published_or_final_version / Orthopaedics and Traumatology / Master / Master of Philosophy

Weakness and subjective fatigue are common features of rheumatoid arthritis (RA). However, whether there is a true increase in the fatigability of rheumatoid skeletal muscle, in which fibre atrophy has been frequently reported, is unclear. Such factors may influence the ability to respond to exercise programmes. In this work, a reliable and sensitive technique for the objective measurement of forearm muscle fatigue during sustained grip was developed, using power spectral analysis of the surface myoelectric signal (SMES).The inter-relationships between grip force (hand function) and the activity and severity of the rheumatoid disease process with muscle fatigue (defined as the decline in the median frequency of the SMES with work, (MDFG)) and the initial median frequency of the SMES (IMF) were examined. It has been previously suggested that the IMF of the SMES may reflect the fibre type of the underlying muscle. The response to a 12-week progressive right hand grip strengthening programme in healthy females and those with RA was also evaluated. Potential predictors of outcome and the mechanisms of strength gain were examined. Forearm muscle fatigue in RA was not significantly greater than in healthy controls. However, higher levels of fatigue were associated with greater systemic disease activity and greater disease severity. The IMF of the SMES was shown to be stable over a wide range of grip forces for a given individual. It was significantly elevated in rheumatoid subjects, and showed a direct association with greater disease severity. Handgrip exercise was highly effective in improving hand function in females with RA. Strength gains were also demonstrated in healthy controls. Subjects with more severe disease and greater IMF of the SMES showed the greatest improvement in hand function. Greater systemic and local disease activity during the 12-week programme were limiting factors to improvement in grip. Local (right hand) disease activity remained stable or improved in the RA group overall, in spite of a trend towards deteriorating systemic and left handed disease activity. The two main potential mechanisms of strength gain (neural adaptation and gains in muscle mass) were assessed in both rheumatoid and healthy groups. The former was assessed by evaluation of the neuromuscular efficiency, derived from the relationship of the root mean square of the SMES at a given grip force. Gains in muscle mass were also assessed using this technique and by volumetric analysis of forearm musculature using magnetic resonance imaging. Although significant gains in muscle mass were demonstrated in the control group, no such gains were seen in the rheumatoid subjects. This indicates that neural adaptation was an effective method of strength gain in the rheumatoid group.

A partir do espectro de freqüência do sinal eletromiográfico pode-se calcular a freqüência mediana, a freqüência média e a moda da freqüência, podendo se avaliar a fadiga muscular de um indivíduo. Atualmente as análises miográficas, do Depto de Fisioterapia da UNESP - Presidente Prudente, a coleta das medidas e a análise dos resultados são feitas em sistemas separados, isto é, há um sistema para aquisição dos sinais miográficos e outro para análise dos dados, em computadores diferentes. Isto causa problemas pois o indivíduo é submetido ao exercício e somente depois do exercício concluído o sinal é analisado. Com a intenção de melhorar a análise dos sinais miográficos foi desenvolvido um programa computacional no qual os cálculos de FFT e o tratamento do sinal são feitos simultaneamente a aquisição, isto é, em tempo real. A grande vantagem é a possibilidade de se corrigir possíveis erros durante a aquisição devidos a eletrodos mal posicionados, ruídos, evitar o cansaço excessivo do paciente ou até detectar um possível processo de lesão musculara antes que este ocorra. O aplicativo foi implementado em linguagem Visual Basic e rotinas do Matlab, encontra-se em funcionamento e os resultados práticos são discutidos neste trabalho. / From the frequency spectrum of a electromiographic signal the frequency mediana, the mean frequency and the frequency modal can be calculated. Using such parameters the muscular fading of a patient can be evaluated, for instance, using the FFT procedure. In the Phisiotherapy Department of Unesp at Presidente Prudente, experimental data are collected and analyzed using two separated systems. The data corresponding to the electro miographic signal are measured in the first step and then transferred and analyzed in another computer. This procedure is not straightforward since the patient is submitted to a given exercise and only after finishing it the data could be analyzed. Aiming to improve the analysis of the electromiographic signals a software was developed allowing the FFT calculations and the signal analysis to be performed during the data acquisition. The advantage is the possibility to adjust and correct the experimental procedure during the acquisition. Effects of electrodes malpositioning on the patient, electrical noise and excessive fatigue of the patient or even it is possible to detect a muscular lesion during the exercise. The software was developed in the Visual Basic language and using Matlab routines, it is now running and practical results are discussed in this work.

