Orientador: Eliane Mauerberg-de-Castro / Banca: Renato de Moraes / Banca: José Angelo Barela / Resumo: Os sistemas sensoriais e motor trabalham de forma integrada para restabelecer o equilíbrio corporal durante a realização de outras tarefas (e.g., carregar uma bandeja com copos, trocar uma lâmpada enquanto equilibramos numa escada, etc.), as quais identificamos como "supra-posturais". Ainda, indivíduos usam a percepção háptica para incorporar ferramentas na realização dessas tarefas que podem, concomitantemente, auxiliar no controle da postura. Uma ferramenta identificada como útil ao controle postural é o sistema âncora que consiste numa tarefa de manipular sutilmente cabos flexíveis anexos a cargas de reduzida massa que ficam em contato com o solo. Segurando a ponta desses cabos com as mãos, os indivíduos, via exploração ativa do sistema háptico, ajustam seu corpo no espaço mais eficientemente do que sem esta ferramenta. O objetivo desse estudo é analisar em tarefa de ancoragem háptica como componentes de tarefa supra-postural (i.e., deslocar o sistema âncora ritmicamente para cima e para baixo; com e sem contato com o solo e com e sem presença de cargas anexas ao sistema âncora) afetam os níveis de oscilação corporal em tarefas de equilíbrio. Participaram do estudo 15 adultos jovens que realizaram duas sessões de coleta em dias distintos (sessão de ancoragem com cargas e sessão de ancoragem sem cargas). Os participantes ficaram em pé sobre uma plataforma de força com os pés na posição tandem, vendados, durante 30 segundos, e, ao som de um metrônomo (55 BPM), levantaram e a... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The sensory and motor systems work in an integrated way to reestablish balance while performing other motor tasks (e.g., carry a tray with cups, changing a light bulb while balancing on a ladder, etc.), which we identify as "supra-postural." Moreover, individuals use haptic perception to control tools while performing these tasks that can, at the same time, aid the postural control system. A tool identified as useful to the postural function is the anchor system, which consists in subtle manipulation of flexible cables attached to low mass loads that are kept in contact with the ground. Holding these cables with their hands, individuals, via active exploration, adjust their bodies in space more efficiently than without this tool. The purpose of this study is to analyze in haptic anchorage tasks how does supra-postural components (e.g., intentionally move rhythmically the anchor system up and down; with or without anchor masses touching the ground, and with or without the end loads attached to the anchor system) affect body sway during balancing tasks. Fifteen young adults participated in this study in two sessions of data collection separated in two different days (anchors with loads and free-load anchors). The participants stood on a force platform with their feet in tandem position, blindfolded, for 30 seconds. To the sound of a metronome (55 BPM), they moved anchor system or the nylon strings (e.g., without the attached loads) up and down according to the following conditi... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:30:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-05-16Bitstream added on 2014-06-13T20:01:00Z : No. of bitstreams: 1 lerena_mam_dr_rcla.pdf: 2646904 bytes, checksum: 23ae262ab005dc313ac98fb498d516f0 (MD5) / Universidade Estadual Paulista (UNESP) / Este estudo foi elaborado a partir da execução de dois experimentos que permitiram testar alguns dos pressupostos da disfunção sacroilíaca e avaliar os efeitos proporcionados pela terapia manipulativa da articulação sacroilíaca. O primeiro experimento investigou em dez participantes com disfunção sacroilíaca a concordância do teste de Gillet com os resultados de assimetria sacral observados em estudo radiológico. Ainda, este experimento avaliou o índice de simetria das estruturas pélvicas nas condições, neutra e em estresse, antes e após a terapia manipulativa da articulação sacroilíaca. Os resultados indicaram uma concordância de 90% entre o tipo de disfunção diagnosticado no teste de Gillet com o padrão de assimetria radiológica e uma redução da assimetria sacral após a intervenção com terapia manipulativa da articulação sacroilíaca. O segundo experimento analisou a simetria da marcha em dez participantes com hipomobilidade sacroilíaca e em dez participantes com disfunção sacroilíaca nos aspectos descritivos, na oscilação lombopélvica, nas forças de reação solo e na atividade eletromiográfica dos mm. multífidos, mm. glúteos máximos e mm. bíceps femorais. Também foi investigado o efeito da terapia manipulativa da articulação sacroilíaca sobre o comportamento da marcha. Em nenhuma das análises realizadas os dois grupos de participantes apresentaram diferença no comportamento de simetria da marcha. Entretanto, a terapia manipulativa da articulação sacroilíaca proporcionou uma importante reorganização da marcha, tornando menor o comportamento de assimetria em todos os aspectos analisados. / This study was elaborated from the enforcement of two experiments that permitted to test some of presupposition of sacroiliac joint dysfunction and evaluate the effects proportionated by the sacroiliac joint manipulative therapy. In the first experiment, ten participants with the sacroiliac joint disfunction were examinated by the agreement of Gillet’s test with the results of sacral asymmetry observed in radiologic study. Still, this experiment evaluated the symptom of symmetry of pelvics structures in neuter and stressed conditions before and after the sacroiliac joint manipulative therapy. The results pointed out an agreement of 90% between a sort of dysfunction diagnosticated in the Gillet’s test with the asymmetry radiologic pattern and a reduction of sacral asymmetry after an intervention with the manipulated therapy of sacroiliac joint. The second experiment analysed the symmetry of the gait in ten participants with sacroiliac joint hipomobility and in ten participants with sacroiliac joint dysfunction in the temporal aspects, in the lumbo-pelvic oscillation, in the ground reaction forces and in the electromyography activity of the multifidus, gluteus maximus and biceps femoris muscles. It was also examined the effect of sacroiliac joint manipulative therapy about a gait behavior. In none of the carried out analysis, the two groups of participants reported differences in their behavior of the gait symmetry. However, the sacroiliac joint manipulative therapy proportionated one important gait reorganization, turning it into a lower asymmetry behavior in all of the analysed aspects.

Orientador: José Angelo Barela / Banca: Lilian Teresa Bucken Gobbi / Banca: Marcos Duarte / Resumo: Com o avanço da idade, principalmente após a idade adulta, os seres humanos apresentam alterações comportamentais no controle postural, provavelmente devido a alterações estruturais e funcionais que ocorrem nos sistemas sensoriais e motor com o processo de envelhecimento. Por exemplo, os idosos oscilam mais que adultos jovens durante a manutenção da postura ereta e executam ajustes posturais antecipatórios e reativos menos eficazes que os adultos jovens quando submetidos a perturbações. Todavia, ainda não se sabe quando tais alterações começam a ocorrer e o que estaria causando estas alterações. Assim, o objetivo deste estudo foi verificar as características comportamentais do controle postural de jovens, adultos e idosos para determinar em que momento, durante ou após a idade adulta, começam ocorrer alterações no controle postural e quais os fatores responsáveis por tais alterações. Para verificar tais características, quatro experimentos foram realizados. Dez adultos jovens (GAJ), 10 adultos entre 40 e 45 anos (GA), 10 adultos de meia-idade entre 50 e 55 anos (GMI) e 10 idosos entre 60 e 65 anos (GI) participaram deste estudo. No primeiro, os participantes mantiveram uma postura ereta, a mais estável possível, com os olhos abertos ou fechados. No segundo, os participantes mantiveram a mesma posição dentro de uma sala móvel que foi movimentada nas freqüências de 0,2, 0,5, e 0,8 Hz. No terceiro, os participantes foram submetidos a perturbações esperadas e inesperadas ao equilíbrio durante a manutenção da postura ereta. E no quarto experimento, os participantes foram submetidos a movimentos da superfície de suporte ora para frente, ora para trás. Os resultados do primeiro experimento indicaram que não há diferenças entre os grupos etários durante a manutenção da postura ereta não perturbada... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: With aging, individuals exhibit behavioral changes in postural control, probably, due to structural and functional changes in the sensory and motor systems. For example, elderlies display more sway than young adults during maintenance of quiet upright stance, and execute anticipatory and reactive postural adjustments differently compared to young adults when are submitted to perturbation. However, it is still unclear when in the adult age such changes begin to occur. Besides, it is unclear what would be provoking these changes. Thus, the aim of this study was to verify the behavioral postural control characteristics of young adults, adults and elderlies to determine in which moment in adult or older age changes begin to occur and what would be the causes of these changes. Four experiments were performed to verify the behavioral characteristics of the postural control of the participants. Ten young adults aging from 20 to 25 years (GAJ), 10 adults aging from 40 to 45 years (GA), 10 middle-age adults aging from 50 to 55 years (GMI) and 10 elderlies aging from 60 to 65 years (GI) participated of this study. In the first experiment, the participants maintained quiet stance position with eyes opened and closed. In the second experiment, participants maintained the same position with eyes opened inside a moving room that was moved at the frequencies of 0.2, 0.5, and 0.8 Hz. In the third experiment, the participants were submitted to self-initiated and externally imposed perturbation. And in the forth experiment, the participants were submitted to displacement of support surface either forward or backward direction. The results of the first experiment indicated no differences among groups during the maintenance of quiet stance position. This lack of difference would probably be related to the task demand that did not require that the postural control... (Complete abstract, click electronic address below). / Mestre

Orientador: Camila Coelho Greco / Coorientador: Renato Aparecido Corrêa Caritá / Banca: Adalgiso Coscrato Cardozo / Banca: Luis Fabiano Barbosa / Resumo: O objetivo deste estudo foi testar as hipóteses de que o torque critico (TC) (expresso como % de uma contração voluntária máxima, CVM) é maior para os flexores plantares (FP) com relação aos músculos extensores do joelho (EJ), enquanto o impulso acima do TC (W') é maior para EJ do que FP. Assim, esperamos que a tolerância ao exercício seja maior para EJ do que FP somente durante o exercício realizado acima de TC. Após a determinação da CVM, 11 homens realizaram dois testes All-Out de 5 min para determinar TC e W'. Os onze sujeitos realizaram mais 5 testes isométricos intermitentes até a falha da tarefa, durante 5 visitas, + 5% TC e - 5% TC para ambos os músculos, e 1 teste para EJ na mesma intensidade de exercício em (% CVM) correspondente a + 5% TC do FP. Os onze participantes realizaram mais 4 testes isométricos intermitentes, até a exaustão, + 5% e - 5% do TC e 1 teste para EJ na intensidade do exercício (% CVM) correspondente a + 5% do TC do FP, para o EJ. O W '(7243,2 ± 1942,9 vs. 3357,4 ± 1132,3 N · m · s) e CT (84,4 ± 24,8 vs. 73,9 ± 19,5 N · m) foram significativamente menores para FP em comparação com EJ. A tolerância ao exercício foi significativamente mais longa para FP (300,7 ± 156,7 s) do que EJ (156,7 ± 104,3 s) em CVM semelhante (~60%) e significativamente menor para FP (300,7 ± 156,7 s) do que EJ (697,0 ± 243,7 s) na condição de + 5% do TC. No entanto, nenhuma diferença significativa foi observada para condição de - 5% do TC (EJ = 1030,2 ± 495,4 s vs. FP = 102... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this study was to test the hypotheses that critical torque (CT) (expressed as % maximal voluntary contraction; MVC) is higher for plantar flexors (PF) than knee extensors (KE) muscles, whereas impulse above ET (W') is higher for KE than PF. Thus, we expected that exercise tolerance would be longer for KE than PF only during the exercise performed above ET. After the determination of MVC, 11 men performed two 5-min all-out tests to determine ET and IET. Eleven participants performed a further 4 intermittent isometric tests, to exhaustion, at ET + 5% and ET - 5%, and 1 test for KE at the exercise intensity (%MVC) corresponding to ET + 5% of PF. The W' (7243.2 ± 1942.9 vs. 3357.4 ± 1132.3 N·m·s) and CT (84.4 ± 24.8 vs. 73.9 ± 19.5 N·m) were significantly lower in PF compared with KE. The exercise tolerance was significantly longer for PF (300.7 ± 156.7 s) than KE (156.7 ± 104.3 s) at similar %MVC (�����60%), and significantly shorter for PF (300.7 ± 156.7 s) than KE (697.0 ± 243.7 s) at ET + 5% condition. However, no significant difference was observed for ET - 5% condition (KE = 1030.2 ± 495.4 s vs. PF = 1028.3 ± 514.4 s). Thus, the limit of tolerance during submaximal isometric contractions is influenced by absolute MVC only during exercise performed above ET, which seems to be explained by differences on both CT (expressed as %MVC) and W' values. / Mestre

When a muscle contracts it produces vibrations. The origin of these vibrations is not known in detail. The purpose of this study was to determine the mechanism associated with muscle vibrations. Mechanisms which have been proposed in the literature were described as theories (cross-bridge cycling, vibrating string and unfused motor unit theories). Specific predictions were derived from each theory, and tested in three conceptually different studies. In the first study, the influence of recruitment strategies of motor units (MUs) on the vibromyographic (VMG) signal was studied in the in-situ cat soleus using electrical stimulation of the soleus nerve. VMG signals increased with increasing recruitment and decreased with increasing firing rates of MUs. Similar results were obtained for the human rectus femoris (RF) muscle using percutaneous electrical stimulation of the femoral nerve. The influence of MU activation on muscle vibrations was studied in RF by analyzing VMG signals at different percentages (0-100%) of the maximal voluntary contraction (MVC). In our second study, we tested the effects of changing the material properties of the in-situ cat soleus (through muscle length changes) on the VMG signal. The magnitude of the VMG signal was higher for intermediate muscle lengths compared to the longest and the shortest muscle lengths. The decreased magnitude of the VMG signal at the longest and at the shortest muscle lengths was associated with increased passive stiffness and with decreased force transients during unfused contractions, respectively. In the third study, the effect of fatigue on muscle vibrations was studied in human RF and vastus lateralis (VL) musc1es during isometric voluntary contractions at a leveI of 70% MVC. A decrease in the VMG signal magnitude was observed in RF (presumably due to derecruitment of MUs) and an increase in VL (probably related to the enhancement of physiological tremor, which may have occurred predorninantly in a mediolateral direction) with fatigue. The unfused MU theory, which is based on the idea that force transients produced by MUs during unfused tetanic contraction is the mechanism for muscle vibrations, was supported by the results obtained in the above three studies.

When a muscle contracts it produces vibrations. The origin of these vibrations is not known in detail. The purpose of this study was to determine the mechanism associated with muscle vibrations. Mechanisms which have been proposed in the literature were described as theories (cross-bridge cycling, vibrating string and unfused motor unit theories). Specific predictions were derived from each theory, and tested in three conceptually different studies. In the first study, the influence of recruitment strategies of motor units (MUs) on the vibromyographic (VMG) signal was studied in the in-situ cat soleus using electrical stimulation of the soleus nerve. VMG signals increased with increasing recruitment and decreased with increasing firing rates of MUs. Similar results were obtained for the human rectus femoris (RF) muscle using percutaneous electrical stimulation of the femoral nerve. The influence of MU activation on muscle vibrations was studied in RF by analyzing VMG signals at different percentages (0-100%) of the maximal voluntary contraction (MVC). In our second study, we tested the effects of changing the material properties of the in-situ cat soleus (through muscle length changes) on the VMG signal. The magnitude of the VMG signal was higher for intermediate muscle lengths compared to the longest and the shortest muscle lengths. The decreased magnitude of the VMG signal at the longest and at the shortest muscle lengths was associated with increased passive stiffness and with decreased force transients during unfused contractions, respectively. In the third study, the effect of fatigue on muscle vibrations was studied in human RF and vastus lateralis (VL) musc1es during isometric voluntary contractions at a leveI of 70% MVC. A decrease in the VMG signal magnitude was observed in RF (presumably due to derecruitment of MUs) and an increase in VL (probably related to the enhancement of physiological tremor, which may have occurred predorninantly in a mediolateral direction) with fatigue. The unfused MU theory, which is based on the idea that force transients produced by MUs during unfused tetanic contraction is the mechanism for muscle vibrations, was supported by the results obtained in the above three studies.

Made available in DSpace on 2014-06-11T19:22:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-12-08Bitstream added on 2014-06-13T19:49:09Z : No. of bitstreams: 1 thomaz_t_me_rcla.pdf: 901888 bytes, checksum: 96e22240a3b1710d26349f35b8551430 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este estudo tem como objetivo definir as orientações dos segmentos envolvidos na ação de chutar, comparar dois tipos de chute - potência e precisão através das variáveis angulares do segmento pelve e das articulações do quadril, do joelho e do tornozelo. A orientação dos segmentos pelve, coxa, perna e pé foi feita através da utilização da convenção dos ângulos de Euler (CHAO, 1980; ZATSIORSKY, 1998), através de rotinas desenvolvidas no software Matlab®. Para obtenção das imagens foram utilizadas 4 câmeras digitais JVC GR-9800u, fixas em tripés, o tratamento das imagens foi realizado no software Dvideow (BARROS et al, 1999; Figueroa et al, 2003). Nos resultados encontrados verificou-se que o segmento pelve apresenta diferença entre os dois tipos de chute no movimento de rotação à direita /esquerda e também no movimento de inclinação lateral direita/esquerda. Durante a realização do chute de precisão a pelve apresenta-se em rotação para a direita de maneira mais acentuada quando comparada ao chute de potência. Diferenças também foram encontradas no movimento de inclinação lateral, a pelve apresenta-se mais inclinada à direita na execução do chute de precisão em relação ao chute de potência. A articulação do quadril apresenta diferenças no movimento de abdução/adução, pois durante o chute de precisão foi verificado o movimento de abdução mais acentuado, e no chute de potência o movimento identificado foi o de adução. O joelho apresenta uma flexão mais acentuada no chute de potência. E a articulação do tornozelo apresenta diferença nos movimentos de dorsiflexão/flexão plantar, durante o chute de precisão o segmento pé está em dorsiflexão devido a vi intenção de acertar a bola com a região medial do pé. Conclui-se que os dois chutes diferem-se nos movimento de rotação à direita/esquerda e inclinação lateral... / The goal of the proposed study is to define the positions and orientations of the segments involved in the action of kicking by females, and to compare the two specific types of kicks: potency and precision using the angular variables . These orientations will be defined by the convention of Euler s angles (CHAO, 1980; ZATSIORSKY, 1998) and through routines developed using the software Matlab®. For obtaining images, four digital cameras (JVC GR-9800u) will be used, fixed on tripods. The processing of the images will be performed using the software Dvideow (BARROS et al, 1999; Figueroa et al, 2003). The results show that the pelvis presents differences in the left/right tilt and in the left/right rotation. The hip shows differences in the abduction/adduction movements, the knee has a flexion movement in the potent kick bigger than in the precision kick, and at the ankle join hasn't been found differences in the pronation/evertion movement.

Made available in DSpace on 2014-06-11T19:22:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-12-15Bitstream added on 2014-06-13T18:49:48Z : No. of bitstreams: 1 oliveira_asc_me_rcla.pdf: 1204641 bytes, checksum: 2f663ab68680a4d75547de7f0ac1f958 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo do presente estudo foi analisar o