Electromyographic (EMG) signals contain both neural and muscle information. Consequently, EMG signals can be modelled as the composition of two component signals, one of these being a low frequency neural input, the other a relatively high frequency, constant spectrally shaped, stationary, unitary muscle response. Utilizing this model and homomorphic processing estimates of the two component signals can be obtained. These estimates contain neural and muscle information respectively. This thesis establishes the basis for the use of this multiplicative model. It also outlines the application of multiplicative homomorphic processing to EMG signals. The results of this processing are shown to be valid and to contain useful information. The thesis concludes that the model is both appropriate and useful. It also points out that the use of this model and homomorphic processing allows the simultaneous extraction of both neural and muscle information from the EMG signal,a result which is not possible with other currently used processing techniques. / Thesis / Master of Engineering (ME)

Det har tidigare rapporterats att icke-stammande personer har en tydlig vänstersidig cerebral lateralisering vad gäller talmotoriken, vilket visas genom ökad högersidig aktivering i läppmuskulaturen. Personer med stamning har å andra sidan föreslagits ha ett vänstersidigt eller bilateralt aktiveringsmönster av talmuskulaturen. Detta antas vara en av orsakerna till stamning. Testdeltagarna i aktuell studie bestod av 11 stammande och 13 matchade icke-stammande vuxna. Uppgifterna bestod av ordrepetition, ordgenerering samt att puta med läpparna. EMG-aktivitet från musklerna orbicularis oris och depressor labii inferior registrerades med elektroder på höger och vänster sida av läppmuskulaturen. Syftet med aktuell studie var att undersöka eventuell skillnad i läppasymmetri mellan stammande och icke-stammande vuxna personer. Resultatet kunde inte påvisa signifikanta gruppskillnader i grad av muskelaktivering för läppmuskulaturen. Båda grupperna uppvisade tvärtemot förväntan en nästintill bilateral aktivitet. En tendens till positiv korrelation, om än inte statistiskt signifikant, kunde observeras mellan grad av uppvisad stamning och något mer högersidig muskelaktivering.

The electromyogram (EMG) signal is desired to be used as a control signal for applications such as multifunction prostheses, wheelchair navigation, gait generation, grasping control, virtual keyboards, and gesture-based interfaces [25]. Several research studies have attempted to relate the electromyogram (EMG) activity of the forearm muscles to the mechanical activity of the wrist, hand and/or fingers [41], [42], [43]. A primary interest is for EMG control of powered upper-limb prostheses and rehabilitation orthotics. Existing commercial EMG-controlled devices are limited to rudimentary control capabilities of either discrete states (e.g. hand close/open), or one degree of freedom proportional control [4], [36]. Classification schemes for discriminating between hand/wrist functions and individual finger movements have demonstrated accuracy up to 95% [38], [39], [29]. These methods may provide for increased amputee function, though continuous control of movement is not generally achieved. This thesis considered proportional control via EMG-based estimation of finger forces with the goal of identifying whether multiple degrees of freedom of proportional control information are available from the surface EMG of the forearm. Electromyogram (EMG) activity from the extensor and flexor muscles of the forearm was sensed with bipolar surface electrodes and related to the force produced at the four fingertips during constant-posture, slowly force-varying contractions from 20 healthy subjects. The contractions ranged between 30% maximum voluntary contractions (MVC) extension and 30% MVC flexion. EMG amplitude sampling rate, least squares regularization, linear vs. nonlinear models and number of electrodes used in the system identification were studied. Results are supportive that multiple degrees of freedom of proportional control information are available from the surface EMG of the forearm, at least in healthy subjects. An EMG amplitude sampling frequency of 4.096 Hz was found to produce models which allowed for good EMG amplitude estimates. Least squares regularization with a pseudo-inverse tolerance of 0.055 resulted in significant improvement in modeling results, with an average error of 4.69% MVC-6.59% MVC (maximum voluntary contraction). Increasing polynomial order did not significantly improve modeling results. Results from smaller electrode arrays remained fairly good with as few as six electrodes, with the average %MVC error ranging from 5.13%-7.01% across the four fingers. This study also identified challenges in the current experimental study design and subsequent system identification when EMG-force modeling is performed with four fingers simultaneously. Methods to compensate for these issues have been proposed in this thesis.

