Scaling of avian bipedal locomotion reveals independent effects of body mass and leg posture on gait.

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Daley, Monica A; Birn-Jeffery, Aleksandra

2018-05-22

Birds provide an interesting opportunity to study the relationships between body size, limb morphology and bipedal locomotor function. Birds are ecologically diverse and span a large range of body size and limb proportions, yet all use their hindlimbs for bipedal terrestrial locomotion, for at least some part of their life history. Here, we review the scaling of avian striding bipedal gaits to explore how body mass and leg morphology influence walking and running. We collate literature data from 21 species, spanning a 2500× range in body mass from painted quail to ostriches. Using dynamic similarity theory to interpret scaling trends, we find evidence for independent effects of body mass, leg length and leg posture on gait. We find no evidence for scaling of duty factor with body size, suggesting that vertical forces scale with dynamic similarity. However, at dynamically similar speeds, large birds use relatively shorter stride lengths and higher stride frequencies compared with small birds. We also find that birds with long legs for their mass, such as the white stork and red-legged seriema, use longer strides and lower swing frequencies, consistent with the influence of high limb inertia on gait. We discuss the observed scaling of avian bipedal gait in relation to mechanical demands for force, work and power relative to muscle actuator capacity, muscle activation costs related to leg cycling frequency, and considerations of stability and agility. Many opportunities remain for future work to investigate how morphology influences gait dynamics among birds specialized for different habitats and locomotor behaviors. © 2018. Published by The Company of Biologists Ltd.

Insect-computer hybrid legged robot with user-adjustable speed, step length and walking gait.

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Cao, Feng; Zhang, Chao; Choo, Hao Yu; Sato, Hirotaka

2016-03-01

We have constructed an insect-computer hybrid legged robot using a living beetle (Mecynorrhina torquata; Coleoptera). The protraction/retraction and levation/depression motions in both forelegs of the beetle were elicited by electrically stimulating eight corresponding leg muscles via eight pairs of implanted electrodes. To perform a defined walking gait (e.g., gallop), different muscles were individually stimulated in a predefined sequence using a microcontroller. Different walking gaits were performed by reordering the applied stimulation signals (i.e., applying different sequences). By varying the duration of the stimulation sequences, we successfully controlled the step frequency and hence the beetle's walking speed. To the best of our knowledge, this paper presents the first demonstration of living insect locomotion control with a user-adjustable walking gait, step length and walking speed. © 2016 The Author(s).

Does a crouched leg posture enhance running stability and robustness?

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Blum, Yvonne; Birn-Jeffery, Aleksandra; Daley, Monica A; Seyfarth, Andre

2011-07-21

Humans and birds both walk and run bipedally on compliant legs. However, differences in leg architecture may result in species-specific leg control strategies as indicated by the observed gait patterns. In this work, control strategies for stable running are derived based on a conceptual model and compared with experimental data on running humans and pheasants (Phasianus colchicus). From a model perspective, running with compliant legs can be represented by the planar spring mass model and stabilized by applying swing leg control. Here, linear adaptations of the three leg parameters, leg angle, leg length and leg stiffness during late swing phase are assumed. Experimentally observed kinematic control parameters (leg rotation and leg length change) of human and avian running are compared, and interpreted within the context of this model, with specific focus on stability and robustness characteristics. The results suggest differences in stability characteristics and applied control strategies of human and avian running, which may relate to differences in leg posture (straight leg posture in humans, and crouched leg posture in birds). It has been suggested that crouched leg postures may improve stability. However, as the system of control strategies is overdetermined, our model findings suggest that a crouched leg posture does not necessarily enhance running stability. The model also predicts different leg stiffness adaptation rates for human and avian running, and suggests that a crouched avian leg posture, which is capable of both leg shortening and lengthening, allows for stable running without adjusting leg stiffness. In contrast, in straight-legged human running, the preparation of the ground contact seems to be more critical, requiring leg stiffness adjustment to remain stable. Finally, analysis of a simple robustness measure, the normalized maximum drop, suggests that the crouched leg posture may provide greater robustness to changes in terrain height

Design and Evaluation of the AIRGAIT Exoskeleton: Leg Orthosis Control for Assistive Gait Rehabilitation

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Mohd Azuwan Mat Dzahir

2013-01-01

Full Text Available This paper introduces the body weight support gait training system known as the AIRGAIT exoskeleton and delves into the design and evaluation of its leg orthosis control algorithm. The implementation of the mono- and biarticular pneumatic muscle actuators (PMAs as the actuation system was initiated to generate more power and precisely control the leg orthosis. This research proposes a simple paradigm for controlling the mono- and bi-articular actuator movements cocontractively by introducing a cocontraction model. Three tests were performed. The first test involved control of the orthosis with monoarticular actuators alone without a subject (WO/S; the second involved control of the orthosis with mono- and bi-articular actuators tested WO/S; and the third test involved control of the orthosis with mono- and bi-articular actuators tested with a subject (W/S. Full body weight support (BWS was implemented in this study during the test W/S as the load supported by the orthosis was at its maximum capacity. This assessment will optimize the control system strategy so that the system operates to its full capacity. The results revealed that the proposed control strategy was able to co-contractively actuate the mono- and bi-articular actuators simultaneously and increase stiffness at both hip and knee joints.

Skipping on uneven ground: trailing leg adjustments simplify control and enhance robustness.

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Müller, Roy; Andrada, Emanuel

2018-01-01

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.

A prospective study of gait related risk factors for exercise-related lower leg pain.

Science.gov (United States)

Willems, T M; De Clercq, D; Delbaere, K; Vanderstraeten, G; De Cock, A; Witvrouw, E

2006-01-01

The purpose of this study was to determine prospectively gait related risk factors for exercise-related lower leg pain (ERLLP) in 400 physical education students. Static lower leg alignment was determined, and 3D gait kinematics combined with plantar pressure profiles were collected. After this evaluation, all sports injuries were registered by the same sports physician during the duration of the study. Forty six subjects developed ERLLP and 29 of them developed bilateral symptoms thus giving 75 symptomatic lower legs. Bilateral lower legs of 167 subjects who developed no injuries in the lower extremities served as controls. Cox regression analysis revealed that subjects who developed ERLLP had an altered running pattern before the injury compared to the controls and included (1) a significantly more central heel-strike, (2) a significantly increased pronation, accompanied with more pressure underneath the medial side of the foot, and (3) a significantly more lateral roll-off. These findings suggest that altered biomechanics play a role in the genesis of ERLLP and thus should be considered in prevention and rehabilitation.

Stiffness characteristics of compliant three segment leg with the self-stable region in slow and fast running

Energy Technology Data Exchange (ETDEWEB)

Kwak, Oh Seok; Ha, Sung Mok; Lee, Dong Ha [Convergence Research Center for WellnessDaegu Gyeongbuk Institute of Science and TechnologyDaegu (Korea, Republic of)

2016-12-15

In this paper, we propose the stiffness characteristics of compliant three segment leg that can have a self-stable region in slow and fast running. This proposition can contribute to reducing the control effort and enhancing the locomotion energy efficiency for the compliant three segment legged robot in slow and fast running. Previous research indicated that the running self-stable region of the spring-mass system is located in a relatively fast running region and that of the two segment leg is located in a relatively slow running region. In this paper, we analyze the stiffness characteristics of the spring-mass system and the two segment leg to explain the previous research results. From this analysis, we propose the stiffness characteristics of the compliant three segment leg with a self-stable region in slow and fast running. We further design the compliant three segment leg based on this proposition and check its structural stability. We examine the running self-stable region of this compliant three segment leg to determine whether it has a self-stable region in slow and fast running. We also examine the walking self-stable region of this compliant three segment leg.

Skeleton-Based Abnormal Gait Detection

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Trong-Nguyen Nguyen

2016-10-01

Full Text Available Human gait analysis plays an important role in musculoskeletal disorder diagnosis. Detecting anomalies in human walking, such as shuffling gait, stiff leg or unsteady gait, can be difficult if the prior knowledge of such a gait pattern is not available. We propose an approach for detecting abnormal human gait based on a normal gait model. Instead of employing the color image, silhouette, or spatio-temporal volume, our model is created based on human joint positions (skeleton in time series. We decompose each sequence of normal gait images into gait cycles. Each human instant posture is represented by a feature vector which describes relationships between pairs of bone joints located in the lower body. Such vectors are then converted into codewords using a clustering technique. The normal human gait model is created based on multiple sequences of codewords corresponding to different gait cycles. In the detection stage, a gait cycle with normality likelihood below a threshold, which is determined automatically in the training step, is assumed as an anomaly. The experimental results on both marker-based mocap data and Kinect skeleton show that our method is very promising in distinguishing normal and abnormal gaits with an overall accuracy of 90.12%.

Novel actuation design of a gait trainer with shadow leg approach.

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Meuleman, Jos; Meuleman, Jos; van Asseldonk, Edwin H F; van der Kooij, Herman

2013-06-01

Robotic gait training has developed since the end of the 20(th) century, yet there is much room for improvement in the design of the robots. With the conventional exoskeleton structures, donning of patients in a gait trainer usually is a cumbersome process due to the need of joint alignments and normal walking is often hindered due to obstructed arm swing. Our goal was to design a gait training robots that overcomes these limitations. We propose a novel design in which these drawbacks are reduced to a great amount. By using a parallel structure behind the patient (shadow leg) that is connected to the patient joints with rods, little alignment is needed, the area lateral to the hip is left free, and thus arm swing is not obstructed. The construction is lightweight, because the actuators are mounted on a fixed base and the transmission of power is executed with light weight rods. An end stop in the shadow leg prevents hyper extension of the patient's knee. The relationship between motor displacement and human joint rotations is nonlinear. In this paper we derive the nonlinear relationships between motors and patient joints and verify these. calculations with a measurement. The device has been built, now tests with subjects are required to assess if subjects can indeed walk normally in the robot.

Comparison of peritumoral stromal tissue stiffness obtained by shear wave elastography between benign and malignant breast lesions.

Science.gov (United States)

Park, Hye Sun; Shin, Hee Jung; Shin, Ki Chang; Cha, Joo Hee; Chae, Eun Young; Choi, Woo Jung; Kim, Hak Hee

2018-01-01

Background Aggressive breast cancers produce abnormal peritumoral stiff areas, which can differ between benign and malignant lesions and between different subtypes of breast cancer. Purpose To compare the tissue stiffness of the inner tumor, tumor border, and peritumoral stroma (PS) between benign and malignant breast masses by shear wave elastography (SWE). Material and Methods We enrolled 133 consecutive patients who underwent preoperative SWE. Using OsiriX commercial software, we generated multiple 2-mm regions of interest (ROIs) in a linear arrangement on the inner tumor, tumor border, and PS. We obtained the mean elasticity value (E mean ) of each ROI, and compared the E mean between benign and malignant tumors. Odds ratios (ORs) for prediction of malignancy were calculated. Subgroup analyses were performed among tumor subtypes. Results There were 85 malignant and 48 benign masses. The E mean of the tumor border and PS were significantly different between benign and malignant masses ( P benign and malignant masses. Malignant masses with a stiff rim were larger in size and associated with more aggressive pathologic subtypes.

Extension and customization of self-stability control in compliant legged systems

International Nuclear Information System (INIS)

Ernst, M; Blickhan, R; Geyer, H

2012-01-01

Several recent studies on the control of legged locomotion in animal and robot running focus on the influence of different leg parameters on gait stability. In a preceding investigation self-stability controls showing deadbeat behavior could be obtained by studying the dynamics of the system in dependence of the leg orientation carefully adjusted during the flight phase. Such controls allow to accommodate disturbances of the ground level without having to detect them. Here we further this method in two ways. Besides the leg orientation, we allow changes in leg stiffness during flight and show that this extension substantially improves the rejection of ground disturbances. In a human like example the tolerance of random variation in ground level over many steps increased from 3.5% to 35% of leg length. In single steps changes of about 70% leg length (either up or down) could be negotiated. The variable leg stiffness not only allows to start with flat leg orientations maximizing step tolerances but also increase the control subspace. This allows to customize self-stability controls and to consider physical and technical limitations found in animals and robots. (paper)

Preliminary Assessment of a Compliant Gait Exoskeleton.

Science.gov (United States)

Cestari, Manuel; Sanz-Merodio, Daniel; Garcia, Elena

2017-06-01

Current commercial wearable gait exoskeletons contain joints with stiff actuators that cannot adapt to unpredictable environments. These actuators consume a significant amount of energy, and their stiffness may not be appropriate for safe human-machine interactions. Adjustable compliant actuators are being designed and implemented because of their ability to minimize large forces due to shocks, to safely interact with the user, and to store and release energy in passive elastic elements. Introduction of such compliant actuation in gait exoskeletons, however, has been limited by the larger power-to-weight and volume ratio requirement. This article presents a preliminary assessment of the first compliant exoskeleton for children. Compliant actuation systems developed by our research group were integrated into the ATLAS exoskeleton prototype. The resulting device is a compliant exoskeleton, the ATLAS-C prototype. The exoskeleton is coupled with a special standing frame to provide balance while allowing a semi-natural gait. Experiments show that when comparing the behavior of the joints under different stiffness conditions, the inherent compliance of the implemented actuators showed natural adaptability during the gait cycle and in regions of shock absorption. Torque tracking of the joint is achieved, identifying the areas of loading response. The implementation of a state machine in the control of knee motion allowed reutilization of the stored energy during deflection at the end of the support phase to partially propel the leg and achieve a more natural and free swing.

Improved Leg Tracking Considering Gait Phase and Spline-Based Interpolation during Turning Motion in Walk Tests

Directory of Open Access Journals (Sweden)

Ayanori Yorozu

2015-09-01

Full Text Available Falling is a common problem in the growing elderly population, and fall-risk assessment systems are needed for community-based fall prevention programs. In particular, the timed up and go test (TUG is the clinical test most often used to evaluate elderly individual ambulatory ability in many clinical institutions or local communities. This study presents an improved leg tracking method using a laser range sensor (LRS for a gait measurement system to evaluate the motor function in walk tests, such as the TUG. The system tracks both legs and measures the trajectory of both legs. However, both legs might be close to each other, and one leg might be hidden from the sensor. This is especially the case during the turning motion in the TUG, where the time that a leg is hidden from the LRS is longer than that during straight walking and the moving direction rapidly changes. These situations are likely to lead to false tracking and deteriorate the measurement accuracy of the leg positions. To solve these problems, a novel data association considering gait phase and a Catmull–Rom spline-based interpolation during the occlusion are proposed. From the experimental results with young people, we confirm   that the proposed methods can reduce the chances of false tracking. In addition, we verify the measurement accuracy of the leg trajectory compared to a three-dimensional motion analysis system (VICON.

Bio-inspired control of joint torque and knee stiffness in a robotic lower limb exoskeleton using a central pattern generator.

Science.gov (United States)

Schrade, Stefan O; Nager, Yannik; Wu, Amy R; Gassert, Roger; Ijspeert, Auke

2017-07-01

Robotic lower limb exoskeletons are becoming increasingly popular in therapy and recreational use. However, most exoskeletons are still rather limited in their locomotion speed and the activities of daily live they can perform. Furthermore, they typically do not allow for a dynamic adaptation to the environment, as they are often controlled with predefined reference trajectories. Inspired by human leg stiffness modulation during walking, variable stiffness actuators increase flexibility without the need for more complex controllers. Actuation with adaptable stiffness is inspired by the human leg stiffness modulation during walking. However, this actuation principle also introduces the stiffness setpoint as an additional degree of freedom that needs to be coordinated with the joint trajectories. As a potential solution to this issue a bio-inspired controller based on a central pattern generator (CPG) is presented in this work. It generates coordinated joint torques and knee stiffness modulations to produce flexible and dynamic gait patterns for an exoskeleton with variable knee stiffness actuation. The CPG controller is evaluated and optimized in simulation using a model of the exoskeleton. The CPG controller produced stable and smooth gait for walking speeds from 0.4 m/s up to 1.57 m/s with a torso stabilizing force that simulated the use of crutches, which are commonly needed by exoskeleton users. Through the CPG, the knee stiffness intrinsically adapted to the frequency and phase of the gait, when the speed was changed. Additionally, it adjusted to changes in the environment in the form of uneven terrain by reacting to ground contact forces. This could allow future exoskeletons to be more adaptive to various environments, thus making ambulation more robust.

Asymmetry of Anticipatory Postural Adjustment During Gait Initiation

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Hiraoka Koichi

2014-10-01

Full Text Available The purpose of this study was to investigate the asymmetry of anticipatory postural adjustment (APA during gait initiation and to determine whether the process of choosing the initial swing leg affects APA during gait initiation. The participants initiated gait with the leg indicated by a start tone or initiated gait with the leg spontaneously chosen. The dependent variables of APA were not significantly different among the condition of initiating gait with the preferred leg indicated by the start tone, the condition of initiating gait with the non-preferred leg indicated by the start tone, and the condition of initiating gait with the leg spontaneously chosen. These findings fail to support the view that the process of choosing the initial swing leg affects APA during gait initiation. The lateral displacement of the center of pressure in the period in which shifting the center of pressure to the initial swing phase before initiating gait with the left leg indicated by the external cue was significantly larger than that when initiating gait with the right leg indicated by the external cue, and significantly larger than that when initiating gait with the leg spontaneously chosen. Weight shift to the initial swing side during APA during gait initiation was found to be asymmetrical when choosing the leg in response to an external cue

Biomechanical study on axillary crutches during single-leg swing-through gait.

Science.gov (United States)

Goh, J C; Toh, S L; Bose, K

1986-08-01

This paper describes a kinetic and kinematic study on axillary crutches during one-leg swing-through gait. The primary objective is to evaluate the interplay of forces at the crutch and body interfaces and to relate them in the understanding of problems associated with the use of axillary crutches. Ten normal adult male subjects with simulated left leg impairment participated in the study. For data acquisition, the VICON kinematic system, a Kistler force plate and an instrumented crutch (with force transducers at the two upper struts close to the axillary bar and one near the crutch tip) were used. Results showed that the peak ground reaction force on the weight-bearing leg during lower limb stance increased by 21.6 percent bodyweight. The peak reaction force transmitted to the arm during crutch stance was 44.4 percent bodyweight. These increased loadings could be detrimental to patients with unsound weight-bearing leg and upper extremities respectively. When the crutches were used incorrectly, 34 percent bodyweight was carried by the underarm. This could cause undue pressure over the neurovascular structures at the axillary region.

The impact of elbow and knee joint lesions on abnormal gait and posture of sows

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Jørgensen Bente

2008-02-01

Full Text Available Abstract Background Joint lesions occur widespread in the Danish sow population and they are the most frequent cause for euthanasia. Clinically, it is generally impossible to differentiate between various types of non-inflammatory joint lesions. Consequently, it is often necessary to perform a post mortem examination in order to diagnose these lesions. A study was performed in order to examine the relation of abnormal gait and posture in sows with specific joint lesions, and thereby obtaining a clinical diagnostic tool, to be used by farmers and veterinarians for the evaluation of sows with joint problems. Methods The gait, posture and lesions in elbow- and knee joints of 60 randomly selected sows from one herd were scored clinically and pathologically. Associations between the scorings were estimated. Results The variables 'fore- and hind legs turned out' and 'stiff in front and rear' were associated with lesions in the elbow joint, and the variables 'hind legs turned out' and 'stiff in rear' were associated with lesions in the knee joint. Conclusion It was shown that specified gait and posture variables reflected certain joint lesions. However, further studies are needed to strengthen and optimize the diagnostic tool.

High-speed Dynamic Gait Generation Based on Asymmetrization of Impact Posture Using Telescopic Legs

OpenAIRE

浅野, 文彦

2011-01-01

This paper proposes a novel method for generating a dynamic gait based on anterior-posterior asymmetric impact posture tilting the robo's center of mass forward. The primary purpose of this method is to asymmetrize the impact posture by actuating the robot's telescopic-legs to make overcoming the potential barrier at mid-stance easy, and the mechanical energy is accordingly restored. First, we introduce a planar rimless wheel model with telescopic legs, and investigate the validity of the sta...

Contributions of Hamstring Stiffness to Straight-Leg-Raise and Sit-and-Reach Test Scores.

Science.gov (United States)

Miyamoto, Naokazu; Hirata, Kosuke; Kimura, Noriko; Miyamoto-Mikami, Eri

2018-02-01

The passive straight-leg-raise (PSLR) and the sit-and-reach (SR) tests have been widely used to assess hamstring extensibility. However, it remains unclear to what extent hamstring stiffness (a measure of material properties) contributes to PSLR and SR test scores. Therefore, we aimed to clarify the relationship between hamstring stiffness and PSLR and SR scores using ultrasound shear wave elastography. Ninety-eight healthy subjects completed the study. Each subject completed PSLR testing, and classic and modified SR testing of the right leg. Muscle shear modulus of the biceps femoris, semitendinosus, and semimembranosus was quantified as an index of muscle stiffness. The relationships between shear modulus of each muscle and PSLR or SR scores were calculated using Pearson's product-moment correlation coefficients. Shear modulus of the semitendinosus and semimembranosus showed negative correlations with the two PSLR and two SR scores (absolute r value≤0.484). Shear modulus of the biceps femoris was significantly correlated with the PSLR score determined by the examiner and the modified SR score (absolute r value≤0.308). The present findings suggest that PSLR and SR test scores are strongly influenced by factors other than hamstring stiffness and therefore might not accurately evaluate hamstring stiffness. © Georg Thieme Verlag KG Stuttgart · New York.

Asymmetry of Anticipatory Postural Adjustment During Gait Initiation

OpenAIRE

Hiraoka, Koichi; Hatanaka, Ryota; Nikaido, Yasutaka; Jono, Yasutomo; Nomura, Yoshifumi; Tani, Keisuke; Chujo, Yuta

2014-01-01

The purpose of this study was to investigate the asymmetry of anticipatory postural adjustment (APA) during gait initiation and to determine whether the process of choosing the initial swing leg affects APA during gait initiation. The participants initiated gait with the leg indicated by a start tone or initiated gait with the leg spontaneously chosen. The dependent variables of APA were not significantly different among the condition of initiating gait with the preferred leg indicated by the...

Kinetic changes during a six-week minimal footwear and gait-retraining intervention in runners.

Science.gov (United States)

Warne, Joe P; Smyth, Barry P; Fagan, John O'C; Hone, Michelle E; Richter, Chris; Nevill, Alan M; Moran, Kieran A; Warrington, Giles D

2017-08-01

An evaluation of a six-week Combined minimal footwear transition and gait-retraining combination vs. gait retraining only on impact characteristics and leg stiffness. Twenty-four trained male runners were randomly assigned to either (1) Minimalist footwear transition Combined with gait-retraining over a six-week period ("Combined" group; n = 12) examined in both footwear, or (2) a gait-retraining group only with no minimalist footwear exposure ("Control"; n = 12). Participants were assessed for loading rate, impact peak, vertical, knee and ankle stiffness, and foot-strike using 3D and kinetic analysis. Loading rate was significantly higher in the Combined group in minimal shoes in pre-tests compared to a Control (P ≤ 0.001), reduced significantly in the Combined group over time (P ≤ 0.001), and was not different to the Control group in post-tests (P = 0.16). The impact peak (P = 0.056) and ankle stiffness reduced in both groups (P = 0.006). Loading rate and vertical stiffness was higher in minimalist footwear than conventional running shoes both pre (P ≤ 0.001) and post (P = 0.046) the intervention. There has a higher tendency to non-rearfoot strike in both interventions, but more acute changes in the minimalist footwear. A Combined intervention can potentially reduce impact variables. However, higher loading rate initially in minimalist footwear may increase the risk of injury in this condition.

Pneumatic Artificial Muscles Force Modelling and the Position and Stiffness Control on the Knee Joint of the Musculoskeletal Leg

Directory of Open Access Journals (Sweden)

Jingtao Lei

2017-03-01

Full Text Available Pneumatic artificial muscles (PAMs have properties similar to biological muscle and are widely used in robotics as actuators. A musculoskeletal leg mechanism driven by PAMs is presented in this paper. The joint stiffness of the musculoskeletal bionic leg for jumping movement needs to be analysed. The synchronous control on the position and stiffness of the joint is important to improve the flexibility of leg. The accurate force model of PAM is the foundation to achieving better control and dynamic jumping performance. The experimental platform of PAM is conducted, and the static equal pressure experiments are performed to obtain the PAM force model. According to the testing data, parameter identification method is adopted to determine the force model of PAM. A simulation on the position and stiffness control of the knee joint is performed, and the simulation results show the effectiveness of the presented method.

Relationships Between Lower-Body Muscle Structure and, Lower-Body Strength, Explosiveness and Eccentric Leg Stiffness in Adolescent Athletes

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Josh L. Secomb, Sophia Nimphius, Oliver R.L. Farley, Lina E. Lundgren, Tai T. Tran, Jeremy M. Sheppard

2015-12-01

Full Text Available The purpose of the present study was to determine whether any relationships were present between lower-body muscle structure and, lower-body strength, variables measured during a countermovement jump (CMJ and squat jump (SJ, and eccentric leg stiffness, in adolescent athletes. Thirty junior male (n = 23 and female (n = 7 surfing athletes (14.8 ± 1.7 y; 1.63 ± 0.09 m; 54.8 ± 12.1 kg undertook lower-body muscle structure assessment with ultrasonography and performed a; CMJ, SJ and an isometric mid-thigh pull (IMTP. In addition, eccentric leg stiffness was calculated from variables of the CMJ and IMTP. Moderate to very large relationships (r = 0.46-0.73 were identified between the thickness of the vastus lateralis (VL and lateral gastrocnemius (LG muscles, and VL pennation angle and; peak force (PF in the CMJ, SJ and IMTP. Additionally, moderate to large relationships (r = 0.37-0.59 were found between eccentric leg stiffness and; VL and LG thickness, VL pennation angle, and LG fascicle length, with a large relationship (r = 0.59 also present with IMTP PF. These results suggest that greater thickness of the VL and LG were related to improved maximal dynamic and isometric strength, likely due to increased hypertrophy of the extensor muscles. Furthermore, this increased thickness was related to greater eccentric leg stiffness, as the associated enhanced lower-body strength likely allowed for greater neuromuscular activation, and hence less compliance, during a stretch-shortening cycle.

The influence of applying additional weight to the affected leg on gait patterns during aquatic treadmill walking in people poststroke.

Science.gov (United States)

Jung, Taeyou; Lee, Dokyeong; Charalambous, Charalambos; Vrongistinos, Konstantinos

2010-01-01

Jung T, Lee D, Charalambous C, Vrongistinos K. The influence of applying additional weight to the affected leg on gait patterns during aquatic treadmill walking in people poststroke. To investigate how the application of additional weights to the affected leg influences gait patterns of people poststroke during aquatic treadmill walking. Comparative gait analysis. University-based aquatic therapy center. Community-dwelling volunteers (n=22) with chronic hemiparesis caused by stroke. Not applicable. Spatiotemporal and kinematic gait parameters. The use of an ankle weight showed an increase in the stance phase percentage of gait cycle (3%, P=.015) when compared with no weight. However, the difference was not significant after a Bonferroni adjustment was applied for a more stringent statistical analysis. No significant differences were found in cadence and stride length. The use of an ankle weight showed a significant decrease of the peak hip flexion (7.9%, P=.001) of the affected limb as compared with no weight condition. This decrease was marked as the reduction of unwanted limb flotation because people poststroke typically show excessive hip flexion of the paretic leg in the late swing phase followed by fluctuating hip movements during aquatic treadmill walking. The frontal and transverse plane hip motions did not show any significant differences but displayed a trend of a decrease in the peak hip abduction during the swing phase with additional weights. The use of additional weight did not alter sagittal plane kinematics of the knee and ankle joints. The use of applied weight on the affected limb can reduce unwanted limb flotation on the paretic side during aquatic treadmill walking. It can also assist the stance stability by increasing the stance phase percentage closer to 60% of gait cycle. Both findings can contribute to the development of more efficient motor patterns in gait training for people poststroke. The use of a cuff weight does not seem to reduce the

Treadmill training with an incline reduces ankle joint stiffness and improves active range of movement during gait in adults with cerebral palsy

DEFF Research Database (Denmark)

Lorentzen, Jakob; Kirk, Henrik; Fernandez-Lago, Helena

2017-01-01

of gait were obtained before and after the intervention/control period. Intervention subjects trained 31.4 SD 10.1 days for 29.0 SD 2.3 min (total) 15.2 h. RESULTS: Passive ankle joint stiffness was reduced (F = 5.1; p = 0.031), maximal gait speed increased (F = 42.8, p ...PURPOSE: We investigated if 30 min of daily treadmill training with an incline for 6 weeks would reduce ankle joint stiffness and improve active range of movement in adults with cerebral palsy (CP). METHODS: The study was designed as a randomized controlled clinical trial including 32 adults...... prior to heel strike increased (F = 5.3, p reduces ankle joint stiffness and increases active ROM during...

Subtle abnormalities of gait detected early in vitamin B6 deficiency in aged and weanling rats with hind leg gait analysis.

Science.gov (United States)

Schaeffer, M C; Cochary, E F; Sadowski, J A

1990-04-01

Motor abnormalities have been observed in every species made vitamin B6 deficient, and have been detected and quantified early in vitamin B6 deficiency in young adult female Long-Evans rats with hind leg gait analysis. Our objective was to determine if hind leg gait analysis could be used to detect vitamin B6 deficiency in weanling (3 weeks) and aged (23 months) Fischer 344 male rats. Rats (n = 10 per group) were fed: the control diet ad libitum (AL-CON); the control diet devoid of added pyridoxine hydrochloride (DEF); or the control diet pair-fed to DEF (PF-CON). At 10 weeks, plasma pyridoxal phosphate concentration confirmed deficiency in both age groups. Gait abnormalities were detected in the absence of gross motor disturbances in both aged and weanling DEF rats at 2-3 weeks. Width of step was significantly reduced (16%, p less than 0.003) in DEF aged rats compared to AL- and PF-CON. This pattern of response was similar to that reported previously in young adult rats. In weanling rats, pair feeding alone reduced mean width of step (+/- SEM) by 25% compared to ad libitum feeding (2.7 +/- 0.1 vs 3.6 +/- 0.1 cm for PF- vs AL-CON, respectively, p less than 0.05). In DEF weanling rats, width (3.0 +/- 0.1 cm) was increased compared to PF-CON (11%, p less than 0.05) but decreased compared to AL-CON (16%, p less than 0.05). Width of step was significantly altered early in B6 deficiency in rats of different ages and strains and in both sexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Robot-Crawler: Statically Balanced Gaits

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S. Parasuraman

2012-12-01

Full Text Available This paper presents a new statically balanced walking technique for a robot-crawler. The gait design and the control of the robot crawler aim to achieve stability while walking. This statically balanced gait has to be designed in a different fashion to a wheeled robot, as there are discrete changes in the support of the robot when its legs are lifted or placed on the ground. The stability of the robot depends on how the legs are positioned relative to the body and also on the sequence and timing with which the legs are lifted and placed. In order to reduce the risk of stability loss while walking, a measure for the robot stability (so-called stability margin is typically used in the gait and motion planning. In this paper different biological behaviours of four-legged animals are studied and mapped on a quad-legrobot-crawler. Experiments were carried out on the forward walking gaits of lizards and horses. Based on these results, the stability margins of different gaits are discussed and compared.

Effects of Quadriceps Muscle Fatigue on Stiff-Knee Gait in Patients with Hemiparesis

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Boudarham, Julien; Roche, Nicolas; Pradon, Didier; Delouf, Eric; Bensmail, Djamel; Zory, Raphael

2014-01-01

The relationship between neuromuscular fatigue and locomotion has never been investigated in hemiparetic patients despite the fact that, in the clinical context, patients report to be more spastic or stiffer after walking a long distance or after a rehabilitation session. The aim of this study was to evaluate the effects of quadriceps muscle fatigue on the biomechanical gait parameters of patients with a stiff-knee gait (SKG). Thirteen patients and eleven healthy controls performed one gait analysis before a protocol of isokinetic quadriceps fatigue and two after (immediately after and after 10 minutes of rest). Spatiotemporal parameters, sagittal knee and hip kinematics, rectus femoris (RF) and vastus lateralis (VL) kinematics and electromyographic (EMG) activity were analyzed. The results showed that quadriceps muscle weakness, produced by repetitive concentric contractions of the knee extensors, induced an improvement of spatiotemporal parameters for patients and healthy subjects. For the patient group, the increase in gait velocity and step length was associated with i) an increase of sagittal hip and knee flexion during the swing phase, ii) an increase of the maximal normalized length of the RF and VL and of the maximal VL lengthening velocity during the pre-swing and swing phases, and iii) a decrease in EMG activity of the RF muscle during the initial pre-swing phase and during the latter 2/3 of the initial swing phase. These results suggest that quadriceps fatigue did not alter the gait of patients with hemiparesis walking with a SKG and that neuromuscular fatigue may play the same functional role as an anti-spastic treatment such as botulinum toxin-A injection. Strength training of knee extensors, although commonly performed in rehabilitation, does not seem to be a priority to improve gait of these patients. PMID:24718087

Effect of boot shaft stiffness on stability joint energy and muscular co-contraction during walking on uneven surface.

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Böhm, Harald; Hösl, Matthias

2010-09-17

Increased boot shaft stiffness may have a noticeable impact on the range of motion of the ankle joint. Therefore, the ability of the ankle joint to generate power for propulsion might be impaired. This might result in compensatory changes at the knee and hip joint. Besides, adaptability of the subtalar joint to uneven surface might be reduced, which could in turn affect stability. The aim of the study was therefore to investigate the influence of boot shaft stiffness on biomechanical gait parameters. Fifteen healthy young adults walked over coarse gravel wearing two different hiking boots that differed by 50% in passive shaft stiffness. Leg kinematics, kinetics and electromyography were measured. Gait velocity and indicators for stability were not different when walking with the hard and soft boot shaft over the gravel surface. However, the hard boot shaft decreased the ankle range of motion as well as the eccentric energy absorbed at the ankle joint. As a consequence, compensatory changes at the knee joint were observed. Co-contraction was increased, and greater eccentric energy was absorbed. Therefore, the efficiency of gait with hard boots might be decreased and joint loading at the knee might be increased, which might cause early fatigue of knee muscles during walking or hiking. The results of this study suggest that stiffness and blocking of joint motion at the ankle should not be equated with safety. A trade-off between lateral stiffness and free natural motion of the ankle joint complex might be preferable.

The Effects of Varying Ankle Foot Orthosis Stiffness on Gait in Children with Spastic Cerebral Palsy Who Walk with Excessive Knee Flexion.

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Kerkum, Yvette L; Buizer, Annemieke I; van den Noort, Josien C; Becher, Jules G; Harlaar, Jaap; Brehm, Merel-Anne

2015-01-01

Rigid Ankle-Foot Orthoses (AFOs) are commonly prescribed to counteract excessive knee flexion during the stance phase of gait in children with cerebral palsy (CP). While rigid AFOs may normalize knee kinematics and kinetics effectively, it has the disadvantage of impeding push-off power. A spring-like AFO may enhance push-off power, which may come at the cost of reducing the knee flexion less effectively. Optimizing this trade-off between enhancing push-off power and normalizing knee flexion in stance is expected to maximize gait efficiency. This study investigated the effects of varying AFO stiffness on gait biomechanics and efficiency in children with CP who walk with excessive knee flexion in stance. Fifteen children with spastic CP (11 boys, 10±2 years) were prescribed with a ventral shell spring-hinged AFO (vAFO). The hinge was set into a rigid, or spring-like setting, using both a stiff and flexible performance. At baseline (i.e. shoes-only) and for each vAFO, a 3D-gait analysis and 6-minute walk test with breath-gas analysis were performed at comfortable speed. Lower limb joint kinematics and kinetics were calculated. From the 6-minute walk test, walking speed and the net energy cost were determined. A generalized estimation equation (ppush-off power did not lead to greater reductions in walking energy cost. These findings suggest that, in this specific group of children with spastic CP, the vAFO stiffness that maximizes gait efficiency is primarily determined by its effect on knee kinematics and kinetics rather than by its effect on push-off power. Dutch Trial Register NTR3418.

GaitKeeper: A System for Measuring Canine Gait

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Cassim Ladha

2017-02-01

Full Text Available It is understood gait has the potential to be used as a window into neurodegenerative disorders, identify markers of subclinical pathology, inform diagnostic algorithms of disease progression and measure the efficacy of interventions. Dogs’ gaits are frequently assessed in a veterinary setting to detect signs of lameness. Despite this, a reliable, affordable and objective method to assess lameness in dogs is lacking. Most described canine lameness assessments are subjective, unvalidated and at high risk of bias. This means reliable, early detection of canine gait abnormalities is challenging, which may have detrimental implications for dogs’ welfare. In this paper, we draw from approaches and technologies used in human movement science and describe a system for objectively measuring temporal gait characteristics in dogs (step-time, swing-time, stance-time. Asymmetries and variabilities in these characteristics are of known clinical significance when assessing lameness but presently may only be assessed on coarse scales or under highly instrumented environments. The system consists an inertial measurement unit, containing a 3-axis accelerometer and gyroscope coupled with a standardized walking course. The measurement unit is attached to each leg of the dog under assessment before it is walked around the course. The data by the measurement unit is then processed to identify steps and subsequently, micro-gait characteristics. This method has been tested on a cohort of 19 healthy dogs of various breeds ranging in height from 34.2 cm to 84.9 cm. We report the system as capable of making precise step delineations with detections of initial and final contact times of foot-to-floor to a mean precision of 0.011 s and 0.048 s, respectively. Results are based on analysis of 12,678 foot falls and we report a sensitivity, positive predictive value and F-score of 0.81, 0.83 and 0.82 respectively. To investigate the effect of gait on system performance

Effects of combined aerobic and resistance exercise on central arterial stiffness and gait velocity in patients with chronic poststroke hemiparesis.

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Lee, Yong Hee; Park, Soo Hyun; Yoon, Eun Sun; Lee, Chong-Do; Wee, Sang Ouk; Fernhall, Bo; Jae, Sae Young

2015-09-01

The effects of combined aerobic and resistance exercise training on central arterial stiffness and gait velocity in patients with chronic poststroke hemiparesis were investigated. Twenty-six patients with chronic poststroke hemiparesis were randomly assigned to either the combined aerobic and resistance exercise group (n = 14) or the control group (n = 12). The exercise intervention group received a combined aerobic and resistance exercise training (1 hr/day, three times/week for 16 wks), whereas the control group received usual care. Central arterial stiffness was determined by pulse wave velocity and augmentation index. Gait velocity was assessed using the 6-min walk test, 10-m walk test, and the Timed Up-and-Go test. Patients in the exercise intervention group had greater improvement of mean pulse wave velocity (P hemiparesis.

Neuromorphic walking gait control.

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Still, Susanne; Hepp, Klaus; Douglas, Rodney J

2006-03-01

We present a neuromorphic pattern generator for controlling the walking gaits of four-legged robots which is inspired by central pattern generators found in the nervous system and which is implemented as a very large scale integrated (VLSI) chip. The chip contains oscillator circuits that mimic the output of motor neurons in a strongly simplified way. We show that four coupled oscillators can produce rhythmic patterns with phase relationships that are appropriate to generate all four-legged animal walking gaits. These phase relationships together with frequency and duty cycle of the oscillators determine the walking behavior of a robot driven by the chip, and they depend on a small set of stationary bias voltages. We give analytic expressions for these dependencies. This chip reduces the complex, dynamic inter-leg control problem associated with walking gait generation to the problem of setting a few stationary parameters. It provides a compact and low power solution for walking gait control in robots.

The effects of onabotulinum toxin A injection into rectus femoris muscle in hemiplegic stroke patients with stiff-knee gait: a placebo-controlled, nonrandomized trial.

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Tok, Fatih; Balaban, Birol; Yaşar, Evren; Alaca, Rdvan; Tan, Arif Kenan

2012-04-01

This study aimed to compare the efficacy of onabotulinum toxin A (onabot) injection into the rectus femoris muscle with that of placebo in the treatment of hemiplegic stroke patients presenting with stiff-knee gait. Twenty-five chronic hemiparetic stroke patients presenting with a stiff-knee gait were included in this study. Fifteen patients received 100-125 U of onabot, and 10 patients received placebo into the rectus femoris muscle. Three-dimensional gait analysis, energy expenditure, 10-m and 6-min walk tests, and spasticity level of the rectus femoris were evaluated at baseline and 2 mos posttreatment. The mean age of patients who received onabot was 53.86 ± 14.74 yrs and of those who received placebo was 59.00 ± 8.11 yrs. At study onset, groups were similar with respect to all parameters (P > 0.05). We observed significant improvement in knee flexion (7 degrees average) during swing and a reduction in energy cost of 0.8-J/kg per meter response to injection of 100-125 U of onabot into the rectus femoris muscle. Onabot treatment significantly reduced muscle tone and improved knee kinematics, energy expenditure during walking, and functional assessments at 2 mos (P application of onabot into the rectus femoris muscle in stroke patients who presented with stiff-knee gait may be a treatment option to provide independent, safe, and less tiring ambulation.

Periodic gaits for the CMU Ambler

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Dwivedi, Suren N.; Mahalingam, Swaminathan

1992-02-01

The configuration of the Carnegie-Mellon University Ambler, a six-legged autonomous walking vehicle for exploring Mars, enables the recovery of a trailing leg past the leading leg to reduce the energy expenditure in terrain interactions. In this article, gaits developed for this unprecedented configuration are described. A stability criterion has been developed that ensures stability of the vehicle in the event of failure of any one of the supporting legs. Periodic gaits developed for the Ambler utilize the Ambler's unique abilities and continuously satisfy the stability criterion.

The effect of ankle foot orthosis stiffness on the energy cost of walking: a simulation study.

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Bregman, D J J; van der Krogt, M M; de Groot, V; Harlaar, J; Wisse, M; Collins, S H

2011-11-01

In stroke and multiple sclerosis patients, gait is frequently hampered by a reduced ability to push-off with the ankle caused by weakness of the plantar-flexor muscles. To enhance ankle push-off and to decrease the high energy cost of walking, spring-like carbon-composite Ankle Foot Orthoses are frequently prescribed. However, it is unknown what Ankle Foot Orthoses stiffness should be used to obtain the most efficient gait. The aim of this simulation study was to gain insights into the effect of variation in Ankle Foot Orthosis stiffness on the amount of energy stored in the Ankle Foot Orthosis and the energy cost of walking. We developed a two-dimensional forward-dynamic walking model with a passive spring at the ankle representing the Ankle Foot Orthosis and two constant torques at the hip for propulsion. We varied Ankle Foot Orthosis stiffness while keeping speed and step length constant. We found an optimal stiffness, at which the energy delivered at the hip joint was minimal. Energy cost decreased with increasing energy storage in the ankle foot orthosis, but the most efficient gait did not occur with maximal energy storage. With maximum storage, push-off occurred too late to reduce the impact of the contralateral leg with the floor. Maximum return prior to foot strike was also suboptimal, as push-off occurred too early and its effects were subsequently counteracted by gravity. The optimal Ankle Foot Orthosis stiffness resulted in significant push-off timed just prior to foot strike and led to greater ankle plantar-flexion velocity just before contralateral foot strike. Our results suggest that patient energy cost might be reduced by the proper choice of Ankle Foot Orthosis stiffness. Copyright © 2011 Elsevier Ltd. All rights reserved.

Artificial Leg Design and Control Research of a Biped Robot with Heterogeneous Legs Based on PID Control Algorithm

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Hualong Xie

2015-04-01

Full Text Available A biped robot with heterogeneous legs (BRHL is proposed to provide an ideal test-bed for intelligent bionic legs (IBL. To make artificial leg gait better suited to a human, a four-bar mechanism is used as its knee joint, and a pneumatic artificial muscle (PAM is used as its driving source. The static mathematical model of PAM is established and the mechanical model of a single degree of freedom of a knee joint driven by PAM is analyzed. A control simulation of an artificial leg based on PID control algorithm is carried out and the simulation results indicate that the artificial leg can simulate precisely a normal human walking gait.

Lower Body Stiffness Modulation Strategies in Well Trained Female Athletes.

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Millett, Emma L; Moresi, Mark P; Watsford, Mark L; Taylor, Paul G; Greene, David A

2016-10-01

Millett, EL, Moresi, MP, Watsford, ML, Taylor, PG, and Greene, DA. Lower body stiffness modulation strategies in well trained female athletes. J Strength Cond Res 30(10): 2845-2856, 2016-Lower extremity stiffness quantifies the relationship between the amount of leg compression and the external load to which the limb are subjected. This study aimed to assess differences in leg and joint stiffness and the subsequent kinematic and kinetic control mechanisms between athletes from various training backgrounds. Forty-seven female participants (20 nationally identified netballers, 13 high level endurance athletes and 14 age and gender matched controls) completed a maximal unilateral countermovement jump, drop jump and horizontal jump to assess stiffness. Leg stiffness, joint stiffness and associated mechanical parameters were assessed with a 10 camera motion analysis system and force plate. No significant differences were evident for leg stiffness measures between athletic groups for any of the tasks (p = 0.321-0.849). However, differences in joint stiffness and its contribution to leg stiffness, jump performance outcome measures and stiffness control mechanisms were evident between all groups. Practitioners should consider the appropriateness of the task utilised in leg stiffness screening. Inclusion of mechanistic and/or more sports specific tasks may be more appropriate for athletic groups.

Distal muscle activity alterations during the stance phase of gait in restless leg syndrome (RLS) patients.

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Dafkin, Chloe; Green, Andrew; Olivier, Benita; McKinon, Warrick; Kerr, Samantha

2018-05-01

To assess if there is a circadian variation in electromyographical (EMG) muscle activity during gait in restless legs syndrome (RLS) patients and healthy control participants. Gait assessment was done in 14 RLS patients and 13 healthy control participants in the evening (PM) and the morning (AM). Muscle activity was recorded bilaterally from the tibialis anterior (TA), lateral gastrocnemius (GL), rectus femoris (RF) and biceps femoris (BF) muscles. A circadian variation during the stance phase in only TA (PM > AM, p  Controls, p < 0.05) during early stance and decreased GL activity (RLS < Controls, p < 0.01) during terminal stance in comparison to control participants in the evening. No other significant differences were noted between RLS patients and control participants. Activation of GL during the swing phase was noted in 79% of RLS patients and in 23% of control participants in the morning compared to 71% and 38% in the evening, respectively. EMG muscle activity shows no circadian variation in RLS patients. Evening differences in gait muscle activation patterns between RLS patients and control participants are evident. These results extend our knowledge about alterations in spinal processing during gait in RLS. A possible explanation for these findings is central pattern generator sensitization caused by increased sensitivity in cutaneous afferents in RLS patients. Copyright © 2018 Elsevier B.V. All rights reserved.

A novel approach to gait synchronization and transition for reconfigurable walking platforms

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Shunsuke Nansai

2015-04-01

Full Text Available Legged robots based on one degree-of-freedom reconfigurable planar leg mechanisms, that are capable of generating multiple useful gaits, are highly desired due to the possibility of handling environments and tasks of high complexity while maintaining simple control schemes. An essential consideration in these reconfigurable legged robots is to attain stability in motion, at rest as well as while transforming from one configuration to another with the minimum number of legs as long as the full range of their walking patterns, resulting from the different gait cycles of their legs, is achieved. To this end, in this paper, we present a method for the generation of input joint trajectories to properly synchronize the movement of quadruped robots with reconfigurable legs. The approach is exemplified in a four-legged robot with reconfigurable Jansen legs capable of generating up to six useful different gait cycles. The proposed technique is validated through simulated results that show the platform׳s stability across its six feasible walking patterns and during gait transition phases, thus considerably extending the capabilities of the non-reconfigurable design.

The Effects of Varying Ankle Foot Orthosis Stiffness on Gait in Children with Spastic Cerebral Palsy Who Walk with Excessive Knee Flexion.

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Yvette L Kerkum

Full Text Available Rigid Ankle-Foot Orthoses (AFOs are commonly prescribed to counteract excessive knee flexion during the stance phase of gait in children with cerebral palsy (CP. While rigid AFOs may normalize knee kinematics and kinetics effectively, it has the disadvantage of impeding push-off power. A spring-like AFO may enhance push-off power, which may come at the cost of reducing the knee flexion less effectively. Optimizing this trade-off between enhancing push-off power and normalizing knee flexion in stance is expected to maximize gait efficiency. This study investigated the effects of varying AFO stiffness on gait biomechanics and efficiency in children with CP who walk with excessive knee flexion in stance. Fifteen children with spastic CP (11 boys, 10±2 years were prescribed with a ventral shell spring-hinged AFO (vAFO. The hinge was set into a rigid, or spring-like setting, using both a stiff and flexible performance. At baseline (i.e. shoes-only and for each vAFO, a 3D-gait analysis and 6-minute walk test with breath-gas analysis were performed at comfortable speed. Lower limb joint kinematics and kinetics were calculated. From the 6-minute walk test, walking speed and the net energy cost were determined. A generalized estimation equation (p<0.05 was used to analyze the effects of different conditions. Compared to shoes-only, all vAFOs improved the knee angle and net moment similarly. Ankle power generation and work were preserved only by the spring-like vAFOs. All vAFOs decreased the net energy cost compared to shoes-only, but no differences were found between vAFOs, showing that the effects of spring-like vAFOs to promote push-off power did not lead to greater reductions in walking energy cost. These findings suggest that, in this specific group of children with spastic CP, the vAFO stiffness that maximizes gait efficiency is primarily determined by its effect on knee kinematics and kinetics rather than by its effect on push-off power

Optimization of prosthetic foot stiffness to reduce metabolic cost and intact knee loading during below-knee amputee walking: a theoretical study.

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Fey, Nicholas P; Klute, Glenn K; Neptune, Richard R

2012-11-01

Unilateral below-knee amputees develop abnormal gait characteristics that include bilateral asymmetries and an elevated metabolic cost relative to non-amputees. In addition, long-term prosthesis use has been linked to an increased prevalence of joint pain and osteoarthritis in the intact leg knee. To improve amputee mobility, prosthetic feet that utilize elastic energy storage and return (ESAR) have been designed, which perform important biomechanical functions such as providing body support and forward propulsion. However, the prescription of appropriate design characteristics (e.g., stiffness) is not well-defined since its influence on foot function and important in vivo biomechanical quantities such as metabolic cost and joint loading remain unclear. The design of feet that improve these quantities could provide considerable advancements in amputee care. Therefore, the purpose of this study was to couple design optimization with dynamic simulations of amputee walking to identify the optimal foot stiffness that minimizes metabolic cost and intact knee joint loading. A musculoskeletal model and distributed stiffness ESAR prosthetic foot model were developed to generate muscle-actuated forward dynamics simulations of amputee walking. Dynamic optimization was used to solve for the optimal muscle excitation patterns and foot stiffness profile that produced simulations that tracked experimental amputee walking data while minimizing metabolic cost and intact leg internal knee contact forces. Muscle and foot function were evaluated by calculating their contributions to the important walking subtasks of body support, forward propulsion and leg swing. The analyses showed that altering a nominal prosthetic foot stiffness distribution by stiffening the toe and mid-foot while making the ankle and heel less stiff improved ESAR foot performance by offloading the intact knee during early to mid-stance of the intact leg and reducing metabolic cost. The optimal design also

The effects of stair climbing on arterial stiffness, blood pressure, and leg strength in postmenopausal women with stage 2 hypertension.

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Wong, Alexei; Figueroa, Arturo; Son, Won-Mok; Chernykh, Oksana; Park, Song-Young

2018-02-12

Menopause is accompanied by a progressive arterial stiffening associated with increases in blood pressure (BP) and decline in muscular function. It is crucial to prevent or reduce the negative effects of menopause on vascular and muscular function by implementing appropriate lifestyle interventions, such as exercise training. We examined the effects of a stair climbing (SC) regimen on arterial stiffness (pulse wave velocity [PWV]), BP, and leg strength in postmenopausal women with stage 2 hypertension. Using a parallel experimental design, participants were randomly assigned to either SC (n = 21) or nonexercising control group (n = 20) for 12 weeks. Participants in the SC group trained 4 d/wk, climbing 192 steps 2 to 5 times/d. Participants' brachial-to-ankle PWV (baPWV), BP, and leg strength were measured at baseline and after 12 weeks of their assigned intervention. There was a significant group by time interaction (P hypertensive postmenopausal women. The decrease in arterial stiffness partially explained the improvements in SBP and leg strength. SC may be an effective intervention in the prevention and treatment of menopause/aging-related vascular complications and muscle weakness.

Human Gait Feature Extraction Including a Kinematic Analysis toward Robotic Power Assistance

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Mario I. Chacon-Murguia

2012-09-01

Full Text Available The present work proposes a method for human gait and kinematic analysis. Gait analysis consists of the determination of hip, knee and ankle positions through video analysis. Gait kinematic for the thigh and knee is then generated from this data. Evaluations of the gait analysis method indicate an acceptable performance of 86.66% for hip and knee position estimation, and comparable findings with other reported works for gait kinematic. A coordinate systems assignment is performed according to the DH algorithm and a direct kinematic model of the legs is obtained. The legs' angles obtained from the video analysis are applied to the kinematic model in order to revise the application of this model to robotic legs in a power assisted system.

Lower limb progressive resistance training improves leg strength but not gait speed or balance in Parkinson's disease: a systematic review and meta-analysis.

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Tillman, Alex; Muthalib, Makii; Hendy, Ashlee M; Johnson, Liam G; Rantalainen, Timo; Kidgell, Dawson J; Enticott, Peter G; Teo, Wei-Peng

2015-01-01

The use of progressive resistance training (PRT) to improve gait and balance in people with Parkinson's disease (PD) is an emerging area of interest. However, the main effects of PRT on lower limb functions such as gait, balance, and leg strength in people with PD remain unclear. Therefore, the aim of the meta-analysis is to evaluate the evidence surrounding the use of PRT to improve gait and balance in people with PD. Five electronic databases, from inception to December 2014, were searched to identify the relevant studies. Data extraction was performed by two independent reviewers and methodological quality was assessed using the PEDro scale. Standardized mean differences (SMD) and 95% confidence intervals (CIs) of fixed and random effects models were used to calculate the effect sizes between experimental and control groups and I (2) statistics were used to determine levels of heterogeneity. In total, seven studies were identified consisting of 172 participants (experimental n = 84; control n = 88). The pooled results showed a moderate but significant effect of PRT on leg strength (SMD 1.42, 95% CI 0.464-2.376); however, no significant effects were observed for gait speed (SMD 0.418, 95% CI -0.219 to 1.055). No significant effects were observed for balance measures included in this review. In conclusion, our results showed no discernable effect of PRT on gait and balance measures, although this is likely due to the lack of studies available. It may be suggested that PRT be performed in conjunction with balance or task-specific functional training to elicit greater lower limb functional benefits in people with PD.

Effects of unilateral real-time biofeedback on propulsive forces during gait.

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Schenck, Christopher; Kesar, Trisha M

2017-06-06

In individuals with post-stroke hemiparesis, reduced push-off force generation in the paretic leg negatively impacts walking function. Gait training interventions that increase paretic push-off can improve walking function in individuals with neurologic impairment. During normal locomotion, push-off forces are modulated with variations in gait speed and slope. However, it is unknown whether able-bodied individuals can selectively modulate push-off forces from one leg in response to biofeedback. Here, in a group of young, neurologically-unimpaired individuals, we determined the effects of a real-time visual and auditory biofeedback gait training paradigm aimed at unilaterally increasing anteriorly-directed ground reaction force (AGRF) in the targeted leg. Ground reaction force data during were collected from 7 able-bodied individuals as they walked at a self-selected pace on a dual-belt treadmill instrumented with force platforms. During 11-min of gait training, study participants were provided real-time AGRF biofeedback encouraging a 20-30% increase in peak AGRF generated by their right (targeted) leg compared to their baseline (pre-training) AGRF. AGRF data were collected before, during, and after the biofeedback training period, as well as during two retention tests performed without biofeedback and after standing breaks. Compared to AGRFs generated during the pre-training gait trials, participants demonstrated a significantly greater AGRF in the targeted leg during and immediately after training, indicating that biofeedback training was successful at inducing increased AGRF production in the targeted leg. Additionally, participants continued to demonstrate greater AGRF production in the targeted leg after two standing breaks, showing short-term recall of the gait pattern learned during the biofeedback training. No significant effects of training were observed on the AGRF in the non-targeted limb, showing the specificity of the effects of biofeedback toward the

Grounded running in quails: simulations indicate benefits of observed fixed aperture angle between legs before touch-down.

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Andrada, Emanuel; Rode, Christian; Blickhan, Reinhard

2013-10-21

Many birds use grounded running (running without aerial phases) in a wide range of speeds. Contrary to walking and running, numerical investigations of this gait based on the BSLIP (bipedal spring loaded inverted pendulum) template are rare. To obtain template related parameters of quails (e.g. leg stiffness) we used x-ray cinematography combined with ground reaction force measurements of quail grounded running. Interestingly, with speed the quails did not adjust the swing leg's angle of attack with respect to the ground but adapted the angle between legs (which we termed aperture angle), and fixed it about 30ms before touchdown. In simulations with the BSLIP we compared this swing leg alignment policy with the fixed angle of attack with respect to the ground typically used in the literature. We found symmetric periodic grounded running in a simply connected subset comprising one third of the investigated parameter space. The fixed aperture angle strategy revealed improved local stability and surprising tolerance with respect to large perturbations. Starting with the periodic solutions, after step-down step-up or step-up step-down perturbations of 10% leg rest length, in the vast majority of cases the bipedal SLIP could accomplish at least 50 steps to fall. The fixed angle of attack strategy was not feasible. We propose that, in small animals in particular, grounded running may be a common gait that allows highly compliant systems to exploit energy storage without the necessity of quick changes in the locomotor program when facing perturbations. © 2013 Elsevier Ltd. All rights reserved.

Modeling of the pliant surfaces of the thigh and leg during gait

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Ball, Kevin A.; Pierrynowski, Michael R.

1998-05-01

Rigid Body Modeling, a 6 degree of freedom (DOF) method, provides state of the art human movement analysis, but with one critical limitation; it assumes segment rigidity. A non- rigid 12 DOF method, Pliant Surface Modeling (PSM) was developed to model the simultaneous pliant characteristics (scaling and shearing) of the human body's soft tissues. For validation, bone pins were surgically inserted into the tibia and femur of three volunteers. Infrared markers (44) were placed upon the thigh, leg, and bone pin surfaces. Two synchronized OPTOTRAK/3020TM cameras (Northern Digital Inc., Waterloo, ON) were used to record 120 seconds of treadmill gait per subject. In comparison to the 'gold standard' bone pin rotational results, PSM located the tibia, femur and tibiofemoral joint with root mean square (RMS) errors of 2.4 degrees, 4.0 degrees and 4.6 degrees, respectively. These performances met or exceeded (P less than .01) the current state of the art for surface data, Rigid Surface Modeling. The thigh's measured surface experienced uniform repeatable changes in scale: 40% mediolateral, 5% anterioposterior, 5% superioinferior, and planar shears of: 25 degrees transverse, 15 degrees sagittal, 5 degrees frontal. With the brief exception of push-off, the lower leg demonstrated much greater rigidity: less than 5% scaling and less than 5 degrees shearing. Thus, PSM offers superior 'rigid' estimates of knee motion with the ability to quantify 'pliant' surface changes.

Lower Limb Progressive Resistance Training Improves Leg Strength but Not Gait Speed or Balance in Parkinson’s Disease: A Systematic Review and Meta-Analysis

Science.gov (United States)

Tillman, Alex; Muthalib, Makii; Hendy, Ashlee M.; Johnson, Liam G.; Rantalainen, Timo; Kidgell, Dawson J.; Enticott, Peter G.; Teo, Wei-Peng

2015-01-01

The use of progressive resistance training (PRT) to improve gait and balance in people with Parkinson’s disease (PD) is an emerging area of interest. However, the main effects of PRT on lower limb functions such as gait, balance, and leg strength in people with PD remain unclear. Therefore, the aim of the meta-analysis is to evaluate the evidence surrounding the use of PRT to improve gait and balance in people with PD. Five electronic databases, from inception to December 2014, were searched to identify the relevant studies. Data extraction was performed by two independent reviewers and methodological quality was assessed using the PEDro scale. Standardized mean differences (SMD) and 95% confidence intervals (CIs) of fixed and random effects models were used to calculate the effect sizes between experimental and control groups and I2 statistics were used to determine levels of heterogeneity. In total, seven studies were identified consisting of 172 participants (experimental n = 84; control n = 88). The pooled results showed a moderate but significant effect of PRT on leg strength (SMD 1.42, 95% CI 0.464–2.376); however, no significant effects were observed for gait speed (SMD 0.418, 95% CI −0.219 to 1.055). No significant effects were observed for balance measures included in this review. In conclusion, our results showed no discernable effect of PRT on gait and balance measures, although this is likely due to the lack of studies available. It may be suggested that PRT be performed in conjunction with balance or task-specific functional training to elicit greater lower limb functional benefits in people with PD. PMID:25852550

A prospective study on gait-related intrinsic risk factors for lower leg overuse injuries.

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Ghani Zadeh Hesar, N; Van Ginckel, A; Cools, A; Peersman, W; Roosen, P; De Clercq, D; Witvrouw, E

2009-12-01

To determine prospectively gait-related risk factors for lower leg overuse injury (LLOI). A prospective cohort study. Male and female recruits from a start-to-run (STR) programme during a 10-week training period. 131 healthy subjects (20 men and 111 women), without a history of any lower leg complaint, participated in the study. Before the start of the 10-week STR programme, plantar force measurements during running were performed. During STR, lower leg injuries were diagnosed and registered by a sports physician. Plantar force measurements during running were performed using a footscan pressure plate. During the STR, 27 subjects (five men and 22 women) developed a LLOI. Logistic regression analysis revealed that subjects who developed a LLOI had a significantly more laterally directed force distribution at first metatarsal contact and forefoot flat, a more laterally directed force displacement in the forefoot contact phase, foot flat phase and at heel-off. These subjects also had a delayed change of the centre of force (COF) at forefoot flat, a higher force and loading underneath the lateral border of the foot, and a significantly higher directed force displacement of the COF at forefoot flat. These findings suggest that a less pronated heel strike and a more laterally directed roll-off can be considered as risk factors for LLOI. Clinically, the results of this study can be considered important in identifying individuals at risk of LLOI.

A mechanical energy analysis of gait initiation

Science.gov (United States)

Miller, C. A.; Verstraete, M. C.

1999-01-01

The analysis of gait initiation (the transient state between standing and walking) is an important diagnostic tool to study pathologic gait and to evaluate prosthetic devices. While past studies have quantified mechanical energy of the body during steady-state gait, to date no one has computed the mechanical energy of the body during gait initiation. In this study, gait initiation in seven normal male subjects was studied using a mechanical energy analysis to compute total body energy. The data showed three separate states: quiet standing, gait initiation, and steady-state gait. During gait initiation, the trends in the energy data for the individual segments were similar to those seen during steady-state gait (and in Winter DA, Quanbury AO, Reimer GD. Analysis of instantaneous energy of normal gait. J Biochem 1976;9:253-257), but diminished in amplitude. However, these amplitudes increased to those seen in steady-state during the gait initiation event (GIE), with the greatest increase occurring in the second step due to the push-off of the foundation leg. The baseline level of mechanical energy was due to the potential energy of the individual segments, while the cyclic nature of the data was indicative of the kinetic energy of the particular leg in swing phase during that step. The data presented showed differences in energy trends during gait initiation from those of steady state, thereby demonstrating the importance of this event in the study of locomotion.

Measuring Clearance Mechanics Based on Dynamic Leg Length

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Khamis, Sam; Danino, Barry; Hayek, Shlomo; Carmeli, Eli

2018-01-01

The aim of this study was to quantify clearance mechanics during gait. Seventeen children diagnosed with hemiplegic cerebral palsy underwent a three-dimensional gait analysis evaluation. Dynamic leg lengths were measured from the hip joint center to the heel, to the ankle joint center and to the forefoot throughout the gait cycle. Significant…

Relationship between activation of ankle muscles and quasi-joint stiffness in early and middle stances during gait in patients with hemiparesis.

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Sekiguchi, Yusuke; Muraki, Takayuki; Tanaka, Naofumi; Izumi, Shin-Ichi

2015-09-01

It is unclear whether muscle contraction is necessary to increase quasi-joint stiffness (QJS) of the ankle joint during gait in patients with hemiparesis. The purpose of the present study was to investigate the relationship between QJS and muscle activation at the ankle joint in the stance phase during gait in patients with hemiparesis. Spatiotemporal and kinetic gait parameters and activation of the medial head of the gastrocnemius (MG), soleus (SOL), and tibialis anterior (TA) muscles were measured using a 3-dimensional motion analysis system and surface electromyography, in 21 patients with hemiparesis due to stroke and 10 healthy individuals. In the early stance, the QJS on the paretic side (PS) of patients was greater than that on the non-PS (phemiparesis, plantarflexor activation may not contribute to QJS in the early stance. On the other hand, QJS in the middle stance may be attributed to activation of the MG and SOL. Our findings suggest that activation of the MG and SOL in the middle stance on the PS may require to be enhanced to increase QJS during gait in patients with hemiparesis. Copyright © 2015 Elsevier B.V. All rights reserved.

Modeling posture-dependent leg actuation in sagittal plane locomotion

International Nuclear Information System (INIS)

Schmitt, J; Clark, J

2009-01-01

The spring loaded inverted pendulum template has been shown to accurately model the steady locomotion dynamics of a variety of running animals, and has served as the inspiration for an entire class of dynamic running robots. While the template models the leg dynamics by an energy-conserving spring, insects and animals have structures that dissipate, store and produce energy during a stance phase. Recent investigations into the spring-like properties of limbs, as well as animal response to drop-step perturbations, suggest that animals use their legs to manage energy storage and dissipation, and that this management is important for gait stability. In this paper, we extend our previous analysis of control of the spring loaded inverted pendulum template via changes in the leg touch-down angle to include energy variations during the stance phase. Energy variations are incorporated through leg actuation that varies the force-free leg length during the stance phase, yet maintains qualitatively correct force and velocity profiles. In contrast to the partially asymptotically stable gaits identified in previous analyses, incorporating energy and leg angle variations in this manner produces complete asymptotic stability. Drop-step perturbation simulations reveal that the control strategy is rather robust, with gaits recovering from drops of up to 30% of the nominal hip height.

Restoration of ankle movements with the ActiGait implantable drop foot stimulator: a safe and reliable treatment option for permanent central leg palsy.

Science.gov (United States)

Martin, Klaus Daniel; Polanski, Witold Henryk; Schulz, Anne-Kathrin; Jöbges, Michael; Hoff, Hansjoerg; Schackert, Gabriele; Pinzer, Thomas; Sobottka, Stephan B

2016-01-01

OBJECT The ActiGait drop foot stimulator is a promising technique for restoration of lost ankle function by an implantable hybrid stimulation system. It allows ankle dorsiflexion by active peroneal nerve stimulation during the swing phase of gait. In this paper the authors report the outcome of the first prospective study on a large number of patients with stroke-related drop foot. METHODS Twenty-seven patients who experienced a stroke and with persisting spastic leg paresis received an implantable ActiGait drop foot stimulator for restoration of ankle movement after successful surface test stimulation. After 3 to 5 weeks, the stimulator was activated, and gait speed, gait endurance, and activation time of the system were evaluated and compared with preoperative gait tests. In addition, patient satisfaction was assessed using a questionnaire. RESULTS Postoperative gait speed significantly improved from 33.9 seconds per 20 meters to 17.9 seconds per 20 meters (p < 0.0001), gait endurance from 196 meters in 6 minutes to 401 meters in 6 minutes (p < 0.0001), and activation time from 20.5 seconds to 10.6 seconds on average (p < 0.0001). In 2 patients with nerve injury, surgical repositioning of the electrode cuff became necessary. One patient showed a delayed wound healing, and in another patient the system had to be removed because of a wound infection. Marked improvement in mobility, social participation, and quality of life was confirmed by 89% to 96% of patients. CONCLUSIONS The ActiGait implantable drop foot stimulator improves gait speed, endurance, and quality of life in patients with stroke-related drop foot. Regarding gait speed, the ActiGait system appears to be advantageous compared with foot orthosis or surface stimulation devices. Randomized trials with more patients and longer observation periods are needed to prove the long-term benefit of this device.

Is adult gait less susceptible than paediatric gait to hip joint centre regression equation error?

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Kiernan, D; Hosking, J; O'Brien, T

2016-03-01

Hip joint centre (HJC) regression equation error during paediatric gait has recently been shown to have clinical significance. In relation to adult gait, it has been inferred that comparable errors with children in absolute HJC position may in fact result in less significant kinematic and kinetic error. This study investigated the clinical agreement of three commonly used regression equation sets (Bell et al., Davis et al. and Orthotrak) for adult subjects against the equations of Harrington et al. The relationship between HJC position error and subject size was also investigated for the Davis et al. set. Full 3-dimensional gait analysis was performed on 12 healthy adult subjects with data for each set compared to Harrington et al. The Gait Profile Score, Gait Variable Score and GDI-kinetic were used to assess clinical significance while differences in HJC position between the Davis and Harrington sets were compared to leg length and subject height using regression analysis. A number of statistically significant differences were present in absolute HJC position. However, all sets fell below the clinically significant thresholds (GPS <1.6°, GDI-Kinetic <3.6 points). Linear regression revealed a statistically significant relationship for both increasing leg length and increasing subject height with decreasing error in anterior/posterior and superior/inferior directions. Results confirm a negligible clinical error for adult subjects suggesting that any of the examined sets could be used interchangeably. Decreasing error with both increasing leg length and increasing subject height suggests that the Davis set should be used cautiously on smaller subjects. Copyright © 2016 Elsevier B.V. All rights reserved.

Increasing trunk flexion transforms human leg function into that of birds despite different leg morphology.

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Aminiaghdam, Soran; Rode, Christian; Müller, Roy; Blickhan, Reinhard

2017-02-01

Pronograde trunk orientation in small birds causes prominent intra-limb asymmetries in the leg function. As yet, it is not clear whether these asymmetries induced by the trunk reflect general constraints on the leg function regardless of the specific leg architecture or size of the species. To address this, we instructed 12 human volunteers to walk at a self-selected velocity with four postures: regular erect, or with 30 deg, 50 deg and maximal trunk flexion. In addition, we simulated the axial leg force (along the line connecting hip and centre of pressure) using two simple models: spring and damper in series, and parallel spring and damper. As trunk flexion increases, lower limb joints become more flexed during stance. Similar to birds, the associated posterior shift of the hip relative to the centre of mass leads to a shorter leg at toe-off than at touchdown, and to a flatter angle of attack and a steeper leg angle at toe-off. Furthermore, walking with maximal trunk flexion induces right-skewed vertical and horizontal ground reaction force profiles comparable to those in birds. Interestingly, the spring and damper in series model provides a superior prediction of the axial leg force across trunk-flexed gaits compared with the parallel spring and damper model; in regular erect gait, the damper does not substantially improve the reproduction of the human axial leg force. In conclusion, mimicking the pronograde locomotion of birds by bending the trunk forward in humans causes a leg function similar to that of birds despite the different morphology of the segmented legs. © 2017. Published by The Company of Biologists Ltd.

Development of VariLeg, an exoskeleton with variable stiffness actuation: first results and user evaluation from the CYBATHLON 2016.

Science.gov (United States)

Schrade, Stefan O; Dätwyler, Katrin; Stücheli, Marius; Studer, Kathrin; Türk, Daniel-Alexander; Meboldt, Mirko; Gassert, Roger; Lambercy, Olivier

2018-03-13

Powered exoskeletons are a promising approach to restore the ability to walk after spinal cord injury (SCI). However, current exoskeletons remain limited in their walking speed and ability to support tasks of daily living, such as stair climbing or overcoming ramps. Moreover, training progress for such advanced mobility tasks is rarely reported in literature. The work presented here aims to demonstrate the basic functionality of the VariLeg exoskeleton and its ability to enable people with motor complete SCI to perform mobility tasks of daily life. VariLeg is a novel powered lower limb exoskeleton that enables adjustments to the compliance in the leg, with the objective of improving the robustness of walking on uneven terrain. This is achieved by an actuation system with variable mechanical stiffness in the knee joint, which was validated through test bench experiments. The feasibility and usability of the exoskeleton was tested with two paraplegic users with motor complete thoracic lesions at Th4 and Th12. The users trained three times a week, in 60 min sessions over four months with the aim of participating in the CYBATHLON 2016 competition, which served as a field test for the usability of the exoskeleton. The progress on basic walking skills and on advanced mobility tasks such as incline walking and stair climbing is reported. Within this first study, the exoskeleton was used with a constant knee stiffness. Test bench evaluation of the variable stiffness actuation system demonstrate that the stiffness could be rendered with an error lower than 30 Nm/rad. During training with the exoskeleton, both users acquired proficient skills in basic balancing, walking and slalom walking. In advanced mobility tasks, such as climbing ramps and stairs, only basic (needing support) to intermediate (able to perform task independently in 25% of the attempts) skill levels were achieved. After 4 months of training, one user competed at the CYBATHLON 2016 and was able to perform 3

Method for Walking Gait Identification in a Lower Extremity Exoskeleton Based on C4.5 Decision Tree Algorithm

Directory of Open Access Journals (Sweden)

Qing Guo

2015-04-01

Full Text Available A gait identification method for a lower extremity exoskeleton is presented in order to identify the gait sub-phases in human-machine coordinated motion. First, a sensor layout for the exoskeleton is introduced. Taking the difference between human lower limb motion and human-machine coordinated motion into account, the walking gait is divided into five sub-phases, which are ‘double standing’, ‘right leg swing and left leg stance’, ‘double stance with right leg front and left leg back’, ‘right leg stance and left leg swing’, and ‘double stance with left leg front and right leg back’. The sensors include shoe pressure sensors, knee encoders, and thigh and calf gyroscopes, and are used to measure the contact force of the foot, and the knee joint angle and its angular velocity. Then, five sub-phases of walking gait are identified by a C4.5 decision tree algorithm according to the data fusion of the sensors' information. Based on the simulation results for the gait division, identification accuracy can be guaranteed by the proposed algorithm. Through the exoskeleton control experiment, a division of five sub-phases for the human-machine coordinated walk is proposed. The experimental results verify this gait division and identification method. They can make hydraulic cylinders retract ahead of time and improve the maximal walking velocity when the exoskeleton follows the person's motion.

A cable-driven locomotor training system for restoration of gait in human SCI.

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Wu, Ming; Hornby, T George; Landry, Jill M; Roth, Heidi; Schmit, Brian D

2011-02-01

A novel cable-driven robotic locomotor training system was developed to provide compliant assistance/resistance forces to the legs during treadmill training in patients with incomplete spinal cord injury (SCI). Eleven subjects with incomplete SCI were recruited to participate in two experiments to test the feasibility of the robotic gait training system. Specifically, 10 subjects participated in one experimental session to test the characteristics of the robotic gait training system and one subject participated in repeated testing sessions over 8 weeks with the robotic device to test improvements in locomotor function. Limb kinematics were recorded in one experiment to evaluate the system characteristics of the cable-driven locomotor trainer and the overground gait speed and 6 min walking distance were evaluated at pre, 4 and 8 weeks post treadmill training of a single subject as well. The results indicated that the cable driven robotic gait training system improved the kinematic performance of the leg during treadmill walking and had no significant impact on the variability of lower leg trajectory, suggesting a high backdrivability of the cable system. In addition, results from a patient with incomplete SCI indicated that prolonged robotic gait training using the cable robot improved overground gait speed. Results from this study suggested that a cable driven robotic gait training system is effective in improving leg kinematic performance, yet allows variability of gait kinematics. Thus, it seems feasible to improve the locomotor function in human SCI using this cable driven robotic system, warranting testing with a larger group of patients. Copyright © 2010 Elsevier B.V. All rights reserved.

An online gait generator for quadruped walking using motor primitives

Directory of Open Access Journals (Sweden)

Chunlin Zhou

2016-11-01

Full Text Available This article presents implementation of an online gait generator on a quadruped robot. Firstly, the design of a quadruped robot is presented. The robot contains four leg modules each of which is constructed by a 2 degrees of freedom (2-DOF five-bar parallel linkage mechanism. Together with other two rotational DOF, the leg module is able to perform 4-DOF movement. The parallel mechanism of the robot allows all the servos attached on the body frame, so that the leg mass is decreased and motor load can be balanced. Secondly, an online gait generator based on dynamic movement primitives for the walking control is presented. Dynamic movement primitives provide an approach to generate periodic trajectories and they can be modulated in real time, which makes the online adjustment of walking gaits possible. This gait controller is tested by the quadruped robot in regulating walking speed, switching between forward\\backward movements and steering. The controller is easy to apply, expand and is quite effective on phase coordination and online trajectory modulation. Results of simulated experiments are presented.

Comparison of magnetic resonance elastography and diffusion-weighted imaging for differentiating benign and malignant liver lesions.

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Hennedige, Tiffany P; Hallinan, James Thomas Patrick Decourcy; Leung, Fiona P; Teo, Lynette Li San; Iyer, Sridhar; Wang, Gang; Chang, Stephen; Madhavan, Krishna Kumar; Wee, Aileen; Venkatesh, Sudhakar K

2016-02-01

Comparison of magnetic resonance elastography (MRE) and diffusion-weighted imaging (DWI) for differentiating malignant and benign focal liver lesions (FLLs). Seventy-nine subjects with 124 FLLs (44 benign and 80 malignant) underwent both MRE and DWI. MRE was performed with a modified gradient-echo sequence and DWI with a free breathing technique (b = 0.500). Apparent diffusion coefficient (ADC) maps and stiffness maps were generated. FLL mean stiffness and ADC values were obtained by placing regions of interest over the FLLs on stiffness and ADC maps. The accuracy of MRE and DWI for differentiation of benign and malignant FLL was compared using receiver operating curve (ROC) analysis. There was a significant negative correlation between stiffness and ADC (r = -0.54, p 4.54kPa) and DWI (cut-off, benign and malignant FLLs. • MRE is superior to DWI for differentiating benign and malignant focal liver lesions. • Benign lesions with large fibrous components may have higher stiffness with MRE. • Cholangiocarcinomas tend to have higher stiffness than hepatocellular carcinomas. • Hepatocellular adenomas tend to have lower stiffness than focal nodular hyperplasia. • MRE is superior to conventional MRI in differentiating benign and malignant liver lesions.

Simple analytical model reveals the functional role of embodied sensorimotor interaction in hexapod gaits

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Aoi, Shinya; Nachstedt, Timo; Manoonpong, Poramate; Wörgötter, Florentin; Matsuno, Fumitoshi

2018-01-01

Insects have various gaits with specific characteristics and can change their gaits smoothly in accordance with their speed. These gaits emerge from the embodied sensorimotor interactions that occur between the insect’s neural control and body dynamic systems through sensory feedback. Sensory feedback plays a critical role in coordinated movements such as locomotion, particularly in stick insects. While many previously developed insect models can generate different insect gaits, the functional role of embodied sensorimotor interactions in the interlimb coordination of insects remains unclear because of their complexity. In this study, we propose a simple physical model that is amenable to mathematical analysis to explain the functional role of these interactions clearly. We focus on a foot contact sensory feedback called phase resetting, which regulates leg retraction timing based on touchdown information. First, we used a hexapod robot to determine whether the distributed decoupled oscillators used for legs with the sensory feedback generate insect-like gaits through embodied sensorimotor interactions. The robot generated two different gaits and one had similar characteristics to insect gaits. Next, we proposed the simple model as a minimal model that allowed us to analyze and explain the gait mechanism through the embodied sensorimotor interactions. The simple model consists of a rigid body with massless springs acting as legs, where the legs are controlled using oscillator phases with phase resetting, and the governed equations are reduced such that they can be explained using only the oscillator phases with some approximations. This simplicity leads to analytical solutions for the hexapod gaits via perturbation analysis, despite the complexity of the embodied sensorimotor interactions. This is the first study to provide an analytical model for insect gaits under these interaction conditions. Our results clarified how this specific foot contact sensory

Task driven optimal leg trajectories in insect-scale legged microrobots

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Doshi, Neel; Goldberg, Benjamin; Jayaram, Kaushik; Wood, Robert

Origami inspired layered manufacturing techniques and 3D-printing have enabled the development of highly articulated legged robots at the insect-scale, including the 1.43g Harvard Ambulatory MicroRobot (HAMR). Research on these platforms has expanded its focus from manufacturing aspects to include design optimization and control for application-driven tasks. Consequently, the choice of gait selection, body morphology, leg trajectory, foot design, etc. have become areas of active research. HAMR has two controlled degrees-of-freedom per leg, making it an ideal candidate for exploring leg trajectory. We will discuss our work towards optimizing HAMR's leg trajectories for two different tasks: climbing using electroadhesives and level ground running (5-10 BL/s). These tasks demonstrate the ability of single platform to adapt to vastly different locomotive scenarios: quasi-static climbing with controlled ground contact, and dynamic running with un-controlled ground contact. We will utilize trajectory optimization methods informed by existing models and experimental studies to determine leg trajectories for each task. We also plan to discuss how task specifications and choice of objective function have contributed to the shape of these optimal leg trajectories.

Comparison of the Classifier Oriented Gait Score and the Gait Profile Score based on imitated gait impairments.

Science.gov (United States)

Christian, Josef; Kröll, Josef; Schwameder, Hermann

2017-06-01

Common summary measures of gait quality such as the Gait Profile Score (GPS) are based on the principle of measuring a distance from the mean pattern of a healthy reference group in a gait pattern vector space. The recently introduced Classifier Oriented Gait Score (COGS) is a pathology specific score that measures this distance in a unique direction, which is indicated by a linear classifier. This approach has potentially improved the discriminatory power to detect subtle changes in gait patterns but does not incorporate a profile of interpretable sub-scores like the GPS. The main aims of this study were to extend the COGS by decomposing it into interpretable sub-scores as realized in the GPS and to compare the discriminative power of the GPS and COGS. Two types of gait impairments were imitated to enable a high level of control of the gait patterns. Imitated impairments were realized by restricting knee extension and inducing leg length discrepancy. The results showed increased discriminatory power of the COGS for differentiating diverse levels of impairment. Comparison of the GPS and COGS sub-scores and their ability to indicate changes in specific variables supports the validity of both scores. The COGS is an overall measure of gait quality with increased power to detect subtle changes in gait patterns and might be well suited for tracing the effect of a therapeutic treatment over time. The newly introduced sub-scores improved the interpretability of the COGS, which is helpful for practical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Balance control during gait initiation: State-of-the-art and research perspectives.

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Yiou, Eric; Caderby, Teddy; Delafontaine, Arnaud; Fourcade, Paul; Honeine, Jean-Louis

2017-11-18

It is well known that balance control is affected by aging, neurological and orthopedic conditions. Poor balance control during gait and postural maintenance are associated with disability, falls and increased mortality. Gait initiation - the transient period between the quiet standing posture and steady state walking - is a functional task that is classically used in the literature to investigate how the central nervous system (CNS) controls balance during a whole-body movement involving change in the base of support dimensions and center of mass progression. Understanding how the CNS in able-bodied subjects exerts this control during such a challenging task is a pre-requisite to identifying motor disorders in populations with specific impairments of the postural system. It may also provide clinicians with objective measures to assess the efficiency of rehabilitation programs and better target interventions according to individual impairments. The present review thus proposes a state-of-the-art analysis on: (1) the balance control mechanisms in play during gait initiation in able bodied subjects and in the case of some frail populations; and (2) the biomechanical parameters used in the literature to quantify dynamic stability during gait initiation. Balance control mechanisms reviewed in this article included anticipatory postural adjustments, stance leg stiffness, foot placement, lateral ankle strategy, swing foot strike pattern and vertical center of mass braking. Based on this review, the following viewpoints were put forward: (1) dynamic stability during gait initiation may share a principle of homeostatic regulation similar to most physiological variables, where separate mechanisms need to be coordinated to ensure stabilization of vital variables, and consequently; and (2) rehabilitation interventions which focus on separate or isolated components of posture, balance, or gait may limit the effectiveness of current clinical practices.

Stable walking with asymmetric legs

International Nuclear Information System (INIS)

Merker, Andreas; Rummel, Juergen; Seyfarth, Andre

2011-01-01

Asymmetric leg function is often an undesired side-effect in artificial legged systems and may reflect functional deficits or variations in the mechanical construction. It can also be found in legged locomotion in humans and animals such as after an accident or in specific gait patterns. So far, it is not clear to what extent differences in the leg function of contralateral limbs can be tolerated during walking or running. Here, we address this issue using a bipedal spring-mass model for simulating walking with compliant legs. With the help of the model, we show that considerable differences between contralateral legs can be tolerated and may even provide advantages to the robustness of the system dynamics. A better understanding of the mechanisms and potential benefits of asymmetric leg operation may help to guide the development of artificial limbs or the design novel therapeutic concepts and rehabilitation strategies.

A method to differentiate the causes of stiff-knee gait in stroke patients.

Science.gov (United States)

Campanini, I; Merlo, A; Damiano, B

2013-06-01

Stiff-knee gait (SKG) is a common abnormal gait pattern in patients after stroke characterized by insufficient knee flexion (KF) during swing. Overactivity of the rectus femoris (RF) is considered the primary cause of SKG. Inadequate push-off has been indicated as an additional cause in the recent literature, as KF depends on knee flexion velocity in preswing (KFV). We used the peak of vertical acceleration of the malleolus (PMVA) as a kinematic-based indirect measure of push-off and studied its relationship with KF and KFV in a sample of 20 healthy subjects walking fast (v = 95 ± 5%heights(-1)), at self-selected speed (v = 74 ± 5%heights(-1)), slow (v = 54 ± 6%heights(-1)) and very slow (v = 38 ± 5%heights(-1)) and in a sample of 52 stroke patients with SKG (age 60 ± 11, v = 20 ± 11%heights(-1)). In healthy subjects PMVA occurred before knee flexion acceleration (ppush-off. From a regression analysis, the PMVA-KFV cause-effect relationship resulted strictly linear, with R(2) = 0.967, KFV = 0+7.1×PMVA, Ppush-off. Data from 8/52 patients only were statistically outside the 95%CI of the model, thus requiring for a braking mechanism to explain KFV reduction. In stroke adults of our sample the push-off impairment (85% of cases) and not the inappropriate knee extension moment produced by the thigh muscles was the primary cause of SKG. This result could explain the low average efficacy (push-off and braking activity of the thigh muscles, thus increasing the effectiveness of the selected treatment. Copyright © 2013 Elsevier B.V. All rights reserved.

Muscle stiffness of posterior lower leg in runners with a history of medial tibial stress syndrome.

Science.gov (United States)

Saeki, J; Nakamura, M; Nakao, S; Fujita, K; Yanase, K; Ichihashi, N

2018-01-01

Previous history of medial tibial stress syndrome (MTSS) is a risk factor for MTSS relapse, which suggests that there might be some physical factors that are related to MTSS development in runners with a history of MTSS. The relationship between MTSS and muscle stiffness can be assessed in a cross-sectional study that measures muscle stiffness in subjects with a history of MTSS, who do not have pain at the time of measurement, and in those without a history of MTSS. The purpose of this study was to compare the shear elastic modulus, which is an index of muscle stiffness, of all posterior lower leg muscles of subjects with a history of MTSS and those with no history and investigate which muscles could be related to MTSS. Twenty-four male collegiate runners (age, 20.0±1.7 years; height, 172.7±4.8 cm; weight, 57.3±3.7 kg) participated in this study; 14 had a history of MTSS, and 10 did not. The shear elastic moduli of the lateral gastrocnemius, medial gastrocnemius, soleus, peroneus longus, peroneus brevis, flexor hallucis longus, flexor digitorum longus, and tibialis posterior were measured using shear wave elastography. The shear elastic moduli of the flexor digitorum longus and tibialis posterior were significantly higher in subjects with a history of MTSS than in those with no history. However, there was no significant difference in the shear elastic moduli of other muscles. The results of this study suggest that flexor digitorum longus and tibialis posterior stiffness could be related to MTSS. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Implementing gait pattern control and transition for legged locomotion

International Nuclear Information System (INIS)

Yang, Zhijun; Karamanoglu, Mehmet; Rocha, Marlon V; França, Felipe M G; Lima, Priscila M V

2014-01-01

In this work, a generalised central pattern generator (CPG) model is formulated to generate a full range of gait patterns for a hexapod insect. To this end, a recurrent neuronal network module, as the building block for rhythmic patterns, is proposed to extend the concept of oscillatory building blocks (OBB) for constructing a CPG model. The model is able to make transitions between different gait patterns by simply adjusting one model parameter. Simulation results are further presented to show the effectiveness and performance of the CPG network

Gait analysis after successful mobile bearing total ankle replacement.

NARCIS (Netherlands)

Doets, H.C.; van Middelkoop, M.; Houdijk, J.H.P.; Nelissen, R.G.; Veeger, H.E.J.

2007-01-01

Background: The effect of total ankle replacement on gait is not fully known in terms of joint kinematics, ground reaction force, and activity of the muscles of the lower leg. Methods: A comparative gait study was done in 10 patients after uneventful unilateral mobile-bearing total ankle replacement

Generating high-speed dynamic running gaits in a quadruped robot using an evolutionary search.

Science.gov (United States)

Krasny, Darren P; Orin, David E

2004-08-01

Over the past several decades, there has been a considerable interest in investigating high-speed dynamic gaits for legged robots. While much research has been published, both in the biomechanics and engineering fields regarding the analysis of these gaits, no single study has adequately characterized the dynamics of high-speed running as can be achieved in a realistic, yet simple, robotic system. The goal of this paper is to find the most energy-efficient, natural, and unconstrained gallop that can be achieved using a simulated quadrupedal robot with articulated legs, asymmetric mass distribution, and compliant legs. For comparison purposes, we also implement the bound and canter. The model used here is planar, although we will show that it captures much of the predominant dynamic characteristics observed in animals. While it is not our goal to prove anything about biological locomotion, the dynamic similarities between the gaits we produce and those found in animals does indicate a similar underlying dynamic mechanism. Thus, we will show that achieving natural, efficient high-speed locomotion is possible even with a fairly simple robotic system. To generate the high-speed gaits, we use an efficient evolutionary algorithm called set-based stochastic optimization. This algorithm finds open-loop control parameters to generate periodic trajectories for the body. Several alternative methods are tested to generate periodic trajectories for the legs. The combined solutions found by the evolutionary search and the periodic-leg methods, over a range of speeds up to 10.0 m/s, reveal "biological" characteristics that are emergent properties of the underlying gaits.

Toward Balance Recovery With Leg Prostheses Using Neuromuscular Model Control

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Geyer, Hartmut

2016-01-01

Objective Lower limb amputees are at high risk of falling as current prosthetic legs provide only limited functionality for recovering balance after unexpected disturbances. For instance, the most established control method used on powered leg prostheses tracks local joint impedance functions without taking the global function of the leg in balance recovery into account. Here we explore an alternative control policy for powered transfemoral prostheses that considers the global leg function and is based on a neuromuscular model of human locomotion. Methods We adapt this model to describe and simulate an amputee walking with a powered prosthesis using the proposed control, and evaluate the gait robustness when confronted with rough ground and swing leg disturbances. We then implement and partially evaluate the resulting controller on a leg prosthesis prototype worn by a non-amputee user. Results In simulation, the proposed prosthesis control leads to gaits that are more robust than those obtained by the impedance control method. The initial hardware experiments with the prosthesis prototype show that the proposed control reproduces normal walking patterns qualitatively and effectively responds to disturbances in early and late swing. However, the response to mid-swing disturbances neither replicates human responses nor averts falls. Conclusions The neuromuscular model control is a promising alternative to existing prosthesis controls, although further research will need to improve on the initial implementation and determine how well these results transfer to amputee gait. Significance This work provides a potential avenue for future development of control policies that help improve amputee balance recovery. PMID:26315935

Reduced prosthetic stiffness lowers the metabolic cost of running for athletes with bilateral transtibial amputations.

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Beck, Owen N; Taboga, Paolo; Grabowski, Alena M

2017-04-01

Inspired by the springlike action of biological legs, running-specific prostheses are designed to enable athletes with lower-limb amputations to run. However, manufacturer's recommendations for prosthetic stiffness and height may not optimize running performance. Therefore, we investigated the effects of using different prosthetic configurations on the metabolic cost and biomechanics of running. Five athletes with bilateral transtibial amputations each performed 15 trials on a force-measuring treadmill at 2.5 or 3.0 m/s. Athletes ran using each of 3 different prosthetic models (Freedom Innovations Catapult FX6, Össur Flex-Run, and Ottobock 1E90 Sprinter) with 5 combinations of stiffness categories (manufacturer's recommended and ± 1) and heights (International Paralympic Committee's maximum competition height and ± 2 cm) while we measured metabolic rates and ground reaction forces. Overall, prosthetic stiffness [fixed effect (β) = 0.036; P = 0.008] but not height ( P ≥ 0.089) affected the net metabolic cost of transport; less stiff prostheses reduced metabolic cost. While controlling for prosthetic stiffness (in kilonewtons per meter), using the Flex-Run (β = -0.139; P = 0.044) and 1E90 Sprinter prostheses (β = -0.176; P = 0.009) reduced net metabolic costs by 4.3-4.9% compared with using the Catapult prostheses. The metabolic cost of running improved when athletes used prosthetic configurations that decreased peak horizontal braking ground reaction forces (β = 2.786; P = 0.001), stride frequencies (β = 0.911; P < 0.001), and leg stiffness values (β = 0.053; P = 0.009). Remarkably, athletes did not maintain overall leg stiffness across prosthetic stiffness conditions. Rather, the in-series prosthetic stiffness governed overall leg stiffness. The metabolic cost of running in athletes with bilateral transtibial amputations is influenced by prosthetic model and stiffness but not height. NEW & NOTEWORTHY We measured the

Controlling propulsive forces in gait initiation in transfemoral amputees

NARCIS (Netherlands)

van Keeken, Helco G.; Vrieling, Aline H.; Hof, At L.; Halbertsma, Jan P. K.; Schoppen, Tanneke; Postema, Klaas; Otten, Bert

During prosthetic gait initiation, transfemoral (TF) amputees control the spatial and temporal parameters that modulate the propulsive forces, the positions of the center of pressure (CoP), and the center of mass (CoM). Whether their sound leg or the prosthetic leg is leading, the TF amputees reach

Shear-wave elastography and greyscale assessment of palpable probably benign masses: is biopsy always required?

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Giannotti, Elisabetta; Vinnicombe, Sarah; Thomson, Kim; McLean, Dennis; Purdie, Colin; Jordan, Lee; Evans, Andy

2016-06-01

To establish if palpable breast masses with benign greyscale ultrasound features that are soft on shear-wave elastography (SWE) (mean stiffness masses at ultrasound. All underwent ultrasound, SWE and needle core biopsy. Static greyscale images were retrospectively assigned Breast Imaging Reporting and Data System (BI-RADS) scores by two readers blinded to the SWE and pathology findings, but aware of the patient's age. A mean stiffness of 50 kPa was used as the SWE cut-off for calling a lesion soft or stiff. Histological findings were used to establish ground truth. No cancer had benign characteristics on both modalities. 466 (99.8%) of the 467 cancers were classified BI-RADS 4a or above. The one malignant lesion classified as BI-RADS 3 was stiff on SWE. 446 (96%) of the 467 malignancies were stiff on SWE. No cancer in females under 40 years had benign SWE features. 74 (32.6%) of the 227 benign lesions were BI-RADS 3 and soft on SWE; so, biopsy could potentially have been avoided in this group. Lesions which appear benign on greyscale ultrasound and SWE do not require percutaneous biopsy or short-term follow-up, particularly in females under 40 years. None of the cancers had benign characteristics on both greyscale ultrasound and SWE, and 32% of benign lesions were BI-RADS 3 and soft on SWE; lesions that are benign on both ultrasound and SWE may not require percutaneous biopsy or short-term follow-up.

Electromyographic Pattern during Gait Initiation Differentiates Yoga Practitioners among Physically Active Older Subjects

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Thierry Lelard

2017-06-01

Full Text Available During gait initiation, postural adjustments are needed to deal with balance and movement. With aging, gait initiation changes and reflects functional degradation of frailty individuals. However, physical activities have demonstrated beneficial effects of daily motor tasks. The aim of our study was to compare center of pressure (COP displacement and ankle muscle co-activation during gait initiation in two physically active groups: a group of walkers (n = 12; mean age ± SD 72.6 ± 3.2 years and a yoga group (n = 11; 71.5 ± 3.8 years. COP trajectory and electromyography of leg muscles were recorded simultaneously during five successive trials of gait initiation. Our main finding was that yoga practitioners had slower COP displacements (p < 0.01 and lower leg muscles % of coactivation (p < 0.01 in comparison with walkers. These parameters which characterized gait initiation control were correlated (r = 0.76; p < 0.01. Our results emphasize that lengthy ankle muscle co-activation and COP path in gait initiation differentiate yoga practitioners among physically active subjects.

Kinematic analysis quantifies gait abnormalities associated with lameness in broiler chickens and identifies evolutionary gait differences.

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Gina Caplen

Full Text Available This is the first time that gait characteristics of broiler (meat chickens have been compared with their progenitor, jungle fowl, and the first kinematic study to report a link between broiler gait parameters and defined lameness scores. A commercial motion-capturing system recorded three-dimensional temporospatial information during walking. The hypothesis was that the gait characteristics of non-lame broilers (n = 10 would be intermediate to those of lame broilers (n = 12 and jungle fowl (n = 10, tested at two ages: immature and adult. Data analysed using multi-level models, to define an extensive range of baseline gait parameters, revealed inter-group similarities and differences. Natural selection is likely to have made jungle fowl walking gait highly efficient. Modern broiler chickens possess an unbalanced body conformation due to intense genetic selection for additional breast muscle (pectoral hypertrophy and whole body mass. Together with rapid growth, this promotes compensatory gait adaptations to minimise energy expenditure and triggers high lameness prevalence within commercial flocks; lameness creating further disruption to the gait cycle and being an important welfare issue. Clear differences were observed between the two lines (short stance phase, little double-support, low leg lift, and little back displacement in adult jungle fowl; much double-support, high leg lift, and substantial vertical back movement in sound broilers presumably related to mass and body conformation. Similarities included stride length and duration. Additional modifications were also identified in lame broilers (short stride length and duration, substantial lateral back movement, reduced velocity presumably linked to musculo-skeletal abnormalities. Reduced walking velocity suggests an attempt to minimise skeletal stress and/or discomfort, while a shorter stride length and time, together with longer stance and double-support phases, are associated

Association between Thigh Muscle Volume and Leg Muscle Power in Older Women.

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Ulrich Lindemann

Full Text Available The construct of sarcopenia is still discussed with regard to best appropriate measures of muscle volume and muscle function. The aim of this post-hoc analysis of a cross-sectional experimental study was to investigate and describe the hierarchy of the association between thigh muscle volume and measurements of functional performance in older women. Thigh muscle volume of 68 independently living older women (mean age 77.6 years was measured via magnetic resonance imaging. Isometric strength was assessed for leg extension in a movement laboratory in sitting position with the knee flexed at 90° and for hand grip. Maximum and habitual gait speed was measured on an electronic walk way. Leg muscle power was measured during single leg push and during sit-to-stand performance. Thigh muscle volume was associated with sit-to-stand performance power (r = 0.628, leg push power (r = 0.550, isometric quadriceps strength (r = 0.442, hand grip strength (r = 0.367, fast gait speed (r = 0.291, habitual gait speed (r = 0.256, body mass index (r = 0.411 and age (r = -0.392. Muscle power showed the highest association with thigh muscle volume in healthy older women. Sit-to-stand performance power showed an even higher association with thigh muscle volume compared to single leg push power.

Prevention of Potential Falls of Elderly Healthy Women: Gait Asymmetry

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Seo, Jung-suk; Kim, Sukwon

2014-01-01

The study attempted to see if exercise training would alleviate gait asymmetry between nondominant and dominant legs, thus, eliminate the likelihood of slips. The present study provided 18 older adults exercise training for eight weeks and evaluated kinematics and ground reaction forces (GRFs) in both legs. Participants were randomly assigned to…

Stiff person case misdiagnosed as conversion disorder: A case report.

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Razmeh, Saeed; Habibi, Amir Hasan; Sina, Farzad; Alizadeh, Elham; Eslami, Monireh

2017-01-01

Stiff person syndrome (SPS) is a rare neurological disease resulting in stiffness and spasm of muscles. It initially affects the axial muscles and then spread to limb muscles. Emotional stress exacerbated the symptoms and signs of the disease. The pathophysiology of the disease is caused by the decreased level of the glutamic acid decarboxylase (GAD) activity due to an autoantibody against GAD that decreases the level of gamma-aminobutyric acid (GABA). In this paper, we present a case of atypical presentation of SPS with lower limb stiffness misdiagnosed as conversion disorder. We report a patient with atypical presentation of SPS with lower limb stiffness and gait disorder misdiagnosed as conversion disorder for a year. Her antithyroid peroxidase antibody (anti-TPO Ab) level was 75 IU (normal value: 0-34 IU). Intravenous immunoglobulin (IVIG) was administered (2gr/kg, 5 days) for the patient that showed significant improvement in the follow-up visit. It is essential that in any patient with bizarre gait disorder and suspicious to conversion disorder due to the reversibility of symptoms, SPS and other movement disorder should be considered.

Intensive gait training in toddlers with cerebral palsy: A pilot study

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Anna Herskind

2016-07-01

Full Text Available Background: Reduced muscle growth may be involved in the development of contractures in children with cerebral palsy (CP. Here, we report data from a pilot study of intensive gait training in CP toddlers. Methods: Five children with CP aged 8-30 months performed activity-based gait training for one hour/day, five days/week for three consecutive months. Included children were diagnosed with spastic CP, had a Gross Motor Function Classification System (GMFCS score of I–II, and were not epileptic. All children wore pedometers during training. Before and after the training period, kinematic and qualitative gait analysis, clinical and objective evaluation of spasticity, Gross Motor Function Measure-66 (GMFM-66, and ultrasound of the affected medial gastrocnemius (MG muscle were performed. Two children were also tested before and after three months of receiving only standard care (SC. Results: On average 1410 steps/session were logged during 63 days of training. More steps were achieved at home than at a central facility. During training, MG muscle volume increased significantly, while it decreased for SC children. Gait improved qualitatively in all children, and GMFM-66 score improved in four of the five children. Similar improvements were seen among the SC children. Two children had pathologically increased muscle stiffness prior to training, which was reduced during training. Reflex stiffness was unchanged in all five children. Conclusions: This pilot study suggests that intensive gait training may increase muscle volume, improve walking skills and reduce passive muscle stiffness in toddlers with CP.

Gait retraining as part of the treatment programme for soldiers with ...

African Journals Online (AJOL)

Background: Gait retraining as part of a treatment programme for exercise-related leg pain (ERLP) was introduced in the sports medicine department of the Royal ... Conclusion: Soldiers with exercise-related leg pain (ERLP), among them patients with Medial Tibial Stress Syndrome, respond well to a treatment programme ...

Spring-like leg behaviour, musculoskeletal mechanics and control in maximum and submaximum height human hopping

NARCIS (Netherlands)

Bobbert, M.F.

2011-01-01

The purpose of this study was to understand how humans regulate their 'leg stiffness' in hopping, and to determine whether this regulation is intended to minimize energy expenditure. 'Leg stiffness' is the slope of the relationship between ground reaction force and displacement of the centre of mass

The Influence of Ambulatory Aid on Lower-Extremity Muscle Activation During Gait.

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Sanders, Michael; Bowden, Anton E; Baker, Spencer; Jensen, Ryan; Nichols, McKenzie; Seeley, Matthew K

2018-05-10

Foot and ankle injuries are common and often require a nonweight-bearing period of immobilization for the involved leg. This nonweight-bearing period usually results in muscle atrophy for the involved leg. There is a dearth of objective data describing muscle activation for different ambulatory aids that are used during the aforementioned nonweight-bearing period. To compare activation amplitudes for 4 leg muscles during (1) able-bodied gait and (2) ambulation involving 3 different ambulatory aids that can be used during the acute phase of foot and ankle injury care. Within-subject, repeated measures. University biomechanics laboratory. Sixteen able-bodied individuals (7 females and 9 males). Each participant performed able-bodied gait and ambulation using 3 different ambulatory aids (traditional axillary crutches, knee scooter, and a novel lower-leg prosthesis). Muscle activation amplitude quantified via mean surface electromyography amplitude throughout the stance phase of ambulation. Numerous statistical differences (P < .05) existed for muscle activation amplitude between the 4 observed muscles, 3 ambulatory aids, and able-bodied gait. For the involved leg, comparing the 3 ambulatory aids: (1) knee scooter ambulation resulted in the greatest vastus lateralis activation, (2) ambulation using the novel prosthesis and traditional crutches resulted in greater biceps femoris activation than knee scooter ambulation, and (3) ambulation using the novel prosthesis resulted in the greatest gastrocnemius activation (P < .05). Generally speaking, muscle activation amplitudes were most similar to able-bodied gait when subjects were ambulating using the knee scooter or novel prosthesis. Type of ambulatory aid influences muscle activation amplitude. Traditional axillary crutches appear to be less likely to mitigate muscle atrophy during the nonweighting, immobilization period that often follows foot or ankle injuries. Researchers and clinicians should consider

THE RELATION BETWEEN MILD LEG-LENGTH INEQUALITY AND ABLE-BODIED GAIT ASYMMETRY

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Matthew K. Seeley

2010-12-01

Full Text Available The causes of able-bodied gait asymmetries are unclear. Mild ( 1 cm; n = 7. Statistically significant relationships were observed between LLI and the symmetry coefficient for knee joint moment (r = -0.48 and power (r = -0.51, and ankle joint moment (r = -0.41 and power (r = -0.42. Similarly, subjects with relatively large LLI exhibited significantly lower symmetry coefficients for knee joint moment (p = 0.40 and power (p = 0.35, and ankle joint moment (p = 0.40 and power (p = 0.22 than subjects with relatively small LLI. Degree of bilateral symmetry for knee and ankle joint kinetics appears to be related to LLI in able- bodied gait. This finding supports the idea that LLI is one cause of able-bodied gait asymmetries. Other factors, however, are also likely to contribute to these gait asymmetries; these may include other morphological asymmetries as well as asymmetrical neuromuscular input to the lower limb muscles

Gait characteristics under different walking conditions: Association with the presence of cognitive impairment in community-dwelling older people.

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Anne-Marie De Cock

Full Text Available Gait characteristics measured at usual pace may allow profiling in patients with cognitive problems. The influence of age, gender, leg length, modified speed or dual tasking is unclear.Cross-sectional analysis was performed on a data registry containing demographic, physical and spatial-temporal gait parameters recorded in five walking conditions with a GAITRite® electronic carpet in community-dwelling older persons with memory complaints. Four cognitive stages were studied: cognitively healthy individuals, mild cognitive impaired patients, mild dementia patients and advanced dementia patients.The association between spatial-temporal gait characteristics and cognitive stages was the most prominent: in the entire study population using gait speed, steps per meter (translation for mean step length, swing time variability, normalised gait speed (corrected for leg length and normalised steps per meter at all five walking conditions; in the 50-to-70 years old participants applying step width at fast pace and steps per meter at usual pace; in the 70-to-80 years old persons using gait speed and normalised gait speed at usual pace, fast pace, animal walk and counting walk or steps per meter and normalised steps per meter at all five walking conditions; in over-80 years old participants using gait speed, normalised gait speed, steps per meter and normalised steps per meter at fast pace and animal dual-task walking. Multivariable logistic regression analysis adjusted for gender predicted in two compiled models the presence of dementia or cognitive impairment with acceptable accuracy in persons with memory complaints.Gait parameters in multiple walking conditions adjusted for age, gender and leg length showed a significant association with cognitive impairment. This study suggested that multifactorial gait analysis could be more informative than using gait analysis with only one test or one variable. Using this type of gait analysis in clinical practice

Carotid flow pulsatility is higher in women with greater decrement in gait speed during multi-tasking.

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Gonzales, Joaquin U; James, C Roger; Yang, Hyung Suk; Jensen, Daniel; Atkins, Lee; Al-Khalil, Kareem; O'Boyle, Michael

2017-05-01

Central arterial hemodynamics is associated with cognitive impairment. Reductions in gait speed during walking while performing concurrent tasks known as dual-tasking (DT) or multi-tasking (MT) is thought to reflect the cognitive cost that exceeds neural capacity to share resources. We hypothesized that central vascular function would associate with decrements in gait speed during DT or MT. Gait speed was measured using a motion capture system in 56 women (30-80y) without mild-cognitive impairment. Dual-tasking was considered walking at a fast-pace while balancing a tray. Multi-tasking was the DT condition plus subtracting by serial 7's. Applanation tonometry was used for measurement of aortic stiffness and central pulse pressure. Doppler-ultrasound was used to measure blood flow velocity and β-stiffness index in the common carotid artery. The percent change in gait speed was larger for MT than DT (14.1±11.2 vs. 8.7±9.6%, p decrement (third tertile) as compared to women with less decrement (first tertile) in gait speed during MT after adjusting for age, gait speed, and task error. Carotid pulse pressure and β-stiffness did not contribute to these tertile differences. Elevated carotid flow pulsatility and resistance are characteristics found in healthy women that show lower cognitive capacity to walk and perform multiple concurrent tasks. Copyright © 2017 Elsevier B.V. All rights reserved.

Nonlinear dynamics near resonances of a rotor-active magnetic bearings system with 16-pole legs and time varying stiffness

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Wu, R. Q.; Zhang, W.; Yao, M. H.

2018-02-01

In this paper, we analyze the complicated nonlinear dynamics of rotor-active magnetic bearings (rotor-AMB) with 16-pole legs and the time varying stiffness. The magnetic force with 16-pole legs is obtained by applying the electromagnetic theory. The governing equation of motion for rotor-active magnetic bearings is derived by using the Newton's second law. The resulting dimensionless equation of motion for the rotor-AMB system is expressed as a two-degree-of-freedom nonlinear system including the parametric excitation, quadratic and cubic nonlinearities. The averaged equation of the rotor-AMB system is obtained by using the method of multiple scales when the primary parametric resonance and 1/2 subharmonic resonance are taken into account. From the frequency-response curves, it is found that there exist the phenomena of the soft-spring type nonlinearity and the hardening-spring type nonlinearity in the rotor-AMB system. The effects of different parameters on the nonlinear dynamic behaviors of the rotor-AMB system are investigated. The numerical results indicate that the periodic, quasi-periodic and chaotic motions occur alternately in the rotor-AMB system.

Dynamic Functional Stiffness Index of the Ankle Joint During Daily Living.

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Argunsah Bayram, Hande; Bayram, Mehmed B

2018-03-30

Exploring ankle joint physiologic functional stiffness is crucial for improving the design of prosthetic feet that aim to mimic normal gait. We hypothesized that ankle joint stiffness would vary among the different activities of daily living and that the magnitude of the stiffness would indicate the degree of energy storage element sufficiency in terms of harvesting and returning energy. We examined sagittal plane ankle moment versus flexion angle curves from 12 healthy subjects during the daily activities. The slopes of these curves were assessed to find the calculated stiffness during the peak energy return and harvest phases. For the energy return and harvest phases, stiffness varied from 0.016 to 0.283 Nm/kg° and 0.025 and 0.858 Nm/kg°, respectively. The optimum stiffness during the energy return phase was 0.111 ± 0.117 Nm/kg° and during the energy harvest phase was 0.234 ± 0.327 Nm/kg°. Ankle joint stiffness varied significantly during the activities of daily living, indicating that an energy storage unit with a constant stiffness would not be sufficient in providing energy regenerative gait during all activities. The present study was directed toward the development of a complete data set to determine the torque-angle properties of the ankle joint to facilitate a better design process. Copyright © 2017 The American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Spatial-temporal parameters of gait in women with fibromyalgia.

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Heredia Jiménez, José María; Aparicio García-Molina, Virginia A; Porres Foulquie, Jesús M; Delgado Fernández, Manuel; Soto Hermoso, Victor M

2009-05-01

The aim of the present study was to determine if there are differences in such parameters among patients affected by fibromyalgia (FM) and healthy subjects and whether the degree of affectation by FM can decrease the gait parameters. We studied 55 women with FM and 44 controls. Gait analysis was performed using an instrumented walkway for measurement of the kinematic parameters of gait (GAITRite system), and patients completed a Spanish version of Fibromyalgia Impact Questionnaire (FIQ). Significant differences (p Gait parameters of women affected by FM were severely impaired when compared to those of healthy women. Different factors such as lack of physical activity, bradikinesia, overweight, fatigue, and pain together with a lower isometric force in the legs can be responsible for the alterations in gait and poorer life quality of women with FM.

Neuro-Mechanics of Recumbent Leg Cycling in Post-Acute Stroke Patients.

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Ambrosini, Emilia; De Marchis, Cristiano; Pedrocchi, Alessandra; Ferrigno, Giancarlo; Monticone, Marco; Schmid, Maurizio; D'Alessio, Tommaso; Conforto, Silvia; Ferrante, Simona

2016-11-01

Cycling training is strongly applied in post-stroke rehabilitation, but how its modular control is altered soon after stroke has been not analyzed yet. EMG signals from 9 leg muscles and pedal forces were measured bilaterally during recumbent pedaling in 16 post-acute stroke patients and 12 age-matched healthy controls. Patients were asked to walk over a GaitRite mat and standard gait parameters were computed. Four muscle synergies were extracted through nonnegative matrix factorization in healthy subjects and patients unaffected legs. Two to four synergies were identified in the affected sides and the number of synergies significantly correlated with the Motricity Index (Spearman's coefficient = 0.521). The reduced coordination complexity resulted in a reduced biomechanical performance, with the two-module sub-group showing the lowest work production and mechanical effectiveness in the affected side. These patients also exhibited locomotor impairments (reduced gait speed, asymmetrical stance time, prolonged double support time). Significant correlations were found between cycling-based metrics and gait parameters, suggesting that neuro-mechanical quantities of pedaling can inform on walking dysfunctions. Our findings support the use of pedaling as a rehabilitation method and an assessment tool after stroke, mainly in the early phase, when patients can be unable to perform a safe and active gait training.

Associations between measures of gait stability, leg strength and fear of falling

NARCIS (Netherlands)

Toebes, M.J.P.; Hoozemans, M.J.M.; Dekker, J.; van Dieen, J.H.

2015-01-01

Fear of falling (FoF) in elderly frequently leads to decreased quality of life. FoF is suggested to be associated with changes in gait quality and muscle strength with aging. The aim of this study was to determine whether gait quality and maximal voluntary torque (MVT) of knee extensor muscles are

Immediate effects of a single session of robot-assisted gait training using Hybrid Assistive Limb (HAL) for cerebral palsy.

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Matsuda, Mayumi; Mataki, Yuki; Mutsuzaki, Hirotaka; Yoshikawa, Kenichi; Takahashi, Kazushi; Enomoto, Keiko; Sano, Kumiko; Mizukami, Masafumi; Tomita, Kazuhide; Ohguro, Haruka; Iwasaki, Nobuaki

2018-02-01

[Purpose] Robot-assisted gait training (RAGT) using Hybrid Assistive Limb (HAL, CYBERDYNE) was previously reported beneficial for stroke and spinal cord injury patients. Here, we investigate the immediate effect of a single session of RAGT using HAL on gait function for cerebral palsy (CP) patients. [Subjects and Methods] Twelve patients (average age: 16.2 ± 7.3 years) with CP received a single session of RAGT using HAL. Gait speed, step length, cadence, single-leg support per gait cycle, hip and knee joint angle in stance, and swing phase per gait cycle were assessed before, during, and immediately after HAL intervention. [Results] Compared to baseline values, single-leg support per gait cycle (64.5 ± 15.8% to 69.3 ± 12.1%), hip extension angle in mid-stance (149.2 ± 19.0° to 155.5 ± 20.1°), and knee extension angle in mid-stance (137.6 ± 20.2° to 143.1 ± 19.5°) were significantly increased immediately after intervention. Further, the knee flexion angle in mid-swing was significantly decreased immediately after treatment (112.0 ± 15.5° to 105.2 ± 17.1°). Hip flexion angle in mid-swing also decreased following intervention (137.2 ± 14.6° to 129.7 ± 16.6°), but not significantly. Conversely, gait speed, step length, and cadence were unchanged after intervention. [Conclusion] A single-time RAGT with HAL improved single-leg support per gait cycle and hip and knee joint angle during gait, therapeutically improving gait function in CP patients.

Neuro fuzzy control of the FES assisted freely swinging leg of paraplegic subjects

NARCIS (Netherlands)

van der Spek, J.H.; Velthuis, W.J.R.; Veltink, Petrus H.; de Vries, Theodorus J.A.

1996-01-01

The authors designed a neuro fuzzy control strategy for control of cyclical leg movements of paraplegic subjects. The cyclical leg movements were specified by three `swing phase objectives', characteristic of natural human gait. The neuro fuzzy controller is a combination of a fuzzy logic controller

An automatic hinge system for leg orthoses

NARCIS (Netherlands)

Rietman, J.S.; Goudsmit, J.; Meulemans, D.; Halbertsma, J.P.K.; Geertzen, J.H.B.

This paper describes a new, automatic hinge system for leg orthoses, which provides knee stability in stance, and allows knee-flexion during swing. Indications for the hinge system are a paresis or paralysis of the quadriceps muscles. Instrumented gait analysis was performed in three patients,

Adaptive leg coordination with a biologically inspired neurocontroller

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Braught, Grant; Thomopoulos, Stelios C.

1996-10-01

Natural selection is responsible for the creation of robust and adaptive control systems. Nature's control systems are created only from primitive building blocks. Using insect neurophysiology as a guide, a neural architecture for leg coordination in a hexapod robot has been developed. Reflex chains and sensory feedback mechanisms from various insects and crustacea form the basis of a pattern generator for intra-leg coordination. The pattern generator contains neural oscillators which learn from sensory feedback to produce stepping patterns. Using sensory feedback as the source of learning information allows the pattern generator to adapt to changes in the leg dynamics due to internal or external causes. A coupling between six of the single leg pattern generators is used to produce the inter-leg coordination necessary to establish stable gaits.

Gait analysis in anorexia and bulimia nervosa.

Science.gov (United States)

Cimolin, Veronica; Galli, Manuela; Vismara, Luca; Vimercati, Sara Laura; Precilios, Helmer; Cattani, Laila; Fabris De Souza, Shirley; Petroni, Maria Letizia; Capodaglio, Paolo

2013-09-13

Anorexia (AN) and Bulimia Nervosa (BN) are two common eating disorders, which appear to share some reduced motor capacities, such as a reduced balance. The presence and the extent of other motor disorders have not been investigated in a comprehensive way. The aim of this study was to quantify gait pattern in AN and BN individuals in order to ascertain possible differences from the normality range and provide novel data for developing some evidence-based rehabilitation strategies. Nineteen AN patients (age 30.16+9.73) and 20 BN patients (age 26.8+8.41) were assessed with quantitative 3D computerized Gait Analysis. Results were compared with a group of healthy controls (CG; 30.7+5.6). AN and BN patients were characterized by different gait strategies compared to CG. Spatio-temporal parameters indicated shorter step length, with AN showing the shortest values. AN walked slower than BN and CG. As for kinematics, AN and BN showed a nonphysiologic pattern at pelvis and hip level on the sagittal and frontal plane, with BN yielding the most abnormal values. Both AN and BN patients were characterized by high ankle plantar flexion capacity at toe-off when compared to CG. As for ankle kinetics, both AN and BN showed physiologic patterns. Stiffness at hip level was close to CG in both pathologic groups; at the ankle level, stiffness was significantly decreased in both groups, with AN displaying lower values. Both AN and BN were characterized by an altered gait pattern compared to CG. Biomechanical differences were evident mainly at pelvis and hip level. Loss of lean mass may lead to musculoskeletal adaptation, ultimately causing alterations in the gait pattern.

