While research shows that a patient’s success in using a myoelectric prosthetic arm is dependent on receiving effective training, current methods of training are not designed to effectively hold attention long enough for optimal training. This study focused on evaluating a novel myoelectric training device, consisting of a toy car controlled by EMG signals from the arm. Subjects’ performance with the trainer was evaluated to determine its ability to provide experience with EMG controls. Eight healthy adult subjects were taken through typical initial stages of myoelectric training, then asked to drive the car through a slalom course while the time, number of errors, and reversals required to complete the course were recorded, as well as the degree of difficulty subjects reported. The learning induced by using the trainer was found to be statistically significant (p < 0.002), with subjects demonstrating dramatic improvements (> 49%) in performance.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Abstract Introduction: The prevalence of anterior cruciate ligament tear is around 7000 every year within the swedish population and 95% of reconstructive surgery was with a hamstring tendon graft. Six months post surgery a 13% decrease in knee flexion strength compared to non injured side. The need for a study that determine the role of gastrocnemius and foot position in knee flexion is lacking in the litterature and could benefit Physiotheraphy ACL rehabilitation. Purpose: of his study was to investigate M gastrocnemius medialis (MGM) activation in the ipsilateral knee after removal of hamstring tendon for ACLR, and se if ankle position alter knee flexion outcomes. Method: 3 women, mean age 24 years who underwent ACL reconstruction with hamstring graft on one leg was tested. The time since injury was 3, 6 and 7 years respectively with an mean ,5 years wait until surgery. Isokinetic knee flexion and extension testing was done in the Biodex system 3 pro. EMG electrodes measured medial gastrocnemius activation with and without ankle in dorsiflexion. Results: Knee flexion peak strength was higher by a mean of 3 Nm (3,5%) with dorsiflexed foot. Mean (MGM) activation remained the same with or without dorsiflexion. Overall knee flexion strength was higher by a mean of 5 Nm compared to the injured side. Conclusion: Knee flexion in the biodex with foot in dorsiflexion could allow for isometric plantarflexion and increas power output. Certain changes in inclusion criteria and methodology as well more studies is needed to come to a given conclusion. / nej

The standard deviation of surface EMG (EMGσ) is often related to muscle force; the accuracy of EMGσ estimation is valuable for many application areas such as clinical biomechanics, prostheses control and sports medicine. Numerous researchers have developed methods to optimize EMGσ estimation. Whitening the EMG signal has been proved to improve the statistical efficiency of EMGσ estimation, but conventional linear whitening filters fail at low contraction level. An adaptive whitening filter was proposed by Clancy and Farry[14]. This technique has a better performance than prior whitening methods, however, the adaptive whitening filter needs to be calibrated each time electrodes are applied, which increase the complexity of the implementation. We designed a universal whitening filter which can omit most calibration steps for the adaptive whitening filter in future use. We used the ensemble mean of the power spectrum of 512 EMG recordings to form a general shape of a fixed whitening filter that can applied on any EMG signal. The test error on an EMG-torque task based on universal whitening over 512 subjects had a mean error of 4.80% maximum voluntary contraction (MVC) and standard deviation (std) of 2.03% MVC, compared with an original adaptive whitening filter error of 4.84±1.98% MVC. Additionally, the rest contraction modeling hasn’t received enough attention. Existing RMS estimates of EMGσ subtract noise in either the amplitude or power domain. These procedures have never been modeled analytically. We show that power domain noise subtraction is optimal. But rest contractions which are processed using power domain noise subtraction only estimate a zero-valued EMGσ approximately 50% of the time, which is undesirable in prosthesis-control. The prosthesis has a 50% possibility to slowly drift based on the current RMS estimator. We propose a new estimator to improve the zero-amplitude estimation probability during rest. We used 512 rest contraction recordings to validate the probability distribution of rest EMG signal showing that it only has 1.6% difference compared with Gaussian distribution. We also evaluated the percent of zero-valued EMGσ estimates using power domain noise subtraction and our new estimator, matching experimental findings to the theoretic predictions.