O objetivo deste estudo foi avaliar a função mastigatória de sujeitos adultos jovens assintomáticos para Disfunção Temporomandibular (DTM), utilizando eletromiografia (EMG) de superfície e teste de eficiência mastigatória (EM). A partir destes testes, analisar as variáveis eletromiográficas durante a mastigação de materiais (naturais e artificiais) de diferentes texturas, a fim de verificar se: diferentes texturas alimentares promovem diferentes valores de índice eletromiográficos; o índice de simetria mastigatória com a cápsula mastigatória se assemelha a algum alimento natural testado. A amostra foi composta por 30 sujeitos adultos jovens saudáveis, com idade média de 23,46 anos (variando de 18 a 29 anos), sendo 15 homens e 15 mulheres, assintomáticos para DTM, ambos confirmados por exame clínico odontológico e seguindo a classificação proposta pelo protocolo do Research Diagnostic Criteria for Temporomandibular Disorders - RDC/ TMD. Os sujeitos foram submetidos a uma anamnese sobre o comportamento mastigatório incluindo perguntas sobre hábitos e dificuldades mastigatórias. Também foram realizados exame clínico de oclusão e posterior análise EMG (Eletromiógrafo Freely - De Götzen srl; Legano, Milano, Italy) e de EM utilizando cápsulas mastigatória (Sistema de avaliação da Eficiência Mastigatória: ME-mastig - FORP, FCFRP/USP). Os registros eletromiográficos foram realizados em etapas: teste de normalização (Máxima Contração Voluntária com roletes de algodão), teste estático (Máxima Contração Voluntária em Máxima Intercuspidação Habitual) e teste dinâmico (mastigação de goma, uva passa, cápsula mastigatória e amendoim - à direita, esquerda e habitual). Os valores de EM foram obtidos durante a mastigação da cápsula concomitante ao teste dinâmico. Os valores EMG e EM obtidos foram submetidos ao Teste Komogorov-Smirnov, apresentando distribuição normal. Os dados experimentais foram analisados estatisticamente pela Análise de Variância (ANOVA-paramétrico) para os valores de EMG e EM encontrados nos sujeitos da pesquisa. O Teste de Tukey (p≤0,05) foi utilizado para múltiplas comparações. Os resultados EMG do teste estático foram: POCT 84,03%; POCM 85,20%; TORS 10,90%; ASSIM 1,80%; ATTIV -6,85%; IMPACT 104,43%; e os resultados do teste dinâmico foram: goma: Ciclo 22,86; Freq 1,52 Hz; SIMETRIA 43,11%; IMPACT 2590,97 μV/ μV.s%; uva passa: Ciclo 22,93; Freq 1,54 Hz; SIMETRIA 52,62%; IMPACT 3632,49 μV/ μV.s%; cápsula: Ciclo 23,03; Freq 1,53 Hz; SIMETRIA 29,69%; IMPACT 4028,58 μV/ μV.s%; amendoim: Ciclo 24,10; Freq 1,60 Hz; SIMETRIA 44,40%; IMPACT 4498,43 μV/ μV.s%. O Teste de Tukey (p≤0,05) foi utilizado para múltiplas comparações e para todos os materiais testados Ciclo e Frequência foram considerados semelhantes. Para SIMETRIA, goma, uva passa e cápsula foram semelhantes e diferentes do amendoim, assim como uva passa, cápsula e amendoim foram semelhantes e diferentes da goma. Para IMPACTO, uva passa, cápsula e amendoim e diferentes da goma. Os valores de EM direita (0,66 μg/ml), esquerda (0,60 μg/ml) e habitual (0,61 μg/ml) foram considerados semelhantes. A partir dos resultados, foi possível concluir que a função mastigatória foi satisfatória para os materiais utilizados, e a cápsula mastigatória apresentou todos os índices EMG analisados semelhantes aos obtidos com os alimentos naturais de diferentes texturas. / The aim of this study was to evaluate the masticatory function of subjects asymptomatic young adults for Temporomandibular Disorders (TMD) using surface lectromyography (EMG) and testing of masticatory efficiency (ME). From these tests, examine the EMG variables during mastication of materials (natural and artificial) of different textures in order to check that: different food textures promote different electromyographic index values, the rate of symmetry with masticatory chewing the capsule is resembles some natural food tested. The sample consisted of 30 healthy young adult subjects with a mean age of 23.46 years (range 18-29 years), 15 men and 15 women, with no symptoms of TMD, both confirmed by dental examination and following the classification proposed protocol by Research Diagnostic Criteria for Temporomandibular Disorders - RDC/ TMD. The subjects were submitted to an interview on the chewing behavior including questions about habits and chewing difficulty. Were also carried out clinical examination and subsequent occlusion EMG analysis (Electromyograph Freely - De Götzen srl; Legano, Milano, Italy) and ME using capsules masticatory system (Masticatory Efficiency assessment: ME- mastig - FORP, FCFRP/ USP). The EMG recordings were performed in stages: test standards (Maximum Voluntary Contraction with cotton rolls), static test (Maximum Voluntary Contraction in maximal intercuspal Habitual) and dynamic testing (chewing gum, raisins, peanut and capsule chewing right, left and habitual). ME values were obtained during chewing the capsule concomitant dynamic test. EMG values and ME were submitted to Test Komogorov-Smirnov test showed normal distribution. The experimental data were statistically analyzed by analysis of variance (ANOVA - parametric) for values of EMG and ME found in research subjects. The Tukey test (p≤ 0.05) was used for multiple comparisons. The EMG static test results were: POCT 84.03%, POCM 85.20%; TORS 10.90%, ASSIM 1.80%; ATTIV -6.85%, IMPACT 104.43%, and the test results dynamic were: gum: Cycle 22.86; Freq 1.52Hz; SIMETRIA 43.11%; IMPACT 2590.97μV/μV.s%; raisins: Cycle 22.93; Freq 1.54Hz; SYIMETRIA 52,62%; IMPACT 3632.49μV/μV.s%; capsule: Cycle 23.03; Freq 1.53Hz; SYMMETRY 29.69%; IMPACT 4028.58μV/μV.s%; peanuts: Cycle 24.10, Freq 1.60Hz; SIMETRIA 44.40%; IMPACT 4498.43μV/ μV.s%. The Tukey test (p≤ 0.05) was used for multiple comparisons and for all tested materials cycle and frequency were considered similar. To SIMETRIA, gum, raisins and capsule were similar and different peanut, as well as raisins, peanut and capsule were similar and different gum. For IMPACT, raisins, peanuts and different capsule and gum. The values of ME right (0.66μg/ml), left (0.60μg/ml) and usual (0.61μg/ml) was considered similar. From the results, it was concluded that the masticatory function was satisfactory for the materials used, and the capsule masticatory EMG showed all indices analyzed similar to those obtained with the natural foods of different textures.