Effects of walkbot gait training on kinematics, kinetics, and clinical gait function in paraplegia and quadriplegia.

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Hwang, Jongseok; Shin, Yongil; Park, Ji-Ho; Cha, Young Joo; You, Joshua Sung H

2018-04-07

The robotic-assisted gait training (RAGT) system has gained recognition as an innovative, effective paradigm to improve functional ambulation and activities of daily living in spinal cord injury and stroke. However, the effects of the Walkbot robotic-assisted gait training system with a specialized hip-knee-ankle actuator have never been examined in the paraplegia and quadriplegia population. The aim of this study was to determine the long-term effects of Walkbot training on clinical for hips and knee stiffness in individuals with paraplegia or quadriplegia. Nine adults with subacute or chronic paraplegia resulting from spinal cord injury or quadriplegia resulting from cerebral vascular accident (CVA) and/or hypoxia underwent progressive conventional gait retraining combined with the Walkbot RAGT for 5 days/week over an average of 43 sessions for 8 weeks. Clinical outcomes were measured with the Functional Ambulation Category (FAC), Modified Rankin Scale (MRS), Korean version of the Modified Barthel Index (K-MBI), Modified Ashworth Scale (MAS). Kinetic and kinematic data were collected via a built-in Walkbot program. Wilcoxon signed-rank tests showed significant positive intervention effects on K-MBI, maximal hip flexion and extension, maximal knee flexion, active torque in the knee joint, resistive torque, and stiffness in the hip joint (P quadriplegia who had reached a plateau in motor recovery after conventional therapy.

An automatic hinge system for leg orthoses

NARCIS (Netherlands)

Rietman, J. S.; Goudsmit, J.; Meulemans, D.; Halbertsma, J. P. K.; Geertzen, J. H. B.

2004-01-01

This paper describes a new automatic hinge system for leg orthoses, which provides knee stability in stance, and allows knee-flexion during swing. Indications for the hinge system are a paresis or paralysis of the quadriceps muscles. Instrumented gait analysis was performed in three patients, fitted

Markedly impaired bilateral coordination of gait in post-stroke patients: Is this deficit distinct from asymmetry? A cohort study.

NARCIS (Netherlands)

Meijer, R.; Plotnik, M.; Zwaaftink, E.G.; Lummel, R.C. van; Ainsworth, E.; Martina, J.D.; Hausdorff, J.M.

2011-01-01

BACKGROUND: Multiple aspects of gait are typically impaired post-stroke. Asymmetric gait is common as a consequence of unilateral brain lesions. The relationship between the resulting asymmetric gait and impairments in the ability to properly coordinate the reciprocal stepping activation of the legs

Markedly impaired bilateral coordination of gait in post-stroke patients : Is this deficit distinct from asymmetry? A cohort study

NARCIS (Netherlands)

Meijer, Ronald; Plotnik, Meir; Zwaaftink, Esther Groot; van Lummel, Rob C.; Ainsworth, Erik; Martina, Juan D.; Hausdorff, Jeffrey M.

2011-01-01

Background: Multiple aspects of gait are typically impaired post-stroke. Asymmetric gait is common as a consequence of unilateral brain lesions. The relationship between the resulting asymmetric gait and impairments in the ability to properly coordinate the reciprocal stepping activation of the legs

Person identification by gait analysis and photogrammetry

DEFF Research Database (Denmark)

Lynnerup, Niels; Vedel, Jens

2005-01-01

Surveillance images from a bank robbery were analyzed and compared with images of a suspect. Based on general bodily features, gait and anthropometric measurements, we were able to conclude that one of the perpetrators showed strong resemblance to the suspect. Both exhibited a gait characterized...... by hyperextension of the leg joints, and bodily measurements did not differ by more than 6 mm on average. The latter was quantified by photogrammetry: i.e., measuring by using images of the perpetrator as captured by surveillance cameras. Using the computer software Photomodeler Pro, synchronous images from...

Analysis of Interrelationships among Voluntary and Prosthetic Leg Joint Parameters Using Cyclograms.

Science.gov (United States)

Jasni, Farahiyah; Hamzaid, Nur Azah; Mohd Syah, Nor Elleeiana; Chung, Tze Y; Abu Osman, Noor Azuan

2017-01-01

The walking mechanism of a prosthetic leg user is a tightly coordinated movement of several joints and limb segments. The interaction among the voluntary and mechanical joints and segments requires particular biomechanical insight. This study aims to analyze the inter-relationship between amputees' voluntary and mechanical coupled leg joints variables using cyclograms. From this analysis, the critical gait parameters in each gait phase were determined and analyzed if they contribute to a better powered prosthetic knee control design. To develop the cyclogram model, 20 healthy able-bodied subjects and 25 prosthesis and orthosis users (10 transtibial amputees, 5 transfemoral amputees, and 10 different pathological profiles of orthosis users) walked at their comfortable speed in a 3D motion analysis lab setting. The gait parameters (i.e., angle, moment and power for the ankle, knee and hip joints) were coupled to form 36 cyclograms relationship. The model was validated by quantifying the gait disparities of all the pathological walking by analyzing each cyclograms pairs using feed-forward neural network with backpropagation. Subsequently, the cyclogram pairs that contributed to the highest gait disparity of each gait phase were manipulated by replacing it with normal values and re-analyzed. The manipulated cyclograms relationship that showed highest improvement in terms of gait disparity calculation suggested that they are the most dominant parameters in powered-knee control. In case of transfemoral amputee walking, it was identified using this approach that at each gait sub-phase, the knee variables most responsible for closest to normal walking were: knee power during loading response and mid-stance, knee moment and knee angle during terminal stance phase, knee angle and knee power during pre-swing, knee angle at initial swing, and knee power at terminal swing. No variable was dominant during mid-swing phase implying natural pendulum effect of the lower limb between

Analysis of Interrelationships among Voluntary and Prosthetic Leg Joint Parameters Using Cyclograms

Directory of Open Access Journals (Sweden)

Nur Azah Hamzaid

2017-04-01

Full Text Available The walking mechanism of a prosthetic leg user is a tightly coordinated movement of several joints and limb segments. The interaction among the voluntary and mechanical joints and segments requires particular biomechanical insight. This study aims to analyze the inter-relationship between amputees' voluntary and mechanical coupled leg joints variables using cyclograms. From this analysis, the critical gait parameters in each gait phase were determined and analyzed if they contribute to a better powered prosthetic knee control design. To develop the cyclogram model, 20 healthy able-bodied subjects and 25 prosthesis and orthosis users (10 transtibial amputees, 5 transfemoral amputees, and 10 different pathological profiles of orthosis users walked at their comfortable speed in a 3D motion analysis lab setting. The gait parameters (i.e., angle, moment and power for the ankle, knee and hip joints were coupled to form 36 cyclograms relationship. The model was validated by quantifying the gait disparities of all the pathological walking by analyzing each cyclograms pairs using feed-forward neural network with backpropagation. Subsequently, the cyclogram pairs that contributed to the highest gait disparity of each gait phase were manipulated by replacing it with normal values and re-analyzed. The manipulated cyclograms relationship that showed highest improvement in terms of gait disparity calculation suggested that they are the most dominant parameters in powered-knee control. In case of transfemoral amputee walking, it was identified using this approach that at each gait sub-phase, the knee variables most responsible for closest to normal walking were: knee power during loading response and mid-stance, knee moment and knee angle during terminal stance phase, knee angle and knee power during pre-swing, knee angle at initial swing, and knee power at terminal swing. No variable was dominant during mid-swing phase implying natural pendulum effect of the

Robot-assisted practice of gait and stair climbing in nonambulatory stroke patients.

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Hesse, Stefan; Tomelleri, Christopher; Bardeleben, Anita; Werner, Cordula; Waldner, Andreas

2012-01-01

A novel gait robot enabled nonambulatory patients the repetitive practice of gait and stair climbing. Thirty nonambulatory patients with subacute stroke were allocated to two groups. During 60 min sessions every workday for 4 weeks, the experimental group received 30 min of robot training and 30 min of physiotherapy and the control group received 60 min of physiotherapy. The primary variable was gait and stair climbing ability (Functional Ambulation Categories [FAC] score 0-5); secondary variables were gait velocity, Rivermead Mobility Index (RMI), and leg strength and tone blindly assessed at onset, intervention end, and follow-up. Both groups were comparable at onset and functionally improved over time. The improvements were significantly larger in the experimental group with respect to the FAC, RMI, velocity, and leg strength during the intervention. The FAC gains (mean +/- standard deviation) were 2.4 +/- 1.2 (experimental group) and 1.2 +/- 1.5 (control group), p = 0.01. At the end of the intervention, seven experimental group patients and one control group patient had reached an FAC score of 5, indicating an ability to climb up and down one flight of stairs. At follow-up, this superior gait ability persisted. In conclusion, the therapy on the novel gait robot resulted in a superior gait and stair climbing ability in nonambulatory patients with subacute stroke; a higher training intensity was the most likely explanation. A large randomized controlled trial should follow.

Association of baseline knee sagittal dynamic joint stiffness during gait and 2-year patellofemoral cartilage damage worsening in knee osteoarthritis.

Science.gov (United States)

Chang, A H; Chmiel, J S; Almagor, O; Guermazi, A; Prasad, P V; Moisio, K C; Belisle, L; Zhang, Y; Hayes, K; Sharma, L

2017-02-01

Knee sagittal dynamic joint stiffness (DJS) describes the biomechanical interaction between change in external knee flexion moment and flexion angular excursion during gait. In theory, greater DJS may particularly stress the patellofemoral (PF) compartment and thereby contribute to PF osteoarthritis (OA) worsening. We hypothesized that greater baseline knee sagittal DJS is associated with PF cartilage damage worsening 2 years later. Participants all had OA in at least one knee. Knee kinematics and kinetics during gait were recorded using motion capture systems and force plates. Knee sagittal DJS was computed as the slope of the linear regression line for knee flexion moments vs angles during the loading response phase. Knee magnetic resonance imaging (MRI) scans were obtained at baseline and 2 years later. We assessed the association between baseline DJS and baseline-to-2-year PF cartilage damage worsening using logistic regression with generalized estimating equations (GEE). Our sample had 391 knees (204 persons): mean age 64.2 years (SD 10.0); body mass index (BMI) 28.4 kg/m 2 (5.7); 76.5% women. Baseline knee sagittal DJS was associated with baseline-to-2-year cartilage damage worsening in the lateral (OR = 5.35, 95% CI: 2.37-12.05) and any PF (OR = 2.99, 95% CI: 1.27-7.04) compartment. Individual components of baseline DJS (i.e., change in knee moment or angle) were not associated with subsequent PF disease worsening. Capturing the concomitant effect of knee kinetics and kinematics during gait, knee sagittal DJS is a potentially modifiable risk factor for PF disease worsening. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Control Architecture of a 10 DOF Lower Limbs Exoskeleton for Gait Rehabilitation

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Natasa Koceska

2013-01-01

Full Text Available This paper describes the control architecture of a 10 DOF (Degrees of Freedom lower limbs exoskeleton for the gait rehabilitation of patients with gait dysfunction. The system has 4 double-acting rod pneumatic actuators (two for each leg that control the hip and knee joints. The motion of each cylinder's piston is controlled by two proportional pressure valves, connected to both cylinder chambers. The control strategy has been specifically designed in order to ensure a proper trajectory control for guiding patient's legs along a fixed reference gait pattern. An adaptive fuzzy controller which is capable of compensating for the influence of the dry friction was successfully designed, implemented and tested on an embedded real-time PC/104. In order to verify the proposed control architecture, laboratory experiments without a patient were carried out and the results are reported here and discussed.

View-Invariant Gait Recognition Through Genetic Template Segmentation

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Isaac, Ebenezer R. H. P.; Elias, Susan; Rajagopalan, Srinivasan; Easwarakumar, K. S.

2017-08-01

Template-based model-free approach provides by far the most successful solution to the gait recognition problem in literature. Recent work discusses how isolating the head and leg portion of the template increase the performance of a gait recognition system making it robust against covariates like clothing and carrying conditions. However, most involve a manual definition of the boundaries. The method we propose, the genetic template segmentation (GTS), employs the genetic algorithm to automate the boundary selection process. This method was tested on the GEI, GEnI and AEI templates. GEI seems to exhibit the best result when segmented with our approach. Experimental results depict that our approach significantly outperforms the existing implementations of view-invariant gait recognition.

Trotting Gait of a Quadruped Robot Based on the Time-Pose Control Method

Directory of Open Access Journals (Sweden)

Cai RunBin

2013-02-01

Full Text Available We present the Time-Pose control method for the trotting gait of a quadruped robot on flat ground and up a slope. The method, with brief control structure, real-time operation ability and high adaptability, divides quadruped robot control into gait control and pose control. Virtual leg and intuitive controllers are introduced to simplify the model and generate the trajectory of mass centre and location of supporting legs in gait control, while redundancy optimization is used for solving the inverse kinematics in pose control. The models both on flat ground and up a slope are fully analysed, and different kinds of optimization methods are compared using the manipulability measure in order to select the best option. Simulations are performed, which prove that the Time-Pose control method is realizable for these two kinds of environment.

Comparison of magnetic resonance elastography and diffusion-weighted imaging for differentiating benign and malignant liver lesions

Energy Technology Data Exchange (ETDEWEB)

Hennedige, Tiffany P.; Hallinan, James Thomas Patrick Decourcy; Teo, Lynette Li San [National University Hospital, National University Health System, Department of Diagnostic Imaging, Singapore (Singapore); Leung, Fiona P. [National University Hospital, National University Health System, Department of Diagnostic Imaging, Singapore (Singapore); South West Radiology, Liverpool, NSW (Australia); Iyer, Sridhar; Chang, Stephen; Madhavan, Krishna Kumar [National University Health System, Department of Surgery, Singapore (Singapore); Wang, Gang [National University Hospital, National University Health System, Department of Diagnostic Imaging, Singapore (Singapore); University of Calgary, Alberta (Canada); Wee, Aileen [National University Hospital, National University Health System, Department of Pathology, Singapore (Singapore); Venkatesh, Sudhakar K. [Mayo Clinic, Department of Radiology, Rochester, MN (United States)

2016-02-15

Comparison of magnetic resonance elastography (MRE) and diffusion-weighted imaging (DWI) for differentiating malignant and benign focal liver lesions (FLLs). Seventy-nine subjects with 124 FLLs (44 benign and 80 malignant) underwent both MRE and DWI. MRE was performed with a modified gradient-echo sequence and DWI with a free breathing technique (b = 0.500). Apparent diffusion coefficient (ADC) maps and stiffness maps were generated. FLL mean stiffness and ADC values were obtained by placing regions of interest over the FLLs on stiffness and ADC maps. The accuracy of MRE and DWI for differentiation of benign and malignant FLL was compared using receiver operating curve (ROC) analysis. There was a significant negative correlation between stiffness and ADC (r = -0.54, p < 0.0001) of FLLs. Malignant FLLs had significantly higher mean stiffness (7.9kPa vs. 3.1kPa, p < 0.001) and lower mean ADC (129 vs. 200 x 10{sup -3}mm{sup 2}/s, p < 0.001) than benign FLLs. The sensitivity/specificity/positive predictive value/negative predictive value for differentiating malignant from benign FLLs with MRE (cut-off, >4.54kPa) and DWI (cut-off, <151 x 10{sup -3}mm{sup 2}/s) were 96.3/95.5/97.5/93.3 % (p < 0.001) and 85/81.8/88.3/75 % (p < 0.001), respectively. ROC analysis showed significantly higher accuracy for MRE than DWI (0.986 vs. 0.82, p = 0.0016). MRE is significantly more accurate than DWI for differentiating benign and malignant FLLs. (orig.)

Model Predictive Control-based gait pattern generation for wearable exoskeletons.

Science.gov (United States)

Wang, Letian; van Asseldonk, Edwin H F; van der Kooij, Herman

2011-01-01

This paper introduces a new method for controlling wearable exoskeletons that do not need predefined joint trajectories. Instead, it only needs basic gait descriptors such as step length, swing duration, and walking speed. End point Model Predictive Control (MPC) is used to generate the online joint trajectories based on these gait parameters. Real-time ability and control performance of the method during the swing phase of gait cycle is studied in this paper. Experiments are performed by helping a human subject swing his leg with different patterns in the LOPES gait trainer. Results show that the method is able to assist subjects to make steps with different step length and step duration without predefined joint trajectories and is fast enough for real-time implementation. Future study of the method will focus on controlling the exoskeletons in the entire gait cycle. © 2011 IEEE

The Use of Cuff Weights for Aquatic Gait Training in People Post-Stroke with Hemiparesis.

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Nishiyori, Ryota; Lai, Byron; Lee, Do Kyeong; Vrongistinos, Konstantinos; Jung, Taeyou

2016-03-01

This study aimed to examine how spatiotemporal and kinematic gait variables are influenced by the application of a cuff weight during aquatic walking in people post-stroke. The secondary purpose was to compare the differences in gait responses between the placements of cuff weights on the proximal (knee weight) and distal end (ankle weight) of the shank. Twenty-one participants post-stroke with hemiparesis aged 66.3 ± 11.3 years participated in a cross-sectional comparative study. Participants completed two aquatic walking trials at their self-selected maximum walking speed across an 8-m walkway under each of the three conditions: 1) walking with a knee weight; 2) walking with an ankle weight; and 3) walking with no weight. Cuff weights were worn on the paretic leg of each participant. Gait speed, cadence, step width and joint kinematics of the hip, knee and ankle joints were recorded by a customized three-dimensional underwater motion analysis system. Mean aquatic walking speeds significantly increased with the use of cuff weights when compared to walking with no weight. Changes in gait variables were found in the non-paretic leg with the addition of weight, while no significant changes were found in the paretic leg. The results suggest that the use of additional weight can be helpful if the goal of gait training is to improve walking speed of people post-stroke during pool floor walking. However, it is interesting to note that changes in gait variables were not found in the paretic limb where favourable responses were expected to occur. Copyright © 2014 John Wiley & Sons, Ltd.

Abnormalities of the First Three Steps of Gait Initiation in Patients with Parkinson's Disease with Freezing of Gait

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Yohei Okada

2011-01-01

Full Text Available The purpose of this study was to investigate abnormalities of the first three steps of gait initiation in patients with Parkinson's disease (PD with freezing of gait (FOG. Ten PD patients with FOG and 10 age-matched healthy controls performed self-generated gait initiation. The center of pressure (COP, heel contact positions, and spatiotemporal parameters were estimated from the vertical pressures on the surface of the force platform. The initial swing side of gait initiation was consistent among the trials in healthy controls but not among the trials in PD patients. The COP and the heel contact position deviated to the initial swing side during the first step, and the COP passed medial to each heel contact position during the first two steps in PD patients. Medial deviation of the COP from the first heel contact position had significant correlation with FOG questionnaire item 5. These findings indicate that weight shifting between the legs is abnormal and that medial deviation of the COP from the first heel contact position sensitively reflects the severity of FOG during the first three steps of gait initiation in PD patients with FOG.

Extensibility and stiffness of the hamstrings in patients with nonspecific low back pain.

Science.gov (United States)

Halbertsma, J P; Göeken, L N; Hof, A L; Groothoff, J W; Eisma, W H

2001-02-01

To investigate the extensibility and stiffness of the hamstrings in patients with nonspecific low back pain (LBP). An experimental design. A university laboratory for human movement analysis in a department of rehabilitation medicine. Forty subjects, a patient group (20) and a healthy control group (20). Subjects laid supine on an examination table with a lift frame, with left leg placed in a sling at the ankle. Straight leg raising, pulling force, and activity of hamstring and back muscles were recorded with electrodes. Patients indicated when they experienced tension or pain. The lift force, leg excursion, pelvic-femoral angle, first sensation of pain, and the electromyogram of the hamstrings and back muscles measured in an experimental straight-leg raising set-up. The patient group showed a significant restriction in range of motion (ROM) and extensibility of the hamstrings compared with the control group. No significant difference in hamstring muscle stiffness can be assessed between both groups. The restricted ROM and the decreased extensibility of the hamstrings in patients with nonspecific LBP is not caused by increased muscle stiffness of the hamstrings, but determined by the stretch tolerance of the patients.

The Effect of Upper Body Mass and Initial Knee Flexion on the Injury Outcome of Post Mortem Human Subject Pedestrian Isolated Legs.

Science.gov (United States)

Petit, Philippe; Trosseille, Xavier; Dufaure, Nicolas; Dubois, Denis; Potier, Pascal; Vallancien, Guy

2014-11-01

In the ECE 127 Regulation on pedestrian leg protection, as well as in the Euro NCAP test protocol, a legform impactor hits the vehicle at the speed of 40 kph. In these tests, the knee is fully extended and the leg is not coupled to the upper body. However, the typical configuration of a pedestrian impact differs since the knee is flexed during most of the gait cycle and the hip joint applies an unknown force to the femur. This study aimed at investigating the influence of the inertia of the upper body (modelled using an upper body mass fixed at the proximal end of the femur) and the initial knee flexion angle on the lower limb injury outcome. In total, 18 tests were conducted on 18 legs from 9 Post Mortem Human Subjects (PMHS). The principle of these tests was to impact the leg at 40 kph using a sled equipped with 3 crushing steel tubes, the stiffness of which were representative of the front face of a European sedan (bonnet leading edge, bumper and spoiler). The mass of the equipped sled was 74.5 kg. The test matrix was designed to perform 4 tests in 4 configurations combining two upper body masses (either 0 or 3 kg) and two knee angles (0 or 20 degrees) at 40 kph (11 m/s) plus 2 tests at 9 m/s. Autopsies were performed on the lower limbs and an injury assessment was established. The findings of this study were first that the increase of the upper body mass resulted in more severe injuries, second that an initial flexion of the knee, corresponding to its natural position during the gait cycle, decreased the severity of the injuries, and third that based on the injury outcome, a test conducted with no upper body mass and the knee fully extended was as severe as a test conducted with a 3 kg upper body mass and an initial knee flexion of 20°.

One-leg balance is an important predictor of injurious falls in older persons.

Science.gov (United States)

Vellas, B J; Wayne, S J; Romero, L; Baumgartner, R N; Rubenstein, L Z; Garry, P J

1997-06-01

To test the hypothesis that one-leg balance is a significant predictor of falls and injurious falls. Analysis of data from a longitudinal cohort study. Healthy, community-living volunteers older than age 60 enrolled in the Albuquerque Falls Study and followed for 3 years (N = 316; mean age 73 years). Falls and injurious falls detected via reports every other month. Baseline measures of demographics, history, physical examination, Iowa Self Assessment Inventory, balance and gait assessment, and one-leg balance (ability to stand unassisted for 5 seconds on one leg). At baseline, 84.5% of subjects could perform one-leg balance. (Impairment was associated with older age and gait abnormalities.) Over the 3-year follow-up, 71% experienced a fall and 22% an injurious fall. The only independent significant predictor of all falls using logistic regression was age greater than 73. However, impaired one-leg balance was the only significant independent predictor of injurious falls (relative risk: 2.13; 95% CI: 1.04, 4.34; P = .03). One-leg balance appears to be a significant and easy-to-administer predictor of injurious falls, but not of all falls. In our study, it was the strongest individual predictor. However, no single factor seems to be accurate enough to be relied on as a sole predictor of fall risk or fall injury risk because so many diverse factors are involved in falling.

Crossover study of amputee stair ascent and descent biomechanics using Genium and C-Leg prostheses with comparison to non-amputee control.

Science.gov (United States)

Lura, Derek J; Wernke, Matthew W; Carey, Stephanie L; Kahle, Jason T; Miro, Rebecca M; Highsmith, M Jason

2017-10-01

This study was a randomized crossover of stair ambulation of Transfemoral Amputees (TFAs) using the Genium and C-Leg prosthetic knees. TFAs typically have difficulty ascending and descending stairs, limiting community mobility. The objective of this study was to determine the relative efficacy of the Genium and C-Leg prostheses for stair ascent and descent, and their absolute efficacy relative to non-amputees. Twenty TFAs, and five non-amputees participated in the study. TFAs were randomized to begin the study with the Genium or C-Leg prosthesis. Informed consent was obtained from all participants prior to data collection and the study was listed on clinicaltrials.gov (#NCT01473662). After fitting, accommodation, and training, participants were asked to demonstrate their preferred gait pattern for stair ascent and descent and a step-over-step pattern if able. TFAs then switched prosthetic legs and repeated fitting, accommodation, training, and testing. An eight camera Vicon optical motion analysis system, and two AMTI force plates were used to track and analyze the participants' gait patterns, knee flexion angles, knee moment normalized by body weight, and swing time. For stair descent, no significant differences were found between prostheses. For stair ascent, Genium use resulted in: increased ability to use a step-over-step gait pattern (p=0.03), increased prosthetic side peak knee flexion (pstair ascent relative to the C-Leg, by enabling gait patterns that more closely resembled non-amputees. Copyright © 2017 Elsevier B.V. All rights reserved.

Estimating the Mechanical Behavior of the Knee Joint during Crouch Gait: Implications for Real-Time Motor Control of Robotic Knee Orthoses

Science.gov (United States)

Damiano, Diane L.; Bulea, Thomas C.

2016-01-01

Individuals with cerebral palsy frequently exhibit crouch gait, a pathological walking pattern characterized by excessive knee flexion. Knowledge of the knee joint moment during crouch gait is necessary for the design and control of assistive devices used for treatment. Our goal was to 1) develop statistical models to estimate knee joint moment extrema and dynamic stiffness during crouch gait, and 2) use the models to estimate the instantaneous joint moment during weight-acceptance. We retrospectively computed knee moments from 10 children with crouch gait and used stepwise linear regression to develop statistical models describing the knee moment features. The models explained at least 90% of the response value variability: peak moment in early (99%) and late (90%) stance, and dynamic stiffness of weight-acceptance flexion (94%) and extension (98%). We estimated knee extensor moment profiles from the predicted dynamic stiffness and instantaneous knee angle. This approach captured the timing and shape of the computed moment (root-mean-squared error: 2.64 Nm); including the predicted early-stance peak moment as a correction factor improved model performance (root-mean-squared error: 1.37 Nm). Our strategy provides a practical, accurate method to estimate the knee moment during crouch gait, and could be used for real-time, adaptive control of robotic orthoses. PMID:27101612

Applying a pelvic corrective force induces forced use of the paretic leg and improves paretic leg EMG activities of individuals post-stroke during treadmill walking.

Science.gov (United States)

Hsu, Chao-Jung; Kim, Janis; Tang, Rongnian; Roth, Elliot J; Rymer, William Z; Wu, Ming

2017-10-01

To determine whether applying a mediolateral corrective force to the pelvis during treadmill walking would enhance muscle activity of the paretic leg and improve gait symmetry in individuals with post-stroke hemiparesis. Fifteen subjects with post-stroke hemiparesis participated in this study. A customized cable-driven robotic system based over a treadmill generated a mediolateral corrective force to the pelvis toward the paretic side during early stance phase. Three different amounts of corrective force were applied. Electromyographic (EMG) activity of the paretic leg, spatiotemporal gait parameters and pelvis lateral displacement were collected. Significant increases in integrated EMG of hip abductor, medial hamstrings, soleus, rectus femoris, vastus medialis and tibialis anterior were observed when pelvic corrective force was applied, with pelvic corrective force at 9% of body weight inducing greater muscle activity than 3% or 6% of body weight. Pelvis lateral displacement was more symmetric with pelvic corrective force at 9% of body weight. Applying a mediolateral pelvic corrective force toward the paretic side may enhance muscle activity of the paretic leg and improve pelvis displacement symmetry in individuals post-stroke. Forceful weight shift to the paretic side could potentially force additional use of the paretic leg and improve the walking pattern. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

An Approach to Stable Walking over Uneven Terrain Using a Reflex-Based Adaptive Gait

Directory of Open Access Journals (Sweden)

Umar Asif

2011-01-01

Full Text Available This paper describes the implementation of an adaptive gait in a six-legged walking robot that is capable of generating reactive stepping actions with the same underlying control methodology as an insect for stable walking over uneven terrains. The proposed method of gait generation uses feedback data from onboard sensors to generate an adaptive gait in order to surmount obstacles, gaps and perform stable walking. The paper addresses its implementation through simulations in a visual dynamic simulation environment. Finally the paper draws conclusions about the significance and performance of the proposed gait in terms of tracking errors while navigating in difficult terrains.

Restoration of gait for spinal cord injury patients using HAL with intention estimator for preferable swing speed.

Science.gov (United States)

Tsukahara, Atsushi; Hasegawa, Yasuhisa; Eguchi, Kiyoshi; Sankai, Yoshiyuki

2015-03-01

This paper proposes a novel gait intention estimator for an exoskeleton-wearer who needs gait support owing to walking impairment. The gait intention estimator not only detects the intention related to the start of the swing leg based on the behavior of the center of ground reaction force (CoGRF), but also infers the swing speed depending on the walking velocity. The preliminary experiments categorized into two stages were performed on a mannequin equipped with the exoskeleton robot [Hybrid Assistive Limb: (HAL)] including the proposed estimator. The first experiment verified that the gait support system allowed the mannequin to walk properly and safely. In the second experiment, we confirmed the differences in gait characteristics attributed to the presence or absence of the proposed swing speed profile. As a feasibility study, we evaluated the walking capability of a severe spinal cord injury patient supported by the system during a 10-m walk test. The results showed that the system enabled the patient to accomplish a symmetrical walk from both spatial and temporal standpoints while adjusting the speed of the swing leg. Furthermore, the critical differences of gait between our system and a knee-ankle-foot orthosis were obtained from the CoGRF distribution and the walking time. Through the tests, we demonstrated the effectiveness and practical feasibility of the gait support algorithms.

Reflex control of robotic gait using human walking data.

Directory of Open Access Journals (Sweden)

Catherine A Macleod

Full Text Available Control of human walking is not thoroughly understood, which has implications in developing suitable strategies for the retraining of a functional gait following neurological injuries such as spinal cord injury (SCI. Bipedal robots allow us to investigate simple elements of the complex nervous system to quantify their contribution to motor control. RunBot is a bipedal robot which operates through reflexes without using central pattern generators or trajectory planning algorithms. Ground contact information from the feet is used to activate motors in the legs, generating a gait cycle visually similar to that of humans. Rather than developing a more complicated biologically realistic neural system to control the robot's stepping, we have instead further simplified our model by measuring the correlation between heel contact and leg muscle activity (EMG in human subjects during walking and from this data created filter functions transferring the sensory data into motor actions. Adaptive filtering was used to identify the unknown transfer functions which translate the contact information into muscle activation signals. Our results show a causal relationship between ground contact information from the heel and EMG, which allows us to create a minimal, linear, analogue control system for controlling walking. The derived transfer functions were applied to RunBot II as a proof of concept. The gait cycle produced was stable and controlled, which is a positive indication that the transfer functions have potential for use in the control of assistive devices for the retraining of an efficient and effective gait with potential applications in SCI rehabilitation.

Prosthetic model, but not stiffness or height, affects the metabolic cost of running for athletes with unilateral transtibial amputations.

Science.gov (United States)

Beck, Owen N; Taboga, Paolo; Grabowski, Alena M

2017-07-01

Running-specific prostheses enable athletes with lower limb amputations to run by emulating the spring-like function of biological legs. Current prosthetic stiffness and height recommendations aim to mitigate kinematic asymmetries for athletes with unilateral transtibial amputations. However, it is unclear how different prosthetic configurations influence the biomechanics and metabolic cost of running. Consequently, we investigated how prosthetic model, stiffness, and height affect the biomechanics and metabolic cost of running. Ten athletes with unilateral transtibial amputations each performed 15 running trials at 2.5 or 3.0 m/s while we measured ground reaction forces and metabolic rates. Athletes ran using three different prosthetic models with five different stiffness category and height combinations per model. Use of an Ottobock 1E90 Sprinter prosthesis reduced metabolic cost by 4.3 and 3.4% compared with use of Freedom Innovations Catapult [fixed effect (β) = -0.177; P Run (β = -0.139; P = 0.002) prostheses, respectively. Neither prosthetic stiffness ( P ≥ 0.180) nor height ( P = 0.062) affected the metabolic cost of running. The metabolic cost of running was related to lower peak (β = 0.649; P = 0.001) and stance average (β = 0.772; P = 0.018) vertical ground reaction forces, prolonged ground contact times (β = -4.349; P = 0.012), and decreased leg stiffness (β = 0.071; P running. Instead, an optimal prosthetic model, which improves overall biomechanics, minimizes the metabolic cost of running for athletes with unilateral transtibial amputations. NEW & NOTEWORTHY The metabolic cost of running for athletes with unilateral transtibial amputations depends on prosthetic model and is associated with lower peak and stance average vertical ground reaction forces, longer contact times, and reduced leg stiffness. Metabolic cost is unrelated to prosthetic stiffness, height, and stride kinematic symmetry. Unlike nonamputees who decrease leg stiffness with

Dynamic bending of bionic flexible body driven by pneumatic artificial muscles(PAMs) for spinning gait of quadruped robot

Science.gov (United States)

Lei, Jingtao; Yu, Huangying; Wang, Tianmiao

2016-01-01

The body of quadruped robot is generally developed with the rigid structure. The mobility of quadruped robot depends on the mechanical properties of the body mechanism. It is difficult for quadruped robot with rigid structure to achieve better mobility walking or running in the unstructured environment. A kind of bionic flexible body mechanism for quadruped robot is proposed, which is composed of one bionic spine and four pneumatic artificial muscles(PAMs). This kind of body imitates the four-legged creatures' kinematical structure and physical properties, which has the characteristic of changeable stiffness, lightweight, flexible and better bionics. The kinematics of body bending is derived, and the coordinated movement between the flexible body and legs is analyzed. The relationship between the body bending angle and the PAM length is obtained. The dynamics of the body bending is derived by the floating coordinate method and Lagrangian method, and the driving force of PAM is determined. The experiment of body bending is conducted, and the dynamic bending characteristic of bionic flexible body is evaluated. Experimental results show that the bending angle of the bionic flexible body can reach 18°. An innovation body mechanism for quadruped robot is proposed, which has the characteristic of flexibility and achieve bending by changing gas pressure of PAMs. The coordinated movement of the body and legs can achieve spinning gait in order to improve the mobility of quadruped robot.

Biped Robot Gait Planning Based on 3D Linear Inverted Pendulum Model

Science.gov (United States)

Yu, Guochen; Zhang, Jiapeng; Bo, Wu

2018-01-01

In order to optimize the biped robot’s gait, the biped robot’s walking motion is simplify to the 3D linear inverted pendulum motion mode. The Center of Mass (CoM) locus is determined from the relationship between CoM and the Zero Moment Point (ZMP) locus. The ZMP locus is planned in advance. Then, the forward gait and lateral gait are simplified as connecting rod structure. Swing leg trajectory using B-spline interpolation. And the stability of the walking process is discussed in conjunction with the ZMP equation. Finally the system simulation is carried out under the given conditions to verify the validity of the proposed planning method.

A Comparative Study of Biologically Inspired Walking Gaits through Waypoint Navigation

Directory of Open Access Journals (Sweden)

Umar Asif

2011-01-01

Full Text Available This paper investigates the locomotion of a walking robot by delivering a comparative study of three different biologically inspired walking gaits, namely: tripod, ripple, and wave, in terms of ground slippage they experience while walking. The objective of this study is to identify the gait model which experiences the minimum slippage while walking on a ground with a specific coefficient of friction. To accomplish this feat, the robot is steered over a reference path using a waypoint navigation algorithm, and the divergence of the robot from the reference path is investigated in terms of slip errors. Experiments are conducted through closed-loop simulations using an open dynamics engine which emphasizes the fact that due to uneven and unsymmetrical distribution of payload in tripod and ripple gait models, the robot experiences comparatively larger drift in these gaits than when using the wave gait model in which the distribution of payload is even and symmetrical on both sides of the robot body. The paper investigates this phenomenon on the basis of force distribution of supporting legs in each gait model.

Alterations in walking knee joint stiffness in individuals with knee osteoarthritis and self-reported knee instability.

Science.gov (United States)

Gustafson, Jonathan A; Gorman, Shannon; Fitzgerald, G Kelley; Farrokhi, Shawn

2016-01-01

Increased walking knee joint stiffness has been reported in patients with knee osteoarthritis (OA) as a compensatory strategy to improve knee joint stability. However, presence of episodic self-reported knee instability in a large subgroup of patients with knee OA may be a sign of inadequate walking knee joint stiffness. The objective of this work was to evaluate the differences in walking knee joint stiffness in patients with knee OA with and without self-reported instability and examine the relationship between walking knee joint stiffness with quadriceps strength, knee joint laxity, and varus knee malalignment. Overground biomechanical data at a self-selected gait velocity was collected for 35 individuals with knee OA without self-reported instability (stable group) and 17 individuals with knee OA and episodic self-reported instability (unstable group). Knee joint stiffness was calculated during the weight-acceptance phase of gait as the change in the external knee joint moment divided by the change in the knee flexion angle. The unstable group walked with lower knee joint stiffness (p=0.01), mainly due to smaller heel-contact knee flexion angles (pknee flexion excursions (pknee stable counterparts. No significant relationships were observed between walking knee joint stiffness and quadriceps strength, knee joint laxity or varus knee malalignment. Reduced walking knee joint stiffness appears to be associated with episodic knee instability and independent of quadriceps muscle weakness, knee joint laxity or varus malalignment. Further investigations of the temporal relationship between self-reported knee joint instability and walking knee joint stiffness are warranted. Copyright © 2015 Elsevier B.V. All rights reserved.

Gait energy expenditure in children with Duchenne muscular dystrophy: case study

OpenAIRE

Souza, Mariana Angélica de; Ferreira, Marília Ester; Baptista, Cyntia Rogean de Jesus Alves de; Sverzut, Ana Claudia Mattiello

2014-01-01

This case study aimed to verify the model of Rose et al.1 as a feasible to assess energy expenditure in gait of children with Duchenne muscular dystrophy (DMD). Three DMD patients aged 6, 7 and 8 years old participated of this study. It was obtained weight, height, leg length measurement (LLM), resting and gait heart rate (HR) held on as 55-meter oval circuit performed during a two-minute test at each speed. Energy expenditure was calculated using the HR. It was performed a descriptive analys...

Virtual Constraint Control of a Powered Prosthetic Leg: From Simulation to Experiments with Transfemoral Amputees.

Science.gov (United States)

Gregg, Robert D; Lenzi, Tommaso; Hargrove, Levi J; Sensinger, Jonathon W

2014-12-01

Recent powered (or robotic) prosthetic legs independently control different joints and time periods of the gait cycle, resulting in control parameters and switching rules that can be difficult to tune by clinicians. This challenge might be addressed by a unifying control model used by recent bipedal robots, in which virtual constraints define joint patterns as functions of a monotonic variable that continuously represents the gait cycle phase. In the first application of virtual constraints to amputee locomotion, this paper derives exact and approximate control laws for a partial feedback linearization to enforce virtual constraints on a prosthetic leg. We then encode a human-inspired invariance property called effective shape into virtual constraints for the stance period. After simulating the robustness of the partial feedback linearization to clinically meaningful conditions, we experimentally implement this control strategy on a powered transfemoral leg. We report the results of three amputee subjects walking overground and at variable cadences on a treadmill, demonstrating the clinical viability of this novel control approach.

The sensitivity, specificity and reliability of the GALS (gait, arms, legs and spine) examination when used by physiotherapists and physiotherapy students to detect rheumatoid arthritis.

Science.gov (United States)

Beattie, Karen A; Macintyre, Norma J; Pierobon, Jessica; Coombs, Jennifer; Horobetz, Diana; Petric, Alexis; Pimm, Mara; Kean, Walter; Larché, Maggie J; Cividino, Alfred

2011-09-01

To evaluate the sensitivity, specificity and reliability of the gait, arms, legs and spine (GALS) examination to detect signs and symptoms of rheumatoid arthritis when used by physiotherapy students and physiotherapists. Two physiotherapy students and two physiotherapists were trained to perform the GALS examination by viewing an instructional DVD and attending a workshop. Two rheumatologists familiar with the GALS examination also participated in the workshop. All healthcare professionals performed the GALS examination on 25 participants with rheumatoid arthritis recruited through a rheumatology practice and 23 participants without any arthritides recruited from a primary care centre. Each participant was assessed by one rheumatologist, one physiotherapist and one physiotherapy student. Abnormalities of gait, arms, legs and spine, including their location and description, were recorded, along with whether or not a diagnosis of rheumatoid arthritis was suspected. Healthcare professionals understood the study's objective to be their agreement on GALS findings and were unaware that half of the participants had rheumatoid arthritis. Sensitivity, specificity and likelihood ratios were calculated to determine the ability of the GALS examination to screen for rheumatoid arthritis. Using rheumatologists' findings on the study day as the standard for comparison, sensitivity and specificity were 71 to 86% and 69 to 93%, respectively. Positive likelihood ratios ranged from 2.74 to 10.18, while negative likelihood ratios ranged from 0.21 to 0.38. The GALS examination may be a useful tool for physiotherapists to rule out rheumatoid arthritis in a direct access setting. Differences in duration and type of experience of each healthcare professional may contribute to the variation in results. The merits of introducing the GALS examination into physiotherapy curricula and practice should be explored. Copyright © 2010 Chartered Society of Physiotherapy. Published by Elsevier Ltd

Acute effects of repeated bouts of aerobic exercise on arterial stiffness after glucose ingestion.

Science.gov (United States)

Kobayashi, Ryota; Hashimoto, Yuto; Hatakeyama, Hiroyuki; Okamoto, Takanobu

2018-03-22

The aim of this study was to investigate the acute repeated bouts of aerobic exercise decrease leg arterial stiffness. However, the influence of repeated bouts of aerobic exercise on arterial stiffness after glucose ingestion is unknown. The present study investigates the acute effects of repeated bouts of aerobic exercise on arterial stiffness after the 75-g oral glucose tolerance test (OGTT). Ten healthy young men (age, 23.2 ± 0.9 years) performed repeated bouts of aerobic exercise trial (RE, 65% peak oxygen uptake; two 15 min bouts of cycling performed 20 min apart) and control trial (CON, seated and resting in a quiet room) at 80 min before the 75-g OGTT on separate days in a randomized, controlled crossover fashion. Carotid-femoral (aortic) and femoral-ankle (leg) pulse wave velocity, carotid augmentation index, brachial and ankle blood pressure, heart rate and blood glucose and insulin levels were measured before (baseline) and 30, 60 and 120 min after the 75-g OGTT. Leg pulse wave velocity, ankle systolic blood pressure and blood glucose levels increased from baseline after the 75-g OGTT in the CON trial, but not in the RE trial. The present findings indicate that acute repeated bouts of aerobic exercise before glucose ingestion suppress increases in leg arterial stiffness following glucose ingestion. RE trial repeated bouts of aerobic exercise trial; CON trial control trial; BG blood glucose; VO 2peak peak oxygen uptake; PWV Pulse wave velocity; AIx carotid augmentation index; BP blood pressure; HR heart rate; CVs coefficients of variation; RPE Ratings of perceived exertion; SE standard error.

Whole-body vibration exercise training reduces arterial stiffness in postmenopausal women with prehypertension and hypertension.

Science.gov (United States)

Figueroa, Arturo; Kalfon, Roy; Madzima, Takudzwa A; Wong, Alexei

2014-02-01

The purpose of this study was to examine the impact of whole-body vibration (WBV) exercise training on arterial stiffness (pulse wave velocity [PWV]), blood pressure (BP), and leg muscle function in postmenopausal women. Twenty-five postmenopausal women with prehypertension and hypertension (mean [SE]; age, 56 [1] y; systolic BP, 139 [2] mm Hg; body mass index, 34.7 [0.8] kg/m2) were randomized to 12 weeks of WBV exercise training (n = 13) or to the no-exercise control group. Systolic BP, diastolic BP, mean arterial pressure, heart rate, carotid-femoral PWV, brachial-ankle PWV, femoral-ankle PWV (legPWV), leg lean mass, and leg muscle strength were measured before and after 12 weeks. There was a group-by-time interaction (P exercise training compared with no change after control. Heart rate decreased (-3 [1] beats/min, P exercise training, but there was no interaction (P > 0.05). Leg lean mass and carotid-femoral PWV were not significantly (P > 0.05) affected by WBV exercise training or control. Our findings indicate that WBV exercise training improves systemic and leg arterial stiffness, BP, and leg muscle strength in postmenopausal women with prehypertension or hypertension. WBV exercise training may decrease cardiovascular and disability risks in postmenopausal women by reducing legPWV and increasing leg muscle strength.

Noisy interlimb coordination can be a main cause of freezing of gait in patients with little to no parkinsonism.

Directory of Open Access Journals (Sweden)

Takao Tanahashi

Full Text Available Freezing of gait in patients with Parkinson's disease is associated with several factors, including interlimb incoordination and impaired gait cycle regulation. Gait analysis in patients with Parkinson's disease is confounded by parkinsonian symptoms such as rigidity. To understand the mechanisms underlying freezing of gait, we compared gait patterns during straight walking between 9 patients with freezing of gait but little to no parkinsonism (freezing patients and 11 patients with Parkinson's disease (non-freezing patients. Wireless sensors were used to detect foot contact and toe-off events, and the step phase of each foot contact was calculated by defining one stride cycle of the other leg as 360°. Phase-resetting analysis was performed, whereby the relation between the step phase of one leg and the subsequent phase change in the following step of the other leg was quantified using regression analysis. A small slope of the regression line indicates a forceful correction (phase reset at every step of the deviation of step phase from the equilibrium phase, usually at around 180°. The slope of this relation was smaller in freezing patients than in non-freezing patients, but the slope exhibited larger step-to-step variability. This indicates that freezing patients executed a forceful but noisy correction of the deviation of step phase, whereas non-freezing patients made a gradual correction of the deviation. Moreover, freezing patients tended to show more variable step phase and stride time than non-freezing patients. Dynamics of a model of two coupled oscillators interacting through a phase resetting mechanism were examined, and indicated that the deterioration of phase reset by noise provoked variability in step phase and stride time. That is, interlimb coordination can affect regulation of the gait cycle. These results suggest that noisy interlimb coordination, which probably caused forceful corrections of step phase deviation, can be a

Intention detection of gait initiation using EMG and kinematic data

NARCIS (Netherlands)

Wentink, E.C.; Beijen, S.I.; Hermens, Hermanus J.; Rietman, Johan Swanik; Veltink, Petrus H.

2013-01-01

Gait initiation in transfemoral amputees (TFA) is different from non-amputees. This is mainly caused by the lack of stability and push-off from the prosthetic leg. Adding control and artificial push-off to the prosthesis may therefore be beneficial to TFA. In this study the feasibility of real-time

Intention detection of gait initiation using EMG and kinematic data

NARCIS (Netherlands)

Wentink, E.C.; Beijen, S.I.; Hermens, Hermanus J.; Rietman, Johan Swanik; Veltink, Petrus H.

Gait initiation in transfemoral amputees (TFA) is different from non-amputees. This is mainly caused by the lack of stability and push-off from the prosthetic leg. Adding control and artificial push-off to the prosthesis may therefore be beneficial to TFA. In this study the feasibility of real-time

Terminology: resistance or stiffness for medical compression stockings?

Directory of Open Access Journals (Sweden)

André Cornu-Thenard

2013-04-01

Full Text Available Based on previous experimental work with medical compression stockings it is proposed to restrict the term stiffness to measurements on the human leg and rather to speak about resistance when it comes to characterize the elastic property of compression hosiery in the textile laboratory.

Running Economy: Neuromuscular and Joint Stiffness Contributions in Trained Runners.

Science.gov (United States)

Tam, Nicholas; Tucker, Ross; Santos-Concejero, Jordan; Prins, Danielle; Lamberts, Robert P

2018-05-29

It is debated whether running biomechanics make good predictors of running economy, with little known information about the neuromuscular and joint stiffness contributions to economical running gait. The aim of this study was to understand the relationship between certain neuromuscular and spatiotemporal biomechanical factors associated with running economy. Thirty trained runners performed a 6-minute constant-speed running set at 3.3 m∙s -1 , where oxygen consumption was assessed. Overground running trials were also performed at 3.3 m∙s -1 to assess kinematics, kinetics and muscle activity. Spatiotemporal gait variables, joint stiffness, pre-activation and stance phase muscle activity (gluteus medius; rectus femoris (RF); biceps femoris(BF); peroneus longus (PL); tibialis anterior (TA); gastrocnemius lateralis and medius (LG and MG) were variables of specific interest and thus determined. Additionally, pre-activation and ground contact of agonist:antagonist co-activation were calculated. More economical runners presented with short ground contact times (r=0.639, p<0.001) and greater strides frequencies (r=-0.630, p<0.001). Lower ankle and greater knee stiffness were associated with lower oxygen consumption (r=0.527, p=0.007 & r=0.384, p=0.043, respectively). Only LG:TA co-activation during stance were associated with lower oxygen cost of transport (r=0.672, p<0.0001). Greater muscle pre-activation and bi-articular muscle activity during stance were associated with more economical runners. Consequently, trained runners who exhibit greater neuromuscular activation prior to and during ground contact, in turn optimise spatiotemporal variables and joint stiffness, will be the most economical runners.

Don't break a leg: running birds from quail to ostrich prioritise leg safety and economy on uneven terrain.

Science.gov (United States)

Birn-Jeffery, Aleksandra V; Hubicki, Christian M; Blum, Yvonne; Renjewski, Daniel; Hurst, Jonathan W; Daley, Monica A

2014-11-01

Cursorial ground birds are paragons of bipedal running that span a 500-fold mass range from quail to ostrich. Here we investigate the task-level control priorities of cursorial birds by analysing how they negotiate single-step obstacles that create a conflict between body stability (attenuating deviations in body motion) and consistent leg force-length dynamics (for economy and leg safety). We also test the hypothesis that control priorities shift between body stability and leg safety with increasing body size, reflecting use of active control to overcome size-related challenges. Weight-support demands lead to a shift towards straighter legs and stiffer steady gait with increasing body size, but it remains unknown whether non-steady locomotor priorities diverge with size. We found that all measured species used a consistent obstacle negotiation strategy, involving unsteady body dynamics to minimise fluctuations in leg posture and loading across multiple steps, not directly prioritising body stability. Peak leg forces remained remarkably consistent across obstacle terrain, within 0.35 body weights of level running for obstacle heights from 0.1 to 0.5 times leg length. All species used similar stance leg actuation patterns, involving asymmetric force-length trajectories and posture-dependent actuation to add or remove energy depending on landing conditions. We present a simple stance leg model that explains key features of avian bipedal locomotion, and suggests economy as a key priority on both level and uneven terrain. We suggest that running ground birds target the closely coupled priorities of economy and leg safety as the direct imperatives of control, with adequate stability achieved through appropriately tuned intrinsic dynamics. © 2014. Published by The Company of Biologists Ltd.

Leg strength or velocity of movement: which is more influential on the balance of mobility limited elders?

Science.gov (United States)

Mayson, Douglas J; Kiely, Dan K; LaRose, Sharon I; Bean, Jonathan F

2008-12-01

To determine which component of leg power (maximal limb strength or limb velocity) is more influential on balance performance in mobility limited elders. In this cross-sectional analysis we evaluated 138 community-dwelling older adults with mobility limitation. Balance was measured using the Unipedal Stance Test, the Berg Balance Test (BERG), the Dynamic Gait Index, and the performance-oriented mobility assessment. We measured one repetition maximum strength and power at 40% one repetition maximum strength, from which velocity was calculated. The associations between maximal estimated leg strength and velocity with balance performance were examined using separate multivariate logistic regression models. Strength was found to be associated [odds ratio of 1.06 (95% confidence interval, 1.01-1.11)] with performance on the Unipedal Stance Test, whereas velocity showed no statistically significant association. In contrast, velocity was consistently associated with performance on all composite measures of balance (BERG 14.23 [1.84-109.72], performance-oriented mobility assessment 33.92 [3.69-312.03], and Dynamic Gait Index 35.80 [4.77-268.71]). Strength was only associated with the BERG 1.08 (1.01-1.14). Higher leg press velocity is associated with better performance on the BERG, performance-oriented mobility assessment, and Dynamic Gait Index, whereas greater leg strength is associated with better performance on the Unipedal Stance Test and the BERG. These findings are likely related to the intrinsic qualities of each test and emphasize the relevance of limb velocity.

Anticipatory postural adjustment patterns during gait initiation across the adult lifespan.

Science.gov (United States)

Lu, Chiahao; Amundsen Huffmaster, Sommer L; Harvey, Jack C; MacKinnon, Colum D

2017-09-01

Gait initiation involves a complex sequence of anticipatory postural adjustments (APAs) during the transition from steady state standing to forward locomotion. APAs have four core components that function to accelerate the center of mass forwards and towards the initial single-support stance limb. These components include loading of the initial step leg, unloading of the initial stance leg, and excursion of the center of pressure in the posterior and lateral (towards the stepping leg) directions. This study examined the incidence, magnitude, and timing of these components and how they change across the lifespan (ages 20-79). 157 individuals performed five trials of self-paced, non-cued gait initiation on an instrumented walkway. At least one component of the APA was absent in 24% of all trials. The component most commonly absent was loading of the initial step leg (absent in 10% of all trials in isolation, absent in 10% of trials in conjunction with another missing component). Trials missing all four components were rare (1%) and were observed in both younger and older adults. There was no significant difference across decades in the incidence of trials without an APA, the number or type of APA components absent, or the magnitude or timing of the APA components. These data demonstrate that one or more components of the APA sequence are commonly absent in the general population and the spatiotemporal profile of the APA does not markedly change with ageing. Copyright © 2017 Elsevier B.V. All rights reserved.

Example of Synthesis of Control Actions for Six-Legged Walking Robot when Moving on ‎Rough Surface

Directory of Open Access Journals (Sweden)

L. A. Karginov

2015-01-01

Full Text Available Control actions are provided on the basis of inverse kinematic problem. Now there is a set of methods to solve this task.This article considers an example of the author’s approach application to the inverse kinematic problem.The main idea of approach is as follows:1. The limited set of the joints necessary to implement the chosen gait is selected from all joints of the robot. For these joints a strict sequence of the movement within each step and restriction of changing generalized coordinates are specified. 2. The joints non-involved in implementing the chosen gait are disabled, with no calculations performed for them.Thus, the sources of basic data for the inverse kinematic problem are the kinematic scheme of the executive mechanism of the walking robot and the chosen gait.To use the offered approach it is necessary:1. To number the legs and their joints.2. To choose joints to be involved in realization of the chosen gait.3. To appoint a sequence of the change of supporting legs when moving by the chosen gait.4. To specify a motion sequence of the chosen joints within a step for each leg.5. To specify restrictions of changes of the generalized coordinates in the chosen joints.The inverse kinematic problem process consists in gradual approach to the solution by change (increase or decrease of the generalized coordinates in the same order in which the joints of a leg corresponding to these coordinates move within a step by the chosen gait when walking.Criterion of completing calculations is the limits reached or the fact that a leg is fixed on a supporting plane by a contact sensor (or a condition in the modeling program. Changes of generalized coordinates are within a cycle; each generalized coordinate changes by a certain value at each of iterations of a cycle. The total time of a cycle corresponds to the estimated time of a step to be done.Advantages of the approach are following: unambiguity of the received solution, possibility to

Technical note: Use of accelerometers to describe gait patterns in dairy calves

DEFF Research Database (Denmark)

Passillé, A. M. de; Jensen, Margit Bak; Chapinal, N.

2010-01-01

Developments in accelerometer technology offer new opportunities for automatic monitoring of animal behavior. Until now, commercially available accelerometers have been used to measure walking in adult cows but have failed to identify walking in calves. We described the pattern of acceleration...... associated with various gaits in calves and tested whether measures of acceleration could be used to count steps and distinguish among gait types. A triaxial accelerometer (sampling at 33 readings/s with maximum measurement at +/-3.2 g) was attached to 1 hind leg of 7 dairy calves, and each calf was walked...

Inverse association between insulin resistance and gait speed in nondiabetic older men: results from the U.S. National Health and Nutrition Examination Survey (NHANES 1999-2002

Directory of Open Access Journals (Sweden)

Yu Yau-Hua

2009-11-01

Full Text Available Abstract Background Recent studies have revealed the associations between insulin resistance (IR and geriatric conditions such as frailty and cognitive impairment. However, little is known about the relation of IR to physical impairment and limitation in the aging process, eg. slow gait speed and poor muscle strength. The aim of this study is to determine the effect of IR in performance-based physical function, specifically gait speed and leg strength, among nondiabetic older adults. Methods Cross-sectional data were from the population-based National Health and Nutrition Examination Survey (1999-2002. A total of 1168 nondiabetic adults (≥ 50 years with nonmissing values in fasting measures of insulin and glucose, habitual gait speed (HGS, and leg strength were analyzed. IR was assessed by homeostasis model assessment (HOMA-IR, whereas HGS and peak leg strength by the 20-foot timed walk test and an isokinetic dynamometer, respectively. We used multiple linear regression to examine the association between IR and performance-based physical function. Results IR was inversely associated with gait speed among the men. After adjusting demographics, body mass index, alcohol consumption, smoking status, chronic co-morbidities, and markers of nutrition and cardiovascular risk, each increment of 1 standard deviation in the HOMA-IR level was associated with a 0.04 m/sec decrease (p = 0.003 in the HGS in men. We did not find such association among the women. The IR-HGS association was not changed after further adjustment of leg strength. Last, HOMA-IR was not demonstrated in association with peak leg strength. Conclusion IR is inversely associated with HGS among older men without diabetes. The results suggest that IR, an important indicator of gait function among men, could be further investigated as an intervenable target to prevent walking limitation.

Spatiotemporal organization of alpha-motoneuron activity in the human spinal cord during different gaits and gait transitions.

Science.gov (United States)

Ivanenko, Y P; Cappellini, G; Poppele, R E; Lacquaniti, F

2008-06-01

Here we studied the spatiotemporal organization of motoneuron (MN) activity during different human gaits. We recorded the electromyographic (EMG) activity patterns in 32 ipsilateral limb and trunk muscles from normal subjects while running and walking on a treadmill (3-12 km/h). In addition, we recorded backward walking and skipping, a distinct human gait that comprises the features of both walking and running. We mapped the recorded EMG activity patterns onto the spinal cord in approximate rostrocaudal locations of the MN pools. The activation of MNs tends to occur in bursts and be segregated by spinal segment in a gait-specific manner. In particular, sacral and cervical activation timings were clearly gait-dependent. Swing-related activity constituted an appreciable fraction (> 30%) of the total MN activity of leg muscles. Locomoting at non-preferred speeds (running and walking at 5 and 9 km/h, respectively) showed clear differences relative to preferred speeds. Running at low speeds was characterized by wider sacral activation. Walking at high non-preferred speeds was accompanied by an 'atypical' locus of activation in the upper lumbar spinal cord during late stance and by a drastically increased activation of lumbosacral segments. The latter findings suggest that the optimal speed of gait transitions may be related to an optimal intensity of the total MN activity, in addition to other factors previously described. The results overall support the idea of flexibility and adaptability of spatiotemporal activity in the spinal circuitry with constraints on the temporal functional connectivity of hypothetical pulsatile burst generators.

Design of a Quasi-Passive Parallel Leg Exoskeleton to Augment Load Carrying for Walking

National Research Council Canada - National Science Library

Valiente, Andrew

2005-01-01

.... The exoskeleton structure runs parallel to the legs, transferring payload forces to the ground. In an attempt to make the exoskeleton more efficient, passive hip and ankle springs are employed to store and release energy throughout the gait cycle...

Design and Evaluation of the LOPES Exoskeleton Robot for Interactive Gait Rehabilitation

NARCIS (Netherlands)

Veneman, J.F.; Kruidhof, R.; Hekman, Edsko E.G.; Ekkelenkamp, R.; van Asseldonk, Edwin H.F.; van der Kooij, Herman

2007-01-01

This paper introduces a newly developed gait rehabilitation device. The device, called LOPES, combines a freely translatable and 2-D-actuated pelvis segment with a leg exoskeleton containing three actuated rotational joints: two at the hip and one at the knee. The joints are impedance controlled to

[Exoskeleton robot system based on real-time gait analysis for walking assist].

Science.gov (United States)

Xie, Zheng; Wang, Mingjiang; Huang, Wulong; Yong, Shanshan; Wang, Xin'an

2017-04-01

This paper presents a wearable exoskeleton robot system to realize walking assist function, which oriented toward the patients or the elderly with the mild impairment of leg movement function, due to illness or natural aging. It reduces the loads of hip, knee, ankle and leg muscles during walking by way of weight support. In consideration of the characteristics of the psychological demands and the disease, unlike the weight loss system in the fixed or followed rehabilitation robot, the structure of the proposed exoskeleton robot is artistic, lightweight and portable. The exoskeleton system analyzes the user's gait real-timely by the plantar pressure sensors to divide gait phases, and present different control strategies for each gait phase. The pressure sensors in the seat of the exoskeleton system provide real-time monitoring of the support efforts. And the drive control uses proportion-integral-derivative (PID) control technology for torque control. The total weight of the robot system is about 12.5 kg. The average of the auxiliary support is about 10 kg during standing, and it is about 3 kg during walking. The system showed, in the experiments, a certain effect of weight support, and reduction of the pressure on the lower limbs to walk and stand.

Effectiveness of gait training using an electromechanical gait trainer, with and without functional electric stimulation, in subacute stroke: a randomized controlled trial.

Science.gov (United States)

Tong, Raymond K; Ng, Maple F; Li, Leonard S

2006-10-01

To compare the therapeutic effects of conventional gait training (CGT), gait training using an electromechanical gait trainer (EGT), and gait training using an electromechanical gait trainer with functional electric stimulation (EGT-FES) in people with subacute stroke. Nonblinded randomized controlled trial. Rehabilitation hospital for adults. Fifty patients were recruited within 6 weeks after stroke onset; 46 of these completed the 4-week training period. Participants were randomly assigned to 1 of 3 gait intervention groups: CGT, EGT, or EGT-FES. The experimental intervention was a 20-minute session per day, 5 days a week (weekdays) for 4 weeks. In addition, all participants received their 40-minute sessions of regular physical therapy every weekday as part of their treatment by the hospital. Five-meter walking speed test, Elderly Mobility Scale (EMS), Berg Balance Scale, Functional Ambulatory Category (FAC), Motricity Index leg subscale, FIM instrument score, and Barthel Index. The EGT and EGT-FES groups had statistically significantly more improvement than the CGT group in the 5-m walking speed test (CGT vs EGT, P=.011; CGT vs EGT-FES, P=.001), Motricity Index (CGT vs EGT-FES, P=.011), EMS (CGT vs EGT, P=.006; CGT vs EGT-FES, P=.009), and FAC (CGT vs EGT, P=.005; CGT vs EGT-FES, P=.002) after the 4 weeks of training. No statistically significant differences were found between the EGT and EGT-FES groups in all outcome measures. In this sample with subacute stroke, participants who trained on the electromechanical gait trainer with body-weight support, with or without FES, had a faster gait, better mobility, and improvement in functional ambulation than participants who underwent conventional gait training. Future studies with assessor blinding and larger sample sizes are warranted.

Leg Strength or Velocity of Movement Which Is More Influential on the Balance of Mobility Limited Elders?

Science.gov (United States)

Mayson, Douglas J.; Kiely, Dan K.; LaRose, Sharon I.; Bean, Jonathan F.

2009-01-01

Objective To determine which component of leg power (maximal limb strength or limb velocity) is more influential on balance performance in mobility limited elders. Design In this cross-sectional analysis we evaluated 138 community-dwelling older adults with mobility limitation. Balance was measured using the Unipedal Stance Test, the Berg Balance Test (BERG), the Dynamic Gait Index, and the performance-oriented mobility assessment. We measured one repetition maximum strength and power at 40% one repetition maximum strength, from which velocity was calculated. The associations between maximal estimated leg strength and velocity with balance performance were examined using separate multivariate logistic regression models. Results Strength was found to be associated [odds ratio of 1.06 (95% confidence interval, 1.01–1.11)] with performance on the Unipedal Stance Test, whereas velocity showed no statistically significant association. In contrast, velocity was consistently associated with performance on all composite measures of balance [BERG 14.23 (1.84–109.72), performance-oriented mobility assessment 33.92 (3.69–312.03), and Dynamic Gait Index 35.80 (4.77–268.71))]. Strength was only associated with the BERG 1.08 (1.01–1.14). Conclusions Higher leg press velocity is associated with better performance on the BERG, performance-oriented mobility assessment, and Dynamic Gait Index, whereas greater leg strength is associated with better performance on the Unipedal Stance Test and the BERG. These findings are likely related to the intrinsic qualities of each test and emphasize the relevance of limb velocity. PMID:19033758

A case of stiff-person syndrome due to secondary adrenal insufficiency.

Science.gov (United States)

Mizuno, Yuri; Yamaguchi, Hiroo; Uehara, Taira; Yamashita, Kenichiro; Yamasaki, Ryo; Kira, Jun-Ichi

2017-06-28

We report a case of flexion contractures in a patient's legs secondary to postpartum hypopituitarism. A 56-year-old woman presented with a 3-year history of worsening flexion contractures of the hips and knees. On admission, her hips and knees could not be extended, and she had muscle stiffness and tenderness to palpation of the lower extremities. We first suspected stiff-person syndrome or Isaacs' syndrome because of her muscle stiffness. However, multiple hormones did not respond to stimulation tests, and an MRI of the brain showed atrophy of the pituitary gland with an empty sella. A subsequent interview revealed that she had suffered a severe hemorrhage while delivering her third child. She was diagnosed with panhypopituitarism and started on cortisol replacement therapy. After 1 week of treatment with hydrocortisone (10 mg/day), her symptoms quickly improved. We then added 75 μg/day of thyroid hormone. During the course of her treatment, autoantibodies against VGKC complex were found to be weakly positive. However, we considered the antibodies to be unrelated to her disease, because her symptoms improved markedly with low-dose steroid treatment. There are a few reports describing flexion contractures of the legs in patients with primary and secondary adrenal insufficiency. As these symptoms are similar to those seen in stiff-person syndrome, adrenal and pituitary insufficiency should be taken into account to achieve the correct diagnosis and treatment in patients with flexion contractures and muscle stiffness.

Mechanics of toe and heel landing in stepping down in ongoing gait

NARCIS (Netherlands)

van Dieen, J.H.; Spanjaard, M.; Konemann, R.; Bron, L.; Pijnappels, M.A.G.M.

2008-01-01

When stepping down from a height difference in ongoing gait, subjects are known to use a heel landing at small height differences and switch to toe landing for larger height differences. We hypothesized that in toe landing, the leading leg can perform more negative work, to control the momentum

Analysis of Gait Pattern to Recognize the Human Activities

Directory of Open Access Journals (Sweden)

Jay Prakash Gupta

2014-09-01

Full Text Available Human activity recognition based on the computer vision is the process of labelling image sequences with action labels. Accurate systems for this problem are applied in areas such as visual surveillance, human computer interaction and video retrieval. The challenges are due to variations in motion, recording settings and gait differences. Here we propose an approach to recognize the human activities through gait. Activity recognition through Gait is the process of identifying an activity by the manner in which they walk. The identification of human activities in a video, such as a person is walking, running, jumping, jogging etc are important activities in video surveillance. We contribute the use of Model based approach for activity recognition with the help of movement of legs only. Experimental results suggest that our method are able to recognize the human activities with a good accuracy rate and robust to shadows present in the videos.

Measurement of acceleration while walking as an automated method for gait assessment in dairy cattle

DEFF Research Database (Denmark)

Chapinal, N.; de Passillé, A.M.; Pastell, M.

2011-01-01

The aims were to determine whether measures of acceleration of the legs and back of dairy cows while they walk could help detect changes in gait or locomotion associated with lameness and differences in the walking surface. In 2 experiments, 12 or 24 multiparous dairy cows were fitted with five 3...... to be a promising tool for lameness detection on farm and to study walking surfaces, especially when attached to a leg....

Smooth and Energy Saving Gait Planning for Humanoid Robot Using Geodesics

Directory of Open Access Journals (Sweden)

Liandong Zhang

2012-01-01

Full Text Available A novel gait planning method using geodesics for humanoid robot is given in this paper. Both the linear inverted pendulum model and the exact Single Support Phase (SSP are studied in our energy optimal gait planning based on geodesics. The kinetic energy of a 2-dimension linear inverted pendulum is obtained at first. We regard the kinetic energy as the Riemannian metric and the geodesic on this metric is studied and this is the shortest line between two points on the Riemannian surface. This geodesic is the optimal kinetic energy gait for the COG because the kinetic energy along geodesic is invariant according to the geometric property of geodesics and the walking is smooth and energy saving. Then the walking in Single Support Phase is studied and the energy optimal gait for the swing leg is obtained using our geodesics method. Finally, experiments using state-of-the-art method and using our geodesics optimization method are carried out respectively and the corresponding currents of the joint motors are recorded. With the currents comparing results, the feasibility of this new gait planning method is verified.

A pilot study of randomized clinical controlled trial of gait training in subacute stroke patients with partial body-weight support electromechanical gait trainer and functional electrical stimulation: six-month follow-up.

Science.gov (United States)

Ng, Maple F W; Tong, Raymond K Y; Li, Leonard S W

2008-01-01

This study aimed to assess the effectiveness of gait training using an electromechanical gait trainer with or without functional electrical stimulation for people with subacute stroke. This was a nonblinded randomized controlled trial with a 6-month follow-up. Fifty-four subjects were recruited within 6 weeks after stroke onset and were randomly assigned to 1 of 3 gait intervention groups: conventional overground gait training treatment (CT, n=21), electromechanical gait trainer (GT, n=17) and, electromechanical gait trainer with functional electrical stimulation (GT-FES, n=16). All subjects were to undergo an assigned intervention program comprising a 20-minute session every weekday for 4 weeks. The outcome measures were Functional Independence Measure, Barthel Index, Motricity Index leg subscale, Elderly Mobility Scale (EMS), Berg Balance Scale, Functional Ambulatory Category (FAC), and 5-meter walking speed test. Assessments were made at baseline, at the end of the 4-week intervention program, and 6 months after the program ended. By intention-to-treat and multivariate analysis, statistically significant differences showed up in EMS (Wilks' lambda=0.743, P=0.005), FAC (Wilks' lambda=0.744, P=0.005) and gait speed (Wilks' lambda=0.658, Pgait training that used an electromechanical gait trainer compared with conventional overground gait training. The training effect was sustained through to the 6-month follow-up after the intervention.

Acceptability and practicality of a Spanish translation of paediatric Gait Arms Legs and Spine (pGALS) in Peruvian children.

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Abernethy, Katrina; Jandial, Sharmila; Hill, Lucy; Sánchez, Ernesto Salazar; Foster, Helen

2014-01-01

The paediatric Gait, Arms, Legs and Spine (pGALS) musculoskeletal examination tool is validated for use in school-aged English Speaking children and shown to be practical and effective in acute paediatric practice in the UK and Malawi. Our aim was to assess the acceptability and practicality of a Spanish translation of pGALS in an acute paediatric setting in Peru. Fifty-three school-aged children presenting to Hospital Regional de Loreto, Peru were recruited to undergo a pGALS examination using a Spanish translation of the instructions. The pGALS examination was completed in 92.5% (49/53), with the time taken (median 4.42 minutes) being acceptable to most parents (98.1%, 52/53). Most children (88.7%, 47/53), found the pGALS examination caused 'little' or 'no additional discomfort'. Using pGALS, significant findings were observed in 18/53 (34%) children; these related to fractures (4/18), hypermobility (4/18), infectious causes (5/18) and soft tissue trauma (5/18). Using this Spanish translation, pGALS assessment was practical, acceptable and effective in detecting musculoskeletal changes in many children.

Balance and Gait Training With Augmented Feedback Improves Balance Confidence in People With Parkinson's Disease: A Randomized Controlled Trial.

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Shen, Xia; Mak, Margaret K Y

2014-07-01

Background Fear of falling has been identified as an important and independent fall-risk predictor in patients with Parkinson's disease (PD). However, there are inconsistent findings on the effects of balance and gait training on balance confidence. Objective To explore whether balance and gait training with augmented feedback can enhance balance confidence in PD patients immediately after treatment and at 3- and 12-month follow-ups. Methods A total of 51 PD patients were randomly assigned to a balance and gait training (BAL) group or to an active control (CON) group. The BAL group received balance and gait training with augmented feedback, whereas CON participants received lower-limb strength training for 12 weeks. Outcome measures included Activities-Specific Balance Confidence (ABC) Scale, limits-of-stability test, single-leg-stance test, and spatiotemporal gait characteristics. All tests were administered before intervention (Pre), immediately after training (Post), and at 3 months (Post3m) and 12 months (Post12m) after treatment completion. Results The ABC score improved marginally at Post and significantly at Post3m and Post12m only in the BAL group (P point excursion at Post, but only the BAL group maintained the improvement at Post3m. The BAL group maintained significantly longer time-to-loss-of-balance during the single-leg stance test than the CON group at Post3m and Post12m (P balance confidence and balance and gait performance in patients with PD. © The Author(s) 2014.

Artificial Walking Technologies to Improve Gait in Cerebral Palsy: Multichannel Neuromuscular Stimulation.

Science.gov (United States)

Rose, Jessica; Cahill-Rowley, Katelyn; Butler, Erin E

2017-11-01

Cerebral palsy (CP) is the most common childhood motor disability and often results in debilitating walking abnormalities, such as flexed-knee and stiff-knee gait. Current medical and surgical treatments are only partially effective in improving gait abnormalities and may cause significant muscle weakness. However, emerging artificial walking technologies, such as step-initiated, multichannel neuromuscular electrical stimulation (NMES), can substantially improve gait patterns and promote muscle strength in children with spastic CP. NMES may also be applied to specific lumbar-sacral sensory roots to reduce spasticity. Development of tablet computer-based multichannel NMES can leverage lightweight, wearable wireless stimulators, advanced control design, and surface electrodes to activate lower-limb muscles. Musculoskeletal models have been used to characterize muscle contributions to unimpaired gait and identify high muscle demands, which can help guide multichannel NMES-assisted gait protocols. In addition, patient-specific NMES-assisted gait protocols based on 3D gait analysis can facilitate the appropriate activation of lower-limb muscles to achieve a more functional gait: stance-phase hip and knee extension and swing-phase sequence of hip and knee flexion followed by rapid knee extension. NMES-assisted gait treatment can be conducted as either clinic-based or home-based programs. Rigorous testing of multichannel NMES-assisted gait training protocols will determine optimal treatment dosage for future clinical trials. Evidence-based outcome evaluation using 3D kinematics or temporal-spatial gait parameters will help determine immediate neuroprosthetic effects and longer term neurotherapeutic effects of step-initiated, multichannel NMES-assisted gait in children with spastic CP. Multichannel NMES is a promising assistive technology to help children with spastic CP achieve a more upright, functional gait. © 2017 International Center for Artificial Organs and

Effects of real-time gait biofeedback on paretic propulsion and gait biomechanics in individuals post-stroke.

Science.gov (United States)

Genthe, Katlin; Schenck, Christopher; Eicholtz, Steven; Zajac-Cox, Laura; Wolf, Steven; Kesar, Trisha M

2018-04-01

Objectives Gait training interventions that target paretic propulsion induce improvements in walking speed and function in individuals post-stroke. Previously, we demonstrated that able-bodied individuals increase propulsion unilaterally when provided real-time biofeedback targeting anterior ground reaction forces (AGRF). The purpose of this study was to, for the first time, investigate short-term effects of real-time AGRF gait biofeedback training on post-stroke gait. Methods Nine individuals with post-stroke hemiparesis (6 females, age = 54 ± 12.4 years 39.2 ± 24.4 months post-stroke) completed three 6-minute training bouts on an instrumented treadmill. During training, visual and auditory biofeedback were provided to increase paretic AGRF during terminal stance. Gait biomechanics were evaluated before training, and during retention tests conducted 2, 15, and 30 minutes post-training. Primary dependent variables were paretic and non-paretic peak AGRF; secondary variables included paretic and non-paretic peak trailing limb angle, plantarflexor moment, and step length. In addition to evaluating the effects of biofeedback training on these dependent variables, we compared effects of a 6-minute biofeedback training bout to a non-biofeedback control condition. Results Compared to pre-training, significantly greater paretic peak AGRFs were generated during the 2, 15, and 30-minute retention tests conducted after the 18-minute biofeedback training session. Biofeedback training induced no significant effects on the non-paretic leg. Comparison of a 6-minute biofeedback training bout with a speed-matched control bout without biofeedback demonstrated a main effect for training type, with greater peak AGRF generation during biofeedback. Discussion Our results suggest that AGRF biofeedback may be a feasible and promising gait training strategy to target propulsive deficits in individuals post-stroke.

Age and muscle strength mediate the age-related biomechanical plasticity of gait

NARCIS (Netherlands)

Hortobagyi, Tibor; Rider, Patrick; Gruber, Allison H.; DeVita, Paul

Old compared with young adults walk with reduced ankle and increased hip mechanical output. We examined the idea that age, leg strength, or both are related to the age-related changes in mechanical output during gait. Healthy young (n = 32, age 21.5 years) and old adults (n = 32, age 76.8 years)

Test of Gravel to South Leg - Siri Platform

DEFF Research Database (Denmark)

Thomassen, Kristina; Ibsen, Lars Bo

A grout connection between one of the legs of the offshore platform, Siri, and a water caisson at the seabed is failed. The failure leaves a gap in the grout connection meaning that the stiffness of the connection is disappeared resulting in movements of the platform. These movements cause cracks...... in the caisson, hence, the stiffness of the connection must be re-established. In this report the effect of filling a sand material into the gap in the grout connection is investigated. Four types of sand materials is tested; Sand 0-8 mm, Norit 0-2 mm, Norit 0-5 mm, and Sand 0.4-5.6 mm. The comparison...

Dual-energy X-ray absorptiometry and force-plate analysis of gait in dogs with healed femora after leg-lengthening plate fixation

International Nuclear Information System (INIS)

Muir, P.; Markel, M.D.; Bogdanske, J.J.; Johnson, K.A.

1995-01-01

Dual-energy x-ray absorptiometry was used to measure bone mineral density of four regions in healed femora of nine dogs after fracture fixation with a leg-lengthening plate. Six to 85 months (mean, 46 months) after surgery, the bone mineral density of healed femora was not significantly different from the contralateral uninjured femora (P > .05; power = 0.8 at delta = 15%). Radiolucencies around the proximal screws, apparently associated with screw loosening, were seen on radiographic views of the healed femora of three dogs. In one of these dogs, one screw in the proximal metaphysis had broken. Force-plate analysis of gait was also performed on dogs at the time of bone mineral density measurement. Peak vertical force was decreased in the pelvic limb with the healed fracture compared with the contralateral unoperated limb (P < 0.05). Clinically apparent lameness in three dogs did not appear to be associated with altered bone mineral density and may have been caused by hip osteoarthritis, a nondisplaced hairline diaphyseal fracture, and screw loosening in conjunction with extensive post-traumatic soft tissue injury

Perception of Gait Patterns that Deviate from Normal and Symmetric Biped Locomotion

Directory of Open Access Journals (Sweden)

Ismet eHandzic

2015-02-01

Full Text Available This study examines the range of gait patterns that are perceived as healthy and human-like with the goal of understanding how much asymmetry is allowable in a gait pattern before other people start to notice a gait impairment. Specifically, this study explores if certain abnormal walking patterns can be dismissed as unimpaired or not uncanny. Altering gait biomechanics is generally done in the fields of prosthetics and rehabilitation, however the perception of gait is often neglected. Although a certain gait can be functional, it may not be considered as normal by observers. On the other hand, an abnormally perceived gait may be more practical or necessary in some situations, such as limping after an injury or stroke and when wearing a prosthesis. This research will help to find the balance between the form and function of gait. Gait patterns are synthetically created using a passive dynamic walker (PDW model that allows gait patterns to be systematically changed without the confounding influence from human sensorimotor feedback during walking. This standardized method allows the perception of specific changes in gait to be studied. The PDW model was used to produce walking patterns that showed a degree of abnormality in gait cadence, knee height, step length, and swing time created by changing the foot roll-over-shape, knee damping, knee location, and leg masses. The gait patterns were shown to participants who rated them according to separate scales of impairment and uncanniness. The results indicate that some pathological and asymmetric gait patterns are perceived as unimpaired and normal. Step time and step length asymmetries less than 5%, small knee location differences, and gait cadence changes of 25% do not result in a change in perception. The results also show that the parameters of a pathologically or uncanny perceived gait can be beneficially altered by increasing other independent parameters, in some sense masking the initial

The Neuro-Mechanical Processes That Underlie Goal-Directed Medio-Lateral APA during Gait Initiation.

Science.gov (United States)

Honeine, Jean-Louis; Schieppati, Marco; Crisafulli, Oscar; Do, Manh-Cuong

2016-01-01

Gait initiation (GI) involves passing from bipedal to unipedal stance. It requires a rapid movement of the center of foot pressure (CoP) towards the future swing foot and of the center of mass (CoM) in the direction of the stance foot prior to the incoming step. This anticipatory postural adjustment (APA) allows disengaging the swing leg from the ground and establishing favorable conditions for stepping. This study aimed to describe the neuro-mechanical process that underlies the goal-directed medio-lateral (ML) APA. We hypothesized that controlled knee flexion of the stance leg contributes to the initial ML displacement of the CoP and to the calibration of the first step. Fourteen subjects initiated gait starting from three different initial stance widths of 15 cm (Small), 30 cm (Medium), and 45 cm (Large). Optoelectronic, force platform and electromyogram (EMG) measurements were performed. During APA, soleus activity diminished bilaterally, while tibialis anterior (TA) activity increased, more so in the stance leg than in the swing leg, and to a larger extent with increasing initial stance width. Knee flexion of the stance leg was observed during APA and correlated with the ML CoP displacement towards the swing leg. ML CoP and CoM displacements during APA increased with increasing stance width. The activity of stance-leg TA was correlated with the degree of knee flexion. Swing-leg tensor fasciae latae (TFL) was also active during APA. Across subjects, when stance-leg tibialis activity was low, TFL activity was large and vice versa. The modulation of the ML CoP position during APA allowed the gravity-driven torque to place the CoM just lateral to the stance foot during step execution. Accordingly, the gravity-driven torque, the ML CoM velocity during step execution, and the step width at foot contact (FC) were lower in the Small and greater in the Large condition. Consequently, the position of the stepping foot at FC remained close to the sagittal plane in all

Interaction of the human body and surfaces of different stiffness during drop jumps.

Science.gov (United States)

Arampatzis, Adamantios; Stafilidis, Savvas; Morey-Klapsing, Gaspar; Brüggemann, Gert-peter

2004-03-01

The purpose of this study was to examine two hypotheses: (a) the stiffness of the surface influences the leg stiffness of the subjects during drop jumps, and (b) drop jumping performance (jumping height and energy rates of the subject's center of mass during the contact phase) increases when decreasing surface stiffness due to a greater energy storage capacity of the surface for a given acting force. Ten female subjects performed a series of drop jumps from 40-cm height onto two sprung surfaces with different stiffness. Those trials of each subject displaying the maximal mechanical power during the upward phase were analyzed. The ground reaction forces were measured using a force plate. Sagittal kinematics of the subject's body positions and the deformation of the surface were recorded using two high-speed video cameras. On the soft surface, the jumping height and the energy rates of the subjects during the contact phase were greater than on the hard one. The energy delivered by the subjects during the upward phase, the leg and joint stiffness, as well as the range of motion of the subjects remained unchanged for both surfaces. The absolute energy loss is lower for the hard surface, but the jumping performance is greater for the soft one. The reason is a higher ratio of positive to negative mechanical work done by the subjects during the contact phase. The adjustment of the subjects to different surfaces is not only dependent on the stiffness of the surface but also on the intensity of the movement.

Intention detection of gait initiation using EMG and kinematic data.

Science.gov (United States)

Wentink, E C; Beijen, S I; Hermens, H J; Rietman, J S; Veltink, P H

2013-02-01

Gait initiation in transfemoral amputees (TFA) is different from non-amputees. This is mainly caused by the lack of stability and push-off from the prosthetic leg. Adding control and artificial push-off to the prosthesis may therefore be beneficial to TFA. In this study the feasibility of real-time intention detection of gait initiation was determined by mimicking the TFA situation in non-amputees. EMG and inertial sensor data was measured in 10 non-amputees. Only data available in TFA was used to determine if gait initiation can be predicted in time to control a transfemoral prosthesis to generate push-off and stability. Toe-off and heel-strike of the leading limb are important parameters to be detected, to control a prosthesis and to time push-off. The results show that toe-off and heel-strike of the leading limb can be detected using EMG and kinematic data in non-amputees 130-260 ms in advance. This leaves enough time to control a prosthesis. Based on these results we hypothesize that similar results can be found in TFA, allowing for adequate control of a prosthesis during gait initiation. Copyright © 2012 Elsevier B.V. All rights reserved.

Android Platform for Realtime Gait Tracking Using Inertial Measurement Units.

Science.gov (United States)

Aqueveque, Pablo; Sobarzo, Sergio; Saavedra, Francisco; Maldonado, Claudio; Gómez, Britam

2016-06-13

One of the most important movements performed by the humans is gait. Biomechanical Gait analysis is usually by optical capture systems. However, such systems are expensive and sensitive to light and obstacles. In order to reduce those costs a system based on Inertial Measurements Units (IMU) is proposed. IMU are a good option to make movement analisys indoor with a low post-processing data, allowing to connect those systems to an Android platform. The design is based on two elements: a) The IMU sensors and the b) Android device. The IMU sensor is simple, small (35 x 35 mm), portable and autonomous (7.8 hrs). A resolution of 0.01° in their measurements is obtained, and sends data via Bluetooth link. The Android application works for Android 4.2 or higher, and it is compatible with Bluetooth devices 2.0 or higher. Three IMU sensors send data to a Tablet wirelessly, in order to evaluate the angles evolution for each joint of the leg (hip, knee and ankle). This information is used to calculate gait index and evaluate the gait quality online during the physical therapist is working with the patient.

Estimation of Human Hip and Knee Multi-Joint Dynamics Using the LOPES Gait Trainer

NARCIS (Netherlands)

Koopman, Hubertus F.J.M.; van Asseldonk, Edwin H.F.; van der Kooij, Herman

2016-01-01

In this study, we present and evaluate a novel method to estimate multi-joint leg impedance, using a robotic gait training device. The method is based on multi-input–multi-output system identification techniques and is designed for continuous torque perturbations at the hip and knee joint

Design of a minimally constraining, passively supported gait training exoskeleton: ALEX II.

Science.gov (United States)

Winfree, Kyle N; Stegall, Paul; Agrawal, Sunil K

2011-01-01

This paper discusses the design of a new, minimally constraining, passively supported gait training exoskeleton known as ALEX II. This device builds on the success and extends the features of the ALEX I device developed at the University of Delaware. Both ALEX (Active Leg EXoskeleton) devices have been designed to supply a controllable torque to a subject's hip and knee joint. The current control strategy makes use of an assist-as-needed algorithm. Following a brief review of previous work motivating this redesign, we discuss the key mechanical features of the new ALEX device. A short investigation was conducted to evaluate the effectiveness of the control strategy and impact of the exoskeleton on the gait of six healthy subjects. This paper concludes with a comparison between the subjects' gait both in and out of the exoskeleton. © 2011 IEEE

Asterixis in the leg induced by anterior cerebral artery infarction.

Science.gov (United States)

Sunwoo, Mun Kyung; Jang, Hyun-Soon; Roh, Sook Young; Yoo, Hyun Jung; Jeong, Eun Hye; Kim, Byung-Su; Choe, Yeo Reum; Lee, Ko-Eun

2016-06-01

Asterixis commonly occurs in a patient with metabolic encephalopathy, whereas focal brain lesions such as thalamus, cerebellum, or frontal area also cause focal or unilateral asterixis in the arms. We report a novel case of asterixis in the leg after unilateral anterior cerebral artery territory infarction. A 76-year-old man was admitted with sudden-onset mild right leg weakness and postural instability due to knee buckling. He was diagnosed with ischemic stroke in the left prefrontal area and cingulated gyrus by brain magnetic imaging. Needle electromyography of the right vastus lateralis muscle while standing showed intermittent periods of EMG silence, consistent with asterixis. There were no abnormal involuntary movements in the upper extremities. This case suggests that gait disturbance or postural instability after structural lesions in the prefrontal area may be directly related to asterixis in the leg, not in the arm associated with postural failure.

Differentiation of benign and malignant solid pancreatic masses using magnetic resonance elastography with spin-echo echo planar imaging and three-dimensional inversion reconstruction. A prospective study

Energy Technology Data Exchange (ETDEWEB)

Shi, Yu; Yu, Bing; Liu, Yanqing; Guo, Qiyong [Shengjing Hospital of China Medical University, Department of Radiology, Shenyang (China); Gao, Feng [Shengjing Hospital of China Medical University, Department of Hepato-Pancreato-Biliary Tumour Surgery, Shenyang (China); Li, Yue [Shengjing Hospital of China Medical University, Department of Pathology, Shenyang (China); Tao, Shengzhen; Glaser, Kevin J.; Ehman, Richard L. [Mayo Clinic, Department of Radiology, Rochester, MN (United States); Liu, Zaiyi [Guangdong Academy of Medical Sciences, Department of Radiology, Guangdong General Hospital, Guangdong (China)

2018-03-15

To determine the diagnostic performance of MR elastography (MRE) and compare it with serum CA19-9 in differentiating malignant from benign pancreatic masses, with emphasis on differentiating between pancreatic ductal adenocarcinoma (PDAC) and mass-forming pancreatitis (MFP). We performed a prospective, consecutive, 24-month study in 85 patients with solid pancreatic masses confirmed by histopathologic examinations. The mass stiffness and stiffness ratio (calculated as the ratio of mass stiffness to the parenchymal stiffness) were assessed. The diagnostic accuracy was analysed by calculating the area under the ROC curve (AUROC). The final diagnosis included 54 malignant tumours (43 patients with PDAC) and 31 benign masses (24 patients with MFP). The stiffness ratio showed better diagnostic performance than the mass stiffness and serum CA19-9 for the differentiation between malignant and benign masses (AUC: 0.912 vs. 0.845 vs. 0.702; P = 0.026, P < 0.001) and, specifically, between PDAC and MFP (AUC: 0.955 vs. 0.882 vs. 0.745; P = 0.026, P = 0.003). The sensitivity, specificity, and accuracy of stiffness ratio for the differentiation of PDAC and MFP were all higher than 0.9. MRE presents an effective and quantitative strategy for non-invasive differentiation between PDAC and MFP based on their mechanical properties. (orig.)

Changes in the referent body location and configuration may underlie human gait, as confirmed by findings of multi-muscle activity minimizations and phase resetting.

Science.gov (United States)

Feldman, Anatol G; Krasovsky, Tal; Baniña, Melanie C; Lamontagne, Anouk; Levin, Mindy F

2011-04-01

Locomotion is presumably guided by feed-forward shifts in the referent body location in the desired direction in the environment. We propose that the difference between the actual and the referent body locations is transmitted to neurons that virtually diminish this difference by appropriately changing the referent body configuration, i.e. the body posture at which muscles reach their recruitment thresholds. Muscles are activated depending on the gap between the actual and the referent body configurations resulting in a step being made to minimize this gap. This hypothesis implies that the actual and the referent leg configurations can match each other at certain phases of the gait cycle, resulting in minimization of leg muscle activity. We found several leg configurations at which EMG minima occurred, both during forward and backward gait. It was also found that the set of limb configurations associated with EMG minima can be changed by modifying the pattern of forward and backward gait. Our hypothesis predicts that, in response to perturbations of gait, the rate of shifts in the referent body location can temporarily be changed to avoid falling. The rate influences the phase of rhythmic limb movements during gait. Therefore, following the change in the rate of the referent body location, the whole gait pattern, for all four limbs, will irreversibly be shifted in time (long-lasting and global phase resetting) with only transient changes in the gait speed, swing and stance timing and cycle duration. Aside from transient changes in the duration of the swing and/or stance phase in response to perturbation, few previous studies have documented long-lasting and global phase resetting of human gait in response to perturbation. Such resetting was a robust finding in our study. By confirming the notion that feed-forward changes in the referent body location and configuration underlie human locomotion, this study solves the classical problem in the relationship between

Clinical feasibility of gait training with a robotic exoskeleton (WPAL) in an individual with both incomplete cervical and complete thoracic spinal cord injury: A case study.

Science.gov (United States)

Tanabe, Shigeo; Koyama, Soichiro; Saitoh, Eiichi; Hirano, Satoshi; Yatsuya, Kanan; Tsunoda, Tetsuya; Katoh, Masaki; Gotoh, Takeshi; Furumoto, Ayako

2017-01-01

Patients with tetraplegia can achieve independent gait with lateral-type powered exoskeletons; it is unclear whether medial-type powered exoskeletons allow for this. To investigate gait training with a medial-type powered exoskeleton wearable power-assist locomotor (WPAL) in an individual with incomplete cervical (C5) and complete thoracic (T12) spinal cord injury (SCI). The 60-session program was investigated retrospectively using medical records. Upon completion, gait performance was examined using three-dimensional motion analyses and surface electromyography (EMG) of the upper limbs. The subject achieved independent gait with WPAL and a walker in 12 sessions. He continuously extended his right elbow; his left elbow periodically flexed/extended. His pelvic inclination was larger than the trunk inclination during single-leg stance. EMG activity was increased in the left deltoid muscles during ipsilateral foot-contact. The right anterior and medial deltoid muscle EMG activity increased just after foot-off for each leg, as did the right biceps activity. Continuous activity was observed in the left triceps throughout the gait cycle; activity was unclear in the right triceps. These results suggest the importance of upper limb residual motor function, and may be useful in extending the range of clinical applications for robotic gait rehabilitation in patients with SCI.

Continuous free-crab gaits for hexapod robots on a natural terrain with forbidden zones: An application to humanitarian demining

OpenAIRE

Estremera, Joaquín; Cobano, José A.; González de Santos, Pablo

2010-01-01

Autonomous robots are leaving the laboratories to master new outdoor applications, and walking robots in particular have already shown their potential advantages in these environments, especially on a natural terrain. Gait generation is the key to success in the negotiation of natural terrain with legged robots; however, most of the algorithms devised for hexapods have been tested under laboratory conditions. This paper presents the development of crab and turning gaits for hexapod robots on ...

Analytical Study of Active Prosthetic Legs

Science.gov (United States)

Ono, Kyosuke; Katsumata, Mie

Walking with prosthesis has not been well analyzed mathematically and it seems that the design of powered prosthesis has been done empirically so far. This paper presents a dynamic simulation of a normal human walking and walking with an active prosthesis. We also studied the two controlling methods of a powered thigh prosthesis based on multi-body simulation of human walking. First we measured the normal human walking gait, then, we showed that a 3-DOF human walking model can walk on level ground by applying tracking control to the measured walking gait within a certain range of tuned walking period. Next, we applied the tracking control and self-excited control to the powered thigh prosthesis and compared the robustness and efficiency of the two control methods by numerical simulation. As a result, we found that the self-excited control can significantly decrease the hip joint torque and specific cost to 1/3 compared with the tracking control. Moreover, the self-excited control is superior to the tracking control because tuning for the walking period is not needed for the active prosthetic leg.

Energy evaluation of a bio-inspired gait modulation method for quadrupedal locomotion.

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Fukuoka, Yasuhiro; Fukino, Kota; Habu, Yasushi; Mori, Yoshikazu

2015-08-04

We have proposed a bio-inspired gait modulation method, by means of which a simulated quadruped model can successfully perform smooth, autonomous gait transitions from a walk to a trot to a gallop, as observed in animals. The model is equipped with a rhythm generator called a central pattern generator (CPG) for each leg. The lateral neighbouring CPGs are mutually and inhibitorily coupled, and the CPG network is hardwired to produce a trot. Adding only the simple feedback of body tilt to each CPG, which was based on input from the postural reflex, led to the emergence of un-programmed walking and galloping at low and high speeds, respectively. Although this autonomous gait transition was a consequence of postural adaptation, it coincidentally also resulted in the minimization of energy consumption, as observed in real animals. In simulations at a variety of constant speeds the energy cost was lower for walking at low speeds and for galloping at high speeds than it was for trotting. Moreover, each gait transition occurred at the optimal speed, such that the model minimised its energy consumption. Thus, gait transitions in simulations that included the bio-inspired gait modulation method were similar to those observed in animals, even from the perspective of energy consumption. This method should therefore be a preferred choice for motion generation and control in biomimetic quadrupedal locomotion.

Evaluating alternative gait strategies using evolutionary robotics.

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Sellers, William I; Dennis, Louise A; W -J, Wang; Crompton, Robin H

2004-05-01

Evolutionary robotics is a branch of artificial intelligence concerned with the automatic generation of autonomous robots. Usually the form of the robot is predefined and various computational techniques are used to control the machine's behaviour. One aspect is the spontaneous generation of walking in legged robots and this can be used to investigate the mechanical requirements for efficient walking in bipeds. This paper demonstrates a bipedal simulator that spontaneously generates walking and running gaits. The model can be customized to represent a range of hominoid morphologies and used to predict performance parameters such as preferred speed and metabolic energy cost. Because it does not require any motion capture data it is particularly suitable for investigating locomotion in fossil animals. The predictions for modern humans are highly accurate in terms of energy cost for a given speed and thus the values predicted for other bipeds are likely to be good estimates. To illustrate this the cost of transport is calculated for Australopithecus afarensis. The model allows the degree of maximum extension at the knee to be varied causing the model to adopt walking gaits varying from chimpanzee-like to human-like. The energy costs associated with these gait choices can thus be calculated and this information used to evaluate possible locomotor strategies in early hominids.

The VSPA Foot: A Quasi-Passive Ankle-Foot Prosthesis With Continuously Variable Stiffness.

Science.gov (United States)

Shepherd, Max K; Rouse, Elliott J

2017-12-01

Most commercially available prosthetic feet do not exhibit a biomimetic torque-angle relationship, and are unable to modulate their mechanics to assist with other mobility tasks, such as stairs and ramps. In this paper, we present a quasi-passive ankle-foot prosthesis with a customizable torque-angle curve and an ability to quickly modulate ankle stiffness between tasks. The customizable torque-angle curve is obtained with a cam-based transmission and a fiberglass leaf spring. To achieve variable stiffness, the leaf spring's support conditions can be actively modulated by a small motor, shifting the torque-angle curve to be more or less stiff. We introduce the design, characterize the available torque-angle curves, and present kinematics from a transtibial amputee subject performing level-ground walking, stair ascent/descent, and ramp ascent/descent. The subject exhibited a more normative range of motion on stairs and ramps at lower stiffness levels, and preferred different stiffness levels for each task. Paired with an appropriate intent recognition system, our novel ankle prosthesis could improve gait biomechanics during walking and many other mobility tasks.

Evaluation of a Virtual Model Control for the selective support of gait functions using an exoskeleton

NARCIS (Netherlands)

Ekkelenkamp, R.; Ekkelenkamp, R.; Veltink, Petrus H.; Stramigioli, Stefano; van der Kooij, Herman

Robotic gait trainers are used all over the world for the rehabilitation of stroke patients, despite relatively little is known about how the robots should be controlled to achieve the optimal improvement. Most devices control complete joint trajectories and assume symmetry between both legs by

Non-invasive detection of the freezing of gait in Parkinson's disease using spectral and wavelet features.

Science.gov (United States)

Nazarzadeh, Kimia; Arjunan, Sridhar P; Kumar, Dinesh K; Das, Debi Prasad

2016-08-01

In this study, we have analyzed the accelerometer data recorded during gait analysis of Parkinson disease patients for detecting freezing of gait (FOG) episodes. The proposed method filters the recordings for noise reduction of the leg movement changes and computes the wavelet coefficients to detect FOG events. Publicly available FOG database was used and the technique was evaluated using receiver operating characteristic (ROC) analysis. Results show a higher performance of the wavelet feature in discrimination of the FOG events from the background activity when compared with the existing technique.

Investigation of Anticipatory Postural Adjustments during One-Leg Stance Using Inertial Sensors: Evidence from Subjects with Parkinsonism

OpenAIRE

Gianluca Bonora; Martina Mancini; Ilaria Carpinella; Lorenzo Chiari; Maurizio Ferrarin; John G. Nutt; Fay B. Horak; Fay B. Horak

2017-01-01

The One-Leg Stance (OLS) test is a widely adopted tool for the clinical assessment of balance in the elderly and in subjects with neurological disorders. It was previously showed that the ability to control anticipatory postural adjustments (APAs) prior to lifting one leg is significantly impaired by idiopathic Parkinson’s disease (iPD). However, it is not known how APAs are affected by other types of parkinsonism, such as frontal gait disorders (FGD). In this study, an instrumented OLS test ...

Design of a robotic gait trainer using spring over muscle actuators for ankle stroke rehabilitation.

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Bharadwaj, Kartik; Sugar, Thomas G; Koeneman, James B; Koeneman, Edward J

2005-11-01

Repetitive task training is an effective form of rehabilitation for people suffering from debilitating injuries of stroke. We present the design and working concept of a robotic gait trainer (RGT), an ankle rehabilitation device for assisting stroke patients during gait. Structurally based on a tripod mechanism, the device is a parallel robot that incorporates two pneumatically powered, double-acting, compliant, spring over muscle actuators as actuation links which move the ankle in dorsiflex ion/plantarflexion and inversion/eversion. A unique feature in the tripod design is that the human anatomy is part of the robot, the first fixed link being the patient's leg. The kinematics and workspace of the tripod device have been analyzed determining its range of motion. Experimental gait data from an able-bodied person wearing the working RGT prototype are presented.

Model-Based Experimental Development of Passive Compliant Robot Legs from Fiberglass Composites

OpenAIRE

Lin, Shang-Chang; Hu, Chia-Jui; Shih, Wen-Pin; Lin, Pei-Chun

2015-01-01

We report on the methodology of developing compliant, half-circular, and composite robot legs with designable stiffness. First, force-displacement experiments on flat cantilever composites made by one or multifiberglass cloths are executed. By mapping the cantilever mechanics to the virtual spring model, the equivalent elastic ...

Walk-Startup of a Two-Legged Walking Mechanism

Science.gov (United States)

Babković, Kalman; Nagy, László; Krklješ, Damir; Borovac, Branislav

There is a growing interest towards humanoid robots. One of their most important characteristic is the two-legged motion - walk. Starting and stopping of humanoid robots introduce substantial delays. In this paper, the goal is to explore the possibility of using a short unbalanced state of the biped robot to quickly gain speed and achieve the steady state velocity during a period shorter than half of the single support phase. The proposed method is verified by simulation. Maintainig a steady state, balanced gait is not considered in this paper.

Adaptive control of dynamic balance in human gait on a split-belt treadmill.

Science.gov (United States)

Buurke, Tom J W; Lamoth, Claudine J C; Vervoort, Danique; van der Woude, Lucas H V; den Otter, Rob

2018-05-17

Human bipedal gait is inherently unstable and staying upright requires adaptive control of dynamic balance. Little is known about adaptive control of dynamic balance in reaction to long-term, continuous perturbations. We examined how dynamic balance control adapts to a continuous perturbation in gait, by letting people walk faster with one leg than the other on a treadmill with two belts (i.e. split-belt walking). In addition, we assessed whether changes in mediolateral dynamic balance control coincide with changes in energy use during split-belt adaptation. In nine minutes of split-belt gait, mediolateral margins of stability and mediolateral foot roll-off changed during adaptation to the imposed gait asymmetry, especially on the fast side, and returned to baseline during washout. Interestingly, no changes in mediolateral foot placement (i.e. step width) were found during split-belt adaptation. Furthermore, the initial margin of stability and subsequent mediolateral foot roll-off were strongly coupled to maintain mediolateral dynamic balance throughout the gait cycle. Consistent with previous results net metabolic power was reduced during split-belt adaptation, but changes in mediolateral dynamic balance control were not correlated with the reduction of net metabolic power during split-belt adaptation. Overall, this study has shown that a complementary mechanism of relative foot positioning and mediolateral foot roll-off adapts to continuously imposed gait asymmetry to maintain dynamic balance in human bipedal gait. © 2018. Published by The Company of Biologists Ltd.

The Effect of Two Different Cognitive Tests on Gait Parameters during Dual Tasks in Healthy Postmenopausal Women

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Magdalena Hagner-Derengowska

2016-01-01

Full Text Available Introduction. The paper aims to evaluate the influence of two different demanding cognitive tasks on gait parameters using BTS SMART system analysis. Patients and Methods. The study comprised 53 postmenopausal women aged 64.5 ± 6.7 years (range: 47–79. For every subject, gait analysis using a BTS SMART system was performed in a dual-task study design under three conditions: (I while walking only (single task, (II walking while performing a simultaneous simple cognitive task (SCT (dual task, and (III walking while performing a simultaneous complex cognitive task (CCT (dual task. Time-space parameters of gait pertaining to the length of a single support phase, double support phase, gait speed, step length, step width, and leg swing speed were analyzed. Results. Performance of cognitive tests during gait resulted in a statistically significant prolongation of the left (by 7% and right (by 7% foot gait cycle, shortening of the length of steps made with the right extremity (by 4%, reduction of speed of swings made with the left (by 11% and right (by 8% extremity, and reduction in gait speed (by 6%. Conclusions. Performance of cognitive tests during gait changes its individual pattern in relation to the level of the difficulty of the task.

Gait and posture discrimination in sheep using a tri-axial accelerometer.

Science.gov (United States)

Radeski, M; Ilieski, V

2017-07-01

Temporo-spatial observation of the leg could provide important information about the general condition of an animal, especially for those such as sheep and other free-ranging farm animals that can be difficult to access. Tri-axial accelerometers are capable of collecting vast amounts of data for locomotion and posture observations; however, interpretation and optimization of these data records remain a challenge. The aim of the present study was to introduce an optimized method for gait (walking, trotting and galloping) and posture (standing and lying) discrimination, using the acceleration values recorded by a tri-axial accelerometer mounted on the hind leg of sheep. The acceleration values recorded on the vertical and horizontal axes, as well as the total acceleration values were categorized. The relative frequencies of the acceleration categories (RFACs) were calculated in 3-s epochs. Reliable RFACs for gait and posture discrimination were identified with discriminant function and canonical analyses. Post hoc predictions for the two axes and total acceleration were conducted, using classification functions and classification scores for each epoch. Mahalanobis distances were used to determine the level of accuracy of the method. The highest discriminatory power for gait discrimination yielded four RFACs on the vertical axis, and five RFACs each on the horizontal axis and total acceleration vector. Classification functions showed the highest accuracy for walking and galloping. The highest total accuracy on the vertical and horizontal axes were 90% and 91%, respectively. Regarding posture discrimination, the vertical axis exhibited the highest discriminatory power, with values of RFAC (0, 1]=99.95% for standing; and RFAC (-1, 0]=99.50% for lying. The horizontal axis showed strong discrimination for the lying side of the animal, as values were in the acceleration category of (0, 1] for lying on the left side and (-1, 0] on the right side. The algorithm developed by

Virtual Reality to control active participation in a subacute stroke patient during robot-assisted gait training.

Science.gov (United States)

Bergmann, J; Krewer, C; Müller, F; Koenig, A; Riener, R

2011-01-01

Virtual Reality (VR) provides a promising medium to enrich robot assisted rehabilitation. VR applications present the opportunity to engage patients in therapy and control participation. The aim of this study was to investigate two strategies to control active participation of a stroke patient focusing on the involvement of the paretic leg in task solution. A subacute stroke patient with a severe hemiparesis performed two experiments on the driven gait orthosis Lokomat. Patient activity was quantified by weighted interaction torques measured in both legs (experiment A) and the paretic leg only (experiment B). The patient was able to successfully implement both the bilateral and unilateral control modality. Both control modes increased the motor output of the paretic leg, however the paretic leg control mode resulted in a much more differentiated regulation of the activity in the leg. Both control modes are appropriate approaches to enhance active participation and increase motor output in the paretic leg. Further research should evaluate the therapeutic benefit of patients with hemiparesis using the unilateral control mode depending on the severity of their impairment. © 2011 IEEE

Effectiveness of Otolith Repositioning Maneuvers and Vestibular Rehabilitation exercises in elderly people with Benign Paroxysmal Positional Vertigo: a systematic review

OpenAIRE

Ribeiro, Karyna Figueiredo; Oliveira, Bruna Steffeni; Freitas, Raysa V.; Ferreira, Lidiane M.; Deshpande, Nandini; Guerra, Ricardo O.

2018-01-01

Abstract Introduction Benign Paroxysmal Positional Vertigo is highly prevalent in elderly people. This condition is related to vertigo, hearing loss, tinnitus, poor balance, gait disturbance, and an increase in risk of falls, leading to postural changes and quality of life decreasing. Objective To evaluate the outcomes obtained by clinical trials on the effectiveness of Otolith Repositioning Maneuver and Vestibular Rehabilitation exercises in the treatment of Benign Paroxysmal Positional Ve...

Effects of 12-week supervised treadmill training on spatio-temporal gait parameters in patients with claudication.

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Konik, Anita; Kuklewicz, Stanisław; Rosłoniec, Ewelina; Zając, Marcin; Spannbauer, Anna; Nowobilski, Roman; Mika, Piotr

2016-01-01

The purpose of the study was to evaluate selected temporal and spatial gait parameters in patients with intermittent claudication after completion of 12-week supervised treadmill walking training. The study included 36 patients (26 males and 10 females) aged: mean 64 (SD 7.7) with intermittent claudication. All patients were tested on treadmill (Gait Trainer, Biodex). Before the programme and after its completion, the following gait biomechanical parameters were tested: step length (cm), step cycle (cycle/s), leg support time (%), coefficient of step variation (%) as well as pain-free walking time (PFWT) and maximal walking time (MWT) were measured. Training was conducted in accordance with the current TASC II guidelines. After 12 weeks of training, patients showed significant change in gait biomechanics consisting in decreased frequency of step cycle (p gait was more regular, which was expressed via statistically significant decrease of coefficient of variation (p 0.05). Twelve-week treadmill walking training programme may lead to significant improvement of temporal and spatial gait parameters in patients with intermittent claudication. Twelve-week treadmill walking training programme may lead to significant improvement of pain-free walking time and maximum walking time in patients with intermittent claudication.

Generating Human-Like Velocity-Adapted Jumping Gait from sEMG Signals for Bionic Leg’s Control

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Weiwei Yu

2017-01-01

Full Text Available In the case of dynamic motion such as jumping, an important fact in sEMG (surface Electromyogram signal based control on exoskeletons, myoelectric prostheses, and rehabilitation gait is that multichannel sEMG signals contain mass data and vary greatly with time, which makes it difficult to generate compliant gait. Inspired by the fact that muscle synergies leading to dimensionality reduction may simplify motor control and learning, this paper proposes a new approach to generate flexible gait based on muscle synergies extracted from sEMG signal. Two questions were discussed and solved, the first one concerning whether the same set of muscle synergies can explain the different phases of hopping movement with various velocities. The second one is about how to generate self-adapted gait with muscle synergies while alleviating model sensitivity to sEMG transient changes. From the experimental results, the proposed method shows good performance both in accuracy and in robustness for producing velocity-adapted vertical jumping gait. The method discussed in this paper provides a valuable reference for the sEMG-based control of bionic robot leg to generate human-like dynamic gait.

Efficacy of Aquatic Treadmill Training on Gait Symmetry and Balance in Subacute Stroke Patients.

Science.gov (United States)

Lee, Mi Eun; Jo, Geun Yeol; Do, Hwan Kwon; Choi, Hee Eun; Kim, Woo Jin

2017-06-01

To determine the efficacy of aquatic treadmill training (ATT) as a new modality for stroke rehabilitation, by assessing changes in gait symmetry, balance function, and subjective balance confidence for the paretic and non-paretic leg in stroke patients. Twenty-one subacute stroke patients participated in 15 intervention sessions of aquatic treadmill training. The Comfortable 10-Meter Walk Test (CWT), spatiotemporal gait parameters, Berg Balance Scale (BBS), and Activities-specific Balance Confidence scale (ABC) were assessed pre- and post-interventions. From pre- to post-intervention, statistically significant improvements were observed in the CWT (0.471±0.21 to 0.558±0.23, pstroke therapy, with other modalities.

STRETCHING EXERCISES - EFFECT ON PASSIVE EXTENSIBILITY AND STIFFNESS IN SHORT HAMSTRINGS OF HEALTHY-SUBJECTS

NARCIS (Netherlands)

HALBERTSMA, JPK; GOEKEN, LNH

Passive muscle stretch tests are common practice in physical therapy and rehabilitation medicine. However, the effects of stretching exercises are not well known. With an instrumental straight-leg-raising set-up the extensibility, stiffness, and electromyographic activity of the hamstring muscles

Benign acute childhood myositis.

Science.gov (United States)

Rajajee, Sarala; Ezhilarasi, S; Rajarajan, K

2005-05-01

To describe the clinical and laboratory features of benign acute childhood myositis. 40 children of BACM were seen during October 2001 to February 2002, 22 (52%) were male with mean age of 5.3 years. Duration of illness was 3.97 days. Preceding symptoms included fever, leg pain, vomiting and inability to walk. A provisional diagnosis of viral myositis was made in 26 (66%). Guillian Barre Syndrome was the most common referral diagnosis. 11 (27.5%) children had leucopenia with lymphocytic response and 16 (40%) had thrombocytopenia. CRP was negative in 32 (80%). CPK was markedly elevated (more than 1000 IU/l) in 18 (45%) and more than 500 IU/l in 11 (27.5%) remaining between 200 to 500 IU/l. Associated features were hepatitis (elevated SGOT & SGPT) in 28 (70%) and shock in 5 (12.5%). Serological test were indicative of dengue virus (Elisa PAN BIO) in 20 (50%) of which 8 (25%) were primary dengue and 12 (30%) were secondary dengue. The outcome of therapy mainly supportive were excellent. Benign acute myositis occurs often in association with viral infection. In the present study, Dengue virus was positive in 20 (50%) children. Benign acute myositis can be differentiated from more serious causes of walking difficulty by presence of calf and thigh muscle tenderness on stretching, normal power and deep tendon reflex and elevated CPK.

Dynamics and Optimal Feet Force Distributions of a Realistic Four-legged Robot

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Saurav Agarwal

2012-08-01

Full Text Available This paper presents a detailed dynamic modeling of realistic four-legged robot. The direct and inverse kinematic analysis for each leg has been considered in order to develop an overall kinematic model of the robot, when it follows a straight path. This study also aims to estimate optimal feet force distributions of the said robot, which is necessary for its real-time control. Three different approaches namely, minimization of norm of feet forces (approach 1, minimization of norm of joint torques (approach 2 and minimization of norm of joint power (approach 3 have been developed. Simulation result shows that approach 3 is more energy efficient foot force formulation than other two approaches. Lagrange-Euler formulation has been utilized to determine the joint torques. The developed dynamic models have been examined through computer simulation of continuous gait of the four-legged robot.

Arthrodiastasis for stiff hips in young patients

OpenAIRE

Cañadell, J.M. (J. M.); Gonzales, F. (F.); Barrios, R.H. (Raúl H.); Amillo, S. (Santiago)

1993-01-01

Joint distraction (arthrodiastasis) with a unilateral fixator was used to treat 9 patients with stiffness of the hip which had followed Perthes' disease (3), epiphysiolysis (2), congenital dysplasia (2), tuberculosis (1) and idiopathic chondrolysis (1). Their average age was 14 years, and they all had pain, limp and shortening of the leg. Distraction of 0.5 to 1 cm was maintained for an average of 94 days. The average range of movement subsequently was 65 degrees compared with 20 degrees befo...

The Influence of Outdoor Shoe Sole Stiffness on the Metatarsophalangeal Joint Kinematics When Walking and Running in Different Conditions

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Paolo Mistretta

2018-02-01

Full Text Available Understanding the action of the metatarsophalangeal joint (MTP is fundamental to improving the design process of a new outdoor shoe. Coming from the stated consideration, the aim of this research is to study the influence of shoe sole stiffness and terrain slope on the MTP joint angle of subjects walking in different conditions. To pursue this intent, different data collection sessions have been carried out in-vitro and in-vivo, indoor and outdoor. Two different approaches have been used to collect gait kinematics: an IMU (Inertial Measurement Unit based system for the first campaign of tests, and a 2D video analysis for the second. Major findings showed a linear correlation between shoe sole stiffness and peak MTP joint angle during gait, as well as consistency in the value of the slope of the linear regression curves corresponding to the different conditions examined.

Simple diagnosis of benign acute childhood myositis: Lessons from a case report.

Science.gov (United States)

Terlizzi, Vito; Improta, Federica; Raia, Valeria

2014-01-01

Acute muscle pain and walking difficulty are symptoms compatible with both benign and severe degenerative diseases. As a consequence, in some cases invasive tests and hospitalizations are improperly scheduled. We report the case of a 7-year-old child suffering from acute calf pain and abnormal gait following flu-like symptoms. A review of the literature will be helpful to better define differential diagnosis in cases of muscle pain in children. Daily physical examination and urine dipstick are sufficient to confirm the diagnosis of benign acute childhood myositis (BACM) during the acute phase, to promptly detect severe complications and to rule out degenerative diseases. Children with BACM do not require hospitalization, medical interventions or long-term follow-up.

Tai Chi and vestibular rehabilitation improve vestibulopathic gait via different neuromuscular mechanisms: Preliminary report

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Parker Stephen W

2005-02-01

Full Text Available Abstract Background Vestibular rehabilitation (VR is a well-accepted exercise program intended to remedy balance impairment caused by damage to the peripheral vestibular system. Alternative therapies, such as Tai Chi (TC, have recently gained popularity as a treatment for balance impairment. Although VR and TC can benefit people with vestibulopathy, the degree to which gait improvements may be related to neuromuscular adaptations of the lower extremities for the two different therapies are unknown. Methods We examined the relationship between lower extremity neuromuscular function and trunk control in 36 older adults with vestibulopathy, randomized to 10 weeks of either VR or TC exercise. Time-distance measures (gait speed, step length, stance duration and step width, lower extremity sagittal plane mechanical energy expenditures (MEE, and trunk sagittal and frontal plane kinematics (peak and range of linear and angular velocity, were measured. Results Although gait time-distance measures were improved in both groups following treatment, no significant between-groups differences were observed for the MEE and trunk kinematic measures. Significant within groups changes, however, were observed. The TC group significantly increased ankle MEE contribution and decreased hip MEE contribution to total leg MEE, while no significant changes were found within the VR group. The TC group exhibited a positive relationship between change in leg MEE and change in trunk velocity peak and range, while the VR group exhibited a negative relationship. Conclusion Gait function improved in both groups consistent with expectations of the interventions. Differences in each group's response to therapy appear to suggest that improved gait function may be due to different neuromuscular adaptations resulting from the different interventions. The TC group's improvements were associated with reorganized lower extremity neuromuscular patterns, which appear to promote a faster

A study of the passive gait of a compass-like biped robot: Symmetry and chaos

International Nuclear Information System (INIS)

Goswami, A.; Espiau, B.; Thuilot, B.

1998-01-01

The focus of this work is a systematic study of the passive gait of a compass-like planar, biped robot on inclined slopes. The robot is kinematically equivalent to a double pendulum, possessing two kneeless legs with point masses and a third point mass at the hip joint. Three parameters, namely, the ground-slope angle and the normalized mass and length of the robot describe its gait. The authors show that in response to a continuous change in any one of its parameters, the symmetric and steady stable gait of the unpowered robot gradually evolves through a regime of bifurcations characterized by progressively complicated asymmetric gaits, eventually arriving at an apparently chaotic gait where not two steps are identical. The robot can maintain this gait indefinitely. A necessary (but not sufficient) condition for the stability of such gaits is the contraction of the phase-fluid volume. For this frictionless robot, the volume contraction, which the authors compute, is caused by the dissipative effects of the ground-impact model. In the chaotic regime, the fractal dimension of the robot's strange attractor (2.07) compared to its state-space dimension (4) also reveals strong contraction. The authors present a novel graphical technique based on the first return map that compactly captures the entire evolution of the gait, from symmetry to chaos. Additional passive dissipative elements in the robot joint results in a significant improvement in the stability and the versatility of the gait, and provide a rich repertoire for simple controls laws

Gait strategy changes with acceleration to accommodate the biomechanical constraint on push-off propulsion.

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Oh, Keonyoung; Baek, Juhyun; Park, Sukyung

2012-11-15

To maintain steady and level walking, push-off propulsion during the double support phase compensates for the energy loss through heel strike collisions in an energetically optimal manner. However, a large portion of daily gait activities also contains transient gait responses, such as acceleration or deceleration, during which the observed dominance of the push-off work or the energy optimality may not hold. In this study, we examined whether the push-off propulsion during the double support phase served as a major energy source for gait acceleration, and we also studied the energetic optimality of accelerated gait using a simple bipedal walking model. Seven healthy young subjects participated in the over-ground walking experiments. The subjects walked at four different constant gait speeds ranging from a self-selected speed to a maximum gait speed, and then they accelerated their gait from zero to the maximum gait speed using a self-selected acceleration ratio. We measured the ground reaction force (GRF) of three consecutive steps and the corresponding leg configuration using force platforms and an optical marker system, respectively, and we compared the mechanical work performed by the GRF during each single and double support phase. In contrast to the model prediction of an increase in the push-off propulsion that is proportional to the acceleration and minimizes the mechanical energy cost, the push-off propulsion was slightly increased, and a significant increase in the mechanical work during the single support phase was observed. The results suggest that gait acceleration occurs while accommodating a feasible push-off propulsion constraint. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of Duration of Disease on Gait Parameters in Parkinson’s Patients

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Aygün Özşahin

2007-04-01

Full Text Available OBJECTIVE: Posture and gait disturbances are major components which cause functional disability in Parkinson’s disease (PD. Three dimensional gait and motion analysis systems provide quantitative data of gait. OBJECTIVES: The aim of this study is to correlate between duration of disease and gait parameters of Parkinson patients during the on-phase. METHODS: We investigated temporospatial and kinematics variables of gait in 23 subjects with PD as measured in the on-phase of their medication cycle using motion analysis. We evaluated the correlation between all gait parameters and Gait and Balance Scale (GABS, unified Parkinson’s disease rating scale (UPDRS total-motor scores, Hoehn&Yahr (H&Y stages and duration of the disease. RESULTS: We found positive correlation between cadance and duration of disease. Patients had negative correlation between stride time and duration of disease. And also there was positive correlation between UPDRS total score and duration of disease. CONCLUSION: Increasing of cadance and decreasing of stride time exhibited by PD subjects is a compensatory mechanism for the difficulty in regulating stride lenght. It was reported that stride lenght control mediate by basal ganglia. Scaling of lower limb amplitude during locomotion can be controlled by higher levels of the Central Nervous System. Patients tend to increase pelvic rotation to keep their center of mass stabilised because of shortness of stride lenght. We thought that reduction pelvic and hip ROMs in coronal plane are impaired muscles of leg in the swing phase. These findings possibly indicate that shortness of stride lenght with the progression of disease is related to cortical centers. Three dimentional analysis systems provide detailed gait examination in PD patients to assess of progression and efficacy for therapies. Also, this method will guide us to explain physiopathologic mechanisms of PD

Capability of 2 gait measures for detecting response to gait training in stroke survivors: Gait Assessment and Intervention Tool and the Tinetti Gait Scale.

Science.gov (United States)

Zimbelman, Janice; Daly, Janis J; Roenigk, Kristen L; Butler, Kristi; Burdsall, Richard; Holcomb, John P

2012-01-01

To characterize the performance of 2 observational gait measures, the Tinetti Gait Scale (TGS) and the Gait Assessment and Intervention Tool (G.A.I.T.), in identifying improvement in gait in response to gait training. In secondary analysis from a larger study of multimodal gait training for stroke survivors, we measured gait at pre-, mid-, and posttreatment according to G.A.I.T. and TGS, assessing their capability to capture recovery of coordinated gait components. Large medical center. Cohort of stroke survivors (N=44) greater than 6 months after stroke. All subjects received 48 sessions of a multimodal gait-training protocol. Treatment consisted of 1.5 hours per session, 4 sessions per week for 12 weeks, receiving these 3 treatment aspects: (1) coordination exercise, (2) body weight-supported treadmill training, and (3) overground gait training, with 46% of subjects receiving functional electrical stimulation. All subjects were evaluated with the G.A.I.T. and TGS before and after completing the 48-session intervention. An additional evaluation was performed at midtreatment (after session 24). For the total subject sample, there were significant pre-/post-, pre-/mid-, and mid-/posttreatment gains for both the G.A.I.T. and the TGS. According to the G.A.I.T., 40 subjects (91%) showed improved scores, 2 (4%) no change, and 2 (4%) a worsening score. According to the TGS, only 26 subjects (59%) showed improved scores, 16 (36%) no change, and 1 (2%) a worsening score. For 1 treatment group of chronic stroke survivors, the TGS failed to identify a significant treatment response to gait training, whereas the G.A.I.T. measure was successful. The G.A.I.T. is more sensitive than the TGS for individual patients and group treatment response in identifying recovery of volitional control of gait components in response to gait training. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

A tracked robot with novel bio-inspired passive "legs".

Science.gov (United States)

Sun, Bo; Jing, Xingjian

2017-01-01

For track-based robots, an important aspect is the suppression design, which determines the trafficability and comfort of the whole system. The trafficability limits the robot's working capability, and the riding comfort limits the robot's working effectiveness, especially with some sensitive instruments mounted on or operated. To these aims, a track-based robot equipped with a novel passive bio-inspired suspension is designed and studied systematically in this paper. Animal or insects have very special leg or limb structures which are good for motion control and adaptable to different environments. Inspired by this, a new track-based robot is designed with novel "legs" for connecting the loading wheels to the robot body. Each leg is designed with passive structures and can achieve very high loading capacity but low dynamic stiffness such that the robot can move on rough ground similar to a multi-leg animal or insect. Therefore, the trafficability and riding comfort can be significantly improved without losing loading capacity. The new track-based robot can be well applied to various engineering tasks for providing a stable moving platform of high mobility, better trafficability and excellent loading capacity.

Growth performance, carcass yield and gait score of Marshal broiler chicken reared on intensive and semi intensive management systems

Directory of Open Access Journals (Sweden)

Oluwadiya, B. O.

2017-06-01

Full Text Available The rearing system used in highly productive farms is often subjected to harsh criticism, one of the reasons being its failure to provide adequate welfare. A number of attempts have been made to introduce new technologies in rearing poultry for meat production aiming at improving rearing conditions, protecting the environment and enhancing the quality of poultry products. Given the above, one hundred and sixty eight unsexed 14-day old Marshall broiler chicks were used in a completely randomized design study to compare the effect of management systems (intensive and semi intensive on the growth performance, carcass characteristics and gait score of broiler chickens. The experiment lasted for 42 d. Data were collected on weight gain, feed intake, feed conversion ratio, carcass yield and gait score. Result showed that birds on the intensive management system recorded higher weight gain (P 0.05; 66.94%, 11.44% than those in semi-intensive system (54.55%, 10.92%, respectively. For the gait score broiler birds on semi intensive management system recorded reduced number of cases of severe and slight leg problems (P < 0.05, 25.76% vs 49.3%. It was concluded that broiler birds should be reared on intensive management system for better growth performance and carcass yield. However, birds reared on semi intensive management system had fewer leg problems compared to birds reared on intensive management system. The fewer severe leg problems observed in birds on semi intensive management system will help improve their market value thereby making birds more profitable to rear on semi intensive management system.

An accelerometry-based comparison of 2 robotic assistive devices for treadmill training of gait.

Science.gov (United States)

Regnaux, Jean-Philippe; Saremi, Kaveh; Marehbian, Jon; Bussel, Bernard; Dobkin, Bruce H

2008-01-01

Two commercial robotic devices, the Gait Trainer (GT) and the Lokomat (LOKO), assist task-oriented practice of walking. The gait patterns induced by these motor-driven devices have not been characterized and compared. A healthy participant chose the most comfortable gait pattern on each device and for treadmill (TM) walking at 1, 2 (maximum for the GT), and 3 km/h and over ground at similar speeds. A system of accelerometers on the thighs and feet allowed the calculation of spatiotemporal features and accelerations during the gait cycle. At the 1 and 2 km/h speed settings, single-limb stance times were prolonged on the devices compared with overground walking. Differences on the LOKO were decreased by adjusting the hip and knee angles and step length. At the 3 km/h setting, the LOKO approximated the participant's overground parameters. Irregular accelerations and decelerations from toe-off to heel contact were induced by the devices, especially at slower speeds. The LOKO and GT impose mechanical constraints that may alter leg accelerations-decelerations during stance and swing phases, as well as stance duration, especially at their slower speed settings, that are not found during TM and overground walking. The potential impact of these perturbations on training to improve gait needs further study.

More symmetrical gait after split-belt treadmill walking does not modify dynamic and postural balance in individuals post-stroke.

Science.gov (United States)

Miéville, Carole; Lauzière, Séléna; Betschart, Martina; Nadeau, Sylvie; Duclos, Cyril

2018-04-24

Spontaneous gait is often asymmetrical in individuals post-stroke, despite their ability to walk more symmetrically on demand. Given the sensorimotor deficits in the paretic limb, this asymmetrical gait may facilitate balance maintenance. We used a split-belt walking protocol to alter gait asymmetry and determine the effects on dynamic and postural balance. Twenty individuals post-stroke walked on a split-belt treadmill. In two separate periods, the effects of walking with the non-paretic leg, and then the paretic one, on the faster belt on spatio-temporal symmetry and balance were compared before and after these perturbation periods. Kinematic and kinetic data were collected using a motion analysis system and an instrumented treadmill to determine symmetry ratios of spatiotemporal parameters and dynamic and postural balance. Balance, quantified by the concepts of stabilizing and destabilizing forces, was compared before and after split-belt walking for subgroups of participants who improved and worsened their symmetry. The side on the slow belt during split-belt walking, but not the changes in asymmetry, affected balance. Difficulty in maintaining balance was higher during stance phase of the leg that was on the slow belt and lower on the contralateral side after split-belt walking, mostly because the center of pressure was closer (higher difficulty) or further (lower difficulty) from the limit of the base of support, respectively. Changes in spatiotemporal parameters may be sought without additional alteration of balance during gait post-stroke. Copyright © 2018 Elsevier Ltd. All rights reserved.

Variable-stiffness joints with embedded force sensor for high-performance wearable gait exoskeletons

OpenAIRE

Cestari Soto, Manuel

2017-01-01

The growing field of exoskeletons and wearable devices for walking assistance and rehabilitation has advanced considerably over the past few years. The current use of commercial devices is in-hospital rehabilitation of spinal cord injured, nevertheless the purpose of this technology is challenging: to provide gait assistance in daily life activities to the broadest segment of neurological disorders affecting walking and balance. A number of difficulties make this goal a challenge, but to name...

Leg muscle activation during gait in Parkinson's disease : Adaptation and interlimb coordination

NARCIS (Netherlands)

Dietz, [No Value; Zijlstra, W; Prokop, T; Berger, W

1995-01-01

Adaptation in leg muscle activity and coordination between lower limbs were studied during walking on a treadmill with split belts in one group of parkinsonian patients and one of age-matched healthy subjects. Four different belt speeds (0.25/0.5/0.75/1.0 m/sec) were applied in selected combinations

Mechanisms of Gait Asymmetry Due to Push-Off Deficiency in Unilateral Amputees.

Science.gov (United States)

Adamczyk, Peter Gabriel; Kuo, Arthur D

2015-09-01

Unilateral lower-limb amputees exhibit asymmetry in many gait features, such as ground force, step time, step length, and joint mechanics. Although these asymmetries result from weak prosthetic-side push-off, there is no proven mechanistic explanation of how that impairment propagates to the rest of the body. We used a simple dynamic walking model to explore possible consequences of a unilateral impairment similar to that of a transtibial amputee. The model compensates for reduced push-off work from one leg by performing more work elsewhere, for example during the middle of stance by either or both legs. The model predicts several gait abnormalities, including slower forward velocity of the body center-of-mass during intact-side stance, greater energy dissipation in the intact side, and more positive work overall. We tested these predictions with data from unilateral transtibial amputees (N = 11) and nonamputee control subjects (N = 10) walking on an instrumented treadmill. We observed several predicted asymmetries, including forward velocity during stance phases and energy dissipation from the two limbs, as well as greater work overall. Secondary adaptations, such as to reduce discomfort, may exacerbate asymmetry, but these simple principles suggest that some asymmetry may be unavoidable in cases of unilateral limb loss.

Malignant Transformation of Nodular Hidradenoma in the Lower Leg

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Nhuan Ngo

2018-05-01

Full Text Available Nodular hidradenoma (NH is a benign adnexal tumor that arises from either eccrine or apocrine sweat glands. NH can originate from any cutaneous site, but the most common sites are the head and anterior surface of the trunk, with very rare cases in the extremities. Long-standing NH has been reported to undergo malignant transformation to malignant NH (MNH; however, its occurrence in the lower leg is extremely rare with only one other case reported to date. In this report, we present a rare case of MNH occurring in the lower leg which was resected with the intent to make a diagnosis. At the final follow-up after 11 months, no local recurrence or metastasis has been observed.

Association between stride time fractality and gait adaptability during unperturbed and asymmetric walking.

Science.gov (United States)

Ducharme, Scott W; Liddy, Joshua J; Haddad, Jeffrey M; Busa, Michael A; Claxton, Laura J; van Emmerik, Richard E A

2018-04-01

Human locomotion is an inherently complex activity that requires the coordination and control of neurophysiological and biomechanical degrees of freedom across various spatiotemporal scales. Locomotor patterns must constantly be altered in the face of changing environmental or task demands, such as heterogeneous terrains or obstacles. Variability in stride times occurring at short time scales (e.g., 5-10 strides) is statistically correlated to larger fluctuations occurring over longer time scales (e.g., 50-100 strides). This relationship, known as fractal dynamics, is thought to represent the adaptive capacity of the locomotor system. However, this has not been tested empirically. Thus, the purpose of this study was to determine if stride time fractality during steady state walking associated with the ability of individuals to adapt their gait patterns when locomotor speed and symmetry are altered. Fifteen healthy adults walked on a split-belt treadmill at preferred speed, half of preferred speed, and with one leg at preferred speed and the other at half speed (2:1 ratio asymmetric walking). The asymmetric belt speed condition induced gait asymmetries that required adaptation of locomotor patterns. The slow speed manipulation was chosen in order to determine the impact of gait speed on stride time fractal dynamics. Detrended fluctuation analysis was used to quantify the correlation structure, i.e., fractality, of stride times. Cross-correlation analysis was used to measure the deviation from intended anti-phasing between legs as a measure of gait adaptation. Results revealed no association between unperturbed walking fractal dynamics and gait adaptability performance. However, there was a quadratic relationship between perturbed, asymmetric walking fractal dynamics and adaptive performance during split-belt walking, whereby individuals who exhibited fractal scaling exponents that deviated from 1/f performed the poorest. Compared to steady state preferred walking

Gait Characteristics, Symptoms, and Function in Persons With Hip Osteoarthritis

DEFF Research Database (Denmark)

Eitzen, I.; Fernandes, L.; Kallerud, H.

2015-01-01

did not undergo THR were made using independent t tests or Mann-Whitney U tests. Comparisons of baseline measures and 6- to 7-year follow-up for the nonoperated individuals were conducted with paired-samples t tests or Wilcoxon signed-rank tests (P......, 58.9 years) with radiographic and symptomatic hip osteoarthritis participated. Outcome measures included 3-D gait analysis; self-reported pain; stiffness, and function; hip range of motion; and the six-minute walk test. Baseline comparisons between individuals who later underwent THR and those who...

Relationship and significance of gait deviations associated with limb length discrepancy: A systematic review.

Science.gov (United States)

Khamis, Sam; Carmeli, Eli

2017-09-01

Controversy still exists as to the clinical significance of leg length discrepancy (LLD) in spite of the fact that further evidence has been emerging regarding the relationship between several clinical conditions and LLD. The objectives of our study were to review the available research with regard to LLD as a cause of clinically significant gait deviations, to determine if there is a relationship between the magnitude of LLD and the presence of gait deviations and to identify the most common gait deviations associated with LLD. In line with the PRISMA guidelines, a literature search was carried out throughout the Medline, CINAHL and EMBASE databases. Twelve articles met the predetermined inclusion criteria and were included in the review. Quality assessment using the Methodological Index for Non-Randomized Studies (MINORS) scale was completed for all included studies. Two main methodologies were found in 4 studies evaluating gait asymmetry in patients or healthy participants with anatomic LLD and 8 studies evaluating gait deviations while simulating LLD by employing artificial lifts of 1-5cm on healthy subjects. A significant relationship was found between anatomic LLD and gait deviation. Evidence suggests that gait deviations may occur with discrepancies of >1cm, with greater impact seen as the discrepancy increases. Compensatory strategies were found to occur in both the shorter and longer limb, throughout the lower limb. As the discrepancy increases, more compensatory strategies occur. Sagittal plane deviations seem to be the most effective deviations, although, frontal plane compensations also occur in the pelvis, hip and foot. Copyright © 2017 Elsevier B.V. All rights reserved.

A biofeedback cycling training to improve locomotion: a case series study based on gait pattern classification of 153 chronic stroke patients

Science.gov (United States)

2011-01-01

Background The restoration of walking ability is the main goal of post-stroke lower limb rehabilitation and different studies suggest that pedaling may have a positive effect on locomotion. The aim of this study was to explore the feasibility of a biofeedback pedaling treatment and its effects on cycling and walking ability in chronic stroke patients. A case series study was designed and participants were recruited based on a gait pattern classification of a population of 153 chronic stroke patients. Methods In order to optimize participants selection, a k-means cluster analysis was performed to subgroup homogenous gait patterns in terms of gait speed and symmetry. The training consisted of a 2-week treatment of 6 sessions. A visual biofeedback helped the subjects in maintaining a symmetrical contribution of the two legs during pedaling. Participants were assessed before, after training and at follow-up visits (one week after treatment). Outcome measures were the unbalance during a pedaling test, and the temporal, spatial, and symmetry parameters during gait analysis. Results and discussion Three clusters, mainly differing in terms of gait speed, were identified and participants, representative of each cluster, were selected. An intra-subject statistical analysis (ANOVA) showed that all patients significantly decreased the pedaling unbalance after treatment and maintained significant improvements with respect to baseline at follow-up. The 2-week treatment induced some modifications in the gait pattern of two patients: one, the most impaired, significantly improved mean velocity and increased gait symmetry; the other one reduced significantly the over-compensation of the healthy limb. No benefits were produced in the gait of the last subject who maintained her slow but almost symmetrical pattern. Thus, this study might suggest that the treatment can be beneficial for patients having a very asymmetrical and inefficient gait and for those that overuse the healthy leg

A biofeedback cycling training to improve locomotion: a case series study based on gait pattern classification of 153 chronic stroke patients

Directory of Open Access Journals (Sweden)

Molteni Franco

2011-08-01

Full Text Available Abstract Background The restoration of walking ability is the main goal of post-stroke lower limb rehabilitation and different studies suggest that pedaling may have a positive effect on locomotion. The aim of this study was to explore the feasibility of a biofeedback pedaling treatment and its effects on cycling and walking ability in chronic stroke patients. A case series study was designed and participants were recruited based on a gait pattern classification of a population of 153 chronic stroke patients. Methods In order to optimize participants selection, a k-means cluster analysis was performed to subgroup homogenous gait patterns in terms of gait speed and symmetry. The training consisted of a 2-week treatment of 6 sessions. A visual biofeedback helped the subjects in maintaining a symmetrical contribution of the two legs during pedaling. Participants were assessed before, after training and at follow-up visits (one week after treatment. Outcome measures were the unbalance during a pedaling test, and the temporal, spatial, and symmetry parameters during gait analysis. Results and discussion Three clusters, mainly differing in terms of gait speed, were identified and participants, representative of each cluster, were selected. An intra-subject statistical analysis (ANOVA showed that all patients significantly decreased the pedaling unbalance after treatment and maintained significant improvements with respect to baseline at follow-up. The 2-week treatment induced some modifications in the gait pattern of two patients: one, the most impaired, significantly improved mean velocity and increased gait symmetry; the other one reduced significantly the over-compensation of the healthy limb. No benefits were produced in the gait of the last subject who maintained her slow but almost symmetrical pattern. Thus, this study might suggest that the treatment can be beneficial for patients having a very asymmetrical and inefficient gait and for those

Comprehensive non-dimensional normalization of gait data.

Science.gov (United States)

Pinzone, Ornella; Schwartz, Michael H; Baker, Richard

2016-02-01

Normalizing clinical gait analysis data is required to remove variability due to physical characteristics such as leg length and weight. This is particularly important for children where both are associated with age. In most clinical centres conventional normalization (by mass only) is used whereas there is a stronger biomechanical argument for non-dimensional normalization. This study used data from 82 typically developing children to compare how the two schemes performed over a wide range of temporal-spatial and kinetic parameters by calculating the coefficients of determination with leg length, weight and height. 81% of the conventionally normalized parameters had a coefficient of determination above the threshold for a statistical association (pnormalized non-dimensionally. All the conventionally normalized parameters exceeding this threshold showed a reduced association with non-dimensional normalization. In conclusion, non-dimensional normalization is more effective that conventional normalization in reducing the effects of height, weight and age in a comprehensive range of temporal-spatial and kinetic parameters. Copyright © 2015 Elsevier B.V. All rights reserved.

A mechanized gait trainer for restoration of gait.

Science.gov (United States)

Hesse, S; Uhlenbrock, D

2000-01-01

The newly developed gait trainer allows wheel-chair-bound subjects the repetitive practice of a gait-like movement without overstressing therapists. The device simulates the phases of gait, supports the subjects according to their abilities, and controls the center of mass (CoM) in the vertical and horizontal directions. The patterns of sagittal lower limb joint kinematics and of muscle activation for a normal subject were similar when using the mechanized trainer and when walking on a treadmill. A non-ambulatory hemiparetic subject required little help from one therapist on the gait trainer, while two therapists were required to support treadmill walking. Gait movements on the trainer were highly symmetrical, impact free, and less spastic. The vertical displacement of the CoM was bi-phasic instead of mono-phasic during each gait cycle on the new device. Two cases of non-ambulatory patients, who regained their walking ability after 4 weeks of daily training on the gait trainer, are reported.

The Passive Series Stiffness That Optimizes Torque Tracking for a Lower-Limb Exoskeleton in Human Walking

Directory of Open Access Journals (Sweden)

Juanjuan Zhang

2017-12-01

Full Text Available This study uses theory and experiments to investigate the relationship between the passive stiffness of series elastic actuators and torque tracking performance in lower-limb exoskeletons during human walking. Through theoretical analysis with our simplified system model, we found that the optimal passive stiffness matches the slope of the desired torque-angle relationship. We also conjectured that a bandwidth limit resulted in a maximum rate of change in torque error that can be commanded through control input, which is fixed across desired and passive stiffness conditions. This led to hypotheses about the interactions among optimal control gains, passive stiffness and desired quasi-stiffness. Walking experiments were conducted with multiple angle-based desired torque curves. The observed lowest torque tracking errors identified for each combination of desired and passive stiffnesses were shown to be linearly proportional to the magnitude of the difference between the two stiffnesses. The proportional gains corresponding to the lowest observed errors were seen inversely proportional to passive stiffness values and to desired stiffness. These findings supported our hypotheses, and provide guidance to application-specific hardware customization as well as controller design for torque-controlled robotic legged locomotion.

Gait outcome following outpatient physiotherapy based on the Bobath concept in people post stroke.

Science.gov (United States)

Lennon, Sheila; Ashburn, Ann; Baxter, David

The purpose of this study was to characterize the gait cycle of patients with hemiplegia before and after a period of outpatient physiotherapy based on the Bobath concept. Nine patients, at least 6 weeks post stroke and recently discharged from a stroke unit, were measured before and after a period of outpatient physiotherapy (mean duration = 17.4 weeks). Therapy was documented using a treatment checklist for each patient. The primary outcome measures were a number of gait variables related to the therapists' treatment hypothesis, recorded during the gait cycle using the CODA motion analysis system. Other secondary outcome measures were the Motor Assessment Scale, Modified Ashworth Scale, subtests of the Sodring Motor Evaluation Scale, the Step test, a 10-m walk test, the Barthel Index and the London Handicap Score. Recovery of more normal gait patterns in the gait cycle (using motion analysis) did not occur. Significant changes in temporal parameters (loading response, single support time) for both legs, in one kinematic (dorsiflexion during stance) and one kinetic variable on the unaffected side (hip flexor moment), and most of the clinical measures of impairment, activity and participation (with the exception of the Modified Ashworth Scale and the 10-m walk) were noted. Study findings did not support the hypothesis that the Bobath approach restored more normal movement patterns to the gait cycle. Further research is required to investigate the treatment techniques that are effective at improving walking ability in people after stroke.

The role of cable stiffness in the dynamic behaviours of submerged floating tunnel

Directory of Open Access Journals (Sweden)

Muhammad Naik

2017-01-01

Full Text Available Submerged floating tunnel (SFT is a new solution for the transportation infrastructure through sea straits, fjords, and inland waters and can be a good alternative to long span suspension bridges and immersed tunnels. The mooring cables/anchors are main structural components to provide restoring capacity to the SFT. The time domain dynamic problem of SFT moored by vertical and inclined mooring cables/anchors is formulated. The dynamic analysis of SFT subjected to hydrodynamic and seismic excitations is performed. As the cable stiffness determines the deformation ability of SFT, therefore it becomes crucial to evaluate the effect of mooring cable stiffness on the response of SFT. The displacements and internal forces of SFT clearly specify that the vertical/tension leg mooring cables provide very small stiffness as compared to inclined mooring cables. In order to keep the SFT displacements within an acceptable limit, the effect of cable stiffness should be properly evaluated for practical design of SFT.

A robot and control algorithm that can synchronously assist in naturalistic motion during body-weight-supported gait training following neurologic injury.

Science.gov (United States)

Aoyagi, Daisuke; Ichinose, Wade E; Harkema, Susan J; Reinkensmeyer, David J; Bobrow, James E

2007-09-01

Locomotor training using body weight support on a treadmill and manual assistance is a promising rehabilitation technique following neurological injuries, such as spinal cord injury (SCI) and stroke. Previous robots that automate this technique impose constraints on naturalistic walking due to their kinematic structure, and are typically operated in a stiff mode, limiting the ability of the patient or human trainer to influence the stepping pattern. We developed a pneumatic gait training robot that allows for a full range of natural motion of the legs and pelvis during treadmill walking, and provides compliant assistance. However, we observed an unexpected consequence of the device's compliance: unimpaired and SCI individuals invariably began walking out-of-phase with the device. Thus, the robot perturbed rather than assisted stepping. To address this problem, we developed a novel algorithm that synchronizes the device in real-time to the actual motion of the individual by sensing the state error and adjusting the replay timing to reduce this error. This paper describes data from experiments with individuals with SCI that demonstrate the effectiveness of the synchronization algorithm, and the potential of the device for relieving the trainers of strenuous work while maintaining naturalistic stepping.

The mechanical development and construction of the insulating legs for the NSF tandem

International Nuclear Information System (INIS)

Leese, J.M.

1978-06-01

The Science Research Council is constructing at its Daresbury Laboratory a 30 MV tandem Van de Graaff accelerator which will be used as a research tool to accelerate ions of a wide range of elements. Ions are accelerated through an evacuated beam tube by maintaining a high electric field along it. The ion beam is steered and focussed by magnets situated at various positions along the tube, which, together with the beam handling elements, is supported by a vertical insulating stack. The stack consists of eight vertical columns tied together at regular intervals by stiff rings to obtain the necessary mechanical stability. Each column is made up of 'insulating legs' with tubular steel legs at the terminal and dead section positions. This report describes the manufacturing processes and their development for the insulating legs. (author)

Ground reaction force and 3D biomechanical characteristics of walking in short-leg walkers.

Science.gov (United States)

Zhang, Songning; Clowers, Kurt G; Powell, Douglas

2006-12-01

Short-leg walking boots offer several advantages over traditional casts. However, their effects on ground reaction forces (GRF) and three-dimensional (3D) biomechanics are not fully understood. The purpose of the study was to examine 3D lower extremity kinematics and joint dynamics during walking in two different short-leg walking boots. Eleven (five females and six males) healthy subjects performed five level walking trials in each of three conditions: two testing boot conditions, Gait Walker (DeRoyal Industries, Inc.) and Equalizer (Royce Medical Co.), and one pair of laboratory shoes (Noveto, Adidas). A force platform and a 6-camera Vicon motion analysis system were used to collect GRFs and 3D kinematic data during the testing session. A one-way repeated measures analysis of variance (ANOVA) was used to evaluate selected kinematic, GRF, and joint kinetic variables (p<0.05). The results revealed that both short-leg walking boots were effective in minimizing ankle eversion and hip adduction. Neither walker increased the bimodal vertical GRF peaks typically observed in normal walking. However, they did impose a small initial peak (<1BW) earlier in the stance phase. The Gait Walker also exhibited a slightly increased vertical GRF during midstance. These characteristics may be related to the sole materials/design, the restriction of ankle movements, and/or the elevated heel heights of the tested walkers. Both walkers appeared to increase the demand on the knee extensors while they decreased the demand of the knee and hip abductors based on the joint kinetic results.

Transversal stiffness of fibers and desmin content in leg muscles of rats under gravitational unloading of various durations.

Science.gov (United States)

Ogneva, I V

2010-12-01

The aim of this research was the analysis of structural changes in various parts of the sarcolemma and contractile apparatus of muscle fibers by measuring their transversal stiffness by atomic force microscopy under gravitational unloading. Soleus, medial gastrocnemius, and tibialis anterior muscles of Wistar rats were the objects of the study. Gravitational unloading was carried out by antiorthostatic suspension of hindlimbs for 1, 3, 7, and 12 days. It was shown that the transversal stiffness of different parts of the contractile apparatus of soleus muscle fibers decreases during gravitational unloading in the relaxed, calcium-activated, and rigor states, the fibers of the medial gastrocnemius show no changes, whereas the transversal stiffness of tibialis anterior muscle increases. Thus the transversal stiffness of the sarcolemma in the relaxed state is reduced in all muscles, which may be due to the direct action of gravity as an external mechanical factor that can influence the tension on a membrane. The change of sarcolemma stiffness in activated fibers, which is due probably to the transfer of tension from the contractile apparatus, correlates with the dynamics of changes in the content of desmin.

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

Science.gov (United States)

Sartori, Massimo; Maculan, Marco; Pizzolato, Claudio; Reggiani, Monica; Farina, Dario

2015-10-01

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. Copyright © 2015 the American Physiological Society.

Leg-adjustment strategies for stable running in three dimensions

International Nuclear Information System (INIS)

Peuker, Frank; Maufroy, Christophe; Seyfarth, André

2012-01-01

appropriate model to describe human running in three dimensions. The prediction of stable running based on movement-related leg-adjustment strategies indicates that both humans and robots may not require external targets directing the movement to run in three dimensions based on compliant leg function. This new movement-based reference enables the control of 3D running because leg adjustment is less sensitive and gait stability is separated from directional stability. (paper)

Usefulness of acoustic radiation force impulse elastography in the differential diagnosis of benign and malignant solid pancreatic lesions

Energy Technology Data Exchange (ETDEWEB)

Park, Min Kyoung; Jo, Jeong Hyun; Kwon, Hee Jin; Cho, Jin Han; Oh, Jong Young; Noh, Myung Hwan; Nam, Kyung Jin [Dong-A University College of Medicine, Busan (Korea, Republic of)

2014-03-15

The aim of this study was to evaluate the tissue stiffness of solid pancreatic lesions by using acoustic radiation force impulse (ARFI) elastography to differentiate benign from malignant pancreatic lesions. ARFI elastography was performed in 26 patients who had 27 focal solid pancreatic lesions, including 8 benign lesions (mass-forming pancreatitis, 5; autoimmune pancreatitis, 3) and 19 malignant lesions (pancreatic adenocarcinoma, 16; metastasis from colorectal cancer, 2; malignant neuroendocrine tumor, 1). On the elastographic images of virtual touch tissue imaging (VTI), the echogenicity of the mass was categorized on a 5-grade scale. On the elastographic image of virtual touch tissue quantification (VTQ), the shear wave velocities (SWVs) of the lesion and surrounding parenchyma were measured. On the VTI images, the mean echogenicity score of the malignant lesions (3.7±1.0) was higher than that of the benign lesions (3.1±0.4; P=0.023). On the VTQ images, there were no statistical differences in the mean SWV between the benign (2.4±1.1 m/sec) and malignant (3.3±1.0 m/sec) lesions (P=0.101). However, the mean SWV difference values between the lesion and background parenchyma of the malignant lesions (1.5±0.8 m/sec) were higher than those of the benign lesions (0.4±0.3 m/sec; P=0.011). ARFI elastography can determine the relative stiffness between a lesion and the background pancreatic parenchyma using VTI and VTQ, which is helpful in the differentiation between benign and malignant solid pancreatic lesions.

Gait recovery is not associated with changes in the temporal patterning of muscle activity during treadmill walking in patients with post-stroke hemiparesis.

NARCIS (Netherlands)

Otter, A.R. den; Geurts, A.C.H.; Mulder, T.; Duysens, J.E.J.

2006-01-01

OBJECTIVE: To establish whether functional recovery of gait in patients with post-stroke hemiparesis coincides with changes in the temporal patterning of lower extremity muscle activity and coactivity during treadmill walking. METHODS: Electromyographic (EMG) data from both legs, maximum walking

Gait recovery is not associated with changes in the temporal patterning of muscle activity during treadmill walking in patients with post-stroke hemiparesis

NARCIS (Netherlands)

Den Otter, AR; Mulder, T; Duysens, J

Objective: To establish whether functional recovery of gait in patients with post-stroke hemiparesis coincides with changes in the temporal patterning of lower extremity muscle activity and coactivity during treadmill walking. Methods: Electromyographic (EMG) data from both legs, maximum walking

A method to standardize gait and balance variables for gait velocity.

NARCIS (Netherlands)

Iersel, M.B. van; Olde Rikkert, M.G.M.; Borm, G.F.

2007-01-01

Many gait and balance variables depend on gait velocity, which seriously hinders the interpretation of gait and balance data derived from walks at different velocities. However, as far as we know there is no widely accepted method to correct for effects of gait velocity on other gait and balance

Exoskeleton for gait rehabilitation of children: Conceptual design.

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Cornejo, Jorge L; Santana, Jesus F; Salinas, Sergio A

2017-07-01

This paper presents the conceptual design of an exoskeleton for gait rehabilitation of children. This system has electronics, mechanicals and software sections, which are implemented and tested using a mannequin of a child. The prototype uses servomotors to move robotic joints that are attached to simulated patient's legs. The design has 4 DOF (degrees of freedom) two for hip joints and other two for knee joints, in the sagittal plane. A microcontroller measures sensor signals, controls motors and exchanges data with a computer. The user interacts with a graphical interface to configure, control and monitor the exoskeleton activities. The laboratory tests show soften movements in joint angle tracking.

Triceps-surae musculotendinous stiffness: relative differences between obese and non-obese postmenopausal women.

Science.gov (United States)

Faria, Aurélio; Gabriel, Ronaldo; Abrantes, João; Brás, Rui; Moreira, Helena

2009-12-01

There is a lack of research into the relationship between obesity and muscle-tendon unit stiffness in postmenopausal women. Muscle-tendon unit stiffness appears to affect human motion performance and excessive and insufficient stiffness can increase the risk of bone and soft tissue injuries, respectively. The aim of this study was to investigate the relationship between muscle-tendon unit stiffness and obesity in postmenopausal women. 105 postmenopausal women (58 [SD 5.5] years) participated. Four groups (normal weight, pre-obese, obesity class I and obesity class II) were defined according World Health Organization classification of body mass index. The ankle muscle-tendon unit stiffness was assessed in vivo with a free oscillation technique using a load of 30% of maximal voluntary isometric contraction. ANOVA shows significant difference in muscle-tendon unit stiffness among the groups defined (Pnormal weight-pre-obese; normal weight-obesity class I and normal weight-obesity class II. The normal weight group had stiffness of 15789 (SD 2969) N/m, pre-obese of 19971 (SD 3678) N/m, obesity class I of 21435 (SD 4295) N/m, and obesity class II of 23497 (SD 1776) N/m. Obese subjects may have increased muscle-tendon unit stiffness because of fat infiltration in leg skeletal muscles, range of motion restrictions and stability/posture reasons and might be more predisposed to develop musculoskeletal injuries. Normal weight group had identical stiffness values to those reported in studies where subjects were not yet menopausal, suggesting that stiffness might not be influenced by menopause.

System of gait analysis based on ground reaction force assessment

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František Vaverka

2015-12-01

Full Text Available Background: Biomechanical analysis of gait employs various methods used in kinematic and kinetic analysis, EMG, and others. One of the most frequently used methods is kinetic analysis based on the assessment of the ground reaction forces (GRF recorded on two force plates. Objective: The aim of the study was to present a method of gait analysis based on the assessment of the GRF recorded during the stance phase of two steps. Methods: The GRF recorded with a force plate on one leg during stance phase has three components acting in directions: Fx - mediolateral, Fy - anteroposterior, and Fz - vertical. A custom-written MATLAB script was used for gait analysis in this study. This software displays instantaneous force data for both legs as Fx(t, Fy(t and Fz(t curves, automatically determines the extremes of functions and sets the visual markers defining the individual points of interest. Positions of these markers can be easily adjusted by the rater, which may be necessary if the GRF has an atypical pattern. The analysis is fully automated and analyzing one trial takes only 1-2 minutes. Results: The method allows quantification of temporal variables of the extremes of the Fx(t, Fy(t, Fz(t functions, durations of the braking and propulsive phase, duration of the double support phase, the magnitudes of reaction forces in extremes of measured functions, impulses of force, and indices of symmetry. The analysis results in a standardized set of 78 variables (temporal, force, indices of symmetry which can serve as a basis for further research and diagnostics. Conclusions: The resulting set of variable offers a wide choice for selecting a specific group of variables with consideration to a particular research topic. The advantage of this method is the standardization of the GRF analysis, low time requirements allowing rapid analysis of a large number of trials in a short time, and comparability of the variables obtained during different research measurements.

Effect of therapeutic horseback riding on balance and gait of people with multiple sclerosis.

Science.gov (United States)

Muñoz-Lasa, Susana; Ferriero, Giorgio; Valero, Raquel; Gomez-Muñiz, Fernando; Rabini, Alessia; Varela, Enrique

2011-01-01

Exercise therapy is an important part of symptomatic and supportive treatment in patients with multiple sclerosis (PwMS). According to the literature, equine-assisted therapies--such as therapeutic horseback riding (THR) and hippotherapy (HT)--are exercise therapies that can have positive physical effects on coordination, muscle tone, postural alignment, stiffness/flexibility, endurance and strength, correcting abnormal movement patterns and improving gait and balance. While HT is known to have a positive effect on balance in PwMS, data about THR are limited. The aim of the present work was to determine the effect of THR on the balance and gait of ambulatory PwMS. Twenty-seven PwMS were included in the study. Patients were divided into two groups: 12 underwent THR and 15 traditional physiotherapy (for both groups, two series of 10 weekly sessions were performed). Before and after the study period, the following outcome measures were applied: Extended Disability Status Scale (EDSS), Barthel Index, Tinetti Performance-Oriented Mobility Assessment (POMA). In addition, patients of the THR group underwent a gait analysis to assess spatiotemporal gait parameters and ground reaction forces. The THR group showed a significant improvement in POMA scores (p<0.005) and two gait parameters: stride time (p<0.04) and ground reaction forces (p<0.01). No statistically significant change was found in the control group. The results of the study show that THR can improve balance and gait of ambulatory PwMS. Findings are preliminary, but promising and in line with the recent literature.

Effect of minimal shoes and slope on vertical and leg stiffness during running

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Thibault Lussiana

2015-06-01

Conclusion: This study showed that kvert and kleg during running respond differently to change in footwear and/or slope. These two stiffness measures can hence provide a unique insight on the biomechanical adaptations of running under varying conditions and their respective quantification may assist in furthering our understanding of training, performance, and/or injury in this sport.

Feasibility of external rhythmic cueing with the Google Glass for improving gait in people with Parkinson's disease.

Science.gov (United States)

Zhao, Yan; Nonnekes, Jorik; Storcken, Erik J M; Janssen, Sabine; van Wegen, Erwin E H; Bloem, Bastiaan R; Dorresteijn, Lucille D A; van Vugt, Jeroen P P; Heida, Tjitske; van Wezel, Richard J A

2016-06-01

New mobile technologies like smartglasses can deliver external cues that may improve gait in people with Parkinson's disease in their natural environment. However, the potential of these devices must first be assessed in controlled experiments. Therefore, we evaluated rhythmic visual and auditory cueing in a laboratory setting with a custom-made application for the Google Glass. Twelve participants (mean age = 66.8; mean disease duration = 13.6 years) were tested at end of dose. We compared several key gait parameters (walking speed, cadence, stride length, and stride length variability) and freezing of gait for three types of external cues (metronome, flashing light, and optic flow) and a control condition (no-cue). For all cueing conditions, the subjects completed several walking tasks of varying complexity. Seven inertial sensors attached to the feet, legs and pelvis captured motion data for gait analysis. Two experienced raters scored the presence and severity of freezing of gait using video recordings. User experience was evaluated through a semi-open interview. During cueing, a more stable gait pattern emerged, particularly on complicated walking courses; however, freezing of gait did not significantly decrease. The metronome was more effective than rhythmic visual cues and most preferred by the participants. Participants were overall positive about the usability of the Google Glass and willing to use it at home. Thus, smartglasses like the Google Glass could be used to provide personalized mobile cueing to support gait; however, in its current form, auditory cues seemed more effective than rhythmic visual cues.

What are the characteristics of breast cancers misclassified as benign by quantitative ultrasound shear wave elastography?

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Vinnicombe, S J; Whelehan, P; Thomson, K; McLean, D; Purdie, C A; Jordan, L B; Hubbard, S; Evans, A J

2014-04-01

Shear wave elastography (SWE) is a promising adjunct to greyscale ultrasound in differentiating benign from malignant breast masses. The purpose of this study was to characterise breast cancers which are not stiff on quantitative SWE, to elucidate potential sources of error in clinical application of SWE to evaluation of breast masses. Three hundred and two consecutive patients examined by SWE who underwent immediate surgery for breast cancer were included. Characteristics of 280 lesions with suspicious SWE values (mean stiffness >50 kPa) were compared with 22 lesions with benign SWE values (masses were more often soft on SWE than masses representing invasive breast cancer. Invasive cancers that were soft were more frequently: histological grade 1, tubular subtype, ≤10 mm invasive size and detected at screening mammography. No significant differences were found with respect to the presence of invasive lobular cancer, vascular invasion, hormone and HER-2 receptor status. Lymph node positivity was less common in soft cancers. Malignant breast masses classified as benign by quantitative SWE tend to have better prognostic features than those correctly classified as malignant. • Over 90 % of cancers assessable with ultrasound have a mean stiffness >50 kPa. • 'Soft' invasive cancers are frequently small (≤10 mm), low grade and screen-detected. • Pure DCIS masses are more often soft than invasive cancers (>40 %). • Large symptomatic masses are better evaluated with SWE than small clinically occult lesions. • When assessing small lesions, 'softness' should not raise the threshold for biopsy.

Kinematic and Gait Similarities between Crawling Human Infants and Other Quadruped Mammals

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Righetti, Ludovic; Nylén, Anna; Rosander, Kerstin; Ijspeert, Auke Jan

2015-01-01

Crawling on hands and knees is an early pattern of human infant locomotion, which offers an interesting way of studying quadrupedalism in one of its simplest form. We investigate how crawling human infants compare to other quadruped mammals, especially primates. We present quantitative data on both the gait and kinematics of seven 10-month-old crawling infants. Body movements were measured with an optoelectronic system giving precise data on 3-dimensional limb movements. Crawling on hands and knees is very similar to the locomotion of non-human primates in terms of the quite protracted arm at touch-down, the coordination between the spine movements in the lateral plane and the limbs, the relatively extended limbs during locomotion and the strong correlation between stance duration and speed of locomotion. However, there are important differences compared to primates, such as the choice of a lateral-sequence walking gait, which is similar to most non-primate mammals and the relatively stiff elbows during stance as opposed to the quite compliant gaits of primates. These finding raise the question of the role of both the mechanical structure of the body and neural control on the determination of these characteristics. PMID:25709597

Multi-pulse chaotic motions of a rotor-active magnetic bearing system with time-varying stiffness

International Nuclear Information System (INIS)

Zhang, W.; Yao, M.H.; Zhan, X.P.

2006-01-01

In this paper, we investigate the Shilnikov type multi-pulse chaotic dynamics for a rotor-active magnetic bearings (AMB) system with 8-pole legs and the time-varying stiffness. The stiffness in the AMB is considered as the time-varying in a periodic form. The dimensionless equation of motion for the rotor-AMB system with the time-varying stiffness in the horizontal and vertical directions is a two-degree-of-freedom nonlinear system with quadratic and cubic nonlinearities and parametric excitation. The asymptotic perturbation method is used to obtain the averaged equations in the case of primary parametric resonance and 1/2 subharmonic resonance. It is found from the numerical results that there are the phenomena of the Shilnikov type multi-pulse chaotic motions for the rotor-AMB system. A new jumping phenomenon is discovered in the rotor-AMB system with the time-varying stiffness

A new biarticular actuator design facilitates control of leg function in BioBiped3.

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Sharbafi, Maziar Ahmad; Rode, Christian; Kurowski, Stefan; Scholz, Dorian; Möckel, Rico; Radkhah, Katayon; Zhao, Guoping; Rashty, Aida Mohammadinejad; Stryk, Oskar von; Seyfarth, Andre

2016-07-01

Bioinspired legged locomotion comprises different aspects, such as (i) benefiting from reduced complexity control approaches as observed in humans/animals, (ii) combining embodiment with the controllers and (iii) reflecting neural control mechanisms. One of the most important lessons learned from nature is the significant role of compliance in simplifying control, enhancing energy efficiency and robustness against perturbations for legged locomotion. In this research, we investigate how body morphology in combination with actuator design may facilitate motor control of leg function. Inspired by the human leg muscular system, we show that biarticular muscles have a key role in balancing the upper body, joint coordination and swing leg control. Appropriate adjustment of biarticular spring rest length and stiffness can simplify the control and also reduce energy consumption. In order to test these findings, the BioBiped3 robot was developed as a new version of BioBiped series of biologically inspired, compliant musculoskeletal robots. In this robot, three-segmented legs actuated by mono- and biarticular series elastic actuators mimic the nine major human leg muscle groups. With the new biarticular actuators in BioBiped3, novel simplified control concepts for postural balance and for joint coordination in rebounding movements (drop jumps) were demonstrated and approved.

Simulating the effect of muscle weakness and contracture on neuromuscular control of normal gait in children.

Science.gov (United States)

Fox, Aaron S; Carty, Christopher P; Modenese, Luca; Barber, Lee A; Lichtwark, Glen A

2018-03-01

Altered neural control of movement and musculoskeletal deficiencies are common in children with spastic cerebral palsy (SCP), with muscle weakness and contracture commonly experienced. Both neural and musculoskeletal deficiencies are likely to contribute to abnormal gait, such as equinus gait (toe-walking), in children with SCP. However, it is not known whether the musculoskeletal deficiencies prevent normal gait or if neural control could be altered to achieve normal gait. This study examined the effect of simulated muscle weakness and contracture of the major plantarflexor/dorsiflexor muscles on the neuromuscular requirements for achieving normal walking gait in children. Initial muscle-driven simulations of walking with normal musculoskeletal properties by typically developing children were undertaken. Additional simulations with altered musculoskeletal properties were then undertaken; with muscle weakness and contracture simulated by reducing the maximum isometric force and tendon slack length, respectively, of selected muscles. Muscle activations and forces required across all simulations were then compared via waveform analysis. Maintenance of normal gait appeared robust to muscle weakness in isolation, with increased activation of weakened muscles the major compensatory strategy. With muscle contracture, reduced activation of the plantarflexors was required across the mid-portion of stance suggesting a greater contribution from passive forces. Increased activation and force during swing was also required from the tibialis anterior to counteract the increased passive forces from the simulated dorsiflexor muscle contracture. Improvements in plantarflexor and dorsiflexor motor function and muscle strength, concomitant with reductions in plantarflexor muscle stiffness may target the deficits associated with SCP that limit normal gait. Copyright © 2018 Elsevier B.V. All rights reserved.

Model-Based Experimental Development of Passive Compliant Robot Legs from Fiberglass Composites

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Shang-Chang Lin

2015-01-01

Full Text Available We report on the methodology of developing compliant, half-circular, and composite robot legs with designable stiffness. First, force-displacement experiments on flat cantilever composites made by one or multifiberglass cloths are executed. By mapping the cantilever mechanics to the virtual spring model, the equivalent elastic moduli of the composites can be derived. Next, by using the model that links the curved beam mechanics back to the virtual spring, the resultant stiffness of the composite in a half-circular shape can be estimated without going through intensive experimental tryouts. The overall methodology has been experimentally validated, and the fabricated composites were used on a hexapod robot to perform walking and leaping behaviors.

Sliding GAIT Algorithm for the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE)

Science.gov (United States)

Townsend, Julie; Biesiadecki, Jeffrey

2012-01-01

The design of a surface robotic system typically involves a trade between the traverse speed of a wheeled rover and the terrain-negotiating capabilities of a multi-legged walker. The ATHLETE mobility system, with both articulated limbs and wheels, is uniquely capable of both driving and walking, and has the flexibility to employ additional hybrid mobility modes. This paper introduces the Sliding Gait, an intermediate mobility algorithm faster than walking with better terrain-handling capabilities than wheeled mobility.

Toward Multimodal Human-Robot Interaction to Enhance Active Participation of Users in Gait Rehabilitation.

Science.gov (United States)

Gui, Kai; Liu, Honghai; Zhang, Dingguo

2017-11-01

Robotic exoskeletons for physical rehabilitation have been utilized for retraining patients suffering from paraplegia and enhancing motor recovery in recent years. However, users are not voluntarily involved in most systems. This paper aims to develop a locomotion trainer with multiple gait patterns, which can be controlled by the active motion intention of users. A multimodal human-robot interaction (HRI) system is established to enhance subject's active participation during gait rehabilitation, which includes cognitive HRI (cHRI) and physical HRI (pHRI). The cHRI adopts brain-computer interface based on steady-state visual evoked potential. The pHRI is realized via admittance control based on electromyography. A central pattern generator is utilized to produce rhythmic and continuous lower joint trajectories, and its state variables are regulated by cHRI and pHRI. A custom-made leg exoskeleton prototype with the proposed multimodal HRI is tested on healthy subjects and stroke patients. The results show that voluntary and active participation can be effectively involved to achieve various assistive gait patterns.

The link between weight shift asymmetry and gait disturbances in chronic hemiparetic stroke patients

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Szopa A

2017-12-01

Full Text Available Andrzej Szopa,1 Małgorzata Domagalska-Szopa,2 Anetta Lasek-Bal,3 Amadeusz Żak3 1Department of Physiotherapy, 2Department of Medical Rehabilitation, School of Health Sciences in Katowice, 3Department of Neurology, Professor Leszek Giec Upper Silesian Medical Centre, Medical University of Silesia, Katowice, Poland Introduction: While the asymmetry of body posture and the asymmetrical nature of hemiparetic gait in poststroke (PS patients are well documented, the role of weight shift asymmetry in gait disorders after stroke remains unclear. Objective: We examined the association of weight-bearing asymmetry (WBA between paretic and nonparetic lower limbs during quiet standing with the degree of deviation of hemiplegic gait from normal gait evaluated by the Gillette Gait Index (GGI incorporating 16 distinct clinically important kinematic and temporal parameters in chronic PS patients.Participants and methods: Twenty-two ambulatory patients with chronic stroke aged between 50 and 75 years were included in this study. Fourteen patients had hemiparesis on the nondominant side and 8 on the dominant side. The mean time PS was 2 years and 6 months. The reference group consisted of 22 students from the University of the Third Age presenting no neurological disorders. The examination consisted of posturographic weight-bearing (WB distribution and 3-dimensional gait analyses.Results: A significant positive relationship between WBA and GGI was revealed. Moreover, we observed a significant negative association between WBA and paretic step length and walking speed. With regard to kinematic data, the range of motion of knee flexion and peak dorsiflexion in the swing phase of the paretic leg were significantly negatively associated with WBA.Conclusion: Although further research is needed to determine a causal link between postural control asymmetry and gait disturbance in hemiplegics, our findings support the inclusion of WB measurements between paretic and

Gait adjustments in obstacle crossing, gait initiation and gait termination after a recent lower limb amputation

NARCIS (Netherlands)

Vrieling, Aline H.; van Keeken, Helco G.; Schoppen, Tanneke; Hof, At L.; Otten, Bert; Halbertsma, Jan P. K.; Postema, Klaas

Objective: To describe the adjustments in gait characteristics of obstacle crossing, gait initiation and gait termination that occur in subjects with a recent lower limb amputation during the rehabilitation process. Design: Prospective and descriptive study. Subjects: Fourteen subjects with a recent

The effect of eccentric and concentric calf muscle training on Achilles tendon stiffness.

Science.gov (United States)

Morrissey, Dylan; Roskilly, Anna; Twycross-Lewis, Richard; Isinkaye, Tomide; Screen, Hazel; Woledge, Roger; Bader, Dan

2011-03-01

To compare in vivo effects of eccentric and concentric calf muscle training on Achilles tendon stiffness, in subjects without tendinopathy. Thirty-eight recreational athletes completed 6 weeks eccentric (6 males, 13 females, 21.6  ±  2.2 years) or concentric training (8 males, 11 females, 21.1  ±  2.0 years). Achilles tendon stiffness, tendon modulus and single-leg jump height were measured before and after intervention. Exercise adherence was recorded using a diary. All data are reported as mean  ±  SD. Groups were matched for height and weight but the eccentric training group were more active at baseline (P Tendon stiffness was higher in the eccentrically trained group at baseline compared to the concentrically trained group (20.9  ±  7.3 N/mm v 13.38  ±  4.66 N/mm; P = 0.001) and decreased significantly after eccentric training (to 17.2 ( ±  5.9) N/mm (P = 0.035)). There was no stiffness change in the concentric group (P = 0.405). Stiffness modulus showed similar changes to stiffness. An inverse correlation was found between initial, and subsequent, reduction in stiffness (r = -0.66). Jump height did not change and no correlation between stiffness change and adherence was observed in either group (r = 0.01). Six weeks of eccentric training can alter Achilles tendon stiffness while a matched concentric programme shows no similar effects. Studies in patients with Achilles tendinopathy are warranted.

Mechanical Design Of Prototype Exoskeleton Robotic System For Human Leg Movements And Implementation Of Gait Data With Neural Network

Directory of Open Access Journals (Sweden)

Evren Meltem Toygar

2012-06-01

Full Text Available Target of this study is designing a exoskeleton system for single lower extremity disabled person and controlling this exoskeleton system with neural network. Exoskeleton system is modeled by using SolidWorks. At the same time, gait data is acquired on human body and sole is divided four parts after that reaction forces are gauged during the walking. Distributions of strain and deformation are obtained by using experimental gait data. The walking is designed using the obtained data and walking data is derived for control stage. Power requirements of actuators are defined.

Does dance-based therapy increase gait speed in older adults with chronic lower extremity pain: a feasibility study.

Science.gov (United States)

Krampe, Jean; Wagner, Joanne M; Hawthorne, Kelly; Sanazaro, Deborah; Wong-Anuchit, Choochart; Budhathoki, Chakra; Lorenz, Rebecca A; Raaf, Soren

2014-01-01

A decreased gait speed in older adults can lead to dependency when the individuals are no longer able to participate in activities or do things for themselves. Thirty-seven senior apartment residents (31 females; Mean age=80.6 years; SD=8.9) with lower extremity pain/stiffness participated in a feasibility and preliminary efficacy study of 12 weeks (24 sessions). Healthy-Steps dance therapy compared to a wait-list control group. Small improvements in gait speed ([ES]=0.33) were noted for participants completing 19-24 dance sessions. Improvements in gait speed measured by a 10 Meter Walk Test (0.0517 m/s) exceeded 0.05 m/s, a value deemed to be meaningful in community dwelling older adults. These feasibility study findings support the need for additional research using dance-based therapy for older adults with lower extremity pain. Copyright © 2014 Elsevier Inc. All rights reserved.

Modelling and Control of Robotic Leg as Assistive Device

Science.gov (United States)

Jingye, Yee; Zain, Badrul Aisham bin Md

2017-10-01

The ageing population (people older than 60 years old) is expected to constitute 21.8% of global population by year 2050. When human ages, bodily function including locomotors will deteriorate. Besides, there are hundreds of thousands of victims who suffer from multiple health conditions worldwide that leads to gait impairment. A promising solution will be the lower limb powered-exoskeleton. This study is to be a start-up platform to design a lower limb powered-exoskeleton for a normal Malaysian male, by designing and simulating the dynamic model of a 2-link robotic leg to observe its behaviour under different input conditions with and without a PID controller. Simulink in MATLAB software is used as the dynamic modelling and simulation software for this study. It is observed that the 2-links robotic leg behaved differently under different input conditions, and perform the best when it is constrained and controlled by PID controller. Simulink model is formed as a foundation for the upcoming researches and can be modified and utilised by the future researchers.

Model-Based Estimation of Ankle Joint Stiffness

Directory of Open Access Journals (Sweden)

Berno J. E. Misgeld

2017-03-01

Full Text Available We address the estimation of biomechanical parameters with wearable measurement technologies. In particular, we focus on the estimation of sagittal plane ankle joint stiffness in dorsiflexion/plantar flexion. For this estimation, a novel nonlinear biomechanical model of the lower leg was formulated that is driven by electromyographic signals. The model incorporates a two-dimensional kinematic description in the sagittal plane for the calculation of muscle lever arms and torques. To reduce estimation errors due to model uncertainties, a filtering algorithm is necessary that employs segmental orientation sensor measurements. Because of the model’s inherent nonlinearities and nonsmooth dynamics, a square-root cubature Kalman filter was developed. The performance of the novel estimation approach was evaluated in silico and in an experimental procedure. The experimental study was conducted with body-worn sensors and a test-bench that was specifically designed to obtain reference angle and torque measurements for a single joint. Results show that the filter is able to reconstruct joint angle positions, velocities and torque, as well as, joint stiffness during experimental test bench movements.

Model-Based Estimation of Ankle Joint Stiffness.

Science.gov (United States)

Misgeld, Berno J E; Zhang, Tony; Lüken, Markus J; Leonhardt, Steffen

2017-03-29

We address the estimation of biomechanical parameters with wearable measurement technologies. In particular, we focus on the estimation of sagittal plane ankle joint stiffness in dorsiflexion/plantar flexion. For this estimation, a novel nonlinear biomechanical model of the lower leg was formulated that is driven by electromyographic signals. The model incorporates a two-dimensional kinematic description in the sagittal plane for the calculation of muscle lever arms and torques. To reduce estimation errors due to model uncertainties, a filtering algorithm is necessary that employs segmental orientation sensor measurements. Because of the model's inherent nonlinearities and nonsmooth dynamics, a square-root cubature Kalman filter was developed. The performance of the novel estimation approach was evaluated in silico and in an experimental procedure. The experimental study was conducted with body-worn sensors and a test-bench that was specifically designed to obtain reference angle and torque measurements for a single joint. Results show that the filter is able to reconstruct joint angle positions, velocities and torque, as well as, joint stiffness during experimental test bench movements.

Model-Based Estimation of Ankle Joint Stiffness

Science.gov (United States)

Misgeld, Berno J. E.; Zhang, Tony; Lüken, Markus J.; Leonhardt, Steffen

2017-01-01

We address the estimation of biomechanical parameters with wearable measurement technologies. In particular, we focus on the estimation of sagittal plane ankle joint stiffness in dorsiflexion/plantar flexion. For this estimation, a novel nonlinear biomechanical model of the lower leg was formulated that is driven by electromyographic signals. The model incorporates a two-dimensional kinematic description in the sagittal plane for the calculation of muscle lever arms and torques. To reduce estimation errors due to model uncertainties, a filtering algorithm is necessary that employs segmental orientation sensor measurements. Because of the model’s inherent nonlinearities and nonsmooth dynamics, a square-root cubature Kalman filter was developed. The performance of the novel estimation approach was evaluated in silico and in an experimental procedure. The experimental study was conducted with body-worn sensors and a test-bench that was specifically designed to obtain reference angle and torque measurements for a single joint. Results show that the filter is able to reconstruct joint angle positions, velocities and torque, as well as, joint stiffness during experimental test bench movements. PMID:28353683

Feasibility study of a wearable exoskeleton for children: is the gait altered by adding masses on lower limbs?

Directory of Open Access Journals (Sweden)

Stefano Rossi

Full Text Available We are designing a pediatric exoskeletal ankle robot (pediatric Anklebot to promote gait habilitation in children with Cerebral Palsy (CP. Few studies have evaluated how much or whether the unilateral loading of a wearable exoskeleton may have the unwanted effect of altering significantly the gait. The purpose of this study was to evaluate whether adding masses up to 2.5 kg, the estimated overall added mass of the mentioned device, at the knee level alters the gait kinematics. Ten healthy children and eight children with CP, with light or mild gait impairment, walked wearing a knee brace with several masses. Gait parameters and lower-limb joint kinematics were analyzed with an optoelectronic system under six conditions: without brace (natural gait and with masses placed at the knee level (0.5, 1.0, 1.5, 2.0, 2.5 kg. T-tests and repeated measures ANOVA tests were conducted in order to find noteworthy differences among the trial conditions and between loaded and unloaded legs. No statistically significant differences in gait parameters for both healthy children and children with CP were observed in the five "with added mass" conditions. We found significant differences among "natural gait" and "with added masses" conditions in knee flexion and hip extension angles for healthy children and in knee flexion angle for children with CP. This result can be interpreted as an effect of the mechanical constraint induced by the knee brace rather than the effect associated with load increase. The study demonstrates that the mechanical constraint induced by the brace has a measurable effect on the gait of healthy children and children with CP and that the added mass up to 2.5 kg does not alter the lower limb kinematics. This suggests that wearable devices weighing 25 N or less will not noticeably modify the gait patterns of the population examined here.

Effects of the addition of functional electrical stimulation to ground level gait training with body weight support after chronic stroke.

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Prado-Medeiros, Christiane L; Sousa, Catarina O; Souza, Andréa S; Soares, Márcio R; Barela, Ana M F; Salvini, Tania F

2011-01-01

The addition of functional electrical stimulation (FES) to treadmill gait training with partial body weight support (BWS) has been proposed as a strategy to facilitate gait training in people with hemiparesis. However, there is a lack of studies that evaluate the effectiveness of FES addition on ground level gait training with BWS, which is the most common locomotion surface. To investigate the additional effects of commum peroneal nerve FES combined with gait training and BWS on ground level, on spatial-temporal gait parameters, segmental angles, and motor function. Twelve people with chronic hemiparesis participated in the study. An A1-B-A2 design was applied. A1 and A2 corresponded to ground level gait training using BWS, and B corresponded to the same training with the addition of FES. The assessments were performed using the Modified Ashworth Scale (MAS), Functional Ambulation Category (FAC), Rivermead Motor Assessment (RMA), and filming. The kinematics analyzed variables were mean walking speed of locomotion; step length; stride length, speed and duration; initial and final double support duration; single-limb support duration; swing period; range of motion (ROM), maximum and minimum angles of foot, leg, thigh, and trunk segments. There were not changes between phases for the functional assessment of RMA, for the spatial-temporal gait variables and segmental angles, no changes were observed after the addition of FES. The use of FES on ground level gait training with BWS did not provide additional benefits for all assessed parameters.

Effect of Shoes on Stiffness and Energy Efficiency of Ankle-Foot Orthosis: Bench Testing Analysis.

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Kobayashi, Toshiki; Gao, Fan; LeCursi, Nicholas; Foreman, K Bo; Orendurff, Michael S

2017-12-01

Understanding the mechanical properties of ankle-foot orthoses (AFOs) is important to maximize their benefit for those with movement disorders during gait. Though mechanical properties such as stiffness and/or energy efficiency of AFOs have been extensively studied, it remains unknown how and to what extent shoes influence their properties. The aim of this study was to investigate the effect of shoes on stiffness and energy efficiency of an AFO using a custom mechanical testing device. Stiffness and energy efficiency of the AFO were measured in the plantar flexion and dorsiflexion range, respectively, under AFO-alone and AFO-Shoe combination conditions. The results of this study demonstrated that the stiffness of the AFO-Shoe combination was significantly decreased compared to the AFO-alone condition, but no significant differences were found in energy efficiency. From the results, we recommend that shoes used with AFOs should be carefully selected not only based on their effect on alignment of the lower limb, but also their effects on overall mechanical properties of the AFO-Shoe combination. Further study is needed to clarify the effects of differences in shoe designs on AFO-Shoe combination mechanical properties.

Interlimb symmetry of dynamic knee joint stiffness and co-contraction is maintained in early stage knee osteoarthritis.

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Collins, A T; Richardson, R T; Higginson, J S

2014-08-01

Individuals with knee OA often exhibit greater co-contraction of antagonistic muscle groups surrounding the affected joint which may lead to increases in dynamic joint stiffness. These detrimental changes in the symptomatic limb may also exist in the contralateral limb, thus contributing to its risk of developing knee osteoarthritis. The purpose of this study is to investigate the interlimb symmetry of dynamic knee joint stiffness and muscular co-contraction in knee osteoarthritis. Muscular co-contraction and dynamic knee joint stiffness were assessed in 17 subjects with mild to moderate unilateral medial compartment knee osteoarthritis and 17 healthy control subjects while walking at a controlled speed (1.0m/s). Paired and independent t-tests determined whether significant differences exist between groups (pknees compared to the healthy group (p=0.051). Subjects with mild to moderate knee osteoarthritis maintain symmetric control strategies during gait. Copyright © 2014 Elsevier Ltd. All rights reserved.

3D gait analysis with and without an orthopedic walking boot.

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Gulgin, H; Hall, K; Luzadre, A; Kayfish, E

2018-01-01

Orthopedic walking boots have been widely used in place of traditional fiberglass casts for a variety of orthopedic injuries and post-surgical interventions. These walking boots create a leg length discrepancy (LLD). LLD has been shown to alter the kinematics and kinetics of gait and are associated with lumbar and lower limb conditions such as: foot over pronation, low back pain, scoliosis, and osteoarthritis of the hip and knee joints. Past gait analyses research with orthopedic boots is limited to findings on the ipsilateral limb. Thus, the purpose of the study was to examine bilateral gait kinematics & kinetics with and without a walking boot. Forty healthy participants (m=20, f=20, age 20.7±1.8 yrs., ht. 171.6±9.5cm, wt. 73.2±11.0kg, BMI 24.8±3.2) volunteered. An eight camera Vicon Motion Capture System with PIG model and two AMTI force plates were utilized to record the walking trial conditions: (1) bilateral tennis shoes (2) boot on right foot, tennis shoe on left foot (3) boot on right foot, barefoot on left foot. Data were processed in Nexus 2.2.3 and exported to Visual 3D for analysis. When wearing the boot, there were significant differences in most joint angles and moments, with larger effects on long limb. The walking boot alters the gait in the same way as those with existing LLD, putting them at risk for development of secondary knee, hip, and low back pain during treatment protocol. Copyright © 2017 Elsevier B.V. All rights reserved.

Markedly impaired bilateral coordination of gait in post-stroke patients: Is this deficit distinct from asymmetry? A cohort study

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van Lummel Rob C

2011-05-01

Full Text Available Abstract Background Multiple aspects of gait are typically impaired post-stroke. Asymmetric gait is common as a consequence of unilateral brain lesions. The relationship between the resulting asymmetric gait and impairments in the ability to properly coordinate the reciprocal stepping activation of the legs is not clear. The objective of this exploratory study is to quantify the effects of hemiparesis on two putatively independent aspects of the bilateral coordination of gait to gain insight into mechanisms and their relationship and to assess their potential as clinical markers. Methods Twelve ambulatory stroke patients and age-matched healthy adults wore a tri-axial piezo-resistive accelerometer and walked back and forth along a straight path in a hall at a comfortable walking speed during 2 minutes. Gait speed, gait asymmetry (GA, and aspects of the bilateral coordination of gait (BCG were determined. Bilateral coordination measures included the left-right stepping phase for each stride φi, consistency in the phase generation φ_CV, accuracy in the phase generation φ_ABS, and Phase Coordination Index (PCI, a combination of accuracy and consistency of the phase generation. Results Group differences (p Conclusions In ambulatory post-stroke patients, two gait coordination properties, GA and PCI, are markedly impaired. Although these features are not related to each other in healthy controls, they are strongly related in stroke patients, which is a novel finding. A measurement approach based on body-fixed sensors apparently may provide sensitive markers that can be used for clinical assessment and for enhancing rehabilitation targeting in post-stroke patients.

Markedly impaired bilateral coordination of gait in post-stroke patients: Is this deficit distinct from asymmetry? A cohort study

Science.gov (United States)

2011-01-01

Background Multiple aspects of gait are typically impaired post-stroke. Asymmetric gait is common as a consequence of unilateral brain lesions. The relationship between the resulting asymmetric gait and impairments in the ability to properly coordinate the reciprocal stepping activation of the legs is not clear. The objective of this exploratory study is to quantify the effects of hemiparesis on two putatively independent aspects of the bilateral coordination of gait to gain insight into mechanisms and their relationship and to assess their potential as clinical markers. Methods Twelve ambulatory stroke patients and age-matched healthy adults wore a tri-axial piezo-resistive accelerometer and walked back and forth along a straight path in a hall at a comfortable walking speed during 2 minutes. Gait speed, gait asymmetry (GA), and aspects of the bilateral coordination of gait (BCG) were determined. Bilateral coordination measures included the left-right stepping phase for each stride φi, consistency in the phase generation φ_CV, accuracy in the phase generation φ_ABS, and Phase Coordination Index (PCI), a combination of accuracy and consistency of the phase generation. Results Group differences (p stroke patients (r = 0.94; p stroke patients, two gait coordination properties, GA and PCI, are markedly impaired. Although these features are not related to each other in healthy controls, they are strongly related in stroke patients, which is a novel finding. A measurement approach based on body-fixed sensors apparently may provide sensitive markers that can be used for clinical assessment and for enhancing rehabilitation targeting in post-stroke patients. PMID:21545703

Passive Control of Attachment in Legged Space Robots

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Alessandro Gasparetto

2010-01-01

Full Text Available In the space environment the absence of gravity calls for constant safe attachment of any loose object, but the low-pressure conditions prohibit the use of glue-type adhesives. The attachment system of freely hunting spiders, e.g. Evarcha arcuata, employs van der Waals forces and mechanical interlocking. Furthermore, detachment is achieved passively and requires little force. Hence, the spider serves as a model for a versatile legged robot for space applications, e.g. on the outer surface of a space station. In this paper, we analyse the dry attachment systems of E. arcuata and geckos as well as the kinematics of freely hunting spiders. We generalise the results of biological studies on spider locomotion and mobility, including the major movement and the position constraints set by the dry adhesion system. From these results, we define a simplified spider model and study the overall kinematics of the legs both in flight and in contact with the surface. The kinematic model, the data on spider gait characteristics and the adhesion constraints are implemented in a kinematic simulator. The simulator results confirm the principal functionality of our concept.

Region-dependent hamstrings activity in Nordic hamstring exercise and stiff-leg deadlift defined with high-density electromyography.

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Hegyi, A; Péter, A; Finni, T; Cronin, N J

2018-03-01

Recent studies suggest region-specific metabolic activity in hamstring muscles during injury prevention exercises, but the neural representation of this phenomenon is unknown. The aim of this study was to examine whether regional differences are evident in the activity of biceps femoris long head (BFlh) and semitendinosus (ST) muscles during two common injury prevention exercises. Twelve male participants without a history of hamstring injury performed the Nordic hamstring exercise (NHE) and stiff-leg deadlift (SDL) while BFlh and ST activities were recorded with high-density electromyography (HD-EMG). Normalized activity was calculated from the distal, middle, and proximal regions in the eccentric phase of each exercise. In NHE, ST overall activity was substantially higher than in BFlh (d = 1.06 ± 0.45), compared to trivial differences between muscles in SDL (d = 0.19 ± 0.34). Regional differences were found in NHE for both muscles, with different proximal-distal patterns: The distal region showed the lowest activity level in ST (regional differences, d range = 0.55-1.41) but the highest activity level in BFlh (regional differences, d range = 0.38-1.25). In SDL, regional differences were smaller in both muscles (d range = 0.29-0.67 and 0.16-0.63 in ST and BFlh, respectively) than in NHE. The use of HD-EMG in hamstrings revealed heterogeneous hamstrings activity during typical injury prevention exercises. High-density EMG might be useful in future studies to provide a comprehensive overview of hamstring muscle activity in other exercises and high-injury risk tasks. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Failure of gamma-aminobutyrate acid-beta agonist baclofen to improve balance, gait, and postural control after vestibular schwannoma resection.

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De Valck, Claudia F J; Vereeck, Luc; Wuyts, Floris L; Van de Heyning, Paul H

2009-04-01

Incomplete postural control often occurs after vestibular schwannoma (VS) surgery. Customized vestibular rehabilitation in man improves and speeds up this process. Animal experiments have shown an improved and faster vestibular compensation after administration of the gamma-aminobutyrate acid (GABA)-beta agonist baclofen. To examine whether medical treatment with baclofen provides an improvement of the compensation process after VS surgery. A time-series study with historical control. Tertiary referral center. Thirteen patients who underwent VS resection were included and compared with a matched group of patients. In addition to an individualized vestibular rehabilitation protocol, the study group received medical treatment with 30 mg baclofen (a GABA-beta agonist) daily during the first 6 weeks after surgery. Clinical gait and balance tests (Romberg maneuver, standing on foam, tandem Romberg, single-leg stance, Timed Up & Go test, tandem gait, Dynamic Gait Index) and Dizziness Handicap Inventory. Follow-up until 24 weeks after surgery. When examining the postoperative test results, the group treated with baclofen did not perform better when compared with the matched (historical control) group. Repeated-measures analysis of variance revealed no significant group effect, but a significant time effect for almost all balance tests during the acute recovery period was found. An interaction effect between time and intervention was seen concerning single-leg stance and Dizziness Handicap Inventory scores for the acute recovery period. Medical therapy with baclofen did not seem to be beneficial in the process of central vestibular compensation.

Multi-scale complexity analysis of muscle coactivation during gait in children with cerebral palsy

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Wen eTao

2015-07-01

Full Text Available The objective of this study is to characterize complexity of lower-extremity muscle coactivation and coordination during gait in children with cerebral palsy (CP, children with typical development (TD and healthy adults, by applying recently developed multivariate multi-scale entropy (MMSE analysis to surface EMG signals. Eleven CP children (CP group, eight TD children and seven healthy adults (consider as an entire control group were asked to walk while surface EMG signals were collected from 5 thigh muscles and 3 lower leg muscles on each leg (16 EMG channels in total. The 16-channel surface EMG data, recorded during a series of consecutive gait cycles, were simultaneously processed by multivariate empirical mode decomposition (MEMD, to generate fully aligned data scales for subsequent MMSE analysis. In order to conduct extensive examination of muscle coactivation complexity using the MEMD-enhanced MMSE, 14 data analysis schemes were designed by varying partial muscle combinations and time durations of data segments. Both TD children and healthy adults showed almost consistent MMSE curves over multiple scales for all the 14 schemes, without any significant difference (p > 0.09. However, quite diversity in MMSE curve was observed in the CP group when compared with those in the control group. There appears to be diverse neuropathological processes in CP that may affect dynamical complexity of muscle coactivation and coordination during gait. The abnormal complexity patterns emerging in CP group can be attributed to different factors such as motor control impairments, loss of muscle couplings, and spasticity or paralysis in individual muscles. All these findings expand our knowledge of neuropathology of CP from a novel point of view of muscle co-activation complexity, also indicating the potential to derive a quantitative index for assessing muscle activation characteristics as well as motor function in CP.

Design, simulation and modelling of auxiliary exoskeleton to improve human gait cycle.

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Ashkani, O; Maleki, A; Jamshidi, N

2017-03-01

Exoskeleton is a walking assistance device that improves human gait cycle through providing auxiliary force and transferring physical load to the stronger muscles. This device takes the natural state of organ and follows its natural movement. Exoskeleton functions as an auxiliary device to help those with disabilities in hip and knee such as devotees, elderly farmers and agricultural machinery operators who suffer from knee complications. In this research, an exoskeleton designed with two screw jacks at knee and hip joints. To simulate extension and flexion movements of the leg joints, bearings were used at the end of hip and knee joints. The generated torque and motion angles of these joints obtained as well as the displacement curves of screw jacks in the gait cycle. Then, the human gait cycle was simulated in stance and swing phases and the obtained torque curves were compared. The results indicated that they followed the natural circle of the generated torque in joints with a little difference from each other. The maximum displacement obtained 4 and 6 cm in hip and knee joints jack respectively. The maximum torques in hip and knee joints were generated in foot contact phase. Also the minimum torques in hip and knee joints were generated in toe off and heel off phases respectively.

Low tendon stiffness and abnormal ultrastructure distinguish classic Ehlers-Danlos syndrome from benign joint hypermobility syndrome in patients

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Nielsen, Rie Harboe; Couppé, Christian; Jensen, Jacob Kildevang

2014-01-01

There is a clinical overlap between classic Ehlers-Danlos syndrome (cEDS) and benign joint hypermobility syndrome (BJHS), with hypermobility as the main symptom. The purpose of this study was to investigate the role of type V collagen mutations and tendon pathology in these 2 syndromes. In patients...... and abnormal ultrastructure distinguish classic Ehlers-Danlos syndrome from benign joint hypermobility syndrome in patients....

Impaired gait function in adults with cerebral palsy is associated with reduced rapid force generation and increased passive stiffness

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Geertsen, Svend Sparre; Kirk, Henrik; Lorentzen, Jakob

2015-01-01

analysis of the ankle joint during treadmill walking was obtained by 3-D motion analysis. RESULTS: Passive stiffness was significantly increased in adults with CP compared to controls. Passive stiffness and RFDdf were correlated to reduced toe lift. RFDpf provided the best correlation to push-off velocity...

The effect of isokinetic and proprioception training on strength, movement and gait parameters after acute supination injury of the ankle ligaments

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C. Mucha

2009-01-01

Full Text Available The effects of a three-week isokinetic training compared to typical proprio -ceptive training on parameters of strength, movement and gait function after acute ankle ligament sprain were investigated. Thirty-nine patients were randomly allocated to two comparison groups. In group 1 (n=20a proprioceptive training and in group 2 (n=19 an isokinetic strength training (Cybex 6000® were administered. Thepatients of both groups underwent training five times a week for three weeks. Before and at the end of the treatmentcourse, in both groups isokinetic strength was tested, the range of motion in the ankle joint was recorded and gait wasanalyzed (multicomponent strength measurement platform, Henschel-System®. The maximum isokinetic torque(60°/s [Nm] and the contact time (monopedal support time of the injured leg during gait cycle were the basis for evaluation.The data obtained show that in group 2 a significantly greater increase of the maximum isokinetic torque wasattained in almost all range of motion of the ankle joint in the course of treatment. A t the same time, in group 2 theshortening of the contact time in the stance phase of the injured leg could be compensated. The active range of motionin the ankle joint was less at the end of treatment in group 2 than in group 1. The isokinetic training obviously did notonly lead to better strength regeneration, but also to a functionally more stable ankle joint with a rhythmically moreevenly balanced stance phase of the gait cycle.  These results suggest that the used isokinetic training had positive effects on functional stability after acute ankle sprain.

An electromechanical gait trainer for restoration of gait in hemiparetic stroke patients: preliminary results.

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Hesse, S; Werner, C; Uhlenbrock, D; von Frankenberg, S; Bardeleben, A; Brandl-Hesse, B

2001-01-01

Modern concepts of gait rehabilitation after stroke favor a task-specific repetitive approach. In practice, the required physical effort of the therapists limits the realization of this approach. Therefore, a mechanized gait trainer enabling nonambulatory patients to have the repetitive practice of a gait-like movement without overstraining therapists was constructed. This preliminary study investigated whether an additional 4-week daily therapy on the gait trainer could improve gait ability in 14 chronic wheelchair-bound hemiparetic subjects. The 4 weeks of physiotherapy and gait-trainer therapy resulted in a relevant improvement of gait ability in all subjects. Velocity, cadence, and stride length improved significantly (p gait trainer seems feasible as an adjunctive tool in gait rehabilitation after stroke; further studies are needed.

A flexible wearable sensor for knee flexion assessment during gait.

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Papi, Enrica; Bo, Yen Nee; McGregor, Alison H

2018-05-01

Gait analysis plays an important role in the diagnosis and management of patients with movement disorders but it is usually performed within a laboratory. Recently interest has shifted towards the possibility of conducting gait assessments in everyday environments thus facilitating long-term monitoring. This is possible by using wearable technologies rather than laboratory based equipment. This study aims to validate a novel wearable sensor system's ability to measure peak knee sagittal angles during gait. The proposed system comprises a flexible conductive polymer unit interfaced with a wireless acquisition node attached over the knee on a pair of leggings. Sixteen healthy volunteers participated to two gait assessments on separate occasions. Data was simultaneously collected from the novel sensor and a gold standard 10 camera motion capture system. The relationship between sensor signal and reference knee flexion angles was defined for each subject to allow the transformation of sensor voltage outputs to angular measures (degrees). The knee peak flexion angle from the sensor and reference system were compared by means of root mean square error (RMSE), absolute error, Bland-Altman plots and intra-class correlation coefficients (ICCs) to assess test-retest reliability. Comparisons of knee peak flexion angles calculated from the sensor and gold standard yielded an absolute error of 0.35(±2.9°) and RMSE of 1.2(±0.4)°. Good agreement was found between the two systems with the majority of data lying within the limits of agreement. The sensor demonstrated high test-retest reliability (ICCs>0.8). These results show the ability of the sensor to monitor knee peak sagittal angles with small margins of error and in agreement with the gold standard system. The sensor has potential to be used in clinical settings as a discreet, unobtrusive wearable device allowing for long-term gait analysis. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Energy Expenditure of Trotting Gait Under Different Gait Parameters

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Chen, Xian-Bao; Gao, Feng

2017-07-01

Robots driven by batteries are clean, quiet, and can work indoors or in space. However, the battery endurance is a great problem. A new gait parameter design energy saving strategy to extend the working hours of the quadruped robot is proposed. A dynamic model of the robot is established to estimate and analyze the energy expenditures during trotting. Given a trotting speed, optimal stride frequency and stride length can minimize the energy expenditure. However, the relationship between the speed and the optimal gait parameters is nonlinear, which is difficult for practical application. Therefore, a simplified gait parameter design method for energy saving is proposed. A critical trotting speed of the quadruped robot is found and can be used to decide the gait parameters. When the robot is travelling lower than this speed, it is better to keep a constant stride length and change the cycle period. When the robot is travelling higher than this speed, it is better to keep a constant cycle period and change the stride length. Simulations and experiments on the quadruped robot show that by using the proposed gait parameter design approach, the energy expenditure can be reduced by about 54% compared with the 100 mm stride length under 500 mm/s speed. In general, an energy expenditure model based on the gait parameter of the quadruped robot is built and the trotting gait parameters design approach for energy saving is proposed.

On the development a pneumatic four-legged mechanism autonomous vertical wall climbing robot

International Nuclear Information System (INIS)

Mohamad Shukri Zainal Abidin; Shamsudin H.M. Amin . shukri@suria.fke.utm.my

1999-01-01

The paper describes the design of a prototype legged mechanism together with suction mechanism, the mechanical design, on-board controller and an initial performance test. The design is implemented in the form of a pneumatically powered multi-legged robot equipped with suction pads at the sole of the feet for wall climbing purpose. The whole mechanism and suction system is controlled by controller which is housed on-board the robot. The gait of the motion depended on the logic control patterns as dictated by the controller. The robot is equipped with sensors both at the front and rear ends that function as an obstacle avoidance facility. Once objects are detected, signals are sent to the controller to start an evasive action that is to move in the opposite direction. The mechanism has been tested and initial results have shown promising potential for an autonomous mobile. (Author)

Guidelines for Assessment of Gait and Reference Values for Spatiotemporal Gait Parameters in Older Adults: The Biomathics and Canadian Gait Consortiums Initiative

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Olivier Beauchet

2017-08-01

Full Text Available Background: Gait disorders, a highly prevalent condition in older adults, are associated with several adverse health consequences. Gait analysis allows qualitative and quantitative assessments of gait that improves the understanding of mechanisms of gait disorders and the choice of interventions. This manuscript aims (1 to give consensus guidance for clinical and spatiotemporal gait analysis based on the recorded footfalls in older adults aged 65 years and over, and (2 to provide reference values for spatiotemporal gait parameters based on the recorded footfalls in healthy older adults free of cognitive impairment and multi-morbidities.Methods: International experts working in a network of two different consortiums (i.e., Biomathics and Canadian Gait Consortium participated in this initiative. First, they identified items of standardized information following the usual procedure of formulation of consensus findings. Second, they merged databases including spatiotemporal gait assessments with GAITRite® system and clinical information from the “Gait, cOgnitiOn & Decline” (GOOD initiative and the Generation 100 (Gen 100 study. Only healthy—free of cognitive impairment and multi-morbidities (i.e., ≤ 3 therapeutics taken daily—participants aged 65 and older were selected. Age, sex, body mass index, mean values, and coefficients of variation (CoV of gait parameters were used for the analyses.Results: Standardized systematic assessment of three categories of items, which were demographics and clinical information, and gait characteristics (clinical and spatiotemporal gait analysis based on the recorded footfalls, were selected for the proposed guidelines. Two complementary sets of items were distinguished: a minimal data set and a full data set. In addition, a total of 954 participants (mean age 72.8 ± 4.8 years, 45.8% women were recruited to establish the reference values. Performance of spatiotemporal gait parameters based on the recorded

Basal ganglia and gait control: apomorphine administration and internal pallidum stimulation in Parkinson's disease.

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Grasso, R; Peppe, A; Stratta, F; Angelini, D; Zago, M; Stanzione, P; Lacquaniti, F

1999-05-01

Gait coordination was analyzed (four-camera 100 Hz ELITE system) in two groups of idiopathic Parkinson disease (PD) patients. Five patients underwent continuous infusion of apomorphine and were recorded in two different sessions (APO OFF and APO ON) in the same day. Three patients with a previous chronic electrode implantation in both internal globi pallidi (GPi) were recorded in the same experimental session with the electrodes on and off (STIM ON and STIM OFF). The orientation of both the trunk and the lower-limb segments was described with respect to the vertical in the sagittal plane. Lower-limb inter-segmental coordination was evaluated by analyzing the co-variation between thigh, shank, and foot elevation angles by means of orthogonal planar regression. At least 30 gait cycles per experimental condition were processed. We found that the trunk was bent forward in STIM OFF, whereas it was better aligned with the vertical in STIM ON in both PD groups. The legs never fully extended during the gait cycle in STIM OFF, whereas they extended before heel strike in STIM ON. The multisegmental coordination of the lower limb changed almost in parallel with the changes in trunk orientation. In STIM OFF, both the shape and the spatial orientation of the planar gait loops (thigh angle vs. shank angle vs. foot angle) differed from those of physiological locomotion, whereas in STIM ON the gait loop tended to resume features closer to the control. Switching the electrodes on and off in patients with GPi electrodes resulted in quasi-parallel changes of the trunk inclination and of the planar gait loop. The bulk of the data suggest that the basal-ganglia circuitry may be relevant in locomotion by providing an appropriate spatio-temporal framework for the control of posture and movement in a gravity-based body-centered frame of reference. Pallido-thalamic and/or pallido-mesencephalic pathways may influence the timing of the inter-segmental coordination for gait.

Relationship between Static Stiffness and Modal Stiffness of Structures

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Tianjian Ji Tianjian Ji

2010-02-01

Full Text Available This paper derives the relationship between the static stiffness and modal stiffness of a structure. The static stiffness and modal stiffness are two important concepts in both structural statics and dynamics. Although both stiffnesses indicate the capacity of the structure to resist deformation, they are obtained using different methods. The former is calculated by solving the equations of equilibrium and the latter can be obtained by solving an eigenvalue problem. A mathematical relationship between the two stiffnesses was derived based on the definitions of two stiffnesses. This relationship was applicable to a linear system and the derivation of relationships does not reveal any other limitations. Verification of the relationship was given by using several examples. The relationship between the two stiffnesses demonstrated that the modal stiffness of the fundamental mode was always larger than the static stiffness of a structure if the critical point and the maximum mode value are at the same node, i.e. for simply supported beam and seven storeys building are 1.5% and 15% respectively. The relationship could be applied into real structures, where the greater the number of modes being considered, the smaller the difference between the modal stiffness and the static stiffness of a structure.

Gait performance and foot pressure distribution during wearable robot-assisted gait in elderly adults.

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Lee, Su-Hyun; Lee, Hwang-Jae; Chang, Won Hyuk; Choi, Byung-Ok; Lee, Jusuk; Kim, Jeonghun; Ryu, Gyu-Ha; Kim, Yun-Hee

2017-11-28

A robotic exoskeleton device is an intelligent system designed to improve gait performance and quality of life for the wearer. Robotic technology has developed rapidly in recent years, and several robot-assisted gait devices were developed to enhance gait function and activities of daily living in elderly adults and patients with gait disorders. In this study, we investigated the effects of the Gait-enhancing Mechatronic System (GEMS), a new wearable robotic hip-assist device developed by Samsung Electronics Co, Ltd., Korea, on gait performance and foot pressure distribution in elderly adults. Thirty elderly adults who had no neurological or musculoskeletal abnormalities affecting gait participated in this study. A three-dimensional (3D) motion capture system, surface electromyography and the F-Scan system were used to collect data on spatiotemporal gait parameters, muscle activity and foot pressure distribution under three conditions: free gait without robot assistance (FG), robot-assisted gait with zero torque (RAG-Z) and robot-assisted gait (RAG). We found increased gait speed, cadence, stride length and single support time in the RAG condition. Reduced rectus femoris and medial gastrocnemius muscle activity throughout the terminal stance phase and reduced effort of the medial gastrocnemius muscle throughout the pre-swing phase were also observed in the RAG condition. In addition, walking with the assistance of GEMS resulted in a significant increase in foot pressure distribution, specifically in maximum force and peak pressure of the total foot, medial masks, anterior masks and posterior masks. The results of the present study reveal that GEMS may present an alternative way of restoring age-related changes in gait such as gait instability with muscle weakness, reduced step force and lower foot pressure in elderly adults. In addition, GEMS improved gait performance by improving push-off power and walking speed and reducing muscle activity in the lower

A method to simulate motor control strategies to recover from perturbations: application to a stumble recovery during gait.

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Forner-Cordero, Arturo; Ackermann, Marko; de Lima Freitas, Mateus

2011-01-01

Perturbations during human gait such as a trip or a slip can result in a fall, especially among frail populations such as the elderly. In order to recover from a trip or a stumble during gait, humans perform different types of recovery strategies. It is very useful to uncover the mechanisms of the recovery to improve training methods for populations at risk of falling. Moreover, human recovery strategies could be applied to implement controllers for bipedal robot walker, as an application of biomimetic design. A biomechanical model of the response to a trip during gait might uncover the control mechanisms underlying the different recovery strategies and the adaptation of the responses found during the execution of successive perturbation trials. This paper introduces a model of stumble in the multibody system framework. This model is used to assess different feedforward strategies to recover from a trip. First of all, normal gait patterns for the musculoskeletal system model are obtained by solving an optimal control problem. Secondly, the reference gait is perturbed by the application of forces on the swinging foot in different ways: as an instantaneous inelastic collision of the foot with an obstacle, as an impulsive horizontal force or using a force curve measured experimentally during gait perturbation experiments. The influence of the type of perturbation, the timing of the collision with respect to the gait cycle, as well as of the coefficient of restitution was investigated previously. Finally, in order to test the effects of different muscle excitation levels on the initial phases of the recovery response, several muscle excitations were added to selected muscles of the legs, thus providing a simulation of the recovery reactions. These results pave the way for future analysis and modeling of the control mechanisms of gait.

BUILDING A BETTER GLUTEAL BRIDGE: ELECTROMYOGRAPHIC ANALYSIS OF HIP MUSCLE ACTIVITY DURING MODIFIED SINGLE-LEG BRIDGES.

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Lehecka, B J; Edwards, Michael; Haverkamp, Ryan; Martin, Lani; Porter, Kambry; Thach, Kailey; Sack, Richard J; Hakansson, Nils A

2017-08-01

Gluteal strength plays a role in injury prevention, normal gait patterns, eliminating pain, and enhancing athletic performance. Research shows high gluteal muscle activity during a single-leg bridge compared to other gluteal strengthening exercises; however, prior studies have primarily measured muscle activity with the active lower extremity starting in 90 ° of knee flexion with an extended contralateral knee. This standard position has caused reports of hamstring cramping, which may impede optimal gluteal strengthening. The purpose of this study was to determine which modified position for the single-leg bridge is best for preferentially activating the gluteus maximus and medius. Cross-Sectional. Twenty-eight healthy males and females aged 18-30 years were tested in five different, randomized single-leg bridge positions. Electromyography (EMG) electrodes were placed on subjects' gluteus maximus, gluteus medius, rectus femoris, and biceps femoris of their bridge leg (i.e., dominant or kicking leg), as well as the rectus femoris of their contralateral leg. Subjects performed a maximal voluntary isometric contraction (MVIC) for each tested muscle prior to performing five different bridge positions in randomized order. All bridge EMG data were normalized to the corresponding muscle MVIC data. A modified bridge position with the knee of the bridge leg flexed to 135 ° versus the traditional 90 ° of knee flexion demonstrated preferential activation of the gluteus maximus and gluteus medius compared to the traditional single-leg bridge. Hamstring activation significantly decreased (p bridge by flexing the active knee to 135 ° instead of 90 ° minimizes hamstring activity while maintaining high levels of gluteal activation, effectively building a bridge better suited for preferential gluteal activation. 3.

Influence of Moderate Training on Gait and Work Capacity of Fibromyalgia Patients: A Preliminary Field Study

OpenAIRE

Tiidus, Peter M.; Pierrynowski, Michael; Dawson, Kimberley A.

2002-01-01

This field study examined the influence of moderate intensity training on gait patterns and work capacity of individuals with fibromyalgia syndrome (FS). FS is a chronic condition of unknown etiology, characterized by muscle tenderness, pain and stiffness and often accompanied by depression and fatigue which seems to occur primarily in middle aged females. There is no known cure for FS but treatment often includes a prescription of mild exercise. Few studies have evaluated the effectiveness o...

Correlation between static radiographic measurements and intersegmental angular measurements during gait using a multisegment foot model.

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Lee, Dong Yeon; Seo, Sang Gyo; Kim, Eo Jin; Kim, Sung Ju; Lee, Kyoung Min; Farber, Daniel C; Chung, Chin Youb; Choi, In Ho

2015-01-01

Radiographic examination is a widely used evaluation method in the orthopedic clinic. However, conventional radiography alone does not reflect the dynamic changes between foot and ankle segments during gait. Multiple 3-dimensional multisegment foot models (3D MFMs) have been introduced to evaluate intersegmental motion of the foot. In this study, we evaluated the correlation between static radiographic indices and intersegmental foot motion indices. One hundred twenty-five females were tested. Static radiographs of full-leg and anteroposterior (AP) and lateral foot views were performed. For hindfoot evaluation, we measured the AP tibiotalar angle (TiTA), talar tilt (TT), calcaneal pitch, lateral tibiocalcaneal angle, and lateral talcocalcaneal angle. For the midfoot segment, naviculocuboid overlap and talonavicular coverage angle were calculated. AP and lateral talo-first metatarsal angles and metatarsal stacking angle (MSA) were measured to assess the forefoot. Hallux valgus angle (HVA) and hallux interphalangeal angle were measured. In gait analysis by 3D MFM, intersegmental angle (ISA) measurements of each segment (hallux, forefoot, hindfoot, arch) were recorded. ISAs at midstance phase were most highly correlated with radiography. Significant correlations were observed between ISA measurements using MFM and static radiographic measurements in the same segment. In the hindfoot, coronal plane ISA was correlated with AP TiTA (P foot motion indices at midstance phase during gait measured by 3D MFM gait analysis were correlated with the conventional radiographic indices. The observed correlation between MFM measurements at midstance phase during gait and static radiographic measurements supports the fundamental basis for the use of MFM in analysis of dynamic motion of foot segment during gait. © The Author(s) 2014.

Relation between knee extensors' strength, postural stability and variability of centre of pressure displacement during gait in adult women

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Eliza C. de Souza

2017-03-01

Full Text Available Background: It has been shown that variability of walking is related to fall risk similarly as postural control and muscle strength. Joint potential of this group of variables for fall risk assessment is promising, however research interested in relations between them is lacking. Objective: The aim of this study was to investigate the relation between knee extensors' strength, centre of pressure (COP velocity during one-leg stance and variability of COP displacement during various phases of gait cycle in middle-age women. Methods: A single group of 40 healthy women (age 56 ± 4.2 years took part in the study. For assessment of knee extensors' strength (peak torque and average work during concentric and eccentric contractions an isokinetic dynamometer was used. Mean velocity of COP during one-leg stance in anterior-posterior (AP and medial-lateral (ML directions was assessed on a force plate on a rigid surface with eyes open (two 30 s trials. Variability of COP displacement was assessed for loading response, midstance, terminal stance and preswing gait cycle phases (determined by vertical ground reaction force in AP and ML directions. It was measured by two force plates positioned in the middle of an 8 m walkway (5 trials at a self-selected speed. For statistical analysis of relationships between variables Pearson correlation was applied. Results: Our results showed significant correlations between eccentric peak torque and COP velocity in AP direction during one-leg stance, eccentric and concentric peak torque and COP variability during loading response in both ML and AP directions and during terminal stance in AP direction. Conclusion: Loading response and terminal stance seems to be more related to knee extensors' strength. Variables derived from postural stability assessment during one-leg stance are independent from variables derived from assessment of COP displacement variability during walking.

Towards Real-Time Detection of Gait Events on Different Terrains Using Time-Frequency Analysis and Peak Heuristics Algorithm.

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Zhou, Hui; Ji, Ning; Samuel, Oluwarotimi Williams; Cao, Yafei; Zhao, Zheyi; Chen, Shixiong; Li, Guanglin

2016-10-01

Real-time detection of gait events can be applied as a reliable input to control drop foot correction devices and lower-limb prostheses. Among the different sensors used to acquire the signals associated with walking for gait event detection, the accelerometer is considered as a preferable sensor due to its convenience of use, small size, low cost, reliability, and low power consumption. Based on the acceleration signals, different algorithms have been proposed to detect toe off (TO) and heel strike (HS) gait events in previous studies. While these algorithms could achieve a relatively reasonable performance in gait event detection, they suffer from limitations such as poor real-time performance and are less reliable in the cases of up stair and down stair terrains. In this study, a new algorithm is proposed to detect the gait events on three walking terrains in real-time based on the analysis of acceleration jerk signals with a time-frequency method to obtain gait parameters, and then the determination of the peaks of jerk signals using peak heuristics. The performance of the newly proposed algorithm was evaluated with eight healthy subjects when they were walking on level ground, up stairs, and down stairs. Our experimental results showed that the mean F1 scores of the proposed algorithm were above 0.98 for HS event detection and 0.95 for TO event detection on the three terrains. This indicates that the current algorithm would be robust and accurate for gait event detection on different terrains. Findings from the current study suggest that the proposed method may be a preferable option in some applications such as drop foot correction devices and leg prostheses.

Efficacy of ankle control balance training on postural balance and gait ability in community-dwelling older adults: a single-blinded, randomized clinical trial.

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Lee, Kyeongjin; Lee, Yong Woo

2017-09-01

[Purpose] This study was conducted to investigate the effects of ankle control balance training (ACBT) on postural balance and gait ability in community-dwelling older adults. [Subjects and Methods] Fifty-four subjects were randomly divided into two groups, with 27 subjects in the ACBT group and 27 subjects in the control group. Subjects in the ACBT group received ACBT for 60 minutes, twice per week for 4 weeks, and all subjects had undergone fall prevention education for 60 minutes, once per week for 4 weeks. The main outcome measures, including the Berg balance scale; the functional reach test and one leg stance test for postural balance; and the timed up-and-go test and 10-meter walking test for gait ability, were assessed at baseline and after 4 weeks of training. [Results] The postural balance and gait ability in the ACBT group improved significantly compared to those in the control group, except BBS. [Conclusion] The results of this study showed improved postural balance and gait abilities after ACBT and that ACBT is a feasible method for improving postural balance and gait ability in community-dwelling older adults.

Multiple gait parameters derived from iPod accelerometry predict age-related gait changes

NARCIS (Netherlands)

Kosse, Nienke; Vuillerme, Nicolas; Hortobagyi, Tibor; Lamoth, Claude

Introduction Normative data of how natural aging affects gait can serve as a frame of reference for changes in gait dynamics due to pathologies. Therefore, the present study aims (1) to identify gait variables sensitive to age-related changes in gait over the adult life span using the iPod and (2)

Evaluation of a musculoskeletal model with prosthetic knee through six experimental gait trials.

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Kia, Mohammad; Stylianou, Antonis P; Guess, Trent M

2014-03-01

Knowledge of the forces acting on musculoskeletal joint tissues during movement benefits tissue engineering, artificial joint replacement, and our understanding of ligament and cartilage injury. Computational models can be used to predict these internal forces, but musculoskeletal models that simultaneously calculate muscle force and the resulting loading on joint structures are rare. This study used publicly available gait, skeletal geometry, and instrumented prosthetic knee loading data [1] to evaluate muscle driven forward dynamics simulations of walking. Inputs to the simulation were measured kinematics and outputs included muscle, ground reaction, ligament, and joint contact forces. A full body musculoskeletal model with subject specific lower extremity geometries was developed in the multibody framework. A compliant contact was defined between the prosthetic femoral component and tibia insert geometries. Ligament structures were modeled with a nonlinear force-strain relationship. The model included 45 muscles on the right lower leg. During forward dynamics simulations a feedback control scheme calculated muscle forces using the error signal between the current muscle lengths and the lengths recorded during inverse kinematics simulations. Predicted tibio-femoral contact force, ground reaction forces, and muscle forces were compared to experimental measurements for six different gait trials using three different gait types (normal, trunk sway, and medial thrust). The mean average deviation (MAD) and root mean square deviation (RMSD) over one gait cycle are reported. The muscle driven forward dynamics simulations were computationally efficient and consistently reproduced the inverse kinematics motion. The forward simulations also predicted total knee contact forces (166Nphysiological motor control patterns during gait. Consequently, the simulations did not accurately predict medial/lateral tibio-femoral force distribution and muscle activation timing. Copyright

Measuring Gait Quality in Parkinson’s Disease through Real-Time Gait Phase Recognition

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Ilaria Mileti

2018-03-01

Full Text Available Monitoring gait quality in daily activities through wearable sensors has the potential to improve medical assessment in Parkinson’s Disease (PD. In this study, four gait partitioning methods, two based on thresholds and two based on a machine learning approach, considering the four-phase model, were compared. The methods were tested on 26 PD patients, both in OFF and ON levodopa conditions, and 11 healthy subjects, during walking tasks. All subjects were equipped with inertial sensors placed on feet. Force resistive sensors were used to assess reference time sequence of gait phases. Goodness Index (G was evaluated to assess accuracy in gait phases estimation. A novel synthetic index called Gait Phase Quality Index (GPQI was proposed for gait quality assessment. Results revealed optimum performance (G < 0.25 for three tested methods and good performance (0.25 < G < 0.70 for one threshold method. The GPQI resulted significantly higher in PD patients than in healthy subjects, showing a moderate correlation with clinical scales score. Furthermore, in patients with severe gait impairment, GPQI was found higher in OFF than in ON state. Our results unveil the possibility of monitoring gait quality in PD through real-time gait partitioning based on wearable sensors.

Reliability of a Seven-Segment Foot Model with Medial and Lateral Midfoot and Forefoot Segments During Walking Gait.

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Cobb, Stephen C; Joshi, Mukta N; Pomeroy, Robin L

2016-12-01

In-vitro and invasive in-vivo studies have reported relatively independent motion in the medial and lateral forefoot segments during gait. However, most current surface-based models have not defined medial and lateral forefoot or midfoot segments. The purpose of the current study was to determine the reliability of a 7-segment foot model that includes medial and lateral midfoot and forefoot segments during walking gait. Three-dimensional positions of marker clusters located on the leg and 6 foot segments were tracked as 10 participants completed 5 walking trials. To examine the reliability of the foot model, coefficients of multiple correlation (CMC) were calculated across the trials for each participant. Three-dimensional stance time series and range of motion (ROM) during stance were also calculated for each functional articulation. CMCs for all of the functional articulations were ≥ 0.80. Overall, the rearfoot complex (leg-calcaneus segments) was the most reliable articulation and the medial midfoot complex (calcaneus-navicular segments) was the least reliable. With respect to ROM, reliability was greatest for plantarflexion/dorsiflexion and least for abduction/adduction. Further, the stance ROM and time-series patterns results between the current study and previous invasive in-vivo studies that have assessed actual bone motion were generally consistent.

Gait Analysis Using Wearable Sensors

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Hutian Feng

2012-02-01

Full Text Available Gait analysis using wearable sensors is an inexpensive, convenient, and efficient manner of providing useful information for multiple health-related applications. As a clinical tool applied in the rehabilitation and diagnosis of medical conditions and sport activities, gait analysis using wearable sensors shows great prospects. The current paper reviews available wearable sensors and ambulatory gait analysis methods based on the various wearable sensors. After an introduction of the gait phases, the principles and features of wearable sensors used in gait analysis are provided. The gait analysis methods based on wearable sensors is divided into gait kinematics, gait kinetics, and electromyography. Studies on the current methods are reviewed, and applications in sports, rehabilitation, and clinical diagnosis are summarized separately. With the development of sensor technology and the analysis method, gait analysis using wearable sensors is expected to play an increasingly important role in clinical applications.

Gait Analysis Using Wearable Sensors

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Tao, Weijun; Liu, Tao; Zheng, Rencheng; Feng, Hutian

2012-01-01

Gait analysis using wearable sensors is an inexpensive, convenient, and efficient manner of providing useful information for multiple health-related applications. As a clinical tool applied in the rehabilitation and diagnosis of medical conditions and sport activities, gait analysis using wearable sensors shows great prospects. The current paper reviews available wearable sensors and ambulatory gait analysis methods based on the various wearable sensors. After an introduction of the gait phases, the principles and features of wearable sensors used in gait analysis are provided. The gait analysis methods based on wearable sensors is divided into gait kinematics, gait kinetics, and electromyography. Studies on the current methods are reviewed, and applications in sports, rehabilitation, and clinical diagnosis are summarized separately. With the development of sensor technology and the analysis method, gait analysis using wearable sensors is expected to play an increasingly important role in clinical applications. PMID:22438763

Influence of moderate training on gait and work capacity of fibromyalgia patients: a preliminary field study.

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Tiidus, Peter M; Pierrynowski, Michael; Dawson, Kimberley A

2002-12-01

This field study examined the influence of moderate intensity training on gait patterns and work capacity of individuals with fibromyalgia syndrome (FS). FS is a chronic condition of unknown etiology, characterized by muscle tenderness, pain and stiffness and often accompanied by depression and fatigue which seems to occur primarily in middle aged females. There is no known cure for FS but treatment often includes a prescription of mild exercise. Few studies have evaluated the effectiveness of mild exercise on work capacity and gait patterns in FS patients. Participants were 14 females (age 47.0 ± 7.6 y) who participated in a 10 wk community based aerobic, strength and stretching program designed for FS individuals. Subjects were evaluated pre- and post-program and at a 2 month follow up. Work capacity was estimated by a sub-maximal PWC 170 cycle ergometer test and a Borg perceived exertion scale. Gait was assessed using OptoTrack three dimensional kinematics with 16 channel analogue data acquisition system. Trunk flexibility was also assessed. No significant change in estimated work capacity or flexibility was seen between pre- post- and follow up times. Nevertheless, a significant increase in self selected walking speed (p gait pattern that was sustained in the follow up testing was noted. We had previously also reported a significant improvement in muscle pain and other fibromyalgia symptoms in this population consequent to the training program. It was concluded that mild exercise training that does not influence work capacity or trunk flexibility can nevertheless positively influence gait mechanics and fibromyalgia symptoms in female FS patients.

Hardware Development and Locomotion Control Strategy for an Over-Ground Gait Trainer: NaTUre-Gaits.

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Luu, Trieu Phat; Low, Kin Huat; Qu, Xingda; Lim, Hup Boon; Hoon, Kay Hiang

2014-01-01

Therapist-assisted body weight supported (TABWS) gait rehabilitation was introduced two decades ago. The benefit of TABWS in functional recovery of walking in spinal cord injury and stroke patients has been demonstrated and reported. However, shortage of therapists, labor-intensiveness, and short duration of training are some limitations of this approach. To overcome these deficiencies, robotic-assisted gait rehabilitation systems have been suggested. These systems have gained attentions from researchers and clinical practitioner in recent years. To achieve the same objective, an over-ground gait rehabilitation system, NaTUre-gaits, was developed at the Nanyang Technological University. The design was based on a clinical approach to provide four main features, which are pelvic motion, body weight support, over-ground walking experience, and lower limb assistance. These features can be achieved by three main modules of NaTUre-gaits: 1) pelvic assistance mechanism, mobile platform, and robotic orthosis. Predefined gait patterns are required for a robotic assisted system to follow. In this paper, the gait pattern planning for NaTUre-gaits was accomplished by an individual-specific gait pattern prediction model. The model generates gait patterns that resemble natural gait patterns of the targeted subjects. The features of NaTUre-gaits have been demonstrated by walking trials with several subjects. The trials have been evaluated by therapists and doctors. The results show that 10-m walking trial with a reduction in manpower. The task-specific repetitive training approach and natural walking gait patterns were also successfully achieved.

The Effects on Kinematics and Muscle Activity of Walking in a Robotic Gait Trainer During Zero-Force Control.

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van Asseldonk, Edwin H F; Veneman, Jan F; Ekkelenkamp, Ralf; Buurke, Jaap H; van der Helm, Frans C T; van der Kooij, Herman

2008-08-01

"Assist as needed" control algorithms promote activity of patients during robotic gait training. Implementing these requires a free walking mode of a device, as unassisted motions should not be hindered. The goal of this study was to assess the normality of walking in the free walking mode of the LOPES gait trainer, an 8 degrees-of-freedom lightweight impedance controlled exoskeleton. Kinematics, gait parameters and muscle activity of walking in a free walking mode in the device were compared with those of walking freely on a treadmill. Average values and variability of the spatio-temporal gait variables showed no or small (relative to cycle-to-cycle variability) changes and the kinematics showed a significant and relevant decrease in knee angle range only. Muscles involved in push off showed a small decrease, whereas muscles involved in acceleration and deceleration of the swing leg showed an increase of their activity. Timing of the activity was mainly unaffected. Most of the observed differences could be ascribed to the inertia of the exoskeleton. Overall, walking with the LOPES resembled free walking, although this required several adaptations in muscle activity. These adaptations are such that we expect that Assist as Needed training can be implemented in LOPES.

Point shear wave speed measurement in differentiating benign and malignant focal liver lesions.

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Dong, Yi; Wang, Wen-Ping; Xu, Yadan; Cao, Jiaying; Mao, Feng; Dietrich, Cristoph F

2017-06-26

To investigate the value of ElastPQ measurement for differential diagnosis of benign and malignant focal liver lesions (FLLs) by using histologic results as a reference standard. A total of 154 patients were included. ElastPQ measurement was performed for each lesion in which the shear wave speed (SWS) was measured. The difference in SWS and SWS ratio of FLL to surrounding liver were evaluated, and the cut off value was investigated. Receiver operating characteristic (ROC) curve was plotted to evaluate the diagnostic performance. Histology as a gold standard was obtained by surgery in all patients. A total of 154 lesions including 129 (83.7 %) malignant FLLs and 25 (16.3 %) benign ones were analysed. The SWS of malignant and benign FLLs was significantly different, 2.77±0.68 m/s and 1.57±0.55 m/s (p<0.05). The SWS ratio of each FLL to surrounding liver parenchyma was 2.23±0.49 for malignant and 1.14±0.36 for benign FLLs (p<0.05). The cut off value for differential diagnosis was 2.06 m/s for SWS and 1.67 for SWS ratio.  ElastPQ measurement provides reliable quantitative stiffness information of FLLs and may be helpful in the differential diagnosis between malignant and benign FLLs.

[Causes and calculated predictors of a Duchenne gait in adolescents and young adults with cerebral palsy].

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Klum, E; Streicher, H; Böhm, H; Wagner, P; Döderlein, L

2015-02-01

Adolescents with cerebral palsy often complain about a Duchenne gait, which increases the load on the spine, the energy consumption and therefore decreases gait efficiency. However the underlying causes of a Duchenne gait in patients with CP are not clearly researched yet. Nevertheless there is an assumption that excessive trunk lean might assist foot clearance to compensate for muscle weakness or contractures of the legs. In particular weakness, secondary to surgical soft tissue muscle tendon lengthening in childhood, might predispose patients to greater compensatory movements of the trunk. Therefore the aim of this study was to estimate the prevalence, underlying causes and calculated predictors for a Duchenne gait on CP patients with and without previous muscle tendon lengthening. 50 CP patients between 12 and 22 years with diplegia and GMFCS II (GMFCS: Gross Motor Function Classification System) participated in this study. 25 patients had no previous surgeries (CP-0). 25 patients had previous calf, hamstrings and/or adductor muscle tendon lengthening surgeries (CP-1). Data of 20 typically developed adolescents served as controls (TD). Gait was analysed using an instrumented gait analysis system (Vicon, Oxford, UK) The parameter "thorax obliquity range" (TOR) investigated the dimension of Duchenne gait. CP-0 showed a prevalence of 72 %, CP-1 of 66 % for Duchenne gait. TOR was 5 ± 2°, 16 ± 8° and 16 ± 8°, for TD, CP-0 and CP-1, respectively. CP-0 and CP-1 showed significant differences in TOR between TD (both p Duchenne gait is a serious gait pathology in CP. Neither the hypothesis that previous muscle tendon lengthening nor that hip adductor contractures increase Duchenne gait could be confirmed in this study. Weak hip abductor muscle strength only showed a small correlation in CP-0. Best predictor in both groups was hip generation work (st). Certain hip abductors (M. gluteus medius ventral; M. gluteus minimus; M. tensor fasciae latae

The effect of an intensive exercise programme on leg function in chronic stroke patients: a pilot study with one-year follow-up.

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Stock, Roland; Mork, Paul Jarle

2009-09-01

To investigate the effect of two weeks of intensive exercise on leg function in chronic stroke patients and to evaluate the feasibility of an intensive exercise programme in a group setting. Pilot study with one-group pre-test post-test design with two pre-tests and one-year follow-up. Inpatient rehabilitation hospital. Twelve hemiparetic patients completed the intervention. Ten patients participated at one-year follow-up. Six hours of daily intensive exercise for two weeks with focus on weight-shifting towards the affected side and increased use of the affected extremity during functional activities. An insole with nubs in the shoe of the non-paretic limb was used to reinforce weight-shift toward the affected side. Timed Up and Go, Four Square Step Test, gait velocity, gait symmetry and muscle strength in knee and ankle muscles. Maximal gait velocity (P = 0.002) and performance time (seconds) on Timed Up and Go (mean, SD; 12.2, 3.8 vs. 9.4, 3.2) and Four Square Step Test improved from pre- to post-test (P = 0.005). Improvements remained significant at follow-up. Preferred gait velocity and gait symmetry remained unchanged. Knee extensor (Pstroke patients. Most improvements persisted at the one-year follow-up.

A unique combination of autoimmune limbic encephalitis, type 1 diabetes, and Stiff person syndrome associated with GAD-65 antibody

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Chandra Mohan Sharma

2016-01-01

Full Text Available Antibodies to GAD-65 have been implicated in the pathogenesis of type 1 diabetes , limbic encephalitis and Stiff person syndrome, however these diseases rarely occur concurrently. We intend to present a rare case of 35 year old female who was recently diagnosed as having type 1 diabetes presented with 1½ month history of recurrent seizures, subacute onset gait ataxia, dysathria, psychiatric disturbance and cognitive decline. No tumor was found on imaging and the classic paraneoplastic panel was negative. Cerebrospinal fluid and blood was positive for GAD-65 antibodies.Patient showed significant improvement with immunomodulatory therapy. Association of GAD-65 antibodies has been found with various disorders including type 1 diabetes, limbic encephalitis, Stiff person syndrome,cerebellar ataxia and palatal myoclonus.This case presents with unique combination of type 1 diabetes, Stiff person syndrome and limbic encephalitis associated with GAD-65 antibodies that is responsive to immunotherapy. It also highlights the emerging concept of autoimmunity in the causation of various disorders and there associations.

Osteoporosis and gait and balance disturbances in older sarcopenic obese New Zealanders.

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Waters, D L; Hale, L; Grant, A M; Herbison, P; Goulding, A

2010-02-01

Bone, muscle, and fat may affect gait and balance in older adults. Osteoporosis was prevalent in low muscle mass participants and related to gait and balance deficits. Low muscle combined with high fat mass had more functional deficits and poorer bone health, which has implications for falls risk and fractures. Decreasing bone density and muscle mass and increasing fat mass may act synergistically to affect gait and balance in older adults. One hundred eighty-three older adults (age 72.7 +/- 6 years, range 56-93; body mass index 28.2 +/- 4.9, range 16.6-46.0) were recruited from a New Zealand falls prevention intervention trial. Total and appendicular skeletal muscle mass (ASM), percent fat, and bone mineralization were assessed by dual energy X-ray absorptiometry and used to characterize normal lean (NL, n = 51), sarcopenic (SS, n = 18), sarcopenic obese (SO, n = 29), and obese (OO, n = 85) phenotypes. Functional performance was assessed using timed up and go, chair stand, single leg stand, and step test. Regression models were adjusted for age, sex, medications, and physical activity. Femoral neck osteoporosis was present in 22% SS, 17% SO, 12% NL, and 7% OO. Femoral neck osteoporosis with low ASM predicted poor chair stand performance (beta -3.3, standard error 1.6, p = 0.04). SO scored lowest on the chair stand (p = 0.03) and step test (p = 0.03). Higher ASM predicted faster timed up and go performance (p = 0.001). Osteoporosis was prevalent in low ASM groups (SS and SO) and related to gait and balance deficits, particularly in the SO. This has implications for falls risk, fractures, and interventions.

DeepGait: A Learning Deep Convolutional Representation for View-Invariant Gait Recognition Using Joint Bayesian

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Chao Li

2017-02-01

Full Text Available Human gait, as a soft biometric, helps to recognize people through their walking. To further improve the recognition performance, we propose a novel video sensor-based gait representation, DeepGait, using deep convolutional features and introduce Joint Bayesian to model view variance. DeepGait is generated by using a pre-trained “very deep” network “D-Net” (VGG-D without any fine-tuning. For non-view setting, DeepGait outperforms hand-crafted representations (e.g., Gait Energy Image, Frequency-Domain Feature and Gait Flow Image, etc.. Furthermore, for cross-view setting, 256-dimensional DeepGait after PCA significantly outperforms the state-of-the-art methods on the OU-ISR large population (OULP dataset. The OULP dataset, which includes 4007 subjects, makes our result reliable in a statistically reliable way.

Association of Gastrocnemius Muscle Stiffness With Passive Ankle Joint Stiffness and Sex-Related Difference in the Joint Stiffness.

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Chino, Kintaro; Takashi, Hideyuki

2017-11-15

Passive ankle joint stiffness is affected by all structures located within and over the joint, and is greater in men than in women. Localized muscle stiffness can be assessed by ultrasound shear wave elastography, and muscle architecture such as fascicle length and pennation angle can be measured by B-mode ultrasonography. Thus, we assessed localized muscle stiffness of the medial gastrocnemius (MG) with consideration of individual variability in the muscle architecture, and examined the association of the muscle stiffness with passive ankle joint stiffness and the sex-related difference in the joint stiffness. Localized muscle stiffness of the MG in 16 men and 17 women was assessed at 10° and 20° plantar flexion, neutral anatomical position, 10° and 20° dorsiflexion. Fascicle length and pennation angle of the MG were measured at these joint positions. Passive ankle joint stiffness was determined by the ankle joint angle-torque relationship. Localized MG muscle stiffness was not significantly correlated with passive ankle joint stiffness, and did not show significant sex-related difference, even when considering the muscle architecture. This finding suggest that muscle stiffness of the MG would not be a prominent factor to determine passive ankle joint stiffness and the sex-related difference in the joint stiffness.

Controlling patient participation during robot-assisted gait training

Science.gov (United States)

2011-01-01

Background The overall goal of this paper was to investigate approaches to controlling active participation in stroke patients during robot-assisted gait therapy. Although active physical participation during gait rehabilitation after stroke was shown to improve therapy outcome, some patients can behave passively during rehabilitation, not maximally benefiting from the gait training. Up to now, there has not been an effective method for forcing patient activity to the desired level that would most benefit stroke patients with a broad variety of cognitive and biomechanical impairments. Methods Patient activity was quantified in two ways: by heart rate (HR), a physiological parameter that reflected physical effort during body weight supported treadmill training, and by a weighted sum of the interaction torques (WIT) between robot and patient, recorded from hip and knee joints of both legs. We recorded data in three experiments, each with five stroke patients, and controlled HR and WIT to a desired temporal profile. Depending on the patient's cognitive capabilities, two different approaches were taken: either by allowing voluntary patient effort via visual instructions or by forcing the patient to vary physical effort by adapting the treadmill speed. Results We successfully controlled patient activity quantified by WIT and by HR to a desired level. The setup was thereby individually adaptable to the specific cognitive and biomechanical needs of each patient. Conclusion Based on the three successful approaches to controlling patient participation, we propose a metric which enables clinicians to select the best strategy for each patient, according to the patient's physical and cognitive capabilities. Our framework will enable therapists to challenge the patient to more activity by automatically controlling the patient effort to a desired level. We expect that the increase in activity will lead to improved rehabilitation outcome. PMID:21429200

Somatosensory inputs by application of KinesioTaping: Effects on spasticity, balance, and gait in chronic spinal cord injury

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Federica eTamburella

2014-05-01

Full Text Available Introduction: Leg paralysis, spasticity, reduced inter limb coordination and impaired balance are considered the chief limitations to overground ambulation in subjects with incomplete spinal cord injury (SCI. In the last years KinesioTaping (KT application has been proposed for enhancing sensory inputs, decreasing spasticity via proprioception feedback and relieving abnormal muscle tension. No studies addressed KT technique on SCI subjects: our goal was to analyze effects of ankle joint KT application on spasticity, balance and gait. Material and Methods: A randomized cross-over case control design was used to compare KT and conventional non-elastic silk tape (ST application’s effects in 11 chronic SCI subjects, AIS level D, with soleus/gastrocnemius (S/G muscles’ spasticity , balance and gait impairments. Treatment: 48 hours of either KT or ST treatment was followed after 1 week interval by a reverse protocol. Patient treated with KT were subjected to 48 hours of ST treatment and viceversa. Single Y-stripe of Cure©tape (KT and ST were applied to S and G with 0% stretch. Before and after 48 hours of KT and ST application, clinical data of range of motion (ROM, spasticity, clonus, pain, balance and gait were collected. Stabilometric platform assessment of Centre of Pressure (COP movements, bi-dimensional gait analysis and electromyograpich (EMG activity of S, G, Tibialis Anterior and Extensor Hallicus Lungus muscles were also collected. Results: Only After KT treatment significant effects on spasticity, clonus and COP movements, kinematic gait parameters and EMG activities were recorded. Comparison between KT and ST improvements pointed out significant differences for ROM, spasticity, clonus, pain, COP parameters and most of all kinematic gait data. Discussion: KT short term application reduces spasticity and pain and improves balance and gait performances in chronic incomplete SCI subjects.

Semi-autonomous exploration of multi-floor buildings with a legged robot

Science.gov (United States)

Wenger, Garrett J.; Johnson, Aaron M.; Taylor, Camillo J.; Koditschek, Daniel E.

2015-05-01

This paper presents preliminary results of a semi-autonomous building exploration behavior using the hexapedal robot RHex. Stairwells are used in virtually all multi-floor buildings, and so in order for a mobile robot to effectively explore, map, clear, monitor, or patrol such buildings it must be able to ascend and descend stairwells. However most conventional mobile robots based on a wheeled platform are unable to traverse stairwells, motivating use of the more mobile legged machine. This semi-autonomous behavior uses a human driver to provide steering input to the robot, as would be the case in, e.g., a tele-operated building exploration mission. The gait selection and transitions between the walking and stair climbing gaits are entirely autonomous. This implementation uses an RGBD camera for stair acquisition, which offers several advantages over a previously documented detector based on a laser range finder, including significantly reduced acquisition time. The sensor package used here also allows for considerable expansion of this behavior. For example, complete automation of the building exploration task driven by a mapping algorithm and higher level planner is presently under development.

Locomotion on the water surface: hydrodynamic constraints on rowing velocity require a gait change

Science.gov (United States)

Suter; Wildman

1999-10-01

Fishing spiders, Dolomedes triton (Araneae, Pisauridae), propel themselves across the water surface using two gaits: they row with four legs at sustained velocities below 0.2 m s(-)(1) and they gallop with six legs at sustained velocities above 0.3 m s(-)(1). Because, during rowing, most of the horizontal thrust is provided by the drag of the leg and its associated dimple as both move across the water surface, the integrity of the dimple is crucial. We used a balance, incorporating a biaxial clinometer as the transducer, to measure the horizontal thrust forces on a leg segment subjected to water moving past it in non-turbulent flow. Changes in the horizontal forces reflected changes in the status of the dimple and showed that a stable dimple could exist only under conditions that combined low flow velocity, shallow leg-segment depth and a long perimeter of the interface between the leg segment and the water. Once the dimple disintegrated, leaving the leg segment submerged, less drag was generated. Therefore, the disintegration of the dimple imposes a limit on the efficacy of rowing with four legs. The limited degrees of freedom in the leg joints (the patellar joints move freely in the vertical plane but allow only limited flexion in other planes) impose a further constraint on rowing by restricting the maximum leg-tip velocity (to approximately 33 % of that attained by the same legs during galloping). This confines leg-tip velocities to a range at which maintenance of the dimple is particularly important. The weight of the spider also imposes constraints on the efficacy of rowing: because the drag encountered by the leg-cum-dimple is proportional to the depth of the dimple and because dimple depth is proportional to the supported weight, only spiders with a mass exceeding 0.48 g can have access to the full range of hydrodynamically possible dimple depths during rowing. Finally, the maximum velocity attainable during rowing is constrained by the substantial drag

A Validated Smartphone-Based Assessment of Gait and Gait Variability in Parkinson's Disease.

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Robert J Ellis

Full Text Available A well-established connection exists between increased gait variability and greater fall likelihood in Parkinson's disease (PD; however, a portable, validated means of quantifying gait variability (and testing the efficacy of any intervention remains lacking. Furthermore, although rhythmic auditory cueing continues to receive attention as a promising gait therapy for PD, its widespread delivery remains bottlenecked. The present paper describes a smartphone-based mobile application ("SmartMOVE" to address both needs.The accuracy of smartphone-based gait analysis (utilizing the smartphone's built-in tri-axial accelerometer and gyroscope to calculate successive step times and step lengths was validated against two heel contact-based measurement devices: heel-mounted footswitch sensors (to capture step times and an instrumented pressure sensor mat (to capture step lengths. 12 PD patients and 12 age-matched healthy controls walked along a 26-m path during self-paced and metronome-cued conditions, with all three devices recording simultaneously.Four outcome measures of gait and gait variability were calculated. Mixed-factorial analysis of variance revealed several instances in which between-group differences (e.g., increased gait variability in PD patients relative to healthy controls yielded medium-to-large effect sizes (eta-squared values, and cueing-mediated changes (e.g., decreased gait variability when PD patients walked with auditory cues yielded small-to-medium effect sizes-while at the same time, device-related measurement error yielded small-to-negligible effect sizes.These findings highlight specific opportunities for smartphone-based gait analysis to serve as an alternative to conventional gait analysis methods (e.g., footswitch systems or sensor-embedded walkways, particularly when those methods are cost-prohibitive, cumbersome, or inconvenient.

Evidence of end-effector based gait machines in gait rehabilitation after CNS lesion.

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Hesse, S; Schattat, N; Mehrholz, J; Werner, C

2013-01-01

A task-specific repetitive approach in gait rehabilitation after CNS lesion is well accepted nowadays. To ease the therapists' and patients' physical effort, the past two decades have seen the introduction of gait machines to intensify the amount of gait practice. Two principles have emerged, an exoskeleton- and an endeffector-based approach. Both systems share the harness and the body weight support. With the end-effector-based devices, the patients' feet are positioned on two foot plates, whose movements simulate stance and swing phase. This article provides an overview on the end-effector based machine's effectiveness regarding the restoration of gait. For the electromechanical gait trainer GT I, a meta analysis identified nine controlled trials (RCT) in stroke subjects (n = 568) and were analyzed to detect differences between end-effector-based locomotion + physiotherapy and physiotherapy alone. Patients practising with the machine effected in a superior gait ability (210 out of 319 patients, 65.8% vs. 96 out of 249 patients, 38.6%, respectively, Z = 2.29, p = 0.020), due to a larger training intensity. Only single RCTs have been reported for other devices and etiologies. The introduction of end-effector based gait machines has opened a new succesful chapter in gait rehabilitation after CNS lesion.

Gait and its assessment in psychiatry

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Sanders, Richard D.; Gillig, Paulette Marie

2010-01-01

Gait reflects all levels of nervous system function. In psychiatry, gait disturbances reflecting cortical and subcortical dysfunction are often seen. Observing spontaneous gait, sometimes augmented by a few brief tests, can be highly informative. The authors briefly review the neuroanatomy of gait, review gait abnormalities seen in psychiatric and neurologic disorders, and describe the assessment of gait.

Gait Deviation Index, Gait Profile Score and Gait Variable Score in children with spastic cerebral palsy

DEFF Research Database (Denmark)

Rasmussen, Helle Mätzke; Nielsen, Dennis Brandborg; Pedersen, Niels Wisbech

2015-01-01

Abstract The Gait Deviation Index (GDI) and Gait Profile Score (GPS) are the most used summary measures of gait in children with cerebral palsy (CP). However, the reliability and agreement of these indices have not been investigated, limiting their clinimetric quality for research and clinical...... to good reliability with ICCs of 0.4–0.7. The agreement for the GDI and the logarithmically transformed GPS, in terms of the standard error of measurement as a percentage of the grand mean (SEM%) varied from 4.1 to 6.7%, whilst the smallest detectable change in percent (SDC%) ranged from 11.3 to 18...

Effect of exercise-induced enhancement of the leg-extensor muscle-tendon unit capacities on ambulatory mechanics and knee osteoarthritis markers in the elderly.

Science.gov (United States)

Karamanidis, Kiros; Oberländer, Kai Daniel; Niehoff, Anja; Epro, Gaspar; Brüggemann, Gert-Peter

2014-01-01

Leg-extensor muscle weakness could be a key component in knee joint degeneration in the elderly because it may result in altered muscular control during locomotion influencing the mechanical environment within the joint. This work aimed to examine whether an exercise-induced enhancement of the triceps surae (TS) and quadriceps femoris (QF) muscle-tendon unit (MTU) capacities would affect mechanical and biological markers for knee osteoarthritis in the elderly. Twelve older women completed a 14-week TS and QF MTU exercise intervention, which had already been established as increasing muscle strength and tendon stiffness. Locomotion mechanics and serum cartilage oligomeric matrix protein (COMP) levels were examined during incline walking. MTU mechanical properties were assessed using simultaneously ultrasonography and dynamometry. Post exercise intervention, the elderly had higher TS and QF contractile strength and tendon-aponeurosis stiffness. Regarding the incline gait task, the subjects demonstrated a lower external knee adduction moment and lower knee adduction angular impulse during the stance phase post-intervention. Furthermore, post-intervention compared to pre-intervention, the elderly showed lower external hip adduction moment, but revealed higher plantarflexion pushoff moment. The changes in the external knee adduction moment were significantly correlated with the improvement in ankle pushoff function. Serum COMP concentration increased in response to the 0.5-h incline walking exercise with no differences in the magnitude of increment between pre- and post-intervention. This work emphasizes the important role played by the ankle pushoff function in knee joint mechanical loading during locomotion, and may justify the inclusion of the TS MTU in prevention programs aiming to positively influence specific mechanical markers for knee osteoarthritis in the elderly. However, the study was unable to show that COMP is amenable to change in the elderly following a

Spinal cord stimulation for the treatment of abnormal posture and gait disorder in patients with Parkinson's disease.

Science.gov (United States)

Agari, Takashi; Date, Isao

2012-01-01

Patients with advanced Parkinson's disease (PD) often present with axial symptoms, including abnormal posture, postural instability, and gait disorder. Although spinal cord stimulation (SCS) is effective for pain, little is known about the effect of SCS on motor function in PD patients. The present study investigated the effect of SCS on posture and gait in 15 PD patients, 5 men and 10 women aged 63-79 years (mean 71.1 years), with low back pain and leg pain who received SCS. A visual analog scale (VAS) was used for pain evaluation pre- and postoperatively. The Unified Parkinson's Disease Rating Scale, Timed Up and Go tests, and Timed 10-Meter Walk tests were used to evaluate motor function and activities of daily living of patients. Preoperative mean VAS score was 8.9 (range 7.8-10), which showed significant postoperative improvement at 3 months to mean VAS score of 2.0 (range 0-3.3). The improvements in VAS scores persisted at 12 months after surgery with mean VAS score of 2.3 (range 0-4). Posture and postural stability motor subscores were improved at 3 months after SCS, and gait had significantly improved at 3 months and 1 year after surgery. Timed 10-Meter Walk tests also demonstrated that patient gait was significantly improved at 3 months and 12 months after surgery. Most advanced stage PD patients suffer considerable pain that causes abnormal posture and gait disturbance. SCS is expected to lead to both amelioration of pain and improvement of motor function in such patients.

A Wolf in Sheep's Clothing: An "Alien Leg" in Corticobasal Syndrome

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Diana A. Olszewska

2017-04-01

Full Text Available Background: Alien limb phenomenon occurs in 50–60% of patients with corticobasal syndrome (CBS and usually presents with an “alien hand” phenomenon. The “alien foot” presentation is rarer and may be misdiagnosed, as foot involvement can lead to erroneous localization of the clinical problem to the knee, hip, or back. Subsequently misdiagnoses such as myelopathy, radiculopathy, functional disorder, stiff leg syndrome, neuromyotonia, and painful leg moving toes syndrome may occur.Case report: We describe two patients with alien foot symptoms that resulted in multiple opinions from different specialists, multiple diagnostic and therapeutic procedures, and delayed diagnosis. Eventually a diagnosis of CBS was made in both. Alien foot symptoms may be more common than initially thought and can result in a delayed diagnosis of CBS.Conclusion: The inclusion of this clinical finding in recently proposed diagnostic criteria highlights the need for increased clinical awareness. 

Evolution of nodule stiffness might predict response to local ablative therapy: A series of patients with hepatocellular carcinoma.

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Michael Praktiknjo

Full Text Available Early information on treatment response of HCC to local ablative therapy is crucial. Elastography as a non-invasive method has recently been shown to play a potential role in distinguishing between benign and malignant liver lesions. Elastography of hepatocellular carcinoma (HCC in early response to local ablative therapy has not been studied to date.We prospectively included a cohort of 14 patients with diagnosis of HCC who were treated with local ablative therapy (transarterial chemoembolization, TACE and/or radiofrequency ablation, RFA. We used 2D shear-wave elastography (RT 2D-SWE to examine stiffness of HCC lesion before and 3, 30 and 90 days after local ablative therapy. Contrast-enhanced imaging after 90 days was performed to evaluate treatment response. Primary endpoint was stiffness of HCC in response to local ablative therapy. Secondary end point was tumor recurrence.Stiffness of HCC nodules and liver showed no significant difference prior to local ablative therapy. As early as three days after treatment, stiffness of responding HCC was significantly higher compared to non-responding. Higher stiffness before treatment was significantly associated with tumor recurrence.Nodule stiffness in general and RT 2D-SWE in particular could provide a useful tool for early prediction of HCC response to local ablative therapy.

OSTEOPATHIC APPROACH: LEG LENGTH DISCREPANCY AND LOW BACK PAIN

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Taner AYDIN

2015-12-01

Full Text Available Leg length discrepancy (LLD is a biomechanical impediment, which is a potential factor in affecting musculoskeletal disorders in the rest of life, such as scoliosis, osteoarthritis and muscle tightness, or even tenderness in lumbar and pelvic area. Athletes who have developed LLD have symptoms in gait, running, standing posture. Skeletal regions related to the disorder are the lumbar spine, ilium, hip joint, greater trochanter and knee, or even ankle and plantar region. Muscles involved in these areas are numeous. In osteopathic management, the manual practitioner can use a lot of basic techniques to handle these dysfunctions. To cope with musculoskeletal problems, osteopathic manipulation techniques would be an ideal modality to alleviate the LLD syndrome. An overview of the mentioned topics of concern will be discussed in the review.

Investigation of Anticipatory Postural Adjustments during One-Leg Stance Using Inertial Sensors: Evidence from Subjects with Parkinsonism.

Science.gov (United States)

Bonora, Gianluca; Mancini, Martina; Carpinella, Ilaria; Chiari, Lorenzo; Ferrarin, Maurizio; Nutt, John G; Horak, Fay B

2017-01-01

The One-Leg Stance (OLS) test is a widely adopted tool for the clinical assessment of balance in the elderly and in subjects with neurological disorders. It was previously showed that the ability to control anticipatory postural adjustments (APAs) prior to lifting one leg is significantly impaired by idiopathic Parkinson's disease (iPD). However, it is not known how APAs are affected by other types of parkinsonism, such as frontal gait disorders (FGD). In this study, an instrumented OLS test based on wearable inertial sensors is proposed to investigate both the initial anticipatory phase and the subsequent unipedal balance. The sensitivity and the validity of the test have been evaluated. Twenty-five subjects with iPD presenting freezing of gait (FOG), 33 with iPD without FOG, 13 with FGD, and 32 healthy elderly controls were recruited. All subjects wore three inertial sensors positioned on the posterior trunk (L4-L5), and on the left and right frontal face of the tibias. Participants were asked to lift a foot and stand on a single leg as long as possible with eyes open, as proposed by the mini-BESTest. Temporal parameters and trunk acceleration were extracted from sensors and compared among groups. The results showed that, regarding the anticipatory phase, the peak of mediolateral trunk acceleration was significantly reduced compared to healthy controls ( p   0.74), demonstrating the method's validity. Our findings support the validity of the proposed method for assessing the OLS test and its sensitivity in distinguishing among the tested groups. The instrumented test discriminated between healthy controls and people with parkinsonism and among the three groups with parkinsonism. The objective characterization of the initial anticipatory phase represents an interesting improvement compared to most clinical OLS tests.

Gait-related cerebral alterations in patients with Parkinson's disease with freezing of gait

NARCIS (Netherlands)

Snijders, A.H.; Leunissen, H.P.; Bakker, M.; Overeem, S.; Helmich, R.C.G.; Bloem, B.R.; Toni, I.

2011-01-01

Freezing of gait is a common, debilitating feature of Parkinson’s disease. We have studied gait planning in patients with freezing of gait, using motor imagery of walking in combination with functional magnetic resonance imaging. This approach exploits the large neural overlap that exists between

Gait-related cerebral alterations in patients with Parkinson's disease with freezing of gait

NARCIS (Netherlands)

Snijders, A.H.; Leunissen, I.; Bakker, M.; Overeem, S.; Helmich, R.C.G.; Bloem, B.R.; Toni, I.

2011-01-01

Freezing of gait is a common, debilitating feature of Parkinson's disease. We have studied gait planning in patients with freezing of gait, using motor imagery of walking in combination with functional magnetic resonance imaging. This approach exploits the large neural overlap that exists between

A mechanized gait trainer for restoring gait in nonambulatory subjects.

Science.gov (United States)

Hesse, S; Uhlenbrock, D; Werner, C; Bardeleben, A

2000-09-01

To construct an advanced mechanized gait trainer to enable patients the repetitive practice of a gaitlike movement without overstraining therapists. DEVICE: Prototype gait trainer that simulates the phases of gait (by generating a ratio of 40% to 60% between swing and stance phases), supports the subjects according to their ability (lifts the foot during swing phase), and controls the center of mass in the vertical and horizontal directions. Two nonambulatory, hemiparetic patients who regained their walking ability after 4 weeks of daily training on the gait trainer, a 55-year-old woman and a 62-year-old man, both of whom had a first-time ischemic stroke. Four weeks of training, five times a week, each session 20 minutes long. Functional ambulation category (FAC, levels 0-5) to assess gait ability and ground level walking velocity. Rivermead motor assessment score (RMAS, 0-13) to assess gross motor function. Patient 1: At the end of treatment, she was able to walk independently on level ground with use of a walking stick. Her walking velocity had improved from .29m/sec to .59m/sec. Her RMAS score increased from 4 to 10, meaning she could walk at least 40 meters outside, pick up objects from floor, and climb stairs independently. Patient 2: At end of 4-week training, he could walk independently on even surfaces (FAC level 4), using an ankle-foot orthosis and a walking stick. His walking velocity improved from .14m/sec to .63m/sec. His RMAS increased from 3 to 10. The gait trainer enabled severely affected patients the repetitive practice of a gaitlike movement. Future studies may elucidate its value in gait rehabilitation of nonambulatory subjects.

Brain-actuated gait trainer with visual and proprioceptive feedback

Science.gov (United States)

Liu, Dong; Chen, Weihai; Lee, Kyuhwa; Chavarriaga, Ricardo; Bouri, Mohamed; Pei, Zhongcai; Millán, José del R.

2017-10-01

Objective. Brain-machine interfaces (BMIs) have been proposed in closed-loop applications for neuromodulation and neurorehabilitation. This study describes the impact of different feedback modalities on the performance of an EEG-based BMI that decodes motor imagery (MI) of leg flexion and extension. Approach. We executed experiments in a lower-limb gait trainer (the legoPress) where nine able-bodied subjects participated in three consecutive sessions based on a crossover design. A random forest classifier was trained from the offline session and tested online with visual and proprioceptive feedback, respectively. Post-hoc classification was conducted to assess the impact of feedback modalities and learning effect (an improvement over time) on the simulated trial-based performance. Finally, we performed feature analysis to investigate the discriminant power and brain pattern modulations across the subjects. Main results. (i) For real-time classification, the average accuracy was 62.33 +/- 4.95 % and 63.89 +/- 6.41 % for the two online sessions. The results were significantly higher than chance level, demonstrating the feasibility to distinguish between MI of leg extension and flexion. (ii) For post-hoc classification, the performance with proprioceptive feedback (69.45 +/- 9.95 %) was significantly better than with visual feedback (62.89 +/- 9.20 %), while there was no significant learning effect. (iii) We reported individual discriminate features and brain patterns associated to each feedback modality, which exhibited differences between the two modalities although no general conclusion can be drawn. Significance. The study reported a closed-loop brain-controlled gait trainer, as a proof of concept for neurorehabilitation devices. We reported the feasibility of decoding lower-limb movement in an intuitive and natural way. As far as we know, this is the first online study discussing the role of feedback modalities in lower-limb MI decoding. Our results suggest that

INFLUENCE OF MODERATE TRAINING ON GAIT AND WORK CAPACITY OF FIBROMYALGIA PATIENTS: A PRELIMINARY FIELD STUDY

Directory of Open Access Journals (Sweden)

Michael Pierrynowski

2002-12-01

Full Text Available This field study examined the influence of moderate intensity training on gait patterns and work capacity of individuals with fibromyalgia syndrome (FS. FS is a chronic condition of unknown etiology, characterized by muscle tenderness, pain and stiffness and often accompanied by depression and fatigue which seems to occur primarily in middle aged females. There is no known cure for FS but treatment often includes a prescription of mild exercise. Few studies have evaluated the effectiveness of mild exercise on work capacity and gait patterns in FS patients. Participants were 14 females (age 47.0± 7.6 y who participated in a 10 wk community based aerobic, strength and stretching program designed for FS individuals. Subjects were evaluated pre- and post-program and at a 2 month follow up. Work capacity was estimated by a sub-maximal PWC 170 cycle ergometer test and a Borg perceived exertion scale. Gait was assessed using OptoTrack three dimensional kinematics with 16 channel analogue data acquisition system. Trunk flexibility was also assessed. No significant change in estimated work capacity or flexibility was seen between pre- post- and follow up times. Nevertheless, a significant increase in self selected walking speed (p < 0.05 and a trend toward a more normal gait pattern that was sustained in the follow up testing was noted. We had previously also reported a significant improvement in muscle pain and other fibromyalgia symptoms in this population consequent to the training program. It was concluded that mild exercise training that does not influence work capacity or trunk flexibility can nevertheless positively influence gait mechanics and fibromyalgia symptoms in female FS patients

A Comparison of Vertical Stiffness Values Calculated from Different Measures of Center of Mass Displacement in Single-Leg Hopping.

Science.gov (United States)

Mudie, Kurt L; Gupta, Amitabh; Green, Simon; Hobara, Hiroaki; Clothier, Peter J

2017-02-01

This study assessed the agreement between K vert calculated from 4 different methods of estimating vertical displacement of the center of mass (COM) during single-leg hopping. Healthy participants (N = 38) completed a 10-s single-leg hopping effort on a force plate, with 3D motion of the lower limb, pelvis, and trunk captured. Derived variables were calculated for a total of 753 hop cycles using 4 methods, including: double integration of the vertical ground reaction force, law of falling bodies, a marker cluster on the sacrum, and a segmental analysis method. Bland-Altman plots demonstrated that K vert calculated using segmental analysis and double integration methods have a relatively small bias (0.93 kN⋅m -1 ) and 95% limits of agreement (-1.89 to 3.75 kN⋅m -1 ). In contrast, a greater bias was revealed between sacral marker cluster and segmental analysis (-2.32 kN⋅m -1 ), sacral marker cluster and double integration (-3.25 kN⋅m -1 ), and the law of falling bodies compared with all methods (17.26-20.52 kN⋅m -1 ). These findings suggest the segmental analysis and double integration methods can be used interchangeably for the calculation of K vert during single-leg hopping. The authors propose the segmental analysis method to be considered the gold standard for the calculation of K vert during single-leg, on-the-spot hopping.

Gait variability measurements in lumbar spinal stenosis patients: part B. Preoperative versus postoperative gait variability

International Nuclear Information System (INIS)

Papadakis, N C; Christakis, D G; Tzagarakis, G N; Chlouverakis, G I; Kampanis, N A; Stergiopoulos, K N; Katonis, P G

2009-01-01

The objective of this study was to assess the gait variability of lumbar spinal stenosis (LSS) patients and to evaluate its postoperative progression. The hypothesis was that LSS patients' preoperative gait variability in the frequency domain was higher than the corresponding postoperative. A tri-axial accelerometer sensor was used for the gait measurement and a spectral differential entropy algorithm was used to measure the gait variability. Twelve subjects with LSS were measured before and after surgery. Preoperative measurements were performed 2 days before surgery. Postoperative measurements were performed 6 and 12 months after surgery. Preoperative gait variability was higher than the corresponding postoperative. Also, in most cases, gait variability appeared to decrease throughout the year

Bipedal gait model for precise gait recognition and optimal triggering in foot drop stimulator: a proof of concept.

Science.gov (United States)

Shaikh, Muhammad Faraz; Salcic, Zoran; Wang, Kevin I-Kai; Hu, Aiguo Patrick

2018-03-10

Electrical stimulators are often prescribed to correct foot drop walking. However, commercial foot drop stimulators trigger inappropriately under certain non-gait scenarios. Past researches addressed this limitation by defining stimulation control based on automaton of a gait cycle executed by foot drop of affected limb/foot only. Since gait is a collaborative activity of both feet, this research highlights the role of normal foot for robust gait detection and stimulation triggering. A novel bipedal gait model is proposed where gait cycle is realized as an automaton based on concurrent gait sub-phases (states) from each foot. The input for state transition is fused information from feet-worn pressure and inertial sensors. Thereafter, a bipedal gait model-based stimulation control algorithm is developed. As a feasibility study, bipedal gait model and stimulation control are evaluated in real-time simulation manner on normal and simulated foot drop gait measurements from 16 able-bodied participants with three speed variations, under inappropriate triggering scenarios and with foot drop rehabilitation exercises. Also, the stimulation control employed in commercial foot drop stimulators and single foot gait-based foot drop stimulators are compared alongside. Gait detection accuracy (98.9%) and precise triggering under all investigations prove bipedal gait model reliability. This infers that gait detection leveraging bipedal periodicity is a promising strategy to rectify prevalent stimulation triggering deficiencies in commercial foot drop stimulators. Graphical abstract Bipedal information-based gait recognition and stimulation triggering.

Effects of conventional overground gait training and a gait trainer with partial body weight support on spatiotemporal gait parameters of patients after stroke.

Science.gov (United States)

Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Noh, Ji-Woong; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Kim, Junghwan

2015-05-01

[Purpose] The purpose of this study was to confirm the effects of both conventional overground gait training (CGT) and a gait trainer with partial body weight support (GTBWS) on spatiotemporal gait parameters of patients with hemiparesis following chronic stroke. [Subjects and Methods] Thirty stroke patients were alternately assigned to one of two treatment groups, and both groups underwent CGT and GTBWS. [Results] The functional ambulation classification on the affected side improved significantly in the CGT and GTBWS groups. Walking speed also improved significantly in both groups. [Conclusion] These results suggest that the GTBWS in company with CGT may be, in part, an effective method of gait training for restoring gait ability in patients after a stroke.

Deep benign fibrous histiocytoma: computed tomography and histology findings; Histiocitoma fibroso benigno profundo: achados na tomografia computadorizada e histologia

Energy Technology Data Exchange (ETDEWEB)

Farage, Luciano; Castro, Mario Augusto Padula; Macedo, Tulio Augusto Alves [Uberlandia Univ., MG (Brazil). Hospital das Clinicas. Setor de Radiologia; Salomao, Eliana Chaves; Machado, Tania Alcantara; Souza, Lincoln Pereira de; Freitas, Luiz de Oliveira [Uberlandia Univ., MG (Brazil). Faculdade de Medicina. Dept. de Clinica Medica

2005-04-01

We present the computed tomography images of an 83-year-old male patient with a deep benign fibrous histiocytoma at the lateral aspect of the left leg. Computed tomography images showed a well-defined mass with marked peripheral enhancement by iodinated contrast medium. Only few reports of this rare soft tissue tumor can be found in the literature. (author)

Soft Legged Wheel-Based Robot with Terrestrial Locomotion Abilities

Directory of Open Access Journals (Sweden)

Ali Sadeghi

2016-12-01

Full Text Available In recent years robotics has been influenced by a new approach, soft-robotics, bringing the idea that safe interaction with user and more adaptation to the environment can be achieved by exploiting easily deformable materials and flexible components in the structure of robots. In 2016, the soft-robotics community has promoted a new robotics challenge, named RoboSoft Grand Challenge, with the aim of bringing together different opinions on the usefulness and applicability of softness and compliancy in robotics. In this paper we describe the design and implementation of a terrestrial robot based on two soft legged wheels. The tasks predefined by the challenge were set as targets in the robot design, which finally succeeded to accomplish all the tasks. The wheels of the robot can passively climb over stairs and adapt to slippery grounds using two soft legs embedded in their structure. The soft legs, fabricated by integration of soft and rigid materials and mounted on the circumference of a conventional wheel, succeed to enhance its functionality and easily adapt to unknown grounds. The robot has a semi stiff tail that helps in the stabilization and climbing of stairs. An active wheel is embedded at the extremity of the tail in order to increase the robot maneuverability in narrow environments. Moreover two parallelogram linkages let the robot to reconfigure and shrink its size allowing entering inside gates smaller than its initial dimensions.

Changes on Tendon Stiffness and Clinical Outcomes in Athletes Are Associated With Patellar Tendinopathy After Eccentric Exercise.

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Lee, Wai-Chun; Ng, Gabriel Yin-Fat; Zhang, Zhi-Jie; Malliaras, Peter; Masci, Lorenzo; Fu, Siu-Ngor

2017-12-19

Eccentric exercise is commonly used as a form of loading exercise for individuals with patellar tendinopathy. This study investigated the change of mechanical properties and clinical outcomes and their interrelationships after a 12-week single-legged decline-board exercise with and without extracorporeal shockwave therapy (ESWT). Randomized controlled trial. Outpatient clinic of a university. Thirty-four male in-season athletes with patellar tendinopathy for more than 3 months were randomized into exercise and combined groups. The exercise group received a 12-week single-legged decline-squat exercise, and the combined group performed an identical exercise program in addition to a weekly session of ESWT in the initial 6 weeks. Tendon stiffness and strain were examined using ultrasonography and dynamometry. Visual analog scale and Victoria Institute of Sports Assessment-patella (VISA-p) score were used to assess pain and dysfunction. These parameters were measured at preintervention and postintervention. Significant time effect but no significant group effect on the outcome measures; significant reduction in tendon stiffness (P = 0.02) and increase in tendon strain (P = 0.00); and reduction of intensity of pain (P = 0.00) and dysfunction (P = 0.00) were observed. Significant correlations between changes in tendon stiffness and VISA-p score (ρ = -0.58, P = 0.05); alteration in tendon strain, pain intensity (ρ = -0.63, P = 0.03); and VISA-p score (ρ = 0.60, P = 0.04) were detected after the exercise program. Eccentric exercise-induced modulation on tendon mechanical properties and clinical symptoms are associated in athletes with patellar tendinopathy.

Fatigue and muscle-tendon stiffness after stretch-shortening cycle and isometric exercise.

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Toumi, Hechmi; Poumarat, Georges; Best, Thomas M; Martin, Alain; Fairclough, John; Benjamin, Mike

2006-10-01

The purpose of the present study was to compare vertical jump performance after 2 different fatigue protocols. In the first protocol, subjects performed consecutive sets of 10 repetitions of stretch-shortening cycle (SSC) contractions. In the second protocol, successive sets of 10 repetitions of isometric contractions were performed for 10 s with the knee at 90 degrees of flexion. The exercises were stopped when the subjects failed to reach 50% of their maximum voluntary isometric contractions. Maximal isometric force and maximal concentric power were assessed by performing supine leg presses, squat jumps, and drop jumps. Surface EMG was used to determine changes in muscle activation before and after fatigue. In both groups, the fatigue exercises reduced voluntary isometric force, maximal concentric power, and drop jump performance. Kinematic data showed a decrease in knee muscle-tendon stiffness accompanied by a lengthened ground contact time. EMG analysis showed that the squat and drop jumps were performed similarly before and after the fatigue exercise for both groups. Although it was expected that the stiffness would decrease more after SSC than after isometric fatigue (as a result of a greater alteration of the reflex sensitivity SSC), our results showed that both protocols had a similar effect on knee muscle stiffness during jumping exercises. Both fatigue protocols induced muscle fatigue, and the decrease in jump performance was linked to a decrease in the strength and stiffness of the knee extensor muscles.

A Comparison of the Physiology and Mechanics of Exercise in LBNP and Upright Gait

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Boda, W. L.; Watenpaugh, D. E.; Ballard, R. E.; Chang, D.; Looft-Wilson, R.; Hargens, A. R.

1996-01-01

Bone, muscular strength, aerobic capacity, and normal fluid pressure gradients within the body are lost during bed rest and spaceflight. Lower Body Negative Pressure (LBNP) exercise may create musculoskeletal and cardiovascular strains equal to a greater than those experienced on Earth and elucidate some of the mechanisms for maintaining bone integrity. LBNP exercise simulates gravity during supine posture by using negative pressure to pull subjects inward against a treadmill generating footward forces and increasing transmural pressures. Footward forces are generated which equal the product of the pressure differential and the cross-sectional area of the LBNP waist seal. Subjects lie supine within the chamber with their legs suspended from one another via cuffs, bungee cords, and pulleys, such that each leg acts as a counterweight to the other leg during the gait cycle. The subjects then walk or run on a treadmill which is positioned vertically within the chamber. Supine orientation allows only footward force production due to the negative pressure within the chamber. The purpose of this study was to determine if the kinematics, kinetics, and metabolic rate during supine walking and slow running on a vertical treadmill within LBNP are similar to those on a treadmill in 1-g environment in an upright posture.

Force Control Strategies in Hydraulically Actuated Legged Robots

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Hector Montes

2016-03-01

Full Text Available In this contribution, several strategies of force control have been proposed to be implemented and evaluated in ROBOCLIMBER, a quadruped robot of large dimensions. A first group of strategies proposed in this paper is based on impedance control, which is intended to adapt the foot-ground contact forces according to the experimentally specified damping ratio and the undamped natural frequency. A second control strategy of interest for many practical cases is called the parallel force/position control, which has one inner loop position control and two external control loops, one of force and another of position. A third group of control strategies is the posture stabilization for ROBOCLIMBER using the feedback of the ZMP calculation and the position of its legs. Finally, a control strategy for the control of a quasi-static gait using ZMP feedback is proposed and tested by simulation.

Factors influencing the stiffness of fibroadenomas at shear wave elastography

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Elseedawy, M.; Whelehan, P.; Vinnicombe, S.; Thomson, K.; Evans, A.

2016-01-01

Aim: To identify which features of fibroadenomas are associated with false-positive findings at shear wave elastography (SWE). Materials and methods: A total of 151 patients with histologically confirmed fibroadenomata were identified from a prospective database, from a single breast unit. The following features were assessed by two observers who were unaware of the SWE findings: patient age, grey-scale ultrasound lesion diameter (<15 or ≥15 mm), distance from the lesion to skin, composition of surrounding tissue (fatty, mixed or dense), and source of referral (screening or symptomatic). Statistical analysis was carried out using the chi-square test. Results: A statistically significant positive association was found between grey-scale ultrasound lesion size and lesion stiffness. Twenty-nine of 70 (41%) lesions ≥15 mm were stiff, versus 10 of 81 (12%) <15 mm (p=0.001). Patient age, distance from the lesion to skin, make-up of surrounding tissue, and source were not significantly associated with stiffness. Conclusion: Fibroadenomas giving false-positive SWE results tend to be larger in size than those that do not. More compression of adjacent normal tissue is assumed to be the cause of the present findings. As previous studies have shown that large cancers tend to be stiffer than smaller cancers, it may be appropriate to vary the quantitative cut-off value used for benign/malignant differentiation in SWE according to lesion size. - Highlights: • Fibroadenomas giving false positive SWE results tend to be larger in size. • More compression of adjacent normal tissue is assumed to be the cause of our findings. • The age of the patient is not related to fibroadenoma stiffness.

Balzac and human gait analysis.

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Collado-Vázquez, S; Carrillo, J M

2015-05-01

People have been interested in movement analysis in general, and gait analysis in particular, since ancient times. Aristotle, Hippocrates, Galen, Leonardo da Vinci and Honoré de Balzac all used observation to analyse the gait of human beings. The purpose of this study is to compare Honoré de Balzac's writings with a scientific analysis of human gait. Honoré de Balzac's Theory of walking and other works by that author referring to gait. Honoré de Balzac had an interest in gait analysis, as demonstrated by his descriptions of characters which often include references to their way of walking. He also wrote a treatise entitled Theory of walking (Théorie de la demarche) in which he employed his keen observation skills to define gait using a literary style. He stated that the walking process is divided into phases and listed the factors that influence gait, such as personality, mood, height, weight, profession and social class, and also provided a description of the correct way of walking. Balzac considered gait analysis to be very important and this is reflected in both his character descriptions and Theory of walking, his analytical observation of gait. In our own technology-dominated times, this serves as a reminder of the importance of observation. Copyright © 2011 Sociedad Española de Neurología. Published by Elsevier España, S.L.U. All rights reserved.

Analysis and Classification of Stride Patterns Associated with Children Development Using Gait Signal Dynamics Parameters and Ensemble Learning Algorithms

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Meihong Wu

2016-01-01

Full Text Available Measuring stride variability and dynamics in children is useful for the quantitative study of gait maturation and neuromotor development in childhood and adolescence. In this paper, we computed the sample entropy (SampEn and average stride interval (ASI parameters to quantify the stride series of 50 gender-matched children participants in three age groups. We also normalized the SampEn and ASI values by leg length and body mass for each participant, respectively. Results show that the original and normalized SampEn values consistently decrease over the significance level of the Mann-Whitney U test (p<0.01 in children of 3–14 years old, which indicates the stride irregularity has been significantly ameliorated with the body growth. The original and normalized ASI values are also significantly changing when comparing between any two groups of young (aged 3–5 years, middle (aged 6–8 years, and elder (aged 10–14 years children. Such results suggest that healthy children may better modulate their gait cadence rhythm with the development of their musculoskeletal and neurological systems. In addition, the AdaBoost.M2 and Bagging algorithms were used to effectively distinguish the children’s gait patterns. These ensemble learning algorithms both provided excellent gait classification results in terms of overall accuracy (≥90%, recall (≥0.8, and precision (≥0.8077.

Coupling between the Output Force and Stiffness in Different Variable Stiffness Actuators

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Amir Jafari

2014-08-01

Full Text Available The fundamental objective in developing variable stiffness actuators is to enable the actuator to deliberately tune its stiffness. This is done through controlling the energy flow extracted from internal power units, i.e., the motors of a variable stiffness actuator (VSA. However, the stiffness may also be unintentionally affected by the external environment, over which, there is no control. This paper analysis the correlation between the external loads, applied to different variable stiffness actuators, and their resultant output stiffness. Different types of variable stiffness actuators have been studied considering springs with different types of nonlinearity. The results provide some insights into how to design the actuator mechanism and nonlinearity of the springs in order to increase the decoupling between the load and stiffness in these actuators. This would significantly widen the application range of a variable stiffness actuator.

Optical coherence elastography (OCE) as a method for identifying benign and malignant prostate biopsies

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Li, Chunhui; Guan, Guangying; Ling, Yuting; Lang, Stephen; Wang, Ruikang K.; Huang, Zhihong; Nabi, Ghulam

2015-03-01

Objectives. Prostate cancer is the most frequently diagnosed malignancy in men. Digital rectal examination (DRE) - a known clinical tool based on alteration in the mechanical properties of tissues due to cancer has traditionally been used for screening prostate cancer. Essentially, DRE estimates relative stiffness of cancerous and normal prostate tissue. Optical coherence elastography (OCE) are new optical imaging techniques capable of providing cross-sectional imaging of tissue microstructure as well as elastogram in vivo and in real time. In this preliminary study, OCE was used in the setting of the human prostate biopsies ex vivo, and the images acquired were compared with those obtained using standard histopathologic methods. Methods. 120 prostate biopsies were obtained by TRUS guided needle biopsy procedures from 9 patients with clinically suspected cancer of the prostate. The biopsies were approximately 0.8mm in diameter and 12mm in length, and prepared in Formalin solution. Quantitative assessment of biopsy samples using OCE was obtained in kilopascals (kPa) before histopathologic evaluation. The results obtained from OCE and standard histopathologic evaluation were compared provided the cross-validation. Sensitivity, specificity, and positive and negative predictive values were calculated for OCE (histopathology was a reference standard). Results. OCE could provide quantitative elasticity properties of prostate biopsies within benign prostate tissue, prostatic intraepithelial neoplasia, atypical hyperplasia and malignant prostate cancer. Data analysed showed that the sensitivity and specificity of OCE for PCa detection were 1 and 0.91, respectively. PCa had significantly higher stiffness values compared to benign tissues, with a trend of increasing in stiffness with increasing of malignancy. Conclusions. Using OCE, microscopic resolution elastogram is promising in diagnosis of human prostatic diseases. Further studies using this technique to improve the

Gait characteristics after gait-oriented rehabilitation in chronic stroke.

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Peurala, Sinikka H; Titianova, Ekaterina B; Mateev, Plamen; Pitkänen, Kauko; Sivenius, Juhani; Tarkka, Ina M

2005-01-01

To assess the effects of rehabilitation in thirty-seven ambulatory patients with chronic stroke during three weeks in-patient rehabilitation period. In the intervention group, each patient received 75 min physiotherapy daily every workday including 20 minutes in the electromechanical gait trainer with body-weight support (BWS). In the control group, each patient participated in 45 min conventional physiotherapy daily. Motor ability was assessed with the first five items of the Modified Motor Assessment Scale (MMAS1-5) and ten meters walking speed. Spatio-temporal gait characteristics were recorded with an electrical walkway. The MMAS1-5 (pgait characteristics improved only in the intervention group, as seen in increased Functional Ambulation Profile score (p=0.023), velocity (p=0.023), the step lengths (affected side, p=0.011, non-affected side p=0.040), the stride lengths (p=0.018, p=0.006) and decreased step-time differential (p=0.043). Furthermore, all gait characteristics and other motor abilities remained in the discharge level at the six months in the intervention group. It appears that BWS training gives a long-lasting benefit in gait qualities even in chronic stroke patients.

Cognitive and motor dual task gait training improve dual task gait performance after stroke - A randomized controlled pilot trial.

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Liu, Yan-Ci; Yang, Yea-Ru; Tsai, Yun-An; Wang, Ray-Yau

2017-06-22

This study investigated effects of cognitive and motor dual task gait training on dual task gait performance in stroke. Participants (n = 28) were randomly assigned to cognitive dual task gait training (CDTT), motor dual task gait training (MDTT), or conventional physical therapy (CPT) group. Participants in CDTT or MDTT group practiced the cognitive or motor tasks respectively during walking. Participants in CPT group received strengthening, balance, and gait training. The intervention was 30 min/session, 3 sessions/week for 4 weeks. Three test conditions to evaluate the training effects were single walking, walking while performing cognitive task (serial subtraction), and walking while performing motor task (tray-carrying). Parameters included gait speed, dual task cost of gait speed (DTC-speed), cadence, stride time, and stride length. After CDTT, cognitive-motor dual task gait performance (stride length and DTC-speed) was improved (p = 0.021; p = 0.015). After MDTT, motor dual task gait performance (gait speed, stride length, and DTC-speed) was improved (p = 0.008; p = 0.008; p = 0.008 respectively). It seems that CDTT improved cognitive dual task gait performance and MDTT improved motor dual task gait performance although such improvements did not reach significant group difference. Therefore, different types of dual task gait training can be adopted to enhance different dual task gait performance in stroke.

Somatosensory inputs by application of KinesioTaping: effects on spasticity, balance, and gait in chronic spinal cord injury.

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Tamburella, Federica; Scivoletto, Giorgio; Molinari, Marco

2014-01-01

Leg paralysis, spasticity, reduced interlimb coordination, and impaired balance are the chief limitations to overground ambulation in subjects with incomplete spinal cord injury (SCI). In recent years, the application of KinesioTaping (KT) has been proposed to enhance sensory inputs, decreasing spasticity by proprioception feedback and relieving abnormal muscle tension. Because no studies have examined KT-based techniques in SCI subjects, our goal was to analyze the effects of ankle joint KT on spasticity, balance, and gait. A randomized crossover case control design was used to compare the effects of KT and conventional nonelastic silk tape (ST) in 11 chronic SCI subjects, AIS level D, with soleus/gastrocnemius (S/G) muscle spasticity and balance and gait impairments. 48 h of treatment with KT or ST was followed by 48 h with the other technique after 1 week. A single Y-strip of Cure(©) tape (KT) and ST was to the S and G muscles with 0% stretch. Before and 48 h after of application of KT and ST, clinical data on the range of motion (ROM), spasticity, clonus, pain, balance, and gait were collected. Stabilometric platform assessment of center of pressure (COP) movements; bidimensional gait analysis; and recording of electromyographic (EMG) activity of the S, G, and tibialis anterior and extensor hallucis lungus muscles were also performed. Only KT had significant effects on spasticity (p < 0.05), clonus (p < 0.001) and COP movements (p < 0.05), kinematic gait parameters (p < 0.001), and EMG activity (p < 0.001). Comparison between ST and KT improvements pointed out significant differences as concerns ROM (p < 0.001), spasticity (p < 0.001), clonus (p < 0.001), pain (p < 0.001), COP parameters (p < 0.05), and most kinematic gait data (p < 0.05). Short-term application of KT reduces spasticity and pain and improves balance and gait in chronic SCI subjects. Although these data are promising, they require confirmation in a larger cohort of patients.

Gait and Cognition in Parkinson’s Disease: Cognitive Impairment Is Inadequately Reflected by Gait Performance during Dual Task

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Heiko Gaßner

2017-10-01

Full Text Available IntroductionCognitive and gait deficits are common symptoms in Parkinson’s disease (PD. Motor-cognitive dual tasks (DTs are used to explore the interplay between gait and cognition. However, it is unclear if DT gait performance is indicative for cognitive impairment. Therefore, the aim of this study was to investigate if cognitive deficits are reflected by DT costs of spatiotemporal gait parameters.MethodsCognitive function, single task (ST and DT gait performance were investigated in 67 PD patients. Cognition was assessed by the Montreal Cognitive Assessment (MoCA followed by a standardized, sensor-based gait test and the identical gait test while subtracting serial 3’s. Cognitive impairment was defined by a MoCA score <26. DT costs in gait parameters [(DT − ST/ST × 100] were calculated as a measure of DT effect on gait. Correlation analysis was used to evaluate the association between MoCA performance and gait parameters. In a linear regression model, DT gait costs and clinical confounders (age, gender, disease duration, motor impairment, medication, and depression were correlated to cognitive performance. In a subgroup analysis, we compared matched groups of cognitively impaired and unimpaired PD patients regarding differences in ST, DT, and DT gait costs.ResultsCorrelation analysis revealed weak correlations between MoCA score and DT costs of gait parameters (r/rSp ≤ 0.3. DT costs of stride length, swing time variability, and maximum toe clearance (|r/rSp| > 0.2 were included in a regression analysis. The parameters only explain 8% of the cognitive variance. In combination with clinical confounders, regression analysis showed that these gait parameters explained 30% of MoCA performance. Group comparison revealed strong DT effects within both groups (large effect sizes, but significant between-group effects in DT gait costs were not observed.ConclusionThese findings suggest that DT gait performance is not indicative

Gait as evidence

DEFF Research Database (Denmark)

Lynnerup, Niels; Larsen, Peter Kastmand

2014-01-01

This study examines what in Denmark may constitute evidence based on forensic anthropological gait analyses, in the sense of pointing to a match (or not) between a perpetrator and a suspect, based on video and photographic imagery. Gait and anthropometric measures can be used when direct facial...

Technology-assisted balance and gait training reduces falls in patients with Parkinson's disease: a randomized controlled trial with 12-month follow-up.

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Shen, Xia; Mak, Margaret K Y

2015-02-01

Objective. To examine the effects of technology-assisted balance and gait training on reducing falls in patients with Parkinson's disease (PD). Methods. Eligible subjects were randomly allocated to an experimental group given technology-assisted balance and gait training (BAL, n = 26) and an active control group undertaking strengthening exercises (CON, n = 25). The training in each group lasted for 3 months. The number of fallers and fall rate were used as primary outcomes, and single-leg-stance-time, latency of postural response to perturbation, self-selected gait velocity, and stride length as secondary outcomes. Fall incidence was recorded over 15 months after the baseline assessment (Pre). Other tests were performed at Pre, after 3-month intervention (Post(3m)), at 3 months (Post(6m)), and 12 months (Post(15m)) after treatment completion. Results. Forty-five subjects who completed the 3-month training were included in the data analysis. There were fewer fallers in the BAL than in the CON group at Post(3m), Post(6m), and Post(15m) (P fall rate than the CON group at Post(3m) and Post(6m) (incidence rate ratio: 0.111-0.188, P balance and gait training in reducing falls in people with PD. © The Author(s) 2014.

Kinematics of Rotation in Joints of the Lower Limbs and Pelvis during Gait: Early Results—SB ACLR Approach versus DB ACLR Approach

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Andrzej Czamara

2015-01-01

Full Text Available It is difficult to find publications comparing rotation kinematics in large joints of the lower limbs and pelvis during gait in patients after single-bundle (SB reconstruction of the anterior cruciate ligament (ACLR with double-bundle (DB ACLR of the knee. The aim of this study was to compare rotation kinematics in ankle, knee, and hip joints and the pelvis during gait in the 14th week after SB and DB ACLR. The subjects were males after SB (n=10 and DB (n=13 ACLR and a control group (n=15. The values of kinematic parameters were recorded during internal (IR and external (ER rotation in the joints during gait using the BTS SMART. The SB ACLR group obtained significantly higher values of ER in the involved knee comparing to DB ACLR and controls and excessive IR in the hip comparing to controls. In the DB ACLR group, excessive ER was noted in the involved leg's foot. Comparing with the DB ACLR and control groups, SB ACLR subjects had more substantial disorders of rotation kinematics in the lower limb joints. However, in both ACLR groups, 14 weeks of postoperative physiotherapy were not enough to fully restore rotation kinematics in joints of the lower limbs during gait.

Intra-individual gait pattern variability in specific situations: Implications for forensic gait analysis.

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Ludwig, Oliver; Dillinger, Steffen; Marschall, Franz

2016-07-01

In this study, inter- and intra-individual gait pattern differences are examined in various gait situations by means of phase diagrams of the extremity angles (cyclograms). 8 test subjects walked along a walking distance of 6m under different conditions three times each: barefoot, wearing sneakers, wearing combat boots, after muscular fatigue, and wearing a full-face motorcycle helmet restricting vision. The joint angles of foot, knee, and hip were recorded in the sagittal plane. The coupling of movements was represented by time-adjusted cyclograms, and the inter- and intra-individual differences were captured by calculating the similarity between different gait patterns. Gait pattern variability was often greater between the defined test situations than between the individual test subjects. The results have been interpreted considering neurophysiological regulation mechanisms. Footwear, masking, and fatigue were interpreted as disturbance parameters, each being a cause for gait pattern variability and complicating the inference of identity of persons in video recordings. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Therapeutic riding followed by rhythmic auditory stimulation to improve balance and gait in a subject with orthopedic pathologies.

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Ungermann, Cathryn M; Gras, Laura Z

2011-12-01

The study objectives were to investigate the effect of therapeutic riding with a subject who had an orthopedic diagnosis. This is a single-subject case report. The study was conducted at an equestrian facility with an indoor riding arena. The subject was a 59-year-old woman with grade I spondylolisthesis at L4/L5 and multilevel lumbar spinal stenosis in central and foraminal canals. The subject had an anterior cervical fusion of C3-C7. The subject has been ambulating with a straight cane due to her history of frequent falls. Gait, agility, strength, range of motion, and balance testing were performed. The subject had impairments of bilateral lower extremities with an ataxic gait pattern and was at risk for continued falls according to the balance measures. The intervention comprised therapeutic riding sessions 3 times a week for 20 minutes for 4 weeks. Each riding session was immediately followed by a 10-minute independent walking program with a metronome for rhythmic auditory stimulation. The outcome measures were as follows: Manual muscle testing and range of motion of the lower extremities, Gait Speed Test, Dynamic Gait Index, Four-Square Step Test, Chair Stand Test, Single Leg Stance. Improvements were seen in lower extremity strength and range of motion and balance. The subject improved on balance scores, placing her out of the risk for falls category. Therapeutic riding followed by rhythmic auditory stimulation improved lower extremity range of motion, strength, and balance with this subject.

Effects of forefoot bending stiffness of badminton shoes on agility, comfort perception and lower leg kinematics during typical badminton movements.

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Park, Sang-Kyoon; Lam, Wing-Kai; Yoon, Sukhoon; Lee, Ki-Kwang; Ryu, Jiseon

2017-09-01

This study investigated whether an increase in the forefoot bending stiffness of a badminton shoe would positively affect agility, comfort and biomechanical variables during badminton-specific movements. Three shoe conditions with identical shoe upper and sole designs with different bending stiffness (Flexible, Regular and Stiff) were used. Elite male badminton players completed an agility test on a standard badminton court involving consecutive lunges in six directions, a comfort test performed by a pair of participants conducting a game-like practice trial and a biomechanics test involving a random assignment of consecutive right forward lunges. No significant differences were found in agility time and biomechanical variables among the three shoes. The players wearing the shoe with a flexible forefoot outsole demonstrated a decreased perception of comfort in the forefoot cushion compared to regular and stiffer conditions during the comfort test (p badminton-specific tasks. It was concluded that an optimisation of forefoot structure and materials in badminton shoes should consider the individual's perception to maximise footwear comfort in performance.

Balance, gait and quality of life in Parkinson's disease: Effects of whole body vibration treatment

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Ludmylla Teixeira Soares

Full Text Available Introduction Parkinson's disease (PD is a neurodegenerative disorder, which triggers limitations and disability in people. Therefore, rehabilitation therapy is widely recommended in patients with PD, especially those who do not respond to pharmacological treatment.Objective Evaluate the effect of a protocol of Whole-body Vibration (WBV in balance, gait and Quality of Life (QOL of patients with PD, who do not respond to pharmacological treatment.Methods It was performed 12 sessions of a protocol WBV (squat, plantar flexion, isometric contraction of members and single-leg balance, with three sets each, at a vibrating platform (2mm and 35Hz in 10 PD patients. By the first 3 sessions, patients underwent 20 seconds of exercise and 20 seconds of rest. After the third session, the treatment was 40 seconds of exercise and 20 seconds of rest. The Tinetti Test was applied before and after treatment to assess balance and gait, and the Parkinson's Disease Quality of Life-questionnaire (PDQL-BR, to evaluate the PDQL-BR and its subcategories: Parkinson, Systemic, Social and Emotional.Results Treatment did not significantly change the balance (p = 0.438, QOL issue in Emotional (p = 0.450 and Social (p = 0.171, but improved gait (p = 0.003, the Tinetti (p ≤ 0.001, the quality of life in items Parkinson (p ≤ 0.001, Systemic (p ≤ 0.001 and PDQL-BR (p ≤ 0.001.Conclusions WBV exercises on the vibrating platform, according to the parameters used, showed promising results that encourage its use to improve the clinical conditions related to disorders of gait, balance and QOL in patients with PD.

Crowd-Sourced Amputee Gait Data: A Feasibility Study Using YouTube Videos of Unilateral Trans-Femoral Gait.

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James Gardiner

Full Text Available Collecting large datasets of amputee gait data is notoriously difficult. Additionally, collecting data on less prevalent amputations or on gait activities other than level walking and running on hard surfaces is rarely attempted. However, with the wealth of user-generated content on the Internet, the scope for collecting amputee gait data from alternative sources other than traditional gait labs is intriguing. Here we investigate the potential of YouTube videos to provide gait data on amputee walking. We use an example dataset of trans-femoral amputees level walking at self-selected speeds to collect temporal gait parameters and calculate gait asymmetry. We compare our YouTube data with typical literature values, and show that our methodology produces results that are highly comparable to data collected in a traditional manner. The similarity between the results of our novel methodology and literature values lends confidence to our technique. Nevertheless, clear challenges with the collection and interpretation of crowd-sourced gait data remain, including long term access to datasets, and a lack of validity and reliability studies in this area.

Crowd-Sourced Amputee Gait Data: A Feasibility Study Using YouTube Videos of Unilateral Trans-Femoral Gait.

Science.gov (United States)

Gardiner, James; Gunarathne, Nuwan; Howard, David; Kenney, Laurence

2016-01-01

Collecting large datasets of amputee gait data is notoriously difficult. Additionally, collecting data on less prevalent amputations or on gait activities other than level walking and running on hard surfaces is rarely attempted. However, with the wealth of user-generated content on the Internet, the scope for collecting amputee gait data from alternative sources other than traditional gait labs is intriguing. Here we investigate the potential of YouTube videos to provide gait data on amputee walking. We use an example dataset of trans-femoral amputees level walking at self-selected speeds to collect temporal gait parameters and calculate gait asymmetry. We compare our YouTube data with typical literature values, and show that our methodology produces results that are highly comparable to data collected in a traditional manner. The similarity between the results of our novel methodology and literature values lends confidence to our technique. Nevertheless, clear challenges with the collection and interpretation of crowd-sourced gait data remain, including long term access to datasets, and a lack of validity and reliability studies in this area.

The Golden Ratio of Gait Harmony: Repetitive Proportions of Repetitive Gait Phases

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Marco Iosa

2013-01-01

Full Text Available In nature, many physical and biological systems have structures showing harmonic properties. Some of them were found related to the irrational number known as the golden ratio that has important symmetric and harmonic properties. In this study, the spatiotemporal gait parameters of 25 healthy subjects were analyzed using a stereophotogrammetric system with 25 retroreflective markers located on their skin. The proportions of gait phases were compared with , the value of which is about 1.6180. The ratio between the entire gait cycle and stance phase resulted in 1.620 ± 0.058, that between stance and the swing phase was 1.629 ± 0.173, and that between swing and the double support phase was 1.684 ± 0.357. All these ratios did not differ significantly from each other (, , repeated measure analysis of variance or from (, resp., t-tests. The repetitive gait phases of physiological walking were found in turn in repetitive proportions with each other, revealing an intrinsic harmonic structure. Harmony could be the key for facilitating the control of repetitive walking. Harmony is a powerful unifying factor between seemingly disparate fields of nature, including human gait.

Self-perceived gait stability modulates the effect of daily life gait quality on prospective falls in older adults

NARCIS (Netherlands)

Weijer, R H A; Hoozemans, M J M; van Dieën, J H; Pijnappels, M

2018-01-01

BACKGROUND: Quality of gait during daily life activities and perceived gait stability are both independent risk factors for future falls in older adults. RESEARCH QUESTION: We investigated whether perceived gait stability modulates the association between gait quality and falling in older adults.

Association of Dual-Task Gait With Incident Dementia in Mild Cognitive Impairment: Results From the Gait and Brain Study.

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Montero-Odasso, Manuel M; Sarquis-Adamson, Yanina; Speechley, Mark; Borrie, Michael J; Hachinski, Vladimir C; Wells, Jennie; Riccio, Patricia M; Schapira, Marcelo; Sejdic, Ervin; Camicioli, Richard M; Bartha, Robert; McIlroy, William E; Muir-Hunter, Susan

2017-07-01

Gait performance is affected by neurodegeneration in aging and has the potential to be used as a clinical marker for progression from mild cognitive impairment (MCI) to dementia. A dual-task gait test evaluating the cognitive-motor interface may predict dementia progression in older adults with MCI. To determine whether a dual-task gait test is associated with incident dementia in MCI. The Gait and Brain Study is an ongoing prospective cohort study of community-dwelling older adults that enrolled 112 older adults with MCI. Participants were followed up for 6 years, with biannual visits including neurologic, cognitive, and gait assessments. Data were collected from July 2007 to March 2016. Incident all-cause dementia was the main outcome measure, and single- and dual-task gait velocity and dual-task gait costs were the independent variables. A neuropsychological test battery was used to assess cognition. Gait velocity was recorded under single-task and 3 separate dual-task conditions using an electronic walkway. Dual-task gait cost was defined as the percentage change between single- and dual-task gait velocities: ([single-task gait velocity - dual-task gait velocity]/ single-task gait velocity) × 100. Cox proportional hazard models were used to estimate the association between risk of progression to dementia and the independent variables, adjusted for age, sex, education, comorbidities, and cognition. Among 112 study participants with MCI, mean (SD) age was 76.6 (6.9) years, 55 were women (49.1%), and 27 progressed to dementia (24.1%), with an incidence rate of 121 per 1000 person-years. Slow single-task gait velocity (gait cost while counting backward (HR, 3.79; 95% CI, 1.57-9.15; P = .003) and naming animals (HR, 2.41; 95% CI, 1.04-5.59; P = .04) were associated with dementia progression (incidence rate, 155 per 1000 person-years). The models remained robust after adjusting by baseline cognition except for dual-task gait cost when dichotomized. Dual

Is Freezing of Gait in Parkinson's Disease a Result of Multiple Gait Impairments? Implications for Treatment

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Plotnik, Meir; Giladi, Nir; Hausdorff, Jeffrey M.

2012-01-01

Several gait impairments have been associated with freezing of gait (FOG) in patients with Parkinson's disease (PD). These include deteriorations in rhythm control, gait symmetry, bilateral coordination of gait, dynamic postural control and step scaling. We suggest that these seemingly independent gait features may have mutual interactions which, during certain circumstances, jointly drive the predisposed locomotion system into a FOG episode. This new theoretical framework is illustrated by the evaluation of the potential relationships between the so-called “sequence effect”, that is, impairments in step scaling, and gait asymmetry just prior to FOG. We further discuss what factors influence gait control to maintain functional gait. “Triggers”, for example, such as attention shifts or trajectory transitions, may precede FOG. We propose distinct categories of interventions and describe examples of existing work that support this idea: (a) interventions which aim to maintain a good level of locomotion control especially with respect to aspects related to FOG; (b) those that aim at avoiding FOG “triggers”; and (c) those that merely aim to escape from FOG once it occurs. The proposed theoretical framework sets the stage for testable hypotheses regarding the mechanisms that lead to FOG and may also lead to new treatment ideas. PMID:22288021

Wearable Device-Based Gait Recognition Using Angle Embedded Gait Dynamic Images and a Convolutional Neural Network.

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Zhao, Yongjia; Zhou, Suiping

2017-02-28

The widespread installation of inertial sensors in smartphones and other wearable devices provides a valuable opportunity to identify people by analyzing their gait patterns, for either cooperative or non-cooperative circumstances. However, it is still a challenging task to reliably extract discriminative features for gait recognition with noisy and complex data sequences collected from casually worn wearable devices like smartphones. To cope with this problem, we propose a novel image-based gait recognition approach using the Convolutional Neural Network (CNN) without the need to manually extract discriminative features. The CNN's input image, which is encoded straightforwardly from the inertial sensor data sequences, is called Angle Embedded Gait Dynamic Image (AE-GDI). AE-GDI is a new two-dimensional representation of gait dynamics, which is invariant to rotation and translation. The performance of the proposed approach in gait authentication and gait labeling is evaluated using two datasets: (1) the McGill University dataset, which is collected under realistic conditions; and (2) the Osaka University dataset with the largest number of subjects. Experimental results show that the proposed approach achieves competitive recognition accuracy over existing approaches and provides an effective parametric solution for identification among a large number of subjects by gait patterns.

Wearable Device-Based Gait Recognition Using Angle Embedded Gait Dynamic Images and a Convolutional Neural Network

Science.gov (United States)

Zhao, Yongjia; Zhou, Suiping

2017-01-01

The widespread installation of inertial sensors in smartphones and other wearable devices provides a valuable opportunity to identify people by analyzing their gait patterns, for either cooperative or non-cooperative circumstances. However, it is still a challenging task to reliably extract discriminative features for gait recognition with noisy and complex data sequences collected from casually worn wearable devices like smartphones. To cope with this problem, we propose a novel image-based gait recognition approach using the Convolutional Neural Network (CNN) without the need to manually extract discriminative features. The CNN’s input image, which is encoded straightforwardly from the inertial sensor data sequences, is called Angle Embedded Gait Dynamic Image (AE-GDI). AE-GDI is a new two-dimensional representation of gait dynamics, which is invariant to rotation and translation. The performance of the proposed approach in gait authentication and gait labeling is evaluated using two datasets: (1) the McGill University dataset, which is collected under realistic conditions; and (2) the Osaka University dataset with the largest number of subjects. Experimental results show that the proposed approach achieves competitive recognition accuracy over existing approaches and provides an effective parametric solution for identification among a large number of subjects by gait patterns. PMID:28264503

Gait disorders in the elderly and dual task gait analysis: a new approach for identifying motor phenotypes.

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Auvinet, Bernard; Touzard, Claude; Montestruc, François; Delafond, Arnaud; Goeb, Vincent

2017-01-31

Gait disorders and gait analysis under single and dual-task conditions are topics of great interest, but very few studies have looked for the relevance of gait analysis under dual-task conditions in elderly people on the basis of a clinical approach. An observational study including 103 patients (mean age 76.3 ± 7.2, women 56%) suffering from gait disorders or memory impairment was conducted. Gait analysis under dual-task conditions was carried out for all patients. Brain MRI was performed in the absence of contra-indications. Three main gait variables were measured: walking speed, stride frequency, and stride regularity. For each gait variable, the dual task cost was computed and a quartile analysis was obtained. Nonparametric tests were used for all the comparisons (Wilcoxon, Kruskal-Wallis, Fisher or Chi 2 tests). Four clinical subgroups were identified: gait instability (45%), recurrent falls (29%), memory impairment (18%), and cautious gait (8%). The biomechanical severity of these subgroups was ordered according to walking speed and stride regularity under both conditions, from least to most serious as follows: memory impairment, gait instability, recurrent falls, cautious gait (p < 0.01 for walking speed, p = 0.05 for stride regularity). According to the established diagnoses of gait disorders, 5 main pathological subgroups were identified (musculoskeletal diseases (n = 11), vestibular diseases (n = 6), mild cognitive impairment (n = 24), central nervous system pathologies, (n = 51), and without diagnosis (n = 8)). The dual task cost for walking speed, stride frequency and stride regularity were different among these subgroups (p < 0.01). The subgroups mild cognitive impairment and central nervous system pathologies both showed together a higher dual task cost for each variable compared to the other subgroups combined (p = 0.01). The quartile analysis of dual task cost for stride frequency and stride regularity

Gait variability and basal ganglia disorders: stride-to-stride variations of gait cycle timing in Parkinson's disease and Huntington's disease

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Hausdorff, J. M.; Cudkowicz, M. E.; Firtion, R.; Wei, J. Y.; Goldberger, A. L.

1998-01-01

The basal ganglia are thought to play an important role in regulating motor programs involved in gait and in the fluidity and sequencing of movement. We postulated that the ability to maintain a steady gait, with low stride-to-stride variability of gait cycle timing and its subphases, would be diminished with both Parkinson's disease (PD) and Huntington's disease (HD). To test this hypothesis, we obtained quantitative measures of stride-to-stride variability of gait cycle timing in subjects with PD (n = 15), HD (n = 20), and disease-free controls (n = 16). All measures of gait variability were significantly increased in PD and HD. In subjects with PD and HD, gait variability measures were two and three times that observed in control subjects, respectively. The degree of gait variability correlated with disease severity. In contrast, gait speed was significantly lower in PD, but not in HD, and average gait cycle duration and the time spent in many subphases of the gait cycle were similar in control subjects, HD subjects, and PD subjects. These findings are consistent with a differential control of gait variability, speed, and average gait cycle timing that may have implications for understanding the role of the basal ganglia in locomotor control and for quantitatively assessing gait in clinical settings.

Quantitative Maximum Shear-Wave Stiffness of Breast Masses as a Predictor of Histopathologic Severity.

Science.gov (United States)

Berg, Wendie A; Mendelson, Ellen B; Cosgrove, David O; Doré, Caroline J; Gay, Joel; Henry, Jean-Pierre; Cohen-Bacrie, Claude

2015-08-01

The objective of our study was to compare quantitative maximum breast mass stiffness on shear-wave elastography (SWE) with histopathologic outcome. From September 2008 through September 2010, at 16 centers in the United States and Europe, 1647 women with a sonographically visible breast mass consented to undergo quantitative SWE in this prospective protocol; 1562 masses in 1562 women had an acceptable reference standard. The quantitative maximum stiffness (termed "Emax") on three acquisitions was recorded for each mass with the range set from 0 (very soft) to 180 kPa (very stiff). The median Emax and interquartile ranges (IQRs) were determined as a function of histopathologic diagnosis and were compared using the Mann-Whitney U test. We considered the impact of mass size on maximum stiffness by performing the same comparisons for masses 9 mm or smaller and those larger than 9 mm in diameter. The median patient age was 50 years (mean, 51.8 years; SD, 14.5 years; range, 21-94 years), and the median lesion diameter was 12 mm (mean, 14 mm; SD, 7.9 mm; range, 1-53 mm). The median Emax of the 1562 masses (32.1% malignant) was 71 kPa (mean, 90 kPa; SD, 65 kPa; IQR, 31-170 kPa). Of 502 malignancies, 23 (4.6%) ductal carcinoma in situ (DCIS) masses had a median Emax of 126 kPa (IQR, 71-180 kPa) and were less stiff than 468 invasive carcinomas (median Emax, 180 kPa [IQR, 138-180 kPa]; p = 0.002). Benign lesions were much softer than malignancies (median Emax, 43 kPa [IQR, 24-83 kPa] vs 180 kPa [IQR, 129-180 kPa]; p masses. Despite overlap in Emax values, maximum stiffness measured by SWE is a highly effective predictor of the histopathologic severity of sonographically depicted breast masses.

[Subjective Gait Stability in the Elderly].

Science.gov (United States)

Hirsch, Theresa; Lampe, Jasmin; Michalk, Katrin; Röder, Lotte; Munsch, Karoline; Marquardt, Jonas

2017-07-10

It can be assumed that the feeling of gait stability or gait instability in the elderly may be independent of a possible fear of falling or a history of falling when walking. Up to now, there has been a lack of spatiotemporal gait parameters for older people who subjectively feel secure when walking. The aim of the study is to analyse the distribution of various gait parameters for older people who subjectively feel secure when walking. In a cross-sectional study, the gait parameters stride time, step time, stride length, step length, double support, single support, and walking speed were measured using a Vicon three-dimensional motion capture system (Plug-In Gait Lower-Body Marker Set) in 31 healthy people aged 65 years and older (mean age 72 ± 3.54 years) who subjectively feel secure when walking. There was a homogeneous distribution in the gait parameters examined, with no abnormalities. The mean values have a low variance with narrow confidence intervals. This study provides evidence that people who subjectively feel secure when walking demonstrate similarly objective gait parameters..

Automated Gait Analysis Through Hues and Areas (AGATHA): a method to characterize the spatiotemporal pattern of rat gait

Science.gov (United States)

Kloefkorn, Heidi E.; Pettengill, Travis R.; Turner, Sara M. F.; Streeter, Kristi A.; Gonzalez-Rothi, Elisa J.; Fuller, David D.; Allen, Kyle D.

2016-01-01

While rodent gait analysis can quantify the behavioral consequences of disease, significant methodological differences exist between analysis platforms and little validation has been performed to understand or mitigate these sources of variance. By providing the algorithms used to quantify gait, open-source gait analysis software can be validated and used to explore methodological differences. Our group is introducing, for the first time, a fully-automated, open-source method for the characterization of rodent spatiotemporal gait patterns, termed Automated Gait Analysis Through Hues and Areas (AGATHA). This study describes how AGATHA identifies gait events, validates AGATHA relative to manual digitization methods, and utilizes AGATHA to detect gait compensations in orthopaedic and spinal cord injury models. To validate AGATHA against manual digitization, results from videos of rodent gait, recorded at 1000 frames per second (fps), were compared. To assess one common source of variance (the effects of video frame rate), these 1000 fps videos were re-sampled to mimic several lower fps and compared again. While spatial variables were indistinguishable between AGATHA and manual digitization, low video frame rates resulted in temporal errors for both methods. At frame rates over 125 fps, AGATHA achieved a comparable accuracy and precision to manual digitization for all gait variables. Moreover, AGATHA detected unique gait changes in each injury model. These data demonstrate AGATHA is an accurate and precise platform for the analysis of rodent spatiotemporal gait patterns. PMID:27554674

OroSTIFF: Face-referenced measurement of perioral stiffness in health and disease.

Science.gov (United States)

Chu, Shin-Ying; Barlow, Steven M; Kieweg, Douglas; Lee, Jaehoon

2010-05-28

A new device and automated measurement technology known as OroSTIFF is described to characterize non-participatory perioral stiffness in healthy adults for eventual application to patients with orofacial movement disorders associated with neuromotor disease, traumatic injury, or congenital clefts of the upper lip. Previous studies of perioral biomechanics required head stabilization for extended periods of time during measurement, which precluded sampling patients with involuntary body/head movements (dyskinesias), or pediatric subjects. The OroSTIFF device is face-referenced and avoids the complications associated with head-restraint. Supporting data of non-participatory perioral tissue stiffness using OroSTIFF are included from 10 male and 10 female healthy subjects. The OroSTIFF device incorporates a pneumatic glass air cylinder actuator instrumented for pressure, and an integrated subminiature displacement sensor to encode lip aperture. Perioral electromyograms were simultaneously sampled to confirm passive muscle state for the superior and inferior divisions of the orbicularis oris muscles. Perioral stiffness, derived as a quotient from resultant force (DeltaF) and interangle span (DeltaX), was modeled with multilevel regression techniques. Real-time calculation of the perioral stiffness function demonstrated a significant quadratic relation between imposed interangle stretch and resultant force. This stiffness growth function also differed significantly between males and females. This study demonstrates the OroSTIFF 'proof-of-concept' for cost-effective non-invasive stimulus generation and derivation of perioral stiffness in a group of healthy unrestrained adults, and a case study to illustrate the dose-dependent effects of Levodopa on perioral stiffness in an individual with advanced Parkinson's disease who exhibited marked dyskinesia and rigidity. Copyright 2010 Elsevier Ltd. All rights reserved.

DMRT3 is associated with gait type in Mangalarga Marchador horses, but does not control gait ability.

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Patterson, L; Staiger, E A; Brooks, S A

2015-04-01

The Mangalarga Marchador (MM) is a Brazilian horse breed known for a uniquely smooth gait. A recent publication described a mutation in the DMRT3 gene that the authors claim controls the ability to perform lateral patterned gaits (Andersson et al. 2012). We tested 81 MM samples for the DMRT3 mutation using extracted DNA from hair bulbs using a novel RFLP. Horses were phenotypically categorized by their gait type (batida or picada), as recorded by the Brazilian Mangalarga Marchador Breeders Association (ABCCMM). Statistical analysis using the plink toolset (Purcell, 2007) revealed significant association between gait type and the DMRT3 mutation (P = 2.3e-22). Deviation from Hardy-Weinberg equilibrium suggests that selective pressure for gait type is altering allele frequencies in this breed (P = 1.00e-5). These results indicate that this polymorphism may be useful for genotype-assisted selection for gait type within this breed. As both batida and picada MM horses can perform lateral gaits, the DMRT3 mutation is not the only locus responsible for the lateral gait pattern. © 2015 Stichting International Foundation for Animal Genetics.

THE EFFECTS OF SINGLE LEG HOP PROGRESSION AND DOUBLE LEGS HOP PROGRESSION EXERCISE TO INCREASE SPEED AND EXPLOSIVE POWER OF LEG MUSCLE

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Nining W. Kusnanik

2015-05-01

Full Text Available The main purpose of this study was to determine the effect of single leg hop progression and double legs hop progression exercise to increase speed and explosive power of leg muscles. Plyometric is one of the training methods that can increase explosive power. There are many models of plyometric training including single leg hop progression and double leg hop progression. This research was experimental using match subject design techniques. The subjects of this study were 39 students who joined basketball school club. There were 3 groups in this study: Group 1 were 13 students who given sin¬gle leg hop progression exercise, Group 2 were 13 students who given double legs hop progression exercise, Group 3 were 13 students who given conventional exercise. The data was collected during pre test and post test by testing 30m speed running and vertical jump. The data was analyzed using Analysis of Varians (Anova. It was found that there were significantly increased on speed and explosive power of leg muscles of Group 1 and Group 2. It can be stated that single leg hop progression exercise was more effective than double leg hop progression exercise. The recent findings supported the hypothesis that single leg hop progression and double legs hop progression exercise can increase speed and explosive power of leg muscles. These finding were supported by some previous studies (Singh, et al, 2011; Shallaby, H.K., 2010. The single leg hop progression is more effective than double legs hop progression. This finding was consistent with some previous evidences (McCurdy, et al, 2005; Makaruk et al, 2011.

Does robot-assisted gait training ameliorate gait abnormalities in multiple sclerosis? A pilot randomized-control trial.

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Straudi, S; Benedetti, M G; Venturini, E; Manca, M; Foti, C; Basaglia, N

2013-01-01

Gait disorders are common in multiple sclerosis (MS) and lead to a progressive reduction of function and quality of life. Test the effects of robot-assisted gait rehabilitation in MS subjects through a pilot randomized-controlled study. We enrolled MS subjects with Expanded Disability Status Scale scores within 4.5-6.5. The experimental group received 12 robot-assisted gait training sessions over 6 weeks. The control group received the same amount of conventional physiotherapy. Outcomes measures were both biomechanical assessment of gait, including kinematics and spatio-temporal parameters, and clinical test of walking endurance (six-minute walk test) and mobility (Up and Go Test). 16 subjects (n = 8 experimental group, n = 8 control group) were included in the final analysis. At baseline the two groups were similar in all variables, except for step length. Data showed walking endurance, as well as spatio-temporal gait parameters improvements after robot-assisted gait training. Pelvic antiversion and reduced hip extension during terminal stance ameliorated after aforementioned intervention. Robot-assisted gait training seems to be effective in increasing walking competency in MS subjects. Moreover, it could be helpful in restoring the kinematic of the hip and pelvis.

Contribution of the supplementary motor area and the cerebellum to the anticipatory postural adjustments and execution phases of human gait initiation.

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Richard, Aliénor; Van Hamme, Angèle; Drevelle, Xavier; Golmard, Jean-Louis; Meunier, Sabine; Welter, Marie-Laure

2017-09-01

Several brain structures including the brainstem, the cerebellum and the frontal cortico-basal ganglia network, with the primary and premotor areas have been shown to participate in the functional organization of gait initiation and postural control in humans, but their respective roles remain poorly understood. The aim of this study was to better understand the role of the supplementary motor area (SMA) and posterior cerebellum in the gait initiation process. Gait initiation parameters were recorded in 22 controls both before and after continuous theta burst transcranial stimulation (cTBS) of the SMA and cerebellum, and were compared to sham stimulation, using a randomized double-blind design study. The two phases of gait initiation process were analyzed: anticipatory postural adjustments (APAs) and execution, with recordings of soleus and tibialis anterior muscles. Functional inhibition of the SMA led to a shortened APA phase duration with advanced and increased muscle activity; during execution, it also advanced muscle co-activation and decreased the duration of stance soleus activity. Cerebellar functional inhibition did not influence the APA phase duration and amplitude but increased muscle co-activation, it decreased execution duration and showed a trend to increase velocity, with increased swing soleus muscle duration and activity. The results suggest that the SMA contributes to both the timing and amplitude of the APAs with no influence on step execution and the posterior cerebellum in the coupling between the APAs and execution phases and leg muscle activity pattern during gait initiation. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Effects of conventional overground gait training and a gait trainer with partial body weight support on spatiotemporal gait parameters of patients after stroke

OpenAIRE

Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Noh, Ji-Woong; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Kim, Junghwan

2015-01-01

[Purpose] The purpose of this study was to confirm the effects of both conventional overground gait training (CGT) and a gait trainer with partial body weight support (GTBWS) on spatiotemporal gait parameters of patients with hemiparesis following chronic stroke. [Subjects and Methods] Thirty stroke patients were alternately assigned to one of two treatment groups, and both groups underwent CGT and GTBWS. [Results] The functional ambulation classification on the affected side improved signifi...

Benign positional vertigo

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Vertigo - positional; Benign paroxysmal positional vertigo; BPPV: dizziness- positional ... Benign positional vertigo is also called benign paroxysmal positional vertigo (BPPV). It is caused by a problem in the inner ear. ...

Self-perceived gait stability modulates the effect of daily life gait quality on prospective falls in older adults.

Science.gov (United States)

Weijer, R H A; Hoozemans, M J M; van Dieën, J H; Pijnappels, M

2018-05-01

Quality of gait during daily life activities and perceived gait stability are both independent risk factors for future falls in older adults. We investigated whether perceived gait stability modulates the association between gait quality and falling in older adults. In this prospective cohort study, we used one-week daily-life trunk acceleration data of 272 adults over 65 years of age. Sample entropy (SE) of the 3D acceleration signals was calculated to quantify daily life gait quality. To quantify perceived gait stability, the level of concern about falling was assessed using the Falls Efficacy Scale international (FES-I) questionnaire and step length, estimated from the accelerometer data. A fall calendar was used to record fall incidence during a six-month follow up period. Logistic regression analyses were performed to study the association between falling and SE, step length or FES-I score, and their interactions. High (i.e., poor) SE in vertical direction was significantly associated with falling. FES-I scores significantly modulated this association, whereas step length did not. Subgroup analyses based on FES-I scores showed that high SE in the vertical direction was a risk factor for falls only in older adults who had a high (i.e. poor) FES-I score. In conclusion, perceived gait stability modulates the association between gait quality and falls in older adults such that an association between gait quality and falling is only present when perceived gait stability is poor. The results of the present study indicate that the effectiveness of interventions for fall prevention, aimed at improving gait quality, may be affected by a modulating effect of perceived gait stability. Results indicate that interventions to reduce falls in older adults might sort most effectiveness in populations with both a poor physiological and psychological status. Copyright © 2018 Elsevier B.V. All rights reserved.

Quantitative Gait Measurement With Pulse-Doppler Radar for Passive In-Home Gait Assessment

OpenAIRE

Wang, Fang; Skubic, Marjorie; Rantz, Marilyn; Cuddihy, Paul E.

2014-01-01

In this paper, we propose a pulse-Doppler radar system for in-home gait assessment of older adults. A methodology has been developed to extract gait parameters including walking speed and step time using Doppler radar. The gait parameters have been validated with a Vicon motion capture system in the lab with 13 participants and 158 test runs. The study revealed that for an optimal step recognition and walking speed estimation, a dual radar set up with one radar placed at foot level and the ot...

Gait, mobility, and falls in older people

OpenAIRE

Gschwind, Yves Josef

2012-01-01

My doctoral thesis contributes to the understanding of gait, mobility, and falls in older people. All presented projects investigated the most prominent and sensitive markers for fall-related gait changes, that is gait velocity and gait variability. Based on the measurement of these spatio-temporal gait parameters, particularly when using a change-sensitive dual task paradigm, it is possible to make conclusions regarding walking, balance, activities of daily living, and falls in o...

Comparison in lower leg neuromuscular activity between runners with unilateral mid-portion Achilles tendinopathy and healthy individuals.

Science.gov (United States)

Baur, Heiner; Müller, Steffen; Hirschmüller, Anja; Cassel, Michael; Weber, Josefine; Mayer, Frank

2011-06-01

Neuromuscular control in functional situations and possible impairments due to Achilles tendinopathy are not well understood. Thirty controls (CO) and 30 runners with Achilles tendinopathy (AT) were tested on a treadmill at 3.33 ms(-1) (12 km h(-1)). Neuromuscular activity of the lower leg (tibialis anterior, peroneal, and gastrocnemius muscle) was measured by surface electromyography. Mean amplitude values (MAV) for the gait cycle phases preactivation, weight acceptance and push-off were calculated and normalised to the mean activity of the entire gait cycle. MAVs of the tibialis anterior did not differ between CO and AT in any gait cycle phase. The activation of the peroneal muscle was lower in AT in weight acceptance (p=0.006), whereas no difference between CO and AT was found in preactivation (p=0.71) and push-off (p=0.83). Also, MAVs of the gastrocnemius muscle did not differ between AT and CO in preactivity (p=0.71) but were reduced in AT during weight acceptance (p=0.001) and push-off (p=0.04). Achilles tendinopathy does not seem to alter pre-programmed neural control but might induce mechanical deficits of the lower extremity during weight bearing (joint stability). This should be addressed in the therapy process of AT. Copyright © 2010 Elsevier Ltd. All rights reserved.

Congenital pseudarthrosis of lower leg treated by almost outdated method: Case report

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Vukašinović Zoran

2014-01-01

Full Text Available Introduction. Congenital pseudarthrosis of tibia is a rare congenital deformity with progressive evolution. Treatment is vague and difficult, and many methods have been used - from once mandatory early amputation to contemporary operative (Ilizarov method, free microvascular fibular graft and adjuvant methods (electrostimulation, biphosphonates, bone morphogenetic protein. We present the usage of once popular method of homologous graft insertion and intramedullary fixation. Case Outline. This is a case report of male patient with pseudarthrosis involving both crural bones (Boyd type 5, diagnosed in neonatal age. Early conservative treatment was unsuccessful, so child never initiated gait. At the age of three and a half years, operative treatment was applied: resection of pseudarthrosis on both tibia and fibula, and osteoplasty of tibia using cylindric homologous graft and intramedullary fixation with transtarsal Steinman pin, followed by long leg cast immobilization. Pin was removed after ten months, and physical therapy was initiated 1.5 year after surgery, with initial to partial weight bearing and short leg cast throughout another year. Two and a half years after surgery complete union of graft was documented, and then full weight bearing was allowed. At final visit, five years and three months after surgery, shin axis was correct, leg lengths were equal, and child had normal walk with full range of motion. X-ray showed complete union of both tibia and fibula. Conclusion. Despite bad prognostic factors (young age, severe deformity, utilization of obsolete and almost forgotten treatment methods can provide excellent result. [Projekat Ministarstva nauke Republike Srbije, br. III 41004

Advanced Prosthetic Gait Training Tool

Science.gov (United States)

2015-12-01

modules to train individuals to distinguish gait deviations (trunk motion and lower-limb motion). Each of these modules help trainers improve their...AWARD NUMBER: W81XWH-10-1-0870 TITLE: Advanced Prosthetic Gait Training Tool PRINCIPAL INVESTIGATOR: Dr. Karim Abdel-Malek CONTRACTING...study is to produce a computer-based Advanced Prosthetic Gait Training Tool to aid in the training of clinicians at military treatment facilities

Spatio-temporal gait disorder and gait fatigue index in a six-minute walk test in women with fibromyalgia.

Science.gov (United States)

Heredia-Jimenez, Jose; Latorre-Roman, Pedro; Santos-Campos, Maria; Orantes-Gonzalez, Eva; Soto-Hermoso, Victor M

2016-03-01

Gait disorders in fibromyalgia patients affect several gait parameters and different muscle recruitment patterns. The aim of this study was to assess the gait differences observed during a six-minute walk test between fibromyalgia patients and healthy controls. Forty-eight women with fibromyalgia and 15 healthy women were evaluated. Fibromyalgia patients met the American College of Rheumatology criteria for fibromyalgia selected of an ambulatory care. Both patients and controls had a negative history of musculoskeletal disease, neurological disorders, and gait abnormalities. The 15 controls were healthy women matched to the patients in age, height and body weight. Spatio-temporal gait variables and the rate of perceived exertion during the six-minute walk test (all subjects) and Fibromyalgia Impact Questionnaire (fibromyalgia subjects) were evaluated. All walking sets on the GaitRITE were collected and the gait variables were selected at three stages during the six-minute walk test: two sets at the beginning, two sets at 3 min and two sets at the end of the test. In addition, the Fibromyalgia Impact Questionnaire was used for the fibromyalgia patients. Fibromyalgia patients showed a significant decrease in all spatio-temporal gait variables at each of the three stages and had a lower walk distance covered in the six-minute walk test and higher rate of perceived exertion. No correlations were found between the Fibromyalgia Impact Questionnaire and gait variables. The fibromyalgia and control subjects showed lower gait fatigue indices between the middle and last stages. Gait analysis during a six-minute walk test is a good tool to assess the fatigue and physical symptoms of patients with fibromyalgia. Copyright © 2016 Elsevier Ltd. All rights reserved.

ANTHROPOMETRIC, GAIT AND STRENGTH CHARACTERISTICS OF KENYAN DISTANCE RUNNERS

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Pui W. Kong

2008-12-01

Full Text Available This study intended to take a biomechanical approach to understand the success of Kenyan distance runners. Anthropometric, gait and lower extremity strength characteristics of six elite Kenyan distance runners were analyzed. Stride frequency, relative stride length and ground contact time were measured at five running speeds (3.5 - 5.4 m/s using a motion capture system. Isometric knee extension and flexion torques were measured at six angles and hamstrings and quadriceps (H:Q ratios at three angular velocities were determined using an isokinetic dynamometer. These runners were characterized by a low body mass index (20.1 ± 1.8 kg·m- 2, low percentage body fat (5.1 ± 1.6% and small calf circumference (34.5 ± 2.3 cm. At all running speeds, the ground contact time was shorter (p < 0.05 during right (170 - 212 ms compared to left (177 - 220 ms foot contacts. No bilateral difference was observed in other gait or strength variables. Their maximal isometric strength was lower than other runners (knee extension: 1.4 - 2.6 Nm·kg-1, knee flexion: 1.0 - 1.4 Nm·kg-1 but their H:Q ratios were higher than athletes in other sports (1.03 ± 0.51 at 60o/s, 1.44 ± 0.46 at 120o/s, 1.59 ± 0.66 at 180o/s. The slim limbs of Kenyan distance runners may positively contribute to performance by having a low moment of inertia and thus requiring less muscular effort in leg swing. The short ground contact time observed may be related to good running economy since there is less time for the braking force to decelerate forward motion of the body. These runners displayed minor gait asymmetry, though the difference may be too small to be practically significant. Further investigations are needed to confirm whether the bilateral symmetry in strength and high H:Q ratios are related to genetics, training or the lack of injuries in these runners

A Novel Design for Adjustable Stiffness Artificial Tendon for the Ankle Joint of a Bipedal Robot: Modeling & Simulation

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Aiman Omer

2015-12-01

Full Text Available Bipedal humanoid robots are expected to play a major role in the future. Performing bipedal locomotion requires high energy due to the high torque that needs to be provided by its legs’ joints. Taking the WABIAN-2R as an example, it uses harmonic gears in its joint to increase the torque. However, using such a mechanism increases the weight of the legs and therefore increases energy consumption. Therefore, the idea of developing a mechanism with adjustable stiffness to be connected to the leg joint is introduced here. The proposed mechanism would have the ability to provide passive and active motion. The mechanism would be attached to the ankle pitch joint as an artificial tendon. Using computer simulations, the dynamical performance of the mechanism is analytically evaluated.

Effect of interactive cognitive motor training on gait and balance among older adults: A randomized controlled trial.

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Kao, Ching-Chiu; Chiu, Huei-Ling; Liu, Doresses; Chan, Pi-Tuan; Tseng, Ing-Jy; Chen, Ruey; Niu, Shu-Fen; Chou, Kuei-Ru

2018-06-01

Aging is a normal degenerative process that results in a decline in the gait and balance performance of older adults. Interactive cognitive motor training is an intervention that integrates cognitive and motor tasks to promote individuals' physical and cognitive fall risk factors. However, the additive effects of the interactive cognitive motor training on objective quantitative data and comprehensive descriptions of gait and balance warrants further investigation. To investigate the effect of interactive cognitive motor training on older adults' gait and balance from immediate to long-term time points. A double-blind randomized control trial. Four senior service centers and community service centers in Taiwan. 62 older adults who met the inclusion criteria. The study participants were older adults without cognitive impairment, and they were randomly allocated to the experimental group or active control group. In both groups, older adults participated in three sessions of 30-min training per week for a total of 8 weeks, with the total number of training sessions being 24. The primary outcome was gait performance, which was measured using objective and subjective indicators. iWALK was used as an objective indicator to measure pace and dynamic stability; the Functional Gait Assessment was employed as a subjective indicator. The secondary outcome was balance performance, which was measured using iSWAY. A generalized estimating equation was used to identify whether the results of the two groups differ after receiving different intervention measures; the results were obtained from immediate to long-term posttests. Stride length in the pace category of the experimental group improved significantly in immediate posttest (p = 0.01), 3-month follow-up (p = 0.01), and 6-month follow-up (p = 0.04). The range of motion of the leg exhibited significant improvement in immediate posttest (p = 0.04) and 3-month follow-up (p = 0.04). The Functional Gait

Development of a novel virtual reality gait intervention.

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Boone, Anna E; Foreman, Matthew H; Engsberg, Jack R

2017-02-01

Improving gait speed and kinematics can be a time consuming and tiresome process. We hypothesize that incorporating virtual reality videogame play into variable improvement goals will improve levels of enjoyment and motivation and lead to improved gait performance. To develop a feasible, engaging, VR gait intervention for improving gait variables. Completing this investigation involved four steps: 1) identify gait variables that could be manipulated to improve gait speed and kinematics using the Microsoft Kinect and free software, 2) identify free internet videogames that could successfully manipulate the chosen gait variables, 3) experimentally evaluate the ability of the videogames and software to manipulate the gait variables, and 4) evaluate the enjoyment and motivation from a small sample of persons without disability. The Kinect sensor was able to detect stride length, cadence, and joint angles. FAAST software was able to identify predetermined gait variable thresholds and use the thresholds to play free online videogames. Videogames that involved continuous pressing of a keyboard key were found to be most appropriate for manipulating the gait variables. Five participants without disability evaluated the effectiveness for modifying the gait variables and enjoyment and motivation during play. Participants were able to modify gait variables to permit successful videogame play. Motivation and enjoyment were high. A clinically feasible and engaging virtual intervention for improving gait speed and kinematics has been developed and initially tested. It may provide an engaging avenue for achieving thousands of repetitions necessary for neural plastic changes and improved gait. Copyright © 2016 Elsevier B.V. All rights reserved.

Detection of Gait Modes Using an Artificial Neural Network during Walking with a Powered Ankle-Foot Orthosis

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2016-01-01

This paper presents an algorithm, for use with a Portable Powered Ankle-Foot Orthosis (i.e., PPAFO) that can automatically detect changes in gait modes (level ground, ascent and descent of stairs or ramps), thus allowing for appropriate ankle actuation control during swing phase. An artificial neural network (ANN) algorithm used input signals from an inertial measurement unit and foot switches, that is, vertical velocity and segment angle of the foot. Output from the ANN was filtered and adjusted to generate a final data set used to classify different gait modes. Five healthy male subjects walked with the PPAFO on the right leg for two test scenarios (walking over level ground and up and down stairs or a ramp; three trials per scenario). Success rate was quantified by the number of correctly classified steps with respect to the total number of steps. The results indicated that the proposed algorithm's success rate was high (99.3%, 100%, and 98.3% for level, ascent, and descent modes in the stairs scenario, respectively; 98.9%, 97.8%, and 100% in the ramp scenario). The proposed algorithm continuously detected each step's gait mode with faster timing and higher accuracy compared to a previous algorithm that used a decision tree based on maximizing the reliability of the mode recognition. PMID:28070188

Modeling and simulation of normal and hemiparetic gait

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Luengas, Lely A.; Camargo, Esperanza; Sanchez, Giovanni

2015-09-01

Gait is the collective term for the two types of bipedal locomotion, walking and running. This paper is focused on walking. The analysis of human gait is of interest to many different disciplines, including biomechanics, human-movement science, rehabilitation and medicine in general. Here we present a new model that is capable of reproducing the properties of walking, normal and pathological. The aim of this paper is to establish the biomechanical principles that underlie human walking by using Lagrange method. The constraint forces of Rayleigh dissipation function, through which to consider the effect on the tissues in the gait, are included. Depending on the value of the factor present in the Rayleigh dissipation function, both normal and pathological gait can be simulated. First of all, we apply it in the normal gait and then in the permanent hemiparetic gait. Anthropometric data of adult person are used by simulation, and it is possible to use anthropometric data for children but is necessary to consider existing table of anthropometric data. Validation of these models includes simulations of passive dynamic gait that walk on level ground. The dynamic walking approach provides a new perspective of gait analysis, focusing on the kinematics and kinetics of gait. There have been studies and simulations to show normal human gait, but few of them have focused on abnormal, especially hemiparetic gait. Quantitative comparisons of the model predictions with gait measurements show that the model can reproduce the significant characteristics of normal gait.

Measurement of lower leg compression in vivo: recommendations for the performance of measurements of interface pressure and stiffness: consensus statement.

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Partsch, Hugo; Clark, Michael; Bassez, Sophie; Benigni, Jean-Patrick; Becker, Francis; Blazek, Vladimir; Caprini, Joseph; Cornu-Thénard, André; Hafner, Jürg; Flour, Mieke; Jünger, Michael; Moffatt, Christine; Neumann, Martino

2006-02-01

Interface pressure and stiffness characterizing the elastic properties of the material are the parameters determining the dosage of compression treatment and should therefore be measured in future clinical trials. To provide some recommendations regarding the use of suitable methods for this indication. This article was formulated based on the results of an international consensus meeting between a group of medical experts and representatives from the industry held in January 2005 in Vienna, Austria. Proposals are made concerning methods for measuring the interface pressure and for assessing the stiffness of a compression device in an individual patient. In vivo measurement of interface pressure is encouraged when clinical and experimental outcomes of compression treatment are to be evaluated.

Gait Partitioning Methods: A Systematic Review

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Juri Taborri

2016-01-01

Full Text Available In the last years, gait phase partitioning has come to be a challenging research topic due to its impact on several applications related to gait technologies. A variety of sensors can be used to feed algorithms for gait phase partitioning, mainly classifiable as wearable or non-wearable. Among wearable sensors, footswitches or foot pressure insoles are generally considered as the gold standard; however, to overcome some inherent limitations of the former, inertial measurement units have become popular in recent decades. Valuable results have been achieved also though electromyography, electroneurography, and ultrasonic sensors. Non-wearable sensors, such as opto-electronic systems along with force platforms, remain the most accurate system to perform gait analysis in an indoor environment. In the present paper we identify, select, and categorize the available methodologies for gait phase detection, analyzing advantages and disadvantages of each solution. Finally, we comparatively examine the obtainable gait phase granularities, the usable computational methodologies and the optimal sensor placements on the targeted body segments.

Gait Partitioning Methods: A Systematic Review

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Taborri, Juri; Palermo, Eduardo; Rossi, Stefano; Cappa, Paolo

2016-01-01

In the last years, gait phase partitioning has come to be a challenging research topic due to its impact on several applications related to gait technologies. A variety of sensors can be used to feed algorithms for gait phase partitioning, mainly classifiable as wearable or non-wearable. Among wearable sensors, footswitches or foot pressure insoles are generally considered as the gold standard; however, to overcome some inherent limitations of the former, inertial measurement units have become popular in recent decades. Valuable results have been achieved also though electromyography, electroneurography, and ultrasonic sensors. Non-wearable sensors, such as opto-electronic systems along with force platforms, remain the most accurate system to perform gait analysis in an indoor environment. In the present paper we identify, select, and categorize the available methodologies for gait phase detection, analyzing advantages and disadvantages of each solution. Finally, we comparatively examine the obtainable gait phase granularities, the usable computational methodologies and the optimal sensor placements on the targeted body segments. PMID:26751449

Leg Lengthening as a Means of Improving Ambulation Following an Internal Hemipelvectomy

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Wakyo Sato

2016-01-01

Full Text Available Reconstructive surgery following an internal hemipelvectomy for a malignant pelvic tumor is difficult due to the structural complexity of the pelvis and the massive extension of the tumor. While high complication rates have been encountered in various types of reconstructive surgery, resection without reconstruction reportedly involved fewer complications. However, this method often results in limb shortening with resultant instability during walking. We reported herein leg lengthening performed to correct lower limb shortening after an internal hemipelvectomy, which improved ambulatory stability and overall QOL. An 18-year-old male patient came to our hospital to correct a lower limb discrepancy resulting from a left internal hemipelvectomy. His left pelvis and proximal femur had been resected, and the femur remained without an acetabular roof. His left lower limb was about 8 centimeters shorter. The left tibia was lengthened 8 centimeters with an external fixator. After the lengthening, the patient was able to walk without support and his gait remarkably improved. Additionally he no longer required placing a wallet in his back pocket as a pad as a means of raising the left side of his torso while sitting. Leg lengthening was a useful method of improving ambulation after an internal hemipelvectomy.

Unstable gait due to spasticity of the rectus femoris: gait analysis and motor nerve block.

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Gross, R; Leboeuf, F; Rémy-Néris, O; Perrouin-Verbe, B

2012-12-01

We present the case of a 54 year-old man presenting with a right Brown-Séquard plus syndrome (BSPS) after a traumatic cervical spinal cord injury. After being operated on with selective tibial neurotomy and triceps surae lengthening because of a right spastic equinus foot, he developed a gait disorder at high speed. The patient complained about an instability of the right knee. Observational gait analysis exhibited an oscillating, flexion/extension motion of the right knee during stance, which was confirmed by gait analysis. Dynamic electromyographic recordings exhibited a clonus of the right rectus femoris (RF) during stance. The spastic activity of the RF and the abnormal knee motion totally reversed after a motor nerve block of the RF, as well as after botulinum toxin type A injection into the RF. We emphasize that complex, spastic gait disorders can benefit from a comprehensive assessment including gait analysis and nerve blocks. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Surgical therapy by sandwich transplantation using a dermal collagen-elastin matrix and full thickness split grafts and gait rehabilitation with individualized orthesis

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Uwe Wollina

2012-01-01

Full Text Available Painful callosities of the feet (PCOF are a rare complaint in children with severe impairment of mobility and quality of life. There is no medical treatment available.We investigated the usefulness of a recently developed combined transplant technique-the sandwich transplantation with dermal collagen-elastin template in this rare condition. A 14-year-old boy suffered from PCOF for several years without any improvement by topical therapy, dermabrasion, and oral retinoids. He was unable to walk normally and suffered from severe pain. We performed a complete deep excision of the hyperkeratotic plantar tissue in general anaesthesia in combination with sandwich transplantation in the same setting. Dry sheets of collagen-elastin matrix (1 mm thickness were placed on the soft tissue defects and covered by full-thickness mesh graft transplants from the upper leg. An individualized orthosis was produced for gait rehabilitation. Two weeks after surgery the gait-related pain was reduced remarkably. Using the orthosis, the boy was able to walk pain-free even on staircase. Surgery of PCOF with sandwich transplantation and gait rehabilitation appears to be a promising strategy for this rare condition.

Tic-induced gait dysfunction.

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Fasano, A.; Ruzicka, E.; Bloem, B.R.

2012-01-01

BACKGROUND: Many neurological disorders impair gait, but only a few of them are episodic or paroxysmal, the most important ones being freezing of gait and paroxysmal dyskinesias. METHODS: We describe 4 patients with tic disorders (3 with Tourette syndrome, and 1 with a tic disorder secondary to

A Brain–Spinal Interface Alleviating Gait Deficits after Spinal Cord Injury in Primates

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Capogrosso, Marco; Milekovic, Tomislav; Borton, David; Wagner, Fabien; Moraud, Eduardo Martin; Mignardot, Jean-Baptiste; Buse, Nicolas; Gandar, Jerome; Barraud, Quentin; Xing, David; Rey, Elodie; Duis, Simone; Jianzhong, Yang; Ko, Wai Kin D.; Li, Qin; Detemple, Peter; Denison, Tim; Micera, Silvestro; Bezard, Erwan; Bloch, Jocelyne; Courtine, Grégoire

2016-01-01

Spinal cord injury disrupts the communication between the brain and the spinal circuits that orchestrate movement. To bypass the lesion, brain–computer interfaces1–3 have directly linked cortical activity to electrical stimulation of muscles, which have restored grasping abilities after hand paralysis1,4. Theoretically, this strategy could also restore control over leg muscle activity for walking5. However, replicating the complex sequence of individual muscle activation patterns underlying natural and adaptive locomotor movements poses formidable conceptual and technological challenges6,7. Recently, we showed in rats that epidural electrical stimulation of the lumbar spinal cord can reproduce the natural activation of synergistic muscle groups producing locomotion8–10. Here, we interfaced leg motor cortex activity with epidural electrical stimulation protocols to establish a brain–spinal interface that alleviated gait deficits after a spinal cord injury in nonhuman primates. Rhesus monkeys were implanted with an intracortical microelectrode array into the leg area of motor cortex; and a spinal cord stimulation system composed of a spatially selective epidural implant and a pulse generator with real-time triggering capabilities. We designed and implemented wireless control systems that linked online neural decoding of extension and flexion motor states with stimulation protocols promoting these movements. These systems allowed the monkeys to behave freely without any restrictions or constraining tethered electronics. After validation of the brain–spinal interface in intact monkeys, we performed a unilateral corticospinal tract lesion at the thoracic level. As early as six days post-injury and without prior training of the monkeys, the brain–spinal interface restored weight-bearing locomotion of the paralyzed leg on a treadmill and overground. The implantable components integrated in the brain–spinal interface have all been approved for investigational

LOPES: Selective control of gait functions during the gait rehabilitation of CVA patients

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Ekkelenkamp, R.; Veneman, J.F.; van der Kooij, Herman

2005-01-01

LOPES aims for an active role of the patient by selective and partial support of gait functions during robotic treadmill training sessions. Virtual model control (VMC) was applied to the robot as an intuitive method for translating current treadmill gait rehabilitation therapy programs into robotic

Gait recognition based on integral outline

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Ming, Guan; Fang, Lv

2017-02-01

Biometric identification technology replaces traditional security technology, which has become a trend, and gait recognition also has become a hot spot of research because its feature is difficult to imitate and theft. This paper presents a gait recognition system based on integral outline of human body. The system has three important aspects: the preprocessing of gait image, feature extraction and classification. Finally, using a method of polling to evaluate the performance of the system, and summarizing the problems existing in the gait recognition and the direction of development in the future.

Limit cycles and stiffness control with variable stiffness actuators

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Carloni, Raffaella; Marconi, L.

2012-01-01

Variable stiffness actuators realize highly dynamic systems, whose inherent mechanical compliance can be properly exploited to obtain a robust and energy-efficient behavior. The paper presents a control strategy for variable stiffness actuators with the primarily goal of tracking a limit cycle

Evaluation of gait performance of knee osteoarthritis patients after total knee arthroplasty with different assistive devices

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Ana Tereso

Full Text Available IntroductionNowadays Knee Osteoarthritis (KOA affects a large percentage of the elderly, and one solution is to perform a Total Knee Arthroplasty (TKA. In this paper, one intends to study the gait and posture of these patients after the TKA, while walking with three assistive devices (ADs (crutches, standard walker (SW and rollator with forearm supports (RFS.MethodsEleven patients were evaluated in 2 phases: 5 days and 15 days after surgery. This evaluation was conducted with two inertial sensors, one attached to the operated leg ankle, to measure spatiotemporal parameters, and the other at the sacrum, to measure posture and fall risk-related parameters. Multivariate analysis of variance (MANOVA with repeated measures was performed to detect group differences.ResultsThe MANOVA results show that all spatiotemporal parameters are significantly different (p0.05. The interaction between time and ADs only affects significantly the velocity (p<0.05. In terms of fall risk parameters, time only significantly affects the antero-posterior direction (p<0.05 and ADs affects significantly root mean square in medio-lateral direction (p<0.05. In terms of interaction between time and ADs, there are no statistical significant differences.ConclusionThis study concludes that depending on the state of recovery of the patient, different ADs should be prescribed. On the overall, standard walker is good to give stability to the patient and RFS allows the patient to present a gait pattern closer to a natural gait.

First signs of elderly gait for women.

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Kaczmarczyk, Katarzyna; Wiszomirska, Ida; Błażkiewicz, Michalina; Wychowański, Michał; Wit, Andrzej

2017-06-27

The aims of this study have been twofold: to attempt to reduce the number of spatiotemporal parameters used for describing gait through the factor analysis and component analysis; and to explore the critical age of decline for other gait parameters for healthy women. A total of 106 women (aged ≥ 40 years old (N = 76) and ≤ 31 years old (N = 30)) were evaluated using a pressure-sensitive mat (Zebris Medical System, Tübingen, Germany) for collecting spatiotemporal gait parameters. The factor analysis identified 2 factors - labelled Time and Rhythm - that accounted for 72% of the variation in significant free-gait parameters; the principal component analysis identified 4 of these parameters that permit full clinical evaluation of gait quality. No difference was found between the groups in terms of the values of parameters reflecting the temporal nature of gait (Rhythm), namely step time, stride time and cadence, whereas significant differences were found for total double support phase (p gait, we selected 3 parameters: total double support, stride time and velocity. We concluded that the women taking part in the experiment manifested significant signs of senile gait after the age of 60 years old, with the first symptoms thereof already manifesting themselves after 50 years of age. We show that among 26 spatiotemporal parameters that may be used for characterizing gait, at least a half of them may be omitted in the assessment of gait correctness; a finding that may be useful in clinical practice. The finding that the onset of senile gait occurs in the case of women after the age of 60 years old, in turn, may be useful in evaluating the ability for performing types of physical work that mainly require ambulation. Med Pr 2017;68(4):441-448. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Gait variability: methods, modeling and meaning

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Hausdorff Jeffrey M

2005-07-01

Full Text Available Abstract The study of gait variability, the stride-to-stride fluctuations in walking, offers a complementary way of quantifying locomotion and its changes with aging and disease as well as a means of monitoring the effects of therapeutic interventions and rehabilitation. Previous work has suggested that measures of gait variability may be more closely related to falls, a serious consequence of many gait disorders, than are measures based on the mean values of other walking parameters. The Current JNER series presents nine reports on the results of recent investigations into gait variability. One novel method for collecting unconstrained, ambulatory data is reviewed, and a primer on analysis methods is presented along with a heuristic approach to summarizing variability measures. In addition, the first studies of gait variability in animal models of neurodegenerative disease are described, as is a mathematical model of human walking that characterizes certain complex (multifractal features of the motor control's pattern generator. Another investigation demonstrates that, whereas both healthy older controls and patients with a higher-level gait disorder walk more slowly in reduced lighting, only the latter's stride variability increases. Studies of the effects of dual tasks suggest that the regulation of the stride-to-stride fluctuations in stride width and stride time may be influenced by attention loading and may require cognitive input. Finally, a report of gait variability in over 500 subjects, probably the largest study of this kind, suggests how step width variability may relate to fall risk. Together, these studies provide new insights into the factors that regulate the stride-to-stride fluctuations in walking and pave the way for expanded research into the control of gait and the practical application of measures of gait variability in the clinical setting.

Accuracy and reliability of observational gait analysis data: judgments of push-off in gait after stroke.

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McGinley, Jennifer L; Goldie, Patricia A; Greenwood, Kenneth M; Olney, Sandra J

2003-02-01

Physical therapists routinely observe gait in clinical practice. The purpose of this study was to determine the accuracy and reliability of observational assessments of push-off in gait after stroke. Eighteen physical therapists and 11 subjects with hemiplegia following a stroke participated in the study. Measurements of ankle power generation were obtained from subjects following stroke using a gait analysis system. Concurrent videotaped gait performances were observed by the physical therapists on 2 occasions. Ankle power generation at push-off was scored as either normal or abnormal using two 11-point rating scales. These observational ratings were correlated with the measurements of peak ankle power generation. A high correlation was obtained between the observational ratings and the measurements of ankle power generation (mean Pearson r=.84). Interobserver reliability was moderately high (mean intraclass correlation coefficient [ICC (2,1)]=.76). Intraobserver reliability also was high, with a mean ICC (2,1) of.89 obtained. Physical therapists were able to make accurate and reliable judgments of push-off in videotaped gait of subjects following stroke using observational assessment. Further research is indicated to explore the accuracy and reliability of data obtained with observational gait analysis as it occurs in clinical practice.

Is EMG of the lower leg dependent on weekly running mileage?

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Baur, H; Hirschmüller, A; Müller, S; Cassel, M; Mayer, F

2012-01-01

Neuromuscular activity of the lower leg is dependent on the task performed, speed of movement and gender. Whether training volume influences neuromuscular activity is not known. The EMG of physically active persons differing in running mileage was analysed to investigate this. 55 volunteers were allocated to a low (LM:  30 km &  45 km) group according to their weekly running volume. Neuromuscular activity of the lower leg was measured during running (3.33 m·s - 1). Mean amplitude values for preactivation, weight acceptance and push-off were calculated and normalised to the mean activity of the entire gait cycle.Higher activity in the gastrocnemius group was observed in weight acceptance in LM compared to IM (+30%) and HM (+25%) but lower activity was present in the push-off for LM compared to IM and HM. For the peroneal muscle, differences were present in the push-off where HM showed increased activity compared to IM (+24%) and LM (+60%). The tibial muscle revealed slightly lower activity during preactivation for the high mileage runners. Neuromuscular activity differs during stance between the high and intermediate group compared to low mileage runners. Slight adaptations in neuromuscular activation indicate a more target-oriented activation strategy possibly due to repetitive training in runners with higher weekly mileage. © Georg Thieme Verlag KG Stuttgart · New York.

The Relationship among Leg Strength, Leg Power and Alpine Skiing Success.

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Gettman, Larry R.; Huckel, Jack R.

The purpose of this study was to relate leg strength and power to alpine skiing success as measured by FIS points. Isometric leg strength was represented by the knee extension test described by Clarke. Leg power was measured by the vertical jump test and the Margaria-Kalamen stair run. Results in the strength and power tests were correlated with…