Este trabalho visa desenvolver instrumentação de apoio para tratamentos de reabilitação de lesados medulares. Trata de propor um sistema de controle, seus componentes e operações para monitorar o avanço do esgotamento muscular, com o intuito de evitar a fatigamento total da estrutura muscular principalmente se sob efeitos de Estimulação Elétrica Neuro-Muscular (EENM). Foi desenvolvida pesquisa inicial sobre a atividade elétrica de grupos musculares clinicamente normais em contração voluntária e de grupos musculares paralisados sob efeito de eletro-estimulação. Em ambos casos, eletromiogramas de superfície (EMG) foram processados para verificar a manifestação mioelétrica da fadiga. Índices de contração muscular foram selecionados para utilização no sistema de controle da EENM. Serão apresentados os cálculos e rotinas computacionais utilizadas no projeto e simulação do Bloco de processamento digital (BPD), dedicado a monitorar os sinais do sistema de controle da EENM para avaliar o progresso do esgotamento muscular sobre os sinais de EMG, e quantificar o decréscimo da energia muscular em função do tempo em que a estrutura estiver sendo exercitada, contribuindo para monitorar a performance física tanto de indivíduos normais quanto de lesados medulares. / This work aims to develop support instrumentation to be used on Rehabilitation Treatments of medullar injured individuals. It proposes a control system, its components and operations to monitor muscular exhaustion, with the objective to avoid the total muscle structure fatigue mainly under effects of Neural-Muscular Electrical Stimulation (EENM). It was carried out an initial research into the electric activity of clinically normal muscle groups under voluntary contraction and of paralyzed muscles groups under electrical stimulation effects. In both cases, the surface electromyogram signals (EMG) have been processed to verify the myoelectric manifestation of fatigue. Muscular Contraction Indexes were selected to be used in the EENM Control System. It will be presented the calculus and computational routines used in the design and simulation of the Digital Processing Block (BPD), dedicated to monitor the signals of the EENM Control System to evaluate the progress of the muscular exhaustion in EMG signals, and quantify the muscular energy decrease as a function of the time when the structure is exercised, contributing to monitor the physical performance of normal and medullar injured individuals.

Aims: To explore and inform current water immersion recovery practice of high performance athletes; and to compare recovery interventions of 5 minutes cold water immersion, warm water immersion and passive rest, in trained subjects, following intense exercise replicating the demands of game-sports. Methods: Study 1: In a repeated measures design, a measurement approach for use in the evaluation of water immersion efficacy was piloted. The within-day and between-day reliability of surface electromyelography (sEMG), particularly functional wavelet analysis, was evaluated in human lower limb muscles. Functional wavelet analysis provides the opportunity to measure neuromuscular function at the greatest level of detail by differentiating the relative intensity of low and high frequency motor unit recruitment. On 2 consecutive days (Trial 1 & Trial 2), 12 participants performed 3x5 second isometric 80% maximal voluntary contractions (MVC) on a Biodex® dynamometer in each of 150 ankle plantarflexion, 200 knee extension and 200 knee flexion. sEMG was obtained from the medial gastrocnemius (MG), vastis medialis (VM), vastis lateralis (VL) and biceps femoris (BF) muscles. Joint position and force production were controlled. Electrodes remained in situ during each trial. Electrodes were removed upon completion of Trial 1 and replaced in the same position the next day for Trial 2. Simultaneous sEMG metrics for intervals of consistent force production were compared between contractions in Trial 1 and Trial 2 (between-day) and contractions within Trial 2 (within-day). Study 2: 11 trained participants completed the 90 minute Loughborough Intermittent Shuttle Test (LIST). Five minutes of COLD water immersion (8.8 ± 0.30C), WARM water immersion (35.1 ± 1.80C) and REST were compared in a repeated measures randomised cross over design. Recovery was evaluated at 2, 4 and 24 hours post exercise using circulating markers of muscle damage, muscle dynamometry, drop jump and repeated single leg hop performance tests and perceived recovery. Study 3: Current water immersion practice of high performance athletes, practice implications stemming from this study’s findings, and the rationale were explored. In a purposive, theoretical sampling approach of expert consultation, 8 professionals advising internationally competing athletes on water immersion recovery practice were provided with a research brief of this project in advance of a scribed, semi-structured interview. Participants were of Sports Coach, Strength & Conditioning Coach and Sports Physiotherapist professions with a minimum of 5 years’ experience working with internationally competing athletes; and differed in international location and sporting disciplines.

BACKGROUND and AIMS. Patellofemoral pain syndrome (PFPS) is complex and challenging musculoskeletal disorder. Maltracking of the patella is considered to be one of the primary causative factors. Vastus Medialis Oblique (VMO) and Vastus Lateralis (VL) muscle imbalance in terms of EMG magnitude and timed onset is implicated in either initiating or perpetuating the patellofemoral pain (Cowan et al, 2002, Witvrouw et al, 1996). Many physiotherapeutic treatments are aimed at addressing this muscle imbalance despite a lack of evidence confirming or refuting it exists and it's association with pain and function. The ultimate aim of the study was therefore to establish if it is appropriate to continue treating muscle imbalance in patients with clinically defined PFPS. OBJECTIVES. The overall objectives of the study were to establish: 1. If VMO-VL muscle imbalance exists in PFPS patients and if so is it specific to this condition or does a similar VMO-VL muscle imbalance exists in a healthy population? 2. If muscle imbalance does exist is it related to clinical symptoms used as indications of pain syndrome in clinical practice? 3. Is muscle imbalance associated with lower limb muscle physiology i.e. lower limb and quadriceps muscle strength in both fresh and fatigued states. METHODS. The study employed a cross-sectional design. 63 patients with patellofemoral pain syndrome (PFPS) and 63 age/sex matched healthy subjects were recruited and VMO & VL normalised EMG RMS amplitude and time onset differences were assessed during functional and experimental tasks. Additionally, correlations with pain level, functional status, muscular flexibility and biomechanical characteristics of the lower limb were explored. RESULTS. The results revealed that the VMO-VL activation patterns are task specific and most significantly related to functional stepping down task at a fast speed of execution (p=0.000). This interesting link between the type of muscle contraction, the speed of execution and the recruitment pattern of the VMO-VL was also confirmed by the non-functional isokinetic eccentric contraction (p=0.000). Additionally, it is the timing of the VMO-VL activation rather the intensity that is important. Also, a correlation appears to exist between activation pattern and duration of symptoms and knee functional performance (p=0.03) but not with the level of pain. CONCLUSION. The findings of the study suggest that the VMO-VL muscle imbalance does exist in a clinically defined PFPS population. Unlike previous studies however, this thesis suggests that specificity of the functional activities and speed of execution have a significant role to play in the muscular performance and it could be argued that this translates to a role in PFPS. It would therefore seem appropriate to continue addressing and treating this complex and challenging issue with physiotherapeutic interventions but this may need to be targeted to interventions that are tailored to addressing issues in relation to stepping down and at fast speed.

Highly repetitive motion is associated with upper extremity musculoskeletal disorders among industrial workers.Current methods of estimating occupational exposure to "repetitiveness" provide information about the repetitiveness of joint motion, but fail to provide complete information about the repetitiveness of muscular exertion, a more biomechanically meaningful measure of repetition. This thesis introduces an innovative digital signal processing method, from which muscular exertion frequency was estimated. Specifically, time series recordings of muscle activity obtained with surface electromyography (sEMG) were processed with standard root-mean-square (RMS) amplitude calculations and then transformed from the time domain into the frequency domain. The mean power frequencies of the RMS-processed sEMG signals (MPF EMG) were then calculated to estimate muscular exertion frequency. In a laboratory-based validation study involving repetitive isometric hand gripping exertions, MPF EMG was compared to measures of muscular exertion frequency and joint motion frequency across a range of known exertion frequencies, intensities, and durations. Strong linear relationships were observed between MPF EMG and external measures of muscular exertion frequency. However, performance of MPF EMG as a measure of muscular exertion frequency may be improved with an increase of the signal to noise ratio in the sEMG data. Signal processing parameters were therefore investigated. Alternative processing parameters were suggested to minimize difference between MPF EMG and established methods of muscular exertion frequency. A second laboratory-based validation study compared MPF EMG to a measure of muscular exertion frequency and a measure of joint movement frequency during a simulated industrial task. Although a stronger linear relationship was observed between metrics of joint motion frequency and established measures of muscular exertion, the differences between measures were not meaningful and the relationship between MPF EMG and established measures was moderate-to-strong. The final phase of this thesis explored the application of the proposed techniques to field-based data collected during a study of ironworkers involved in construction stud-welding tasks. Limitations in data collection limited the analysis of MPF EMG in this study. The research presented in this thesis introduces a novel metric based on the frequency analysis of RMS processed sEMG data, and presents evidence that MPF EMG has potential to be a valuable assessment technique of exposure to repetitive muscular exertion.

Einführung. In der vorliegenden Studie untersuchten wir durch funktionelle Nahinfrarotspektroskopie (fNIRS) präfrontale Hirnoxygenierung während Ableistung von Sprachaufgaben. FNIRS weist über Bestimmung von Konzentrationsunterschieden von sauerstoffbeladenes (OxyHb) und sauerstofffreies Hämoglobin (DeoxyHb) regionale Blutflussänderungen nach und lässt somit validen Rückschluss auf Hirnaktivität zu. Bereits in früheren Studien konnte nachgewiesen werden, dass Patienten mit Alkoholkrankheit verminderte präfrontale Hirnaktivität zeigen. Teil 2 der Studie untersucht den im Untersuchungsgebiet liegenden Schläfenmuskel (musculus temporalis) auf Einflüsse auf die Methode fNIRS. Methoden. Wir verglichen 15 entgiftete Patienten mit Alkoholkrankheit (Patientengruppe, PG) mit passenden 15 gesunden Kontrollprobanden (Kontrollgruppe, KG)bezüglich deren Hirn- und Muskelaktivität während Ableistung Wortflüssigkeitsaufgabe (VFT; engl. Verbal Fluency Task). Bestimmte, insbesondere präfrontale Hirnareale wurden durch phonologische und semantische Testsaufgaben (TA´s), ebenso durch eine Kontrollaufgabe (KA), (Wochentag aufzählen) aktiviert. Durch EMG wurde während Durchführung der Aufgabe die Aktivität des musculus temporalis gemessen. Wir verwendeten zur Datenanalyse sowohl von fNIRS wie auch EMG eine 2x2x2x6 Varianzanalyse (ANOVA) mit Zwischensubjektfaktor „Gruppe“ und Innersubjektfaktoren „Bedingung“, „Seite“ und „Zeit“, gerechnet wurde dies für jeweils Oxy- und DeoxyHb sowie den phonologischen sowie semantischen Teil. Ergebnisse. Beide Gruppen lieferten eine vergleichbare Menge an Worten, Hirnaktivierung zeigte sich bei beiden Gruppen signifikant höher in den Testaufgaben (phonologisch > semantisch). Die PG zeigte verminderte Hirnaktivierung präfrontal im phonologischen, vergleichbare Hirnaktivität im semantischen Teil. Beide Gruppen zeigten vergleichbare Muskelaktivität, jeweils signifikant höher in den jeweiligen Testaufgaben. Es zeigten sich keine systematischen Assoziationen (Korrelation nach Pearson) zwischen fNIRS und EMG. Schlussfolgerungen. Insgesamt konnten vorherige Studien mit Nachweis niedrigerer präfrontaler Hirnoxygenierung bei entgifteten Patienten mit Alkoholkrankheit gegenüber gesunden Kontrollen bestätigt werden. Die Mehraktivierung beider Gruppen während phonologischer Aufgabe gründet in dem höheren intelektuellen Anspruch der Aufgabe, dies erklärt auch den Gruppenunterschied in speziell dieser Aufgabe. Durch eine vergleichbare Muskelaktivität der beiden Gruppen sowie fehlende Assoziationen zwischen fNIRS und EMG sehen wir keinen Einfluss von Muskelaktivität auf die Hirnaktivitätsmessung durch fNIRS. Auch eine valide Untersuchung von psychiatrisch kranken Probandengruppen wie Patienten mit Alkoholkrankheit ist hierdurch gut möglich. Die Studie befürwortet den künftigen Einsatz und weitere methodische Untersuchungen zur Messung mit fNIRS, einem validen, artefaktunempfindlichen, handlichen und relativ günstigen Messinstrument. / Introduction. In this study we examined prafrontal brain oxygenation using functional near infrared spectroscopy (fNIRS) while performing a speech test. Via changes of concentrations of oxygenated (OxyHb) and deoxygenated (DeoxyHb) hemoglobin fNIRS measures regional bloodflow mirroring brain activity. Former studies already showed that detoxified patients with alcohol dependency have lower prefrontal brain activity. In the second part of the study we investigate the temporal muscle, surfacing the measured prefrontal area, in reference to influence on the method fNIRS. Methods. We compared 15 detoxified patients with alcohol dependency (patient group, PG) with the same amount of 15 matching healthy controls (control Goup, CG) regarding their brain and muscle activity during performing a verbal fluency task (VFT). Spezific prefrontal brain areas were activated by executing a phonological and a semantical test task (TT), as comparison we led them perform a control task (CT), reciting weekdays. Via EMG we measured temporal muscle activity while passing the test. For data analysis for both measuring methods (fNIRS and EMG) we used a 2x2x2x6 Analysis of Variance (ANOVA) with the factors “group”, “condition”, “side” and “time”. We calculated these for both Oxy- and DeoxyHb as well as for phonological and semantical test. Results. Both groups announced a comparable amount of words, brain activity was significantly higher while performing th TT (phonological higher than semantical). The PG achieved less activity in prafrontal areas, only in the phonological part, not in the semantical. Both groups performed comparable muscle activity, however activated the temporal muscle more while performing the TT´s. Systematic correlations (Pearson) between fNIRS and EMG weren’t found. Discussion. Overall like in elder studies we could confirm lower prefrontal brain oxygenation on detoxified patients with alcohol dependency compared to matching controls. Reaching higher activity during the phonological task is defined by the exercises higher level of difficulty, which also explains the difference of group result in especially this test. As muscle activity was comparable between the two groups, we couldn’t find associations between fNIRS and EMG. Thus we don’t see muscle activity interfering with the measurement of brain activity using fNIRS. Also this method proofs reliable and valid being used in subjects with psychiatric illnesses like alcohol dependency. This study supports the future Use just like further methodical investigations of fNIRS, a method nonsensitive to artifacts.

<p>This study is aimed to determine the electromyographic signals of the forearm, using Ag/AgCl electrodes. The four major muscles of forearm, which are providing the bioelectrical currents, have been displayed and analysed to determine the different activities. In order to record the signals, an EMG device has been developed and installed and a schematic has also been presented in this paper.</p>