Dans certaines circonstances, une personne peut être privée de ces capacités à des degrés divers, peut-être en raison de l'amputation des membres, lésions de la moelle épinière ou de maladies dégénératives. Dans ces cas, les appareils fonctionnels sont des outils pertinents pour aider les personnes à améliorer leurs capacités fonctionnelles. Particulièrement adapté dans le cas des personnes atteintes de déficience motrice grave, biosignaux électriques ont été utilisées avec succès pour faire fonctionner les appareils de communication alternatifs. Depuis plus d'un demi-siècle, l'information extraite du signal électromyographique pour operer un dispositif n'a pas examiné les informations fournies par l'unité de base du muscle: l'unité motrice. L'objectif de cette étude est d'examiner comment accéder à l'information au niveau de l'unité motrice permettrait d'améliorer les performances de l'opérateur au cours de la tâche de contrôle du curseur. L'objectif de cette étude est de déterminer si l'accès aux informations au niveau de l'unité motrice permettrait d'améliorer les performances de l'opérateur au cours de la tâche de contrôle du curseur. L'hypothèse est que la méthodologie proposée permettrait de générer des commandes de contrôle plus précises, par rapport aux approches traditionnelles en s'appuyant sur l'information globale obtenue par l'acquisition du signal sEMG conventionnel. Un système pour détecter les potentiels d'action d'unités motrices à partir du signal électromyographique a été conçu, y compris la conception de l'électrode, et la performance évaluée en mesurant le temps pris pour effectuer plusieurs tâches de contrôle du curseur. Les spécifications des tâches ont été extraites d'une étude précédente, qui a utilisé la méthode traditionnelle de traitement du signal électromyographique. La comparaison, basée sur la difficulté de la tâche estimée par la loi de Fitts, a indiqué que le signal de commande généré par la nouvelle méthode a fourni une meilleure précision que celle générée par l'approche traditionnelle, étant 27% plus rapide dans la tâche plus difficile / In some circumstances, a person may be deprived of natural abilities, such as walking and speaking, perhaps due to limb amputation, spinal cord injuries (SCI), or degenerative diseases. Assistive technology devices allows motor-impaired people to overcome their limitations promoting greater independence. Particularly suitable in the case of people with severe motor impairment, electrical biosignals have been successfully utilised to operate alternative communication devices. For over half a century, information extracted from the electromyographic signal for the purpose of operating a given device has not considered the information provided by the basic unit of the muscle: the motor unit. The objective of this study is to investigate how accessing information at motor unit level would improve the operator's performance during a given task. The hypothesis is that the proposed methodology would allow generating more precise control commands, when compared to traditional approaches relying on global information obtained by conventional electromyographic signal acquisition and processing. A system to detect motor unit action potentials from the electromyographic signal was devised, including the electrode design, and the performance evaluated by measuring the time taken to perform several cursor control tasks. The specifications of the cursor control task were extracted from a different study, which used the traditional electromyographic signal-processing approach. Comparing the results from both studies proved that the novel approach provides better control than the traditional one, being 27\% faster in the most difficult task

Modern advances in technology have allowed for an increase in the precision with which we are able to measure, record, and affect behavior. These developments suggest that the domains in which behavior analysis might contribute are considerably broader than previously appreciated, for instance the area of behavioral medicine. One way the field of behavior analysis can begin to address problems in behavioral medicine is with biosensor technology, like surface electromyography (sEMG). For sEMG technology to be useful in behavioral medicine, specifically recovery from total knee arthroplasty, a reference value (the maximum voluntary individual contraction-MVIC) must be established. The MVIC value allows for the comparison of data across days and may allow the programming of contingencies. However, current MVIC methods fall short. Study 1 compares MVIC values produced by a participant given the typical instruction only method with two alternative methods: instruction + feedback, and instruction + feedback in a game context. Across 10 participants both feedback conditions lead to higher MVIC values then the instruction only condition. Study 2 applies the MVIC techniques developed during Study 1 to an exercise procedure. Using an MVIC value as the criteria for feedback Study 2 compares the same three conditions, however this time assessing for the conditions under which exercise performance is optimal. Across all 9 participants the instruction + feedback in a game context lead to the participant ‘working harder' and 8 out of 9 participants exceeded the MVIC value more often during this condition then in the other two conditions.

Title: Comparison of rhythmic stabilization according to Kabat with the techniques used in practice. Objectives: The main aim of this thesis was to measure and compare the level of muscle activity and the level of cocontraction of Muscle quadratus lumborum sinister, obliquus internus abdominis sinister, rectus abdominis sinister and dexter obliquus externus abdominis, which were exposed to different stabilization techniques - rhythmic stabilization and technique used in practice - technique "pushing". Methods: This is an experimental study which is analyzed and then assessing the level of cocontraction of antagonists and the degree of muscle strength in two different ways- the technique of PNF and technique pushing. We use a surface electromyography as an objectification method. The sample consisted of 7 probands. Results: It was discovered that left side lying position not enlarged to the level of activity of all muscles required, therefore the muscles involved in PNF diagonals. Prerequisite increased level of activation during rhythmic stabilization technique according to Kabat was confirmed only in m. quadratus lumborum sinister and m. obliquus externus abdominis dexter and the values statistically insignificant. Participation of the rectus abdominis though its dominant and statistically...

Title: Comparison of rhythmic stabilization according to Kabat with the techniques used in practice. Objectives: The main aim of this thesis was to measure and compare the level of muscle activity and the level of cocontraction of Muscle quadratus lumborum sinister, obliquus internus abdominis sinister, rectus abdominis sinister and dexter obliquus externus abdominis, which were exposed to different stabilization techniques - rhythmic stabilization and technique used in practice - technique "shove". Methods: This is an experimental study which is analyzed and then assessing the level of cocontraction of antagonists and the degree of muscle strength in two different ways- the technique of PNF and technique pushing. We use a surface electromyography as an objectification method. The sample consisted of 7 probands. Results: It was discovered that left side lying position not enlarged to the level of activity of all muscles required, therefore the muscles involved in PNF diagonals. Prerequisite increased level of activation during rhythmic stabilization technique according to Kabat was confirmed only in m. quadratus lumborum sinister and m. obliquus externus abdominis dexter and the values statistically insignificant. Participation of the rectus abdominis though its dominant and statistically...

In some circumstances, a person may be deprived of natural abilities, such as walking and speaking, perhaps due to limb amputation, spinal cord injuries (SCI), or degenerative diseases. Assistive technology devices allows motor-impaired people to overcome their limitations promoting greater independence. Particularly suitable in the case of people with severe motor impairment, electrical biosignals have been successfully utilised to operate alternative communication devices. For over half a century, information extracted from the electromyographic signal for the purpose of operating a given device has not considered the information provided by the basic unit of the muscle: the motor unit. The objective of this study is to investigate how accessing information at motor unit level would improve the operator's performance during a given task. The hypothesis is that the proposed methodology would allow generating more precise control commands, when compared to traditional approaches relying on global information obtained by conventional electromyographic signal acquisition and processing. A system to detect motor unit action potentials from the electromyographic signal was devised, including the electrode design, and the performance evaluated by measuring the time taken to perform several cursor control tasks. The specications of the cursor control task were extracted from a dierent study, which used the traditional electromyographic signal-processing approach. Comparing the results from both studies proved that the novel approach provides better control than the traditional one, being 27% faster in the most dificult task. / Em determinadas circunstâncias, um indivíduo pode ser privado de suas habilidades naturais, tais como andar e falar, no caso de amputações, lesões na medula espinhal ou doenças degenerativas. Dispositivos de tecnologia assistiva permitem que indivíduos com restrições motoras a superem suas limitações promovendo maior independência. Particularmente adequados ao quadro de restrição motora severa, sinais bioelétricos tem sido usados com sucesso para operar dispositivos de comunicação alternativa. Por mais de meio século, informações extraídas do sinal eletromiográfico com o propósito de operar um determinado dispositivo não considera a unidade básica do músculo: a unidade motora. O objetivo deste estudo é investigar como a performance do operador é afetada ao utilizar informações do sinal eletromiográfico provenientes diretamente de unidades motoras. A hipótese é que a metodologia proposta seja capaz de gerar sinais de controle mais precisos quando comparados com a abordagem tradicional que usa informações globais obtidas por métodos tradicionais de aquisição e tratamento do sinal eletromiográfico. Um sistema capaz de detectar e tratar os potenciais de ação de unidades motoras em tempo real foi desenvolvido, incluindo o projeto do eletrodo e a performance foi avaliada ao medir o tempo para execução de tarefas de controle de cursor. As especificações da tarefa de controle de cursor foram retiradas de um estudo anterior, que usava métodos tradicionais de processamento do sinal eletromiográfico. A comparação dos resultados dos dois estudos demonstrou que o novo método oferece melhor controle, sendo até 27% mais rápido na tarefa mais difícil. / Doutor em Ciências

Professional drivers of off-road vehicles, driving on irregular terrain such as in forestry, agriculture and mining, are exposed to whole-body vibration and mechanical shocks. These driver groups have reported severe musculoskeletal problems in the spine, but the association to seated postural reactions is not fully understood. One assumption is that unexpected shocks may create excessive load on spinal joints. The driver’s posture and exposure to mechanical shocks are required to be included in work risk assessments, but muscle activity and body kinematics are not included. The overall aim of this thesis was to describe and analyse seated postural reactions to mechanical shocks and to evaluate measuring of seated postures with relevance for risk assessment and the prevention of musculoskeletal disorders among drivers. The thesis includes four studies, all laboratory-based using a repeated-measures design. Postural reactions were recorded from 23 (Paper I) and 20 (Paper II & III) young, healthy male participants who were seated on a movable platform. The platform delivered mechanical shocks with peak accelerations up to 14 m/s2 in lateral directions during different conditions. Furthermore, twenty participants (Paper IV) were tested by four testers for analysis of test-retest reliability within and between testers measuring seated postures. Kinematics were here detected by means of a motion analysis system (MoLabTM) and described for the spine as angular displacements or range of motion (ROM) using a three-segment model of neck, trunk and pelvis (Paper I–III) and as a more specific model (Paper IV). Surface electromyography (EMG) was recorded bilaterally on the following muscles; trapezius upper part, upper neck, erector spinae and external oblique (Paper I–III). The general findings show that EMG amplitudes normalised to maximum voluntary contractions (MVC) did not exceed 2% in the trapezius, 8% in the upper neck and erector spinae and 18% in the external oblique. The EMG amplitudes and the angular displacements in the neck were significantly reduced from the first compared to the fifth mechanical shock. Adding a cognitive task significantly increased angular displacements. The largest ROM with approximately 20° in each segment was found during a double-sided mechanical shock (shock that changes direction). The reliability within one tester measuring seated postures was mostly considered good and superior to the reliability between several testers, but still insensitive to changes of less than 10°. Exposure to single-sided or double-sided mechanical shocks with accelerations up to 14 m/s2 seem not to cause postural reactions to such an extent that overload of muscles or joint structures should be expected. There seems to be a quick adaptation that causes an improved readiness. The external obliques were most active when restoring equilibrium and seem important for stabilising the whole spinal column. Stability training, in order to improve neuromuscular control of the external obliques could, therefore, be a possible recommendation. The angular displacement in the neck increases if the subject solves a cognitive task of why such activities should be avoided when driving in difficult terrains. Since accurate descriptions of the spinal posture seems difficult even when advanced technical equipment is used, simpler models seem more appropriate. The results show that postural control is maintained even when exposed to considerable mechanical shocks. On the basis of these results, there is no need to change established risk assessment models.

Master of Science / Department of Kinesiology / Thomas J. Barstow / The accumulation of reactive oxygen species (ROS) has been linked to the development of muscular fatigue. Antioxidant administration has the potential to counteract the increased levels of ROS, leading to improvements in performance. N-acetylcysteine (NAC), a nonspecific antioxidant, is especially promising due to its ability to support the biosynthesis of glutathione, one of the primary endogenous antioxidants. Despite this, the effects of NAC on time to fatigue appear to be dependent upon the exercise intensity, with the more pronounced effects evident at submaximal exercise intensities. The purpose of this study was to determine the effects of an acute dose of NAC on whole body fatigue, critical power (CP) and W’ during high-intensity exercise. It was hypothesized that pretreatment with NAC would result in (1) an increase in time to fatigue (TTF), CP and W’, (2) NAC administration would attenuate changes in the EMG responses indicative of fatigue, and (3) speeding of the kinetics of the primary phase of VO2 and a reduction in the slow component. Seven healthy, active males (age: 21.4 ± 1.6 years, weight: 89.1 ± 11.0 kg, height: 183 ± 5 cm) completed an incremental ramp test until exhaustion for the determination of peak VO2 and power. Four tests were subsequently performed at power outputs corresponding to 80, 90, 100, and 110% Pmax under NAC and placebo (PLA) conditions. NAC resulted in a significant increase in [tGSH] in red blood cells compared to baseline and PLA condition. TTF was significantly increased only in the 80% Pmax trial (p = 0.033). CP was also significantly higher with NAC (NAC: 232 ± 28 W vs PLA: 226 ± 31 W; p = 0.032), but W’ showed a tendency to decrease (NAC: 15.5 ± 3.8 kJ vs W’: 16.4 ± 4.5 kJ). The change in W’ was negatively related to CP (r = -0.96), indicating that the increase in CP was associated with a decrease in W’. EMG analysis revealed a tendency for MdPF and RMS to demonstrate less of a change with NAC. There were no significant differences in VO2 kinetics, but an inverse relationship was observed between the change in τp and the magnitude of the slow component expressed both in absolute terms (r = -0.632, p = 0.007) and as a gain (r = -0.751, p = 0.0005). We conclude that NAC was effective in delaying fatigue and improving exercise performance at 80% peak power, although the exact mechanisms are still unclear.

BACKGROUND: Accurate prediction of electromyographic (EMG) signals associated with a variety of motor behaviors could, in theory, serve as activity templates needed to evoke movements in paralyzed individuals using functional electrical stimulation. Such predictions should encompass complex multi-joint movements and include interactions with objects in the environment. METHODS: Here we tested the ability of different artificial neural networks (ANNs) to predict EMG activities of 12 arm muscles while human subjects made free movements of the arm or grasped and moved objects of different weights and dimensions. Inputs to the trained ANNs included hand position, hand orientation, and thumb grip force. RESULTS: The ability of ANNs to predict EMG was equally as good for tasks involving interactions with external loads as for unloaded movements. The ANN that yielded the best predictions was a feed-forward network consisting of a single hidden layer of 30 neural elements. For this network, the average coefficient of determination (R2 value) between predicted and actual EMG signals across all nine subjects and 12 muscles during movements that involved episodes of moving objects was 0.43. CONCLUSION: This reasonable accuracy suggests that ANNs could be used to provide an initial estimate of the complex patterns of muscle stimulation needed to produce a wide array of movements, including those involving object interaction, in paralyzed individuals.

The advancement of technologies that interface with electrically excitable tissues, such as the cortex and muscle, has the potential to lend greater mobility to the disabled, and facilitate the study of the central and peripheral nervous systems. Myoelectric interfaces are currently limited in their signal fidelity, spatial resolution, and interfacial area. Such interfaces are either implanted in muscle or applied to the surface of the muscle or skin. Thus far, the former technology has been limited in its applications due to the stiffness (several orders of magnitude greater than muscle) of its substrates, such as silicon and polyimide, whereas the latter technology suffers from poor spatial resolution and signal quality due to the physical separation between the electrodes and the signal source. We have developed a stretchable microneedle electrode array (sMEA) that can function while stretching and flexing with muscle tissue, thereby enabling multi-site muscle stimulation and electromyography (EMG) measurement across a large interfacial area. The scope of this research encompassed: (i) the development of a stretchable and flexible array of penetrating electrodes for the purposes of stimulating and measuring the electrical activity of excitable tissue, (ii) the characterization of the electrical, mechanical, and biocompatibility properties of this electrode array, (iii) the measurement of regional electrical activity of muscle via the electrode array, (iv) the study of the effect of spatially distributed stimulation of muscle on the fatigue and ripple of muscle contractions, and (v) the assessment of the extent to which the stretch response of electrically stimulated muscle behaves in a physiological manner.

Thesis (MScPhysio)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: This review aims to present the available evidence for the effect of McConnell taping on knee biomechanics in individuals with Anterior Knee Pain (AKP). Pubmed, Medline, Cinahl, Sportdiscus, Pedro and Science Direct electronic databases were searched from inception until September 2014. Experimental research into knee biomechanical or EMG outcomes of McConnell taping compared to no tape or placebo tape were included. Two reviewers completed the searches, selected the full text articles and assessed the risk of bias of eligible studies. Authors were contacted for missing data. Eight heterogeneous studies with a total sample of 220 were included in this review. All of the studies had a moderate to low risk of bias and compared taping to no tape and/ or placebo tape. Pooling of data was possible for three outcomes; average knee extensor moment, average VMO/VL ratio and average VMO-VL onset timing. None of these outcomes revealed significant differences. The evidence is currently insufficient to justify the routine use of the McConnell Taping technique in the treatment of Anterior Knee Pain. There is a need for more evidence on the aetiological pathways of Anterior knee Pain; level one evidence and studies investigating other potential mechanisms of McConnell taping. / AFRIKAANSE OPSOMMING: Die objektief van hierdie resensie was om te bepaal wat die effekte van McConnell Patellar Vasbinding is op knie kinematika, kinetiek en spier aktivering in diegene met Voorafgaande Knie Pyn (VKP). Die navorsers het elektroniese databases soos Pubmed, Medline, Cinahl, Sportdiscus, Pedro en Science Direct, van aanvang tot September 2014, ondersoek. Eksperimenteel studie ontwerpe wat biomeganiese of EMG gevolge van McConnell Vasbinding vergelyk met geen vasbinding of placebo vasbinding, is ingesluit. Twee resente het die ondersoek voltooi, die volle tekse artikels gekies en die partydigheid risiko van die ingeslote studies, geskat. Skrywers is gekontak vir enige verlore data. Agt heterogeen studies uit ‘n totalle monster van 220 is in hierdie resensie ingesluit. Al die studies het ‘n gematigde tot laag risiko vir eensydigheid en vergelyk vasbinding met geen of placebo vasbinding. Data saamvoeging was moontlik vir drie uitslae, naamlik: gemiddelde knie ekstensor moment; gemiddelde VMO/VL ratio en gemiddelde aanval tydmeting. Geen gevolge het veelseggende verskille of afwykings vertoon. Tans is die bewys nie genoegsaam om die routiene gebruik van McConnell Vasbinding tegniek te regverdig nie in die behandeling van VKP. Meer bewyslewering op die etiologiese paaie van VKP; Graad een bewys en studies wat ander moontlike meganisme van Mc Connell Vasbinding ondersoek, is noodsaaklik.