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Nicolopoulos, Christos. "Evaluation of the treatment of foot deformities using foot orthoses." Thesis, University of Strathclyde, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.344073.
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List, Renate Barbara. "Joint kinematics of unconstrained ankle arthroplasties /." [S.l.] : [s.n.], 2009. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18404.
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Weiss, Patrice Lynne. "Position dependence of ankle joint dynamics." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=72042.
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The objective of the work that comprises this thesis was to examine the position-dependent behavior of the human ankle joint dynamics. A series of experiments based on the use of system identification techniques were carried out; the experimental stimulus consisted of small-amplitude, stochastic perturbations of the ankle. The response to this input was modulated by two, experimentally-controlled parameters: tonically-maintained mean joint angles and tonically-maintained triceps surae or tibialis anterior contractions. This permitted the identification of the dynamic response of the torque (passive and active mechanics) and agonist electromyogram (reflex dynamics) for a functionally significant span of mean ankle angles and levels of tonic muscle contractions.<br>The major conclusions of this work were that (1) the position-dependent changes in the passive joint mechanics were large and functionally significant; (2) the active joint mechanics depended entirely on the magnitude of the actively-generated torque with position-dependent changes in the active mechanics being relatively small and variable; and (3) the triceps surae stretch reflexes depended upon the position of the ankle while tibialis anterior stretch reflexes did not. The functional implications of these results and, in particular, the relative importance of the active and passive processes in the behaviour of the ankle joint have been considered in light of these findings.
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Vasquez, Rebecca (Rebecca Ann). "Simulating control of the ankle joint." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/74912.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 33).<br>Computing environments such as Matlab that are conventionally used to simulate dynamics of rigid body systems can be used to model interactions between the system and its environment. However, creating these simulations using Matlab or an equivalent is difficult and there is a need for a more convenient simulation environment for such problems. Two alternative programs, PyODE and OpenSim, were explored to evaluate their ability to fill this need. Models and simulations of the human ankle were created in PyODE. This program is useful for creating simple models where the programmer desires a high level of control over model parameters. Simulations of the ankle kicking a ball and taking a step were created to examine the effect of joint stiffness on these motions and help determine the usefulness of ODE as a simulation tool. Pre-existing models were analyzed in OpenSim. OpenSim is specifically designed for analyzing biomechanical systems. It allows for more complex models to be created but the user has more limited control over the model parameters.<br>by Rebecca Vasquez.<br>S.B.
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Kuganenderan, Nivedah. "Biotribology of the natural ankle joint." Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/22101/.
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The ankle joint is a stable and congruent joint that helps to protect the joint surfaces from high impact forces. However, possible trauma to the joint such as severe ankle sprain or fracture can cause cartilage breakdown and eventually lead to cartilage degeneration, resulting in arthritis. Ankle arthritis is considered to be a major cause of morbidity and disability. Although the ankle joint is least affected by arthritis compared to knee and hip joints, the pain and lack of mobility of end stage ankle osteoarthritis (OA) are equally debilitating and tend to be overlooked compared to hip and knee OA. Differences in the incidence rates of osteoarthritis (OA) across the joints could be partly attributed to the biomechanical properties of the articular cartilage. The aim of the thesis was to improve the understanding of mechanical characteristics of the human ankle cartilage through developing and refining methodologies (i.e. indentation and thickness methods) on immature porcine ankle tissues. As porcine ankle joint seems to closely represent the human ankle with comparable anatomical features, cartilage deformation, cartilage thickness, coefficient of friction, surface roughness, contact mechanics and biological properties were also determined. Comparisons of mechanical characteristics between porcine and human tissues were reported. A methodology was developed to identify the most suitable type of specimen (osteochondral samples versus whole joints) for mechanical characterisation as specimen preparation via pin extraction was hypothesised to have an effect on the tissue quality and thus on biomechanical properties. Specimen preparation of osteochondral pins had no impact on properties as cartilage deformation and thickness measurements of pins were comparable to whole joints. Therefore, for mechanical characterisation of human ankle cartilage, osteochondral pins were studied. Porcine talar cartilage was found to be thicker, with higher surface roughness, increased water content, increased contact pressures and lower glycosaminoglycan (GAG) content compared to porcine tibial cartilage. Based on such results, the talar cartilage in the young porcine tissue (3 to 6 months) appeared more susceptible to deterioration over time when compared to tibial cartilage as these properties were considered as unfavourable potentially affecting joint function and quality of tissue during high impact forces. Overall, there were significant differences in thickness, deformation and roughness measurements (ANOVA, p < 0.05 for all comparators) across the porcine and human tissues. These differences between animal and human tissues can be attributed to many factors such as age, gait, lifestyle and mechanical properties. The immature porcine cartilage was considered to be a poor representative model for tribological studies. On the human ankle joint, cartilage thicknesses, deformation and surface roughness measurements were all in a comparable range between talar and tibial joint surfaces (ANOVA, p < 0.05 for all comparators). Although ankle lesions were reported to be commonly found in the talar surface rather than the tibial surface, and it was assumed to result in unfavourable properties, this was not reported in the current study as no significance was observed between both joint surfaces.
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Wholohan, Aaron J. "An investigation into the immediate effects of ankle joint mobilisation in people with ankle equinus." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/134467/1/Aaron%20J.%20Wholohan%20Thesis.pdf.
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Ankle equinus is a limitation in ankle dorsiflexion, which has been clinically associated with impaired balance and lower limb pathology in adults. This thesis investigated the immediate effects of ankle mobilisation on balance performance, plantar pressures, muscle activity and ankle movement in people with ankle equinus. Through a series of carefully controlled studies, this thesis identified considerable variation in the force applied during ankle mobilisation. Although the findings suggest that mobilisation may result in improvements in patient-reported outcomes, it also questions the rationale behind the use of ankle mobilisation as an intervention in ankle equinus.
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Leardini, Alberto. "Geometry and mechanics of the human ankle complex, and ankle prosthesis design." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343530.
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Murphy, Norman. "Ankle and subtalar joint kinematic description using stereophotogrammetry." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61674.
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Zhao, Yong. "Identification of ankle joint stiffness using subspace methods." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86800.
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Studying joint stiffness against a compliant load is a difficult problem because the intrinsic and reflex torques cannot be measured separately experimentally. Moreover, the joint stiffness is operated within a closed loop because the ankle torque is fed back through the load to change the ankle position. In this thesis, a state space model for ankle joint stiffness is developed. Then, a discrete-time, subspace-based method is used to estimate this state space model for overall stiffness. By using appropriate instrumental variables, the subspace method can estimate the state space model for joint stiffness in both open-loop and in closed-loop conditions. This thesis also presents a subspace method to identify state space models for biomedical systems with short transients or systems with time-varying behaviors, from ensembles of short transients. The simulation and experimental results demonstrate that those algorithms provide accurate estimates under their respective conditions.<br>L'étude de la rigidité articulaire en réponse à une charge est un problème difficile car les couples réflexes et intrinsèques ne peuvent pas être mesurés séparément expérimentalement. En outre, la rigidité articulaire opère en boucle fermée car le couple de la cheville est réinjectée à travers la charge pour modifier la position de la cheville. Dans cette thèse, un modèle d'espace d'état pour la rigidité articulaire de la cheville est développé. Une méthode sous-espace à temps discret est ensuite utilisée pour estimer ce modèle d'espace d'état pour la rigidité globale. En considérant les variables instrumentales appropriées, la méthode sous-espace permet d'estimer le modèle espace d'état pour la rigidité articulaire en boucles ouverte et fermée. Cette thèse présente également une méthode sous-espace pour identifier les modèles d'espace d'état pour les systèmes biomédicauxou les systèmes variant dans le temps caractérisés par des phénomènes transitoires de courte durée. Les simulations et les résultats expérimentaux démontrent que ces algorithmes fournissent des estimations précises en fonction de leurs conditions propres.
