with critical illness. On the other hand, there is currently no data regarding the incidence of vivid thrombosis in ambulatory patients with mild COVID-19 and the incidence of concomitant arterial and venous thrombosis in COVID-19 is extremely rare. Herein, we describe catastrophic outcomes of concomitant lower limb arterial and venous thrombosis in a patient with mild COVID-19. This report highlights the occurrence of concomitant arterial and venous thrombosis in ambulatory setting and that this phenomenon resulted in catastrophic clinical consequences.

scholarly journals Gait Parameter Adjustments for Walking on a Treadmill at Preferred, Slower, and Faster Speeds in Older Adults with Down Syndrome

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Beth A. Smith ◽  
Masayoshi Kubo ◽  
Beverly D. Ulrich
Keyword(s):  
Older Adults ◽  
Down Syndrome ◽  
Stride Frequency ◽  
Gait Patterns ◽  
Gait Stability ◽  
Foot Placement ◽  
Gait Parameters ◽  
Younger Age ◽  
All Speeds ◽  
Walking Speeds

The combined effects of ligamentous laxity, hypotonia, and decrements associated with aging lead to stability-enhancing foot placement adaptations during routine overground walking at a younger age in adults with Down syndrome (DS) compared to their peers with typical development (TD). Our purpose here was to examine real-time adaptations in older adults with DS by testing their responses to walking on a treadmill at their preferred speed and at speeds slower and faster than preferred. We found that older adults with DS were able to adapt their gait to slower and faster than preferred treadmill speeds; however, they maintained their stability-enhancing foot placements at all speeds compared to their peers with TD. All adults adapted their gait patterns similarly in response to faster and slower than preferred treadmill-walking speeds. They increased stride frequency and stride length, maintained step width, and decreased percent stance as treadmill speed increased. Older adults with DS, however, adjusted their stride frequencies significantly less than their peers with TD. Our results show that older adults with DS have the capacity to adapt their gait parameters in response to different walking speeds while also supporting the need for intervention to increase gait stability.

scholarly journals Análisis biomecánico del pie protésico Bioc-dm2

2019 ◽  
Vol 15 (1) ◽  
pp. 80-86
Author(s):  
Jhon Hernandez Martin ◽  
Oscar Heli Bejarano ◽  
Edwin Yamith Martínez ◽  
Luis A. Parra Piñeros ◽  
Jairo Alberto Romero ◽  
...  
Keyword(s):  
Lower Limb ◽  
Quality Standards ◽  
The Other ◽  
Emotional Impact ◽  
Human Wellbeing ◽  
Prosthetic Component ◽  
Analysis Design ◽  
Design And Manufacture ◽  
Fundamental Pattern ◽  
Proper Response

Walking is one of the aspects directly compromising human wellbeing, as it has a physical and emotional impact in daily life.For this study, we delve into the challenge of improving some walking conditions in a patient suffering lower limb loss, specifically at transtibialor transfemoral levels. Given that our purpose was the analysis, design and manufacture of a lower-limb prosthetic component, which fills the needsfor functionality, it became necessary to build a foot with all the quality standards associated to each and all movements required to form thecomplex fundamental pattern of walking. Besides, this foot should also easily endure weight, daily use and physical characteristics of the patientobject of this study. When performing physical validation and during human walk, a proper response is observed in terms of mechanics, materialsand dynamics of the component, thus making evident proper construction and assembly. On the other hand, it is feasible that design and verificationof the component provided a competitive element, as compared to existing elements currently in the market. The previous situation generated theneed for verification from the National Institute for Medications and Food (INVIMA), as well as the revision of the use replying device, forcomponent verification, in accordance with ISO 10328.

scholarly journals Dynamic testing of below-knee prosthesis: Assembly and components

1987 ◽  
Vol 11 (3) ◽  
pp. 117-123 ◽  
Author(s):  
H. W. Wevers ◽  
J. P. Durance
Keyword(s):  
Failure Mechanism ◽  
Lower Limb ◽  
Structural Component ◽  
Dynamic Testing ◽  
Knee Prosthesis ◽  
Axial Loading ◽  
The Other ◽  
Normal Gait ◽  
Component Failures ◽  
Lower Limb Amputees

Prosthetic assemblies for lower limb amputees are highly engineered and consist of several components each with its own failure mechanism. This paper describes the dynamic testing of HDPE rotational moulded sockets in a specially designed machine which mimics normal gait. Thus the components are subjected to all main loadings occurring during a stride such as axial loading and A-P bending about the knee and ankle. Machine details as well as the other components of the system are described. SACH feet appear to be vulnerable by rapid wear and structural component failures at less than 100,000 cycles were observed. The sockets are much less vulnerable and stand up to simulated loading of 1350 N for approximately 400,000 cycles. Metal components such as the foot bolt may also fail in fatigue if not properly tightened. References to proposed ISO standards are also included.

Lower Limb Human Muscle Enhancer

2001 ◽  
Author(s):  
Joseph J. Misuraca ◽  
Constantinos Mavroidis
Keyword(s):  
Lower Limb ◽  
Weight Bearing ◽  
Kinematic Chain ◽  
Human Muscle ◽  
The Body ◽  
Knee Joints ◽  
Lower Body ◽  
Loop Control ◽  
Test Fixture ◽  
Leg Muscles

Abstract This paper describes the design, control, and testing of a Human Muscle Enhancer (HME) system that will augment the muscle capabilities of subjects requiring partial lower-limb weight-bearing gait support. The HME described in this paper is a pneumatically actuated quick connecting exoskeleton system that attaches to the foot and hip area of the body, thus “closing” the lower body kinematic chain. Control of the system is achieved by using encoders at the knee joints and Myo-Pneumatic (MP) Sensors implanted into the shoes and outer garments of the human. To test this design concept, a lower body exoskeleton test fixture has been fabricated. The test fixture mimics the human leg with the top cylinder providing the body weight on the leg. Another cylinder acts as leg muscles to provide the adjustable human reaction of the leg. Preliminary open and closed loop control tests have been performed that demonstate the capability of controlling the HME using the MP sensors.

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