Robotic-powered exoskeletons are increasingly used to assist patients with movement disorders in daily life and rehabilitation. Accurately estimating joint torque, especially for dynamic movement conditions using EMG, is crucial for effective assistance. Machine learning and deep learning have been employed for EMG-based force/torque estimation, but their precision and robustness have been limited, particularly for dynamic movements. This thesis aims at comparing and analyze the results using MLP, CNN, and CNN-LSTM methods to estimate ankle joint torque in dynamic movements based on HD-EMG. Meanwhile, this thesis designed and tested different data augmentation to enhance the performance using HD-EMG data augmentation techniques. The CNN-LSTM model demonstrated superior performance among the machine learning models. Additionally, the combination of spatial and signal augmentation methods showed notable improvements in the inter-subject case performance of the prediction. No augmentation methods have shown notable improvements in the intra-subject case or inter-session case. / Robotdrivna exoskelett används i allt större utsträckning för att hjälpa patienter med rörelsestörningar i det dagliga livet och rehabiliteringen. Att noggrant uppskatta ledmomentet, särskilt för dynamiska rörelseförhållanden med EMG, är avgörande för effektiv assistans. Maskininlärning och djupinlärning har använts för EMG-baserad kraft/vridmomentuppskattning, men deras precision och robusthet har varit begränsad, särskilt för dynamiska rörelser. Denna avhandling syftar till att jämföra och analysera resultaten med MLP-, CNN- och CNN-LSTM-metoder för att uppskatta fotledsvridmoment i dynamiska rörelser med hjälp av HD-EMG datadrivna modeller. Samtidigt designade och testade denna avhandling olika dataförstärkningar för att förbättra prestandan med hjälp av HD-EMG dataförstärkningstekniker. CNN-LSTM-modellen visade överlägsen prestanda bland maskininlärningsmodellerna. Dessutom visade kombinationen av rumsliga och signalförstärkningsmetoder anmärkningsvärda förbättringar i prediktionens inter-subject case performance. Inga förstärkningsmetoder har visat märkbara förbättringar i fallet inom ämnet eller fallet mellan sessioner.

The first aim of this master thesis was to summarize the information on injuries of ligamentous apparatus of an ankle, lateral instability of a talar joint, conservative and operative therapy of these injuries with the emphasis on physiotherapeutical procedures in the therapy of ankle sprains. The second aim of the master thesis was to introduce surface electromyography as a possibility to examine objectively the differences in the activation of foot and shank muscles with healthy people and people with chronic instability of an ankle in different postural situations. The third aim was to use the theoretical knowledge in practice with patients who have sprained their ankle and to make a subjective and objective assessment of the therapy effect which is in progress. Powered by TCPDF (www.tcpdf.org)

Submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, Durban, South Africa, 2016. / Background: Iliotibial band friction syndrome is a common dysfunction seen in athletes. Athletes develop biomechanical changes yet still continue with their sport. However, this syndrome limits their ability to participate at peak performance. This study determined which participants benefitted in terms of biomechanical and clinical outcomes in one of four groups: ankle joint, superior tibio-fibular joint, sacroiliac joint or a combination manipulation group (which contained any two of the three joint restrictions). Methods: This Durban University of Technology Institutional Research and Ethics Committee approved prospective clinical trial, utilised stratified sampling, with 48 participants across four groups: ankle (14); superior tibio-fibular (11), sacroiliac (12) and combination (11). The participants underwent six treatments in three weeks. Data collection occurred before consultations one, three, five and seven. The data included primary measures of the knee score questionnaire (KSQ), the algometer, the visual analogue scale (VAS) and the secondary measures of the Feiss line, the heel leg alignment, bilateral leg length, Q angle and tibio-femoral angle. All data was computed utilising the ANOVA testing, with a p-value <0.05 being significant and a 95% confidence interval. Pearson’s correlations were completed for intragroup associations between primary and secondary outcome measures. Results: The intragroup analysis revealed that all groups had significant changes in the KSQ and VAS, with the exception of the sacroiliac joint manipulation group (KSQ outcome not significant). Intergroup analysis revealed no differences between the groups with the exception of the combination group, which showed a significant increase in the tibio-femoral angle. Most commonly, the Pearson’s correlation revealed that changes in leg length were related to differences in primary outcome measures, irrespective of the group being tested. Conclusion: The outcomes of this study indicated that manipulation of the distal kinematic chain improved alignment and clinical outcomes to a greater degree than manipulating proximal restrictions. It is suggested with caution (due to limited sample size) that patients should first have their distal kinematic chain manipulated before more proximal joints are manipulated to achieve better outcomes. / M

No / When descending stairs bodyweight becomes supported on a single limb while the forwards-reaching contralateral limb is lowered in order to make contact with the step below. This is associated with lowering of the centre of mass (CoM), which in order to occur in a controlled manner, requires increased ankle and knee joint torque production relative to that in overground walking. We have previously shown that when descending steps or stairs older people operate at a higher proportion of their maximum eccentric capacity and at, or in excess of the maximum passive reference joint range of motion. This suggests they have reduced and/or altered control over their CoM and we hypothesised that this would be associated with alterations in muscle activity patterns and in the CoM vertical acceleration and velocity profiles during both the lowering and landing phases of stair descent. 15 older (mean age 75 years) and 17 young (mean age 25 years) healthy adults descended a 4-step staircase, leading with the right limb on each stair, during which CoM dynamics and electromyographic activity patterns for key lower-limb muscles were assessed. Maximum voluntary eccentric torque generation ability at the knee and ankle was also assessed. Older participants compared to young participants increased muscle co-contraction relative duration at the knee and ankle of the trailing limb so that the limb was stiffened for longer during descent. As a result older participants contacted the step below with a reduced downwards CoM velocity when compared to young participants. Peak downwards and peak upwards CoM acceleration during the descent and landing phases respectively, were also reduced in older adults compared to those in young participants. In contrast, young participants descended quickly onto the step below but arrested their downward CoM velocity sooner following landing; a strategy that was associated with longer relative duration lead-limb plantar flexor activity, increased peak upwards CoM acceleration, and a reduced landing duration. These results suggest that a reduced ability to generate high eccentric torque at the ankle in the forward reaching limb is a major factor for older participants adopting a cautious movement control strategy when descending stairs. The implications of this CoM control strategy on the incidences of falling on stairs are discussed.

Fatigue testing of stretch sensors often focuses on high amplitude, low-cycle fatigue (LCF) behavior; however, when used for orthopaedic, athletic, or ergonomic assessments, stretch sensors are subjected to low amplitude, high-cycle fatigue (HCF) conditions. As an added layer of complexity, the fatigue testing of stretch sensors is not only focused on the life of the material comprising the sensor, but also on the reliability of the signal produced during the extension and relaxation of the sensor. Research into the development of a smart sock that can be used to measure the range of motion (ROM) of the ankle joint during athletic practices and competitions using stretch sensors is ongoing at Mississippi State University. The current smart sock prototype utilizes StretchSense™ StretchFABRIC capacitive dielectric elastomer sensors. These sensors are no longer manufactured, and FlexSense stretch sensors are being investigated as a potential replacement. To assess the reliability of the signal of the StretchFABRIC sensors currently used in the prototype, two sensors were subjected to 25,000 cycles of fatigue, under with simultaneous capture of the capacitance. The capacitances of the fatigued sensors were then compared to the capacitance of an unfatigued StretchFABRIC sensor during participant trials. Participants completed four static movements and six dynamic gait trials using either the fatigued or unfatigued sensor. Following completion of the initial static and dynamic movements, the movements were repeated using the opposite sensor. Comparison of the fatigued sensor to the unfatigued sensor revealed an upward drift in the capacitance of the fatigued sensor for all trials. Two FlexSense sensors were then subjected to either 450,000 or 250,000 cycles of fatigue with simultaneous capture of the signal from the sensor. To assess the signal, the peak capacitance recorded during the fatigue test was compared to the peak stretch percentage produced by the sensor. The peak displacement remained tight about the mean, while the peak stretch percentage exhibited a high level of scatter. From a materials standpoint, the sensors conformed to the Rabinowitz-Beardmore model of polymer fatigue where an initial monotonic overload of the material is followed by a transition to cyclic stability of the material.