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Gatt, Alfred. "Biomechanical assessment of passive ankle joint complex dorsiflexion." Thesis, Staffordshire University, 2012. http://eprints.staffs.ac.uk/1991/.
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The measurement of ankle joint dorsiflexion is an important component of the clinical examination of the foot and is also an outcome measure often employed in research. Diagnosis of ankle equinus or limited ankle dorsiflexion is based solely on this measurement. Although a great majority of research papers in this field utilise normal clinical goniometers for obtaining the maximum ankle dorsiflexion angle (MADA) and important clinical decisions are based on these findings, there is overwhelming evidence that this method is highly unreliable. Thus this thesis aimed to investigate alternative methods of measuring ankle dorsiflexion and various issues that affect the MADA in order to obtain a clear picture of foot segment movement from which an Ankle Goniometer could be consequently designed and validated. Ten different techniques were identified that included various apparatuses designed specifically for measuring ankle dorsiflexion. However, during validation, their methodological quality would have benefitted from the use of an actual patient population and comparison with a reference standard, which caused papers to score poorly on methodological quality assessment. It was concluded that issues affecting this measurement and that needed to be researched further include: foot posture, the amount of moment applied and the stretching characteristics of the calf muscle tendon unit. Experiments within this study indicated that in adults, the mean maximum pronated angles were always higher than in other postures, with 8.27o difference between the pronated and supinated postures (p=0.032) and 5.78o between pronated and neutral (p=0.000). However, the reported difference between neutral and supinated (mean angle of 2.49o) is of little clinical significance. It was observed that the forefoot always travels through a greater angle than the hindfoot in all 3 foot postures, while the hindfoot to forefoot angle increases during the application of a moment, indicating that the ‘midtarsal joint locking mechanism’ cannot be applied to passive dorsiflexion of the foot. In adolescents, there are no significant differences in the mean MADA between the 3 postures, implying that this measurement technique may be performed in any of these postures. It was also concluded that there is no need to control moment applied during this measurement procedure to produce consistent results between raters and that the calf muscle tendon unit does not stretch significantly following brief repetitive passive stretching. ii An ankle goniometer that measured purely hindfoot movement by eliminating forefoot influence and that increased reliability by holding the foot in the chosen posture, was consequently designed. This was validated by synchronizing with an electrogoniometer and an optoelectronic motion capture system. Reliability testing, with the foot held in a supinated posture as opposed to the traditional Rootian method of placing the foot at subtalar joint neutral position, spanned a number of different trials, including intra-tester and inter-tester reliability studies utilising both controlled and uncontrolled conditions, in convenience samples of healthy participants and a random sample of patients. Reliability testing between 4 raters with little experience on the utilization of this device was finally conducted. It has been shown that the Ankle Goniometer is a valid and reliable device for measuring ankle joint complex dorsiflexion both in healthy adults and in a patient population.
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Millington, Steven Andrew. "Quantitative stereophotogrammetric & MRI evaluation of ankle articular cartilage and ankle joint contact characteristics." Thesis, University of Nottingham, 2008. http://eprints.nottingham.ac.uk/10484/.
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Osteoarthritis and degenerative cartilage diseases affect millions of people. Therefore, there is huge interest in developing new therapies to repair, replace and/or regenerate cartilage. This necessitates advances in techniques which make earlier non-invasive diagnosis and objective quantitative evaluations of new therapies possible. Most previous research has focused on the knee and neglected the ankle joint. Hence, the aims of this thesis are to describe and quantify the geometric properties of ankle cartilage, to evaluate joint contact characteristics and develop techniques which allow quantitative measurements to be made in vivo. Chapters 3 and 6 describe the application of a high resolution stereophotography system for making highly accurate 3-D geometric models from which quantitative measurements of cartilage parameters and joint area contact can be made. Chapters 4 and 5 report the testing of image analysis algorithms designed to segment cartilage sensitive MR images. Work focused on initially on a semi-automated 2-D segmentation approach and subsequently on a pilot study of 3-D automated segmentation algorithm. The stereophotographic studies were highly accurately and demonstrated that ankle cartilage thickness is greater than previously reported with the thickest cartilage occurring where cartilage injuries are most commonly seen. Furthermore, joint contact area is larger than previously believed and corresponds to the regions of the thickest cartilage over the talar shoulders. The image analysis studies show that it is possible to accurately and reproducibly segment the thin cartilage layers of the ankle joint using a semi-automated approach. The feasibility of a fully automated 3D method for future clinical use is also shown. In conclusion this thesis presents novel methods for examining ankle articular cartilage in vitro and in vivo, showing that the thickest cartilage occurs in highly curved regions over the shoulders of the talus which correspond to regions of greatest contact. Importantly, the image analysis techniques may be used for future clinical monitoring of patients sustaining cartilage injuries or undergoing cartilage repair therapies.
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North, Ian Graham. "First metatarsophalangeal joint range of motion : influence of ankle joint position and gastrocsoleus muscle stretching." University of Western Australia. School of Surgery, 2008. http://theses.library.uwa.edu.au/adt-WU2009.0021.
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[Truncated abstract] First metatarsophalangeal joint (MTPJ1) motion is an important factor in normal weight transference during walking. Disruptions to normal range can influence joints both proximal and distal to the MTPJ1, potentially leading to pain and dysfunction. Whilst the MTPJ1 has been investigated significantly, the numerous methodologies described to quantify range of motion can be questioned and makes comparisons difficult. Range of MTPJ1 motion is commonly assessed in a clinical setting to determine pathology as well as to make decisions on appropriate intervention. The anatomical and biomechanical influence of tendo Achilles load and MTPJ1 motion has been well described; however few studies measuring MTPJ1 range control for Achilles load or describe ankle joint positioning. Further to this the effects of reducing tendo Achilles stiffness on MTPJ1 extensions has yet to be investigated. The purpose of this study was to describe a technique to quantify passive MTPJ1 extension and to determine the influence of ankle joint position on joint range. Secondly the effect of calf muscle stretching on MTPJ1 range was also investigated. The information gathered will assist both research and clinical protocols for quantifying MTPJ1 range, and provide a greater understanding of the anatomic and biomechanical relationship between tendo Achilles load and MTPJ1 extension. In order to fulfil the purposes of the study it was necessary to establish a reliable methodology to quantify non weight bearing MTPJ1 extension. Reliability testing was undertaken in three parts. '...' The results demonstrated a statistically significant increase in joint range immediately following a one minute stretch for variables ankle joint range of motion as well as MTPJ1 extension for ankle joint plantar flexed at 10 Newton's and ankle joint neutral and plantar flexed at 30 Newtons. No significant differences were noted in ankle or MTPJ1 range of motion in either the control group on immediate re-testing, or in both groups after a one week stretch program. The findings of this study support those documented in the literature pertaining to the ankle joint position, tendo Achilles load and plantar fascial stiffness to MTPJ1 range of motion. Increased stiffness at the MTPJ1 was noted dependant on ankle joint position from ankle joint plantar flexion through to ankle joint dorsiflexion. This appears most likely due to increases in tendo Achilles load and subsequent forces transmitted to the plantar aponeurosis. The present study also demonstrated a trend towards increased joint extensibility and limb dominance. The study also supports previous literature into gender differences and joint extensibility, with a positive trend towards increased MTPJ1 range evident in the female subjects tested. The study also demonstrated the immediate effect of calf muscle stretching on ankle and MTPJ1 range of motion. It remains however unclear as to the exact mechanisms involved in producing increased joint range be it reflex inhibition or actual changes to the viscoelastic properties of the soft tissues. Despite this, no changes were evident following a one week stretching program, which supports previous literature describing a short lag time before soft tissues revert to baseline length properties following a single stretch session.
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Näslund, Annika. "Dynamic ankle-foot orthoses in children with spastic diplegia : interview and experimental studies /." Luleå : Division of Physiotherapy, Department of Health Sciences, Luleå University of Technology, 2007. http://epubl.ltu.se/1402-1544/2007/11/.
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Sopher, Ran Salach. "Muscle architecture, loading and joint replacement of the ankle." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/48939.
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The use of total ankle replacement (TAR) for treatment of arthritis is rapidly increasing, but survival rates are of major concern. The primary indication for TAR revision is implant loosening, which is linked with inadequate primary stability manifested in higher levels of initial implant-bone micromotion. Finite-element (FE) modelling has been utilised to assess micromotion of arthroplasty implants, but not TAR. Additionally, the biomechanical consequences of TAR malpositioning during surgery – previously linked with higher failure rates – remain unexplored. The aim of this thesis was therefore to apply FE modelling to estimate implant-bone micromotion and peri-implant bone strains of current TAR designs under optimally-positioned and malpositioned cases, and thereby identify fixation features and malpositioning scenarios that place the reconstructed ankle at risk of early loosening. Computational models simulating commonly-used TAR designs (BOX®, Mobility® and Salto®) implanted into the tibia and talus were developed; the loads applied were the contact forces acting in the ankle during gait, as calculated using a previously-validated musculoskeletal model, while implementing muscle-architecture data obtained through dissections of cadaveric legs. Micromotion and strain outcomes were larger for the tibial compared with the talar components, in agreement with previous clinical observations. The tibial Mobility® and talar Salto® components demonstrated the largest micromotion. A gap between the tibia/talus and implant component resulted in a considerable increase in implant-bone micromotion and peri-implant bone strains; the Salto® design was relatively ‘forgiving’ for such malpositioning. It was concluded that better primary stability can be achieved through fixation nearer to the joint line, while relying on more than a single fixation peg, and preserving more of the cortical sidewalls of the bone; incomplete seating of the implant on the bone increases the risk for TAR failure. The models presented in this thesis may assist implant designers and surgeons in improving TAR designs and surgical techniques.
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Woodburn, James. "Kinematics at the ankle joint complex in rheumatoid arthritis." Thesis, University of Leeds, 2000. http://etheses.whiterose.ac.uk/753/.
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This thesis investigates the three-dimensional kinematics at the ankle joint complex in rheumatoid arthritis. Previous studies have identified the rearfoot as a common site for inflammatory activity in rheumatoid arthritis resulting in painful and disabling deformity for which there are no proven interventions. A generic electromagnetic tracking system was developed to undertake three-dimensional kinematics at the ankle joint complex in the bare and shod foot during gait. A joint simulator was designed, manufactured and commissioned in house to test the accuracy of the system. The results indicated errors of less than 1° in rotation and 1 mm in position measurements. Clinical testing of the measurement system was undertaken in both normal healthy adults and rheumatoid arthritis subjects. The technique was able to measure the characteristic three-dimensional kinematics for the ankle joint complex in the normal subjects and detected accurately abnormal angular rotations in the rheumatoid arthritis group. In both cohorts the within day repeatability of the measurements were good, and over a longer period data were stable in the rheumatoid arthritis group allowing the technique to be used in longitudinal studies. Finally, skin movement artefact where the electromagnetic sensor is attached on the heel was investigated using a magnetic resonance imaging technique and found to be less than 1° across the range of motion for the joint complex. Kinematic measurements were undertaken in two cohorts of rheumatoid arthritis subjects randomised to receive or not custom manufactured foot orthoses to correct early valgus heel deformity. The orthoses were constructed in rigid carbon graphite and modified to offer the correct degree of movement control for each patient. Kinematic data were compared between the rheumatoid arthritis groups and that measured from an age- and sex-matched healthy adult population. In both rheumatoid arthritis groups abnormal kinematics were easily detected with significant alteration of inversion/eversion and internal/external rotation. With foot orthoses the inversion/eversion angular rotations were almost fully restored to normal, but little effect was observed for internal/external rotation. The rheumatoid arthritis patients underwent repeat kinematic measurement over a period of 30-months. In the control group the angular rotations improved slightly from baseline, although in comparison with normal healthy population remained abnormal. In the intervention group the orthotic control of inversion/eversion was sustainable for 30 months. Furthermore, coupling between inversion/eversion and internal/external rotation was partially restored towards the end of the study. In barefoot walking the intervention group demonstrated a substantial correction of the deformity in the frontal plane. It was attempted to explain the results in terms of soft-tissue laxity and adaptation following correction of joint deformity. Three-dimensional kinematic measurements were also conducted at the knee and calcaneotalonavicular joint complex. Abnormal rotations and orthotic response were demonstrable at these joints but with less satisfactory results because of technical limitations of the measurement technique. Plantar pressure distribution was also studied using an in-shoe measurement technique. Custom designed orthoses were found to alter the pressure and force distribution at the interface with the foot. The largest effects were observed at the heel and midfoot regions and these were sustainable and significantly different from the non-intervention control group. The clinical effectiveness of the foot orthoses was also evaluated. A pragmatic randomised controlled trial was undertaken and serial measurements of foot pain and disability, using the Foot Function Index conducted at baseline and 3,6 12,18,24 and 30-months. The results revealed an immediate and significant reduction in foot pain and disability with foot orthoses. Minor adverse reactions were reported but overall comfort levels and compliance were high. The overall reduction in foot pain and disability was sustained up to 30 months.
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Marquardt, Mary Johanna. "Functional morphology of the anthropoid talocrural joint." Diss., Columbia, Mo. : University of Missouri-Columbia, 2008. http://hdl.handle.net/10355/5718.
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Thesis (M.A.)--University of Missouri-Columbia, 2008.<br>The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 13, 2009) Includes bibliographical references.
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Hamilton, Stephanie E. "The influence of passive ankle joint power on balance recovery." Thesis, Michigan Technological University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3724620.
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<p> Over one–third of Americans over the age of 65 fall each year, costing more than $19 billion in health care costs in 2000. Many adults 65+ who have not experienced a fall still fear falling, and fear can decrease quality of life and increase the likelihood of falls. Several factors such as muscle strength, power, stiffness and tendon properties change in the human body with age affecting balance, which has been tagged as a fall risk predictor. Additionally, balance recovery strategies also differ between young and older adults, with young adults primarily utilizing their ankle joint and older adults utilizing their hip. The role of passive ankle joint power in balance recovery is unknown. Therefore, we conducted three studies. In Study 1, we investigated the role of passive ankle joint power in balance recovery of young subjects and tested if the contribution of passive power to net ankle joint power changed with perturbation speed. In Study 2, we explored the factor of age in the contribution of passive ankle joint power to net ankle joint power. In Study 3, we searched for a link between the contribution of passive ankle joint power to net ankle joint power and balance recovery strategy. Passive joint torque through the full range of motion was collected for each subject. Each subject performed 5 stepping tasks at two speeds, fast and slow. Joint kinematics and kinetics were collected for each trial. Inverse dynamics were performed and net ankle joint torque and net ankle joint work were computed. Passive ankle joint torque models were optimized for each subject, and passive ankle joint powers were determined. In Study 1, there appeared to be no difference in net or passive joint powers with respect to perturbation speed. In Study 2, age affected net ankle joint powers and passive uniarticular plantar- and dorsiflexor powers. In Study 3, we noted a change in balance recovery strategy between young and older adults. We were unable to predict balance recovery strategy index based off of the percent contribution of passive ankle joint work to net ankle joint work. These studies bring greater clarity to the role of passive ankle joint power with respect to balance recovery. </p>
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Ganguly, Amartya. "Modelling of the human quiet stance with ankle joint complexity." Thesis, University of Hull, 2014. http://hydra.hull.ac.uk/resources/hull:11634.
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This study derives an inverted pendulum model for quiet stance in humans around the ankle joints with 4×9-element mass-spring-damper (MSD) units as the musculoskeletal connections between the shank and foot bilaterally. The model focuses on the role played by both the stiffness and the damping parameters of muscles, tendons and ligaments about the ankle complex. This model partitions muscles, tendons and ligaments functionally. This novel model is used to study the behaviour of individual components in relation to quiet standing. The Lagrange d’ Alembert principle has been used to derive the equations of motion of the system and resulted in eighteen 2nd order differential equations with nine constraints. Four MSD units connects with the shank (tibia and fibula) and foot bilaterally. The units function passively and are representative of the mechanical functionality of muscles, tendons, and ligaments about the ankle complex. The dynamics of the MSD units are considered linear in nature and their stiffness and damping parameters are calculated by finding the slope of the force vs. deformation length curve and force vs. velocity curve reported in the literature. The simulation results revealed that the torques generated by the internal constraints through the MSD units are significantly greater than the gravitational torque. A case study has been conducted for eyes open vs. eyes closed conditions. It was found that the angular displacement of the shank varied but the overall range of motion of the ankle joint remained constant at 0.6. This was expected as there was no external perturbation applied to facilitate any amount of plantarflexion or dorsiflexion at the point of articulation of the ankle joint. In conclusion, the model derived and analysed in this study explains that the human body was able to maintain its upright posture mechanically during unperturbed quiet standing without the use of an active control system emphasising the importance of damping and its influence on postural balance. Furthermore, this sophisticated model is not limited to only considering the muscle-tendon unit and ligaments play an important role in maintaining balance during quiet stance and are therefore included in the model. This model is physiologically more realistic than previously developed postural models thus providing a deeper insight towards the passive mechanism of postural balance and providing a new approach towards future postural models.
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Huston, Jeffery L. "The effects of fatigue on joint position sense in the ankle." Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=2880.
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Thesis (M.S.)--West Virginia University, 2003.<br>Title from document title page. Document formatted into pages; contains vi, 55 p. : ill. (some col.). Includes abstract. Includes bibliographical references.
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Lee, Sabrina Sien Man Piazza Stephen J. "Musculoskeletal architecture and plantarflexor muscle function in the human ankle joint." [University Park, Pa.] : Pennsylvania State University, 2009. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-4653/index.html.
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Voegtle, Tracy. "The effect of an acute ankle joint injury on neuromuscular function." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ58098.pdf.
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Morier, Rita. "Dynamic joint mechanics as an objective clinical measure of ankle function." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61268.
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The purpose of the work contained in this thesis was to investigate whether experimental paradigms based on the system identification approach are an effective clinical assessment tool. This was accomplished by conducting two companion studies: a reliability study on a group of fifteen control subjects and a case study of an individual who had sustained a unilateral undisplaced ankle fracture. The data collected in both studies included ankle angular position, torque, and Tibialis Anterior and Triceps Surae electromyograms. From these data, measures of both static (e.g. range of motion) and dynamic (e.g. estimated elastic stiffness) joint function, were obtained.<br>A number of clinically relevant variables (plantarflexion MVC, dorsiflexion MVC, range of motion, passive torque, K offset, low K region, and the intercept of the K-absolute torque relation) were shown to be reliable. In addition, the results of the case study demonstrated that it would be feasible to use these experimental procedures and analytic methods on individuals who have sustained orthopedic trauma. Finally, certain variables (the K offset, the slope and intercept of the K-torque relation, and a low stiffness region) appeared to be sensitive to the clinical changes associated with orthopedic pathology.
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Monk, Christopher John. "An investigation of factors affecting proprioception at the ankle joint complex." Thesis, University of Southampton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418616.
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Hoch, Matthew C. "THE EFFECT OF JOINT MOBILIZATION ON FUNCTIONAL OUTCOMES ASSOCIATED WITH CHRONIC ANKLE INSTABILITY." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_diss/166.
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Ankle sprains are among the most common injuries sustained by physically active individuals. Although ankle sprains are often considered innocuous in nature, a large percentage of individuals experience repetitive sprains, residual symptoms, and recurrent ankle instability following a single acute sprain; otherwise known as chronic ankle instability (CAI). In addition to repetitive ankle trauma, those with CAI experience reductions in functional capacity over the life span. This indicates that current intervention strategies for CAI are inadequate and require further investigation.
The objective of this dissertation was to explore differences in walking and running gait parameters between individuals with and without CAI; as well as, examine the effects of a 2-week Maitland Grade III anterior-to-posterior talocrural joint mobilization intervention on self-reported function, ankle mechanics, postural control, and walking and running gait parameters in a cohort of individuals with CAI. It was hypothesized that individuals with CAI would exhibit different gait kinematics and joint coupling variability patterns compared to healthy individuals and the joint mobilization intervention would improve patient-oriented, clinician-oriented, and laboratory-oriented measures of function in those with CAI.
Several observations were made from the results. In the first study, alterations in single joint kinematics and joint coupling variability were found between those with CAI and healthy individuals. In the second study, it was determined that the joint mobilization intervention improved patient-oriented and clinician-oriented measures of function as indicated by improved Foot and Ankle Ability Measure scores, increased weight-bearing dorsiflexion range of motion, and increased reach distances on the Star Excursion Balance Test. However, there were no changes in measures of instrumented ankle arthrometry or laboratory measures of postural control. In the third study, there were no changes in single joint kinematics or joint coupling variability during walking and running associated with the joint mobilization intervention. It can be concluded that joint mobilizations had a significant positive impact on patient-, and clinician-oriented measures of function. Though the laboratory measures did not detect any improvements, joint mobilizations did not produce deleterious effects on function. Therefore, future investigation on the effects of joint mobilization in conjunction with other, more active, rehabilitation strategies is warranted.
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Trent, Vanessa. "An investigation into the effect of stretching frequency on range of motion at the ankle joint thesis submission to Auckland University of Technology in partial fulfilment of the degree of Master in Health Science, September 2002." Full thesis. Abstract, 2002. http://puka2.aut.ac.nz/ait/theses/TrentV.pdf.
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Parameswaran, Luckshman. "The effects of passive joint movement on human ankle stretch reflex dynamics." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ29621.pdf.
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Parameswaran, Luckshman. "The effects of passive joint movement on human ankle stretch reflex dynamics /." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27248.
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The role of the monosynaptic stretch reflex in the realm of human motor activity has been controversial for many years. A non-linear parallel-cascade system identification technique was recently developed to non-invasively elucidate the ankle reflex dynamics. Identification of these dynamics requires the application of stochastic signals to the ankle joint. The stretch reflex is known to be highly modulated and attenuated during on-going cyclical movements and passively applied perturbations. The aim of this study was to investigate these effects.<br>The stretch reflex gain was found to decrease progressively as the average velocity of the applied movement increased. The velocity-mediated effects were a function of the amplitude distribution characteristics, rather than the spectral properties, of the applied motion. The experiments confirmed that although the stretch reflex response is large enough to be important its effects will depend on the functional context.
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Kuska, Elijah. "Ankle and Midtarsal Joint Kinematics During Rearfoot and Non-rearfoot Strike Walking." University of Dayton / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1564222776215818.
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Jalo, Hoor. "Individualized Contractile Ankle Joint Muscular Properties in Healthy and Post-Stroke Subjects." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254376.
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This study investigated the contractile properties of the plantar-and dorsi-flexor muscles controlling the ankle joint. The purpose of this study was to investigate how the muscle strength and muscle architecture change after stroke, and how the muscle strength and architecture are correlated. 13 typically developed (TD) subjects and 8 post-stroke (PS) individuals participated in this study where they performed maximal isometric tests (MVC) at 4 angles and isokinetic tests at 2 velocities. Torque-angle and torque-angular velocity relations were created to examine the muscle group strength. Third order polynomial and rectangular hyperbola were used to fit the torque-angle and torque-angular velocity relations, respectively. In addition, a maximum isometric torque and an optimal angle were reported for the healthy and stroke survivors. Ultrasonography system was used to study the muscle architecture at rest and maximal voluntary isometric conditions in the healthy and post-stroke groups. Fascicle length, muscle thickness and pennation angle of the medial gastrocnemius (MG) and tibialis anterior (TA) muscles were measured and compared between the two tested groups. Second order polynomial was used to study the correlation between the muscle strength and muscle architecture at MVC condition. A reduced range of motion and decreased maximal isometric torque were reported in the PS group. In addition, shorter fascicle lengths and smaller muscle thickness were obtained at rest and maximal voluntary contraction states in the stroke survivors compared to the healthy group. Pennation angle increased in the maximal voluntary isometric state compared to the rest condition. Decreased pennation angle was found in the MG, but it was increased in TA at the MVC state in the PS group compared to the healthy group. In the MG muscle, a positive correlation was found between the muscle strength with fascicle length and with muscle thickness in the healthy and post-stroke groups, but negative correlation was found with the pennationa angle in the two groups. In the TA muscle, positive correlation was found between muscle strength and fascicle length and negative correlation with the pennation angle in the TD and PS groups. However, negative correlation was obtained between muscle strength and muscle thickness in the TD group and no clear correlation in the PS group.<br>Technology
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Palmer, Jasmin Elena. "Design and development of mechanical metatarsophalangeal joint for powered ankle-foot prostheses." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/123272.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (page 46).<br>This thesis seeks to explore passive designs for a mechanical alternative to the metatarsophalangeal (MTP) joint, a critical anatomical component in human feet which allows for various types of anatomical motion. Our goal is to design a system that will act as a platform to test a proof of concept for a passive ankle-foot prosthesis with an MTP joint, but can also be adapted to use an actuated joint in the future. To increase the user's range of motion, our aim was for the mechanical MTP joint to achieve a maximum 600 dorsiflexion angle. We developed 2 MTP joint designs (Rubber Hinge and Fabric Hinge) with 2 body geometries varying at the heel for each (Traditional Heel and Inverted Heel) for a total of 4 models. We performed a static load Finite Element Analysis (FEA) using the Solidworks FEA Simulation Tool. The FEA was performed under the worst-case static load scenarios for the toe and body components of the prosthesis, standing on tiptoe with a dorsiflexion angle of 60' for the toe components and standing with all weight on the heel for the body components. The simulation yielded that not only did no components experience any irreversible deformation, but that the Rubber Hinge design had a minimum safety factor of 5.7, 10, and 4.5 for the Toe, Inverted Heel Body, and Traditional Heel Body respectively and the Fabric Hinge Design had a minimum safety factor 1.4, 9.9 and 4.5 for the Toe, Inverted Heel Body, and Traditional Heel Body respectively. This informed us that though both designs did not undergo failure under the prescribed loads, material utilization was in excess and could be further optimized to decrease the weight. Future designers should focus on implementing this platform into high fidelity physical models to be tested under various static and dynamic loading conditions as well as further optimizing the dimensions of the prosthesis.<br>by Jasmin Elena Palmer.<br>S.B.<br>S.B. Massachusetts Institute of Technology, Department of Mechanical Engineering
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Zamanian, Hashem. "Toward Creating Normal Ankle Joint Behavior for Drop Foot Patients Using an Ankle Foot Orthosis (AFO) with Superplastic NiTi Springs." University of Toledo / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1501856335099577.
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Singh, Navrag B. "Evaluation of Circumferential Ankle Pressure as an Ergonomic Intervention to Maintain Balance Perturbed by Localized Muscular Fatigue of the Ankle Joint." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/35686.
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Application of pressure in the form of taping and bracing has been shown to improve proprioception, and inducing localized muscle fatigue at various musculatures has been shown to adversely affect postural control. However, the potential for pressure application to mitigate the effects of localized muscle fatigue on postural control has not yet been determined. This study investigated specifically the effects of circumferential ankle pressure (CAP) and induced ankle fatigue on postural control. Fourteen young participants (seven males and seven females) performed fatiguing sub-maximal isotonic plantar flexion exercises on an isokinetic dynamometer, in the absence and presence of a pressure cuff (60 mm Hg) used to apply CAP. Proprioceptive acuity (PA) was determined using a passive-active joint position sense test, with categorical scores (low or high PA) used as a covariate. Postural sway during quiet standing was assessed using a force platform both pre- and post-fatigue as well as in the absence and presence of CAP. Application of CAP resulted in larger postural sway in individuals with low PA, and reduced postural sway in individuals with high PA. Fatigue effects on postural sway in individuals with low PA were more substantial as compared to individuals with high PA. CAP was found to be ineffective in mitigating the effects of fatigue on postural sway in individuals with lower PA. As a whole, the results suggest a potential for CAP as an ergonomic intervention in controlling fatigue-related fall incidents, though conclusive recommendations for use are not justified.<br>Master of Science
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Barrett, Christopher. "The effect of proprioceptive neuromuscular facilitation with warm-up on ankle joint dynamics." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0022/MQ50590.pdf.
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Barrett, Christopher 1970. "The effect of proprioceptive neuromuscular facilitation with warm-up on ankle joint dynamics /." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20900.
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System identification techniques were used to obtain a parametric description of the mechanical stiffness of the ankle, which was then used to assess the effect of four weeks of stretching the ankle flexors and extensors. The ankle musculo-articular system was described in terms of elastic stiffness, viscosity and inertia. This description of the mechanical behaviour of the ankle joint provided an objective basis for evaluating the effects of a long-term stretching program that utilized proprioceptive neuromuscular facilitation (PNF). PNF, preceded by a warm-up, was performed daily on the soleus, tibialis anterior and gastrocnemius of six healthy subjects, for four weeks.<br>The question that we asked in this study was: "Does stretching have an effect on the dynamic stiffness of the ankle joint?" A significant increase in ankle range of motion (p < 0.02) was observed. However, the intrinsic stiffness of the ankle joint did not change. We concluded that the gains in joint range of motion achieved by long-term stretching were due to an increase in the subjects' tolerance to stretching and not to changes in the dynamic stiffness of the joint.
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Jenkyn, Thomas Richard. "Biomechanics of the ankle joint complex using a muscle model assisted optimisation model." Thesis, University of Strathclyde, 2001. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21444.
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A seven segment model of the right leg and foot was developed with segments: thigh, lower leg, talus, hindfoot, midfoot and lateral and medial forefoot. Three-dimensional mapping of internal structures was made from CT scans and anatomical photographs (Visible Human Project). Twelve healthy subjects performed level walking and medial walking turns at slow, preferred and fast speed. Equilibrium about the two joints of the ankle complex (ankle and subtalar), was solved using Muscle Model Assisted Optimisation (MMAO). A three component, Hill-type muscle model determined tensions in eight muscles of the lower leg using EMG. Linear optimisation then corrected muscle tensions and solved for ligament tensions and articular surface compression. MMAO was successful in modeling ankle complex equilibrium during walking and walking turn. External forces acting on the right foot were similar for all subjects. Despite similar external loading, subjects employed different muscle tension strategies to produce equilibrium about the ankle and subtalar joints. For all subjects, triceps surae muscle tensions were largest. Peak tension in achilles tendon was 7.9xBW during walking and 8.0xBW during walking turn. The two heads of gastrocnernius behaved as distinct muscles performing different roles during stance. Peroneus brevis produced movement about the subtalar joint while peroneus longus had a stabilising role. The dorsi-flexors were significantly active during stance phase, antagonistic to triceps surae muscle group. This antagonism has not been predicted by previous models. Ligaments acted in an all-or-nothing manner when constraining the ankle complex. Ligaments were either slack or tensed at constant tension. Maximum ligament tension was 1.75xBW in the lateral ligaments of the ankle joint during walking turn. No difference between the walking and walking turn was seen in compressive loading of articular surfaces. Maximum compression of ankle joint was 10.0xBW and of subtalar joint was 8.0xBW.
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Gladish, Jonathan Randolph. "Recovery of Balance and Lower Extremity Joint Contributions in Total Ankle Arthroplasty Patients." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/78029.
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Ankle arthritis is a debilitating condition that causes severe pain and decreased function in the affected limb on the order of end-stage hip arthrosis, end-stage kidney disease, and congestive heart failure. Total ankle replacement is a viable surgical option for treating end-stage ankle arthritis, but few have studied its effects on balance over time. Therefore, the purpose of this study was to test the accuracy of a single-marker method of tracking center of mass, evaluate center of pressure measurements in total ankle replacement patients, and analyze lower extremity joint contributions over a two-year recovery period. Subjects stood on two force platforms for ten seconds in different conditions, and relevant variables were calculated from the force platform and 3D motion capture data. Results showed that increasing recovery time restored partial symmetry between the surgical and non-surgical limbs in ground reaction force, ankle range of motion, and ankle and hip moment contribution in static balance tasks. Furthermore, the ankle and hip may have different roles in postural stability. The results of the studies suggest that total ankle replacement is an effective treatment for end-stage ankle arthritis in terms of restoring postural stability. While patients may not have returned to the level of healthy control subjects, they are more functional and more stable after a two-year recovery period. While further work is needed, the results are encouraging for the outlook of ankle arthritis patients who may need total ankle replacement surgery.<br>Master of Science
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Coglianese, Mark J. "Effects of Vibration on Vertical and Joint Stiffness in Ankle Instability and Healthy Subjects." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3591.
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Some have suggested acute increases in musculotendinous stiffness (k) following whole body vibration (WBV). Others propose that chronic ankle instability (CAI) may alter k of the lower extremity. Changes in proprioceptive activity and/or gamma motoneuron activation post-WBV and/or due to CAI could lead to alterations in k. However, little is known about acute effects of WBV on k and less is known about changes in k with CAI. PURPOSE: Assess differences in vertical and joint k between healthy and CAI subjects during single-limb landings and detect alterations in k measures post-vibration. METHODS: Subjects were identified as CAI via the FAAM, MAII and special testing. Thirty-five CAI subjects (17 males, 18 females; age = 22 ± 7 yr; height = 1.73 ± 0.23 m; mass = 70 ± 30 kg) and 35 matched healthy subjects (17 males, 18 females; age = 23 ± 5 yr; height = 1.73 ± 0.21 m; mass = 70 ± 35 kg) qualified for this study. Kinetic (2000 Hz) and kinematic (250 Hz) data were recorded during several jump landings pre- and post-WBV. Five repetitions of WBV, at 26 Hz and 4 mm amplitude, were introduced between pre- and post-WBV jump trials. The jump task included a double-limb jump followed by a single-limb landing and a subsequent contralateral hop. Vertical k (∆vertical GRF/center of mass vertical displacement), hip, knee and ankle joint k (∆joint moment/∆joint angle) were calculated, averaged across five successful pre-WBV and across six post-WBV trials. An ANOVA was used to detect between-group differences, while an ANCOVA was used to analyze within-group differences post-WBV using pre-measures as covariates. A pseudo-Bonferroni adjustment was performed prior to statistical analysis (p < 0.01). RESULTS: No between-group differences were observed for any of the variables (F1,68 = 0.020 to 1.400, p = 0.240 to 0.890). A significant increase in vertical k was observed post-WBV for the healthy group (t67 = 2.760, p = 0.008), but not for the CAI group (t67 = 0.370, p = 0.720). The CAI group did demonstrate a decrease in ankle (t67 = -3.130, p = 0.003) and knee (t67 = -3.490, p = 0.001) joint k post-vibration. No other within-group differences were observed post-WBV (p > 0.01). CONCLUSIONS: It appears that WBV does acutely increase vertical k in healthy subjects. However, this treatment effect was not observed in CAI. Further research is needed to assess how k is regulated in CAI subjects and why CAI subjects responded differently to WBV.
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Zimmerman, Allison M. "Comparative Digital Examination of the Talocrural (ankle) Joint Provides Insight into Human bipedal locomotion." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1365158588.
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Mohd, Radzi Shairah Binte. "Development of a method to assess the quality of ankle joint reduction in 3D." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/87380/1/Shairah%20Binte_Mohd%20Radzi_Thesis.pdf.
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This project developed a quantitative method for determining the quality of the surgical alignment of the bone fragments after an ankle fracture. The research examined the feasibility of utilising MRI-based bone models versus the gold standard CT-based bone models in order to reduce the amount of ionising radiation the patient is exposed to. In doing so, the thesis reports that there is potential for MRI to be used instead of CT depending on the scanning parameters used to obtain the medical images, the distance of the implant relative to the joint surface, and the implant material.
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Coleman, Scott. "Functional analysis of the articulating figure skate." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 0.38 Mb., 40 p, 2006. http://proquest.umi.com/pqdlink?did=1037890041&Fmt=7&clientId=79356&RQT=309&VName=PQD.
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Kozakiewicz, Andrzej. "Impedance control of an electrohydraulic actuator interacting with a human ankle joint, a new experimental setup for studying ankle dynamic stiffness during voluntary movements." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0029/MQ64231.pdf.
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Kozakiewicz, Andrzej 1973. "Impedance control of an electrohydraulic actuator interacting with a human ankle joint : a new experimental setup for studying ankle dynamic stiffness during voluntary movements." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=30255.
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A position-based impedance controller was designed and implemented to regulate the interaction between forces produced at the ankle joint and the position of an electrohydraulic actuator. The goal was to provide a test environment suitable for studying ankle dynamic stiffness during voluntary movements. The new experimental setup allows: (1) subjects to perform voluntary movements, where both the length of the muscles associated with the ankle joint and their activation level change, (2) the simultaneous application of position perturbation to the joint (maximum bandwidth of 50 Hz), (3) evoking and responding to reflex activity at the ankle joint.<br>The setup was validated by demonstrating that it can be used to correctly estimate ankle dynamic stiffness when the subject maintains a steady voluntary contraction.
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Wells, Ashley M. "Effects of Joint Mobilization on Ankle Dorsiflexion Range of Motion, Dynamic Postural Control and Self-Reported Patient Outcomes in Individuals with Chronic Ankle Instability." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1333373756.
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Turley, Kevin. "Ankle Morphology: Interface of Genetics, Ontogeny and Use." Thesis, University of Oregon, 2013. http://hdl.handle.net/1794/13266.
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A central concept in Evolutionary theory is the character trait. It provides a context in which to explore differences and similarities among taxa, both extant and extinct. It is expanded in scope in Evolutionary Developmental theory to functional units with a biological role, "evolutionarily stable configurations." The talo-crural joint is such a configuration, a highly canalized structural unit in primates forming the interface between organism, and foot and substrate. It is a microcosm in which to examine the relationship of shape with environment and function and the interplay of genetics, ontogeny, and use.
Geometric Morphometric analysis of landmark data was employed in studying the articular surfaces of the talus in a diverse sample of adult specimens in nine catarrhine taxa. The influence of four factors on talar shape was examined: superfamily, a proxy for phylogeny; size and mass, a proxy for physical attributes; and substrate preference, a proxy for behavior. All significantly affected shape, and substrate preference was unrelated to the others. Appositional articular morphology, the shape of the subchondral bone surfaces of the talo-crural joints in an expanded sample of 12 taxa, showed a significant effect of the four proxies on the tibial and talar components, and substrate preference was weakly related to the other proxies in each. Singular Warp analysis of the cross-covariance matrices of the joints demonstrated sorting of taxa by substrate use and signals of convergent and divergent evolution among hominoids and cercopithecoids in joint shape. The ontogeny of the appositional articular shape was examined using adult and subadult specimens grouped by molar eruption. Singular Warp analysis demonstrated a genetic signal in the subadults, strongest in the slowly maturing African hominoids, and an epigenetic signal across taxa to substrate use in the adults.
The talo-crural joint, a highly canalized, modular, and integrated "evolutionarily stable configuration," provides a model for the study of the evolution of shape. The epigenetic signal observed is consistent with plasticity or developmental plasticity in response to the interaction of the joint complex with the environment due to a behavioral effect, substrate use.
This dissertation included previously unpublished, co-authored material.
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Skoss, Ann Rachel Locke. "Stabilisation of the human ankle joint in varying degrees of freedom : investigation of neuromuscular mechanisms." University of Western Australia. School of Human Movement and Exercise Science, 2002. http://theses.library.uwa.edu.au/adt-WU2003.0021.
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Previous research investigating the stability of the ankle joint complex may be categorised into two methodological groups, employing either an actuator to perturb the limb, or a form of standing balance disturbance such as a tilting platform, both of which test the joint in single degree of freedom (DOF). The aim of this thesis was to investigate how we control foot position and stabilise the joint when there is potential for movement in three DOF. A secondary aim of the thesis was to model the intrinsic mechanical properties of the ankle joint complex in three dimensions when coupled movement of the tibio-talar and talo-calcaneal joints are possible. This thesis details (i) the development of a perturbation rig that allows foot movement in single- or three-DOF with associated real-time visual target-matching software, and (ii) the use of the rig to investigate the stabilisation of the ankle joint complex in single- and three-DOF. The experimental procedure used a common task performed in three experimental conditions. Subjects were required to maintain a neutral foot position while developing varying levels of plantar-flexion torque. A perturbation was applied to the foot if subjects were within specified tolerance for both foot position and torque, represented by the visual display. Performance of the task in the first condition required the subject to only match torque as the foot position was fixed, with the perturbation being applied in dorsi-flexion (ie, single-DOF). The second experimental condition allowed the foot to move in the sagittal plane, hence subjects were required to control both torque and foot position in single-DOF, with perturbation applied in dorsi-flexion. The third condition enabled movement in dorsi/plantar-flexion, inversion/eversion and adduction/abduction (three-DOF) in both task and perturbation. Subjects were required to maintain the neutral foot position and the necessary torque level. There were three areas of interest common to each experimental protocol. The muscle strategy used to complete the task was investigated using a combination of surface and fine-wire electromyography on lower leg and thigh muscles. The 500ms period prior to perturbation was investigated to determine if synergies were evident between muscles such as medial and lateral gastrocnemius, soleus and peroneus longus. Two classes of activation strategies for the three-DOF condition emerged from the subject population: differential activation of the triceps surae group, and co-contraction. The former strategy may take advantage of the distinct morphology of the lateral gastrocnemius and peroneus longus muscles to best perform the position-matching component of the 3D task. The results suggest that the ankle joint is mostly stabilised in 3D by the intrinsic mechanical actions of the muscles producing plantar flexion moments. The muscles stabilised the foot in inversion, but not in eversion where there was very little motion. However, the different activation strategies employed may have varied efficacy in contributing to joint stability. This form of active stabilisation means that the previous literature focus on reflexes to stabilise the joint may need to be reassessed. Likewise, it may be appropriate to use the perturbation rig to quantify active ankle joint stability in order to assess the probability of ankle injury, rather than the current clinical measures employed. The reflexive response due to the perturbation was examined in the 200ms following perturbation. Variation in the modulation of monosynaptic reflexes was observed between subjects in various muscles in the higher DOF tasks. This is likely due to the differing activation strategies used to perform the task, and the variability in the kinematic response to perturbation. An attempt was made to calculate the intrinsic mechanical properties of the joint in 3-D using the kinematic and kinetic data during the first 15 ms period of perturbation. The system was modelled as a spring-damper using a constrained non-linear least squares, with stiffness and viscous terms for each axis, and inertial tensor elements as variables in the routine. The effect of increased muscle activation on the displacement of the foot about each of the anatomical axes was to significantly lower the movement of the sub-talar joint.
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Forster, Shauna. "A bilateral electro-hydraulic actuator system to measure dynamic ankle joint stiffness during human stance /." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80012.
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The role of the stretch reflex during upright stance remains unclear despite research that has been conducted to date. We have developed a bilateral electro-hydraulic actuator system to measure the dynamic joint stiffness of the human ankle during standing and help understand the role of the stretch reflex in the control of posture. The apparatus consists of two foot pedals that are each connected to an electro-hydraulic rotary actuator. Transducers were incorporated to measure the position and torque of each actuator, the angle of the ankle with respect to the foot plate, and the positions of the knee and hip. The experimental apparatus allows independent perturbations to be applied to each ankle. One subject was studied using the new apparatus and the results showed that reflexes are present during the perturbed standing task.
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Wan, Lu Ph D. Massachusetts Institute of Technology. "In-vivo cartilage contact biomechanics : an experimental and computational investigation of human ankle joint complex." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45439.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2008.<br>Includes bibliographical references (p. 236-259).<br>Osteoarthritis is affecting over 20 million people in the United States, the etiology of which is still unclear. As abnormal stress is believed to be one of the factors causing the degeneration of cartilage, the combined dual-orthogonal fluoroscopic and magnetic resonance imaging technique was applied to investigate the in-vivo biomechanics of human ankle joint complex in this work. The in-vivo kinematic data showed that the talocrural joint contributes more in dorsi/plantarflexion, while the subtalar joint is more responsible for inversion/eversion and internal/external rotation of the joint. During the stance phase of walking there is a complicated combination of the motion of the talocrural and subtalar joints. Cartilage-to-cartilage contact area during the stance phase of walking was determined by quantifying the amount of overlap of the cartilage surfaces of the tibia and talus. The in-vivo cartilage contact data showed significant changes in cartilage contact areas at different positions during the stance phase of walking. The articular cartilage contact was only observed in less than 50% of the cartilage coverage areas in the talocrural joint at various positions of the simulated stance phase of walking. The 3D compressive contact strain distribution within the ankle joint was determined under full body weight based on the thickness distribution and the deformation of the cartilage layers. The mean of the average cartilage contact strain of the entire contact area was only 7.5% whereas the mean peak contact strain reached 34.5%. With Young's modulus as 7.5 MPa and Poisson's ratio as 0.4, the average peak pressure was 6.87 ± 1.76 MPa and the average joint contact force was 1.66 ± 0.12 body weight. The in-vivo creep test of human ankle joint was also carried out and the contact deformation occurred mostly in early 30 to 40 seconds after loading the ankle joints. The in-vivo material properties was calculated and compared with the in vitro data. More computational research was performed focusing on the finite element analysis of the in-vivo ankle cartilage with biphasic/poroelastic material properties. The variation of the cartilage surface layer permeability was shown to have significant effects on the biomechanics behavior of human ankle cartilage.<br>by Lu Wan.<br>Ph.D.
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Aresu, Federica. "Comparison of high density and bipolar surface EMG for ankle joint kinetics using machine learning." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-294473.
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The relationship between sEMG signals and muscle force, and associated joint torque, is an object of study for clinical applications such as rehabilitation robotics and commercial applications as wearable motion control devices. The information type and quality obtained by sEMG can impact the classification and prediction accuracy of ankle joint torque. In this thesis project, HD-sEMG based data was collected together with ankle joint torque measurements from 5 subjects during MVIC of plantarflexors and dorsiflexors. Machine learning approaches ideally suited for nonlinear regression tasks, such as MLP and LSTM, have been implemented and evaluated to best predict joint torque profiles given extracted features from sEMG data. An evaluation of machine learning performances using HD-sEMG data over bipolar sEMG data has been conducted in intra-session, inter-subjective and intra-subjective study cases.
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Conconi, Michele <1979>. "An New Energetic Approach to the Modeling of Human Joint Kinematics: Application to the Ankle." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2765/1/Concon_Michele_tesi.pdf.
Full textAbstract:
The objective of this dissertation is to develop and test a predictive model for the
passive kinematics of human joints based on the energy minimization principle. To
pursue this goal, the tibio-talar joint is chosen as a reference joint, for the reduced
number of bones involved and its simplicity, if compared with other sinovial joints
such as the knee or the wrist.
Starting from the knowledge of the articular surface shapes, the spatial trajectory
of passive motion is obtained as the envelop of joint configurations that
maximize the surfaces congruence. An increase in joint congruence corresponds
to an improved capability of distributing an applied load, allowing the joint to attain
a better strength with less material. Thus, joint congruence maximization is a
simple geometric way to capture the idea of joint energy minimization.
The results obtained are validated against in vitro measured trajectories. Preliminary
comparison provide strong support for the predictions of the theoretical
model.
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Conconi, Michele <1979>. "An New Energetic Approach to the Modeling of Human Joint Kinematics: Application to the Ankle." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2765/.
Full textAbstract:
The objective of this dissertation is to develop and test a predictive model for the
passive kinematics of human joints based on the energy minimization principle. To
pursue this goal, the tibio-talar joint is chosen as a reference joint, for the reduced
number of bones involved and its simplicity, if compared with other sinovial joints
such as the knee or the wrist.
Starting from the knowledge of the articular surface shapes, the spatial trajectory
of passive motion is obtained as the envelop of joint configurations that
maximize the surfaces congruence. An increase in joint congruence corresponds
to an improved capability of distributing an applied load, allowing the joint to attain
a better strength with less material. Thus, joint congruence maximization is a
simple geometric way to capture the idea of joint energy minimization.
The results obtained are validated against in vitro measured trajectories. Preliminary
comparison provide strong support for the predictions of the theoretical
model.