Knee joint osteoarthritis is recognised as a significant subset of osteoarthritis. Little work has examined muscle changes that occur with knee joint osteoarthritis. Much of this work has centred on strength deficits, while little work has examined the effect of joint pathologies, such as osteoarthritis, on the fatigue resistance of the muscles associated with an affected joint. The purpose of this study was to investigate the relative fatigue-resistance characteristics of the vastus medialis in subjects with and without knee joint osteoarthritis, as well as the ability to predict endurance times in these groups, using high spatial resolution electromyography and a sub-maximal isometric endurance test. Twenty-six subjects with unilateral knee osteoarthritis and seventeen subjects with no known knee pathology were evaluated. All subjects performed initial tests to evaluate maximum voluntary contraction (MVC), voluntary activation levels, and true maximum force (TMF). Endurance time was assessed during an isometric quadriceps contraction at 50% of the true maximum force. Surface electromyography (sEMG) data was collected from the vastus medialis muscle of the quadriceps group during the endurance test. MVC tests showed that the affected leg of the group with osteoarthritis was significantly weaker (p < 0.05) than the unaffected leg. Voluntary activation data showed that subjects with osteoarthritis presented with significant bilateral deficits (p < 0.05). TMF data showed a significantly lower (p < 0.05) true potential for force generation in the affected compared to the unaffected leg of the osteoarthritis group. Endurance time data showed no significant difference between groups. Electromyography data showed significant differences (p < 0.05) between the affected and unaffected legs in initial values of Median Frequency (MDF), Mean Power Frequency (MPF) and Conduction Velocity (CV), the percentage change in CV and the relative rate of change in the frequency band between 5 and 30Hz (FB1). Finally, significant correlations were seen between endurance time and the relative rate of change of MDF, MPF and CV calculated over the initial thirty seconds of the endurance test. There were no significant correlations from either leg of the group with knee joint osteoarthritis.It can be concluded from this study that there are differences in strength measures, and in the sEMG signal collected from the vastus medialis muscle of the affected and unaffected legs of subjects with knee osteoarthritis. It appears likely that the differences observed in the sEMG signals were related to a decrease in the representation of type-2 muscle fibres in the vastus medialis of the affected leg. Furthermore, these changes in the behaviour of the signal appear to indicate an improvement in the relative fatigue resistance of the affected leg in relation to the unaffected leg of the group with knee osteoarthritis.Moderate success was seen with the prediction of endurance time in control subjects in the current work using a short duration (30-second) endurance test. This relationship was not seen in either the affected or unaffected leg of the subjects with knee osteoarthritis. Further investigation utilising different sEMG collection and analysis techniques in this area may improve prediction of endurance time in unaffected and affected subjects.