L'étendue et l'étiologie de la fatigue neuromusculaire dépendent des caractéristiques de la tâche. Parmi ces caractéristiques, l'effet des facteurs matériels est peu documenté. Le tennis est un modèle intéressant pour étudier cet effet puisque cette activité se déroule sur différentes surfaces, susceptibles d'influencer le développement de la fatigue. Cette hypothèse reste à vérifier. Par ailleurs, l'évolution des matériaux a rendu les raquettes modernes plus légères, plus rigides que les raquettes en bois. Aussi, afin de garder du contrôle dans le jeu, les joueurs ont adopter des cordages plus rigides, susceptibles de favoriser le développement de la fatigue. Les objectifs de ce travail étaient donc (i), d'évaluer les origines et l'étendue de la fatigue neuromusculaire en fonction de la surface de jeu à la suite d'un match de longue durée, et (ii) de tester l'effet du cordage sur le développement de la fatigue des muscles de l'avant-bras durant un match de tennis simulé. Dans notre première étude, aucune différence significative de fatigue neuromusculaire n'était mesurée lors de matchs disputés sur différentes surfaces. Nos résultats démontrent une baisse limitée de la force des fléchisseurs plantaires à la suite des matchs, majoritairement attribuée à des altérations des capacités contractiles des fléchisseurs plantaires. Le rôle des facteurs centraux étaient moins clair. Dans la seconde étude, nous avons démontré que jouer avec un cordage rigide favorisait le développement de la fatigue sur les muscles de l'avant-bras par rapport à des cordages souples. La baisse de vitesse mesurée au cours du match simulé pourrait être partiellement liée à cette fatigue localisée. / The etiology and amplitude of neuromuscular fatigue depend on the task characteristics. Among these characteristics, the effect of material factors on the development of neuromuscular fatigue has been scarcely documented. Tennis is an interesting model to study this effect since it is played on different surfaces. Playing surfaces may therefore differently influence the development of fatigue on the lower-limb muscles. However, this hypothesis remains to be tested. In addition, the use of composite materials and the progress of engineering have allowed racquet engineers to design tennis racquet frames which are stiffer, lighter, and more powerfull than old wooden racquets. To keep controling the ball, players now use stiffer string that can influence the development of fatigue on the upper-limb muscles. The objectives of this thesis were (i) to evaluate the effect of the playing surface properties on the development of neuromuscular fatigue in tennis and (ii) to test the influence of string stiffness on the occurrence of forearm muscle fatigue during a simulated tennis match. In the first study, no significant difference of neuromuscular fatigue was observed between surfaces. We have reported a moderate reduction of the maximal voluntary force, which was mainly associated with an alteration of the contractile properties of the plantar flexor muscles. The implication of central factors in the voluntary force decrement was less clear. In the second experimentation, we have demonstrated that playing tennis with high-stiffness string promotes forearm muscle fatigue development, which could partly contribute to the groundstroke ball speed decrement during the game.

A relação entre eletromiografia e força é objeto de numerosos estudos, porém tal relação ainda não está totalmente elucidada e necessita de uma melhor fundamentação. Uma possível razão para as divergências entre esses estudos reside na dificuldade em determinar a força de um músculo individualmente de forma direta. Dentro deste contexto, procurou-se utilizar a análise do sinal eletromiográfico, associada a um modelo biomecânico do segmento articular para a avaliação das forças internas do músculo. O objetivo do presente trabalho é avaliar o comportamento eletromiográfico do músculo quadríceps durante exercícios isométricos e isotônicos concêntricos e correlacioná-lo com a força muscular, calculada através de simulações, usando modelos biomecânicos. Busca-se também uma forma de reconstruir a sobrecarga a que o músculo é submetido durante o exercício isotônico, através do tratamento do sinal eletromiográfico. Para tanto, o exercício isotônico é realizado em baixa velocidade e com pequena sobrecarga, e além disso, utiliza-se o procedimento de normalizar o sinal eletromiográfico ponto-a-ponto. Tal procedimento não possibilitou que a força externa, aplicada pelo membro, fosse obtida a partir do tratamento do sinal eletromiográfico, porém permitiu a correlação da eletromiografia com a força interna, gerada pelo músculo. Verificou-se também que a relação entre eletromiografia e força varia com a posição angular, com a força, com a velocidade de contração muscular e com a velocidade angular. No que se refere às análises da atividade isotônica, uma importante conclusão é que a relação entre eletromiografia e força não é linear; no entanto, quando normalizados pelos seus valores máximos podem ser considerados proporcionais. / The relationship between electromyography and force is largely investigated, however, such relation is not yet fully understood, still requiring better foundation. One of the reasons that might cause discrepancies between studies lies on directly calculating a single muscle force. Our approach handles the electromyographic signal coupled with a biomechanical model of the joint for assessment of internal muscle forces. This study aims at an evaluation of electromyographic behavior of the quadriceps muscle throughout isometric and concentric exercises, relating it to muscle force calculated by means of simulations, using biomechanical models. It is also handled in our study a means of assessing muscle overloading throughout dynamic exercises using eletromiographic signals. Accordingly, the dynamic exercise is undergone at slow speed and low resistance; and the electromyographic signal is normalized angle by angle. The approach did not allow the external force, produced by the limb, be assessed by means of electromyographic treatment, however, it allowed a relation between electromyography with internal force produced by the limb. It is worth mentioning that the electromyography-force relationship undergoes variations according to angular position, to degree of force, to muscle contraction velocity, to angular velocity. As to isotonic activity analysis, one important conclusion is the relation between electromyography and force is non-linear, with the proviso, that when normalized by peak values electromyography and force may be considered proportional.

No description available.

The analysis of electromyographic (EMG) signals detected during muscle contraction provides important information to aid in the diagnosis and characterization of neuromuscular disorders. One important analysis measures neuromuscular jitter, which is the variability of the time intervals between two muscle fibre potentials (MFPs) belonging to the same motor unit over a set of discharges. Conventionally, neuromuscular jitter is measured using single fibre (SF) EMG techniques, which can identify individual MFPs by using a SF needle electrode. However, SF electrodes are expensive, very sensitive to needle movement and not easy to operate in practise. <br /><br /> A method is studied in this thesis for automatically measuring neuromuscular jitter in motor unit potentials (MUP), it measures jitter using routine EMG techniques, which detect MUPs using a concentric needle (CN) electrode. The method is based on the detection of near MFP contributions, which correspond to individual muscle fibre contributions to MUPs, and the identification of individual MFP pairs. The method was evaluated using simulated EMG data. After an EMG signal is decomposed into MUP trains, a second-order differentiator, McGill filter, is applied to detect near MFP contributions to MUPs. Then, using nearest neighbour clustering and minimum spanning tree algorithms, the sets of available filtered MUPs can be selected and individual MFPs can be identified according to the features of their shapes. Finally, individual MFP pairs are selected and neuromuscular jitter is measured. <br /><br /> Using the McGill filter, near MFP contributions to detected CN MUPs can be consistently detected across an ensemble of successive firings of a motor unit. The method is an extension of the work Sheng Ma, compared to previous works, more efficient algorithms are used which have demonstrated acceptable performance, and which can consistently measure neuromuscular jitter in a variety of EMG signals.

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

Hand and arm gestures are a great way of communication when you don't want to be heard, quieter and often more reliable than whispering into a radio mike. In recent years hand gesture identification became a major active area of research due its use in various applications. The objective of my work is to develop an integrated sensor system, which will enable tactical squads and SWAT teams to communicate when there is absence of a Line of Sight or in the presence of any obstacles. The gesture set involved in this work is the standardized hand signals for close range engagement operations used by military and SWAT teams. The gesture sets involved in this work are broadly divided into finger movements and arm movements. The core components of the integrated sensor system are: Surface EMG sensors, Flex sensors and accelerometers. Surface EMG is the electrical activity produced by muscle contractions and measured by sensors directly attached to the skin. Bend Sensors use a piezo resistive material to detect the bend. The sensor output is determined by both the angle between the ends of the sensor as well as the flex radius. Accelerometers sense the dynamic acceleration and inclination in 3 directions simultaneously. EMG sensors are placed on the upper and lower forearm and assist in the classification of the finger and wrist movements. Bend sensors are mounted on a glove that is worn on the hand. The sensors are located over the first knuckle of each figure and can determine if the finger is bent or not. An accelerometer is attached to the glove at the base of the wrist and determines the speed and direction of the arm movement. Classification algorithm SVM is used to classify the gestures.

<p>To get the maximal output of your exercise in gym machines, there are different factors</p><p>to be considered. For example the strength of the muscle varies dependent on the position</p><p>of the muscles. To get the best results of the exercise the load has to reduce and increase</p><p>at specific positions.</p><p>This study was made in cooperation with Caretaker Scandinavia AB, a company for</p><p>sales, marketing and development in health care. They are general agent for Nordic Gym</p><p>who works with manufacturing of equipment and machines for gym and fitness.</p><p>The aim of this study was to generate a method of measurement to evaluate and control</p><p>the biomechanics of Nordic Gym´s workout equipment. A protocol for an ergonomic</p><p>analysis on the equipment has also been elaborated.</p><p>One of the methods to measure the biomechanics was to measure the torque through the</p><p>whole movement. The other method was electromyography (EMG). The EMGequipment</p><p>registers electric signals that are generated in a working muscle, and makes it</p><p>possible to see when the maximum muscle activity achieves. The results of those</p><p>measurements will be compared to the muscles strengthprofile which describes how the</p><p>muscle generates power in different positions throughout the movement.</p><p>To measure the ergonomics an ergonomic protocol where produced, which was based on</p><p>ergonomics aspect, adapted to gym machines.</p><p>The method of measurement where tested on Nordic Gym´s training machine 101SE leg</p><p>extension and Free Motion´s machine Leg Extension GZF18013 and this machines where</p><p>controlled and evaluated. Two test persons tried out the machines and the machines</p><p>where analysed in an ergonomic and a biomechanical perspective. The result shows that</p><p>the biomechanics of Nordic Gym´s machine where a bit better than the biomechanics of</p><p>FreeMotion´s machine. But in the both case the difference between the values of torque is</p><p>marginal, to improve the biomechanics insistence a bigger different should be necessary</p><p>to use. The ergonomic analyse of the machines showed that the ergonomics where good</p><p>and well planed. Both machines had some small ergonomic lacks, which can be</p><p>improved.</p>