<p><p>The intention of this thesis project report is to control a servo motor by using Electromyography(EMG) signals in the purpose of learning about bioamplifers and how ATMEL AVR Series microcontrollers work.</p><p>EMG is the a test that is used to record the electrical activity of muscles. In order to fulfill our intention an EMG amplifier, an ADC converter and a servo motor controller is build to be used with the simple mechenical gripper where the control of the gripper is directly related with the amplitude of the EMG signals taken from the hand muscles. In the development and USART serial communication part is also added enabling to see the ADC results in computer.</p></p>

The sternocleidomastoid (SCM) and upper trapezius (UT) muscles are the primary dynamic stabilizers of the head and neck and likely attenuate head acceleration with direct and indirect impacts. Increasing the strength of the SCM and UT through cervical resistance training has been recommended to prevent concussions in football players. The purpose of this study was to examine the effects of an eight-week isoinertial cervical resistance training program on SCM and UT muscle activity (EMG) and kinematic responses of the head and neck during a standard football tackle in college-aged males. Sixteen college-aged males (21.6 ± 2.8 y, 94.6 ± 13.3 kg) with previous high school football or rugby playing experience completed an eight-week isoinertial cervical resistance training program consisting of three sets of 10 repetitions of neck extension, flexion, right and left lateral flexion at 60-80% of 10 repetition maximum two to three times a week. Isometric cervical strength, neck girth, EMG, and kinematic responses of the head and neck during a standard football tackle were measured before and after training. All kinematic data were gathered using a three-dimensional motion capturing system. Training resulted in 7 and 10% increases in isometric cervical extension and left lateral flexion strength, respectively, but no changes were seen in isometric flexion or right lateral flexion strength or neck girth. Additionally, training had no influence on the EMG responses of the SCM or UT, peak linear (7.23 vs. 7.59 g, p = 0.115; pre- vs. post-training) or angular (431.96 vs. 452.37 rad/s2, p = 0.864) head accelerations during the standard football tackle. The UT demonstrated approximately 40% higher absolute EMG activity than the SCM during tackling both before and after training. Under the current experimental conditions, despite modest increases in isometric cervical extension and left lateral flexion strength, the eight-week isoinertial cervical resistance training program failed to augment dynamic stabilization of the head and neck during a standard football tackle in college-aged males. Future research should examine the effects of both slow speed load-intensive and high speed low-to-moderate load intensity isoinertial training as well as plyometric training in decreasing head acceleration during football tackling for injury prevention purposes.

The intention of this thesis project report is to control a servo motor by using Electromyography(EMG) signals in the purpose of learning about bioamplifers and how ATMEL AVR Series microcontrollers work. EMG is the a test that is used to record the electrical activity of muscles. In order to fulfill our intention an EMG amplifier, an ADC converter and a servo motor controller is build to be used with the simple mechenical gripper where the control of the gripper is directly related with the amplitude of the EMG signals taken from the hand muscles. In the development and USART serial communication part is also added enabling to see the ADC results in computer.

Thesis (M. Phil.)--University of Hong Kong, 2010. / Includes bibliographical references (leaves 132-164). Also available in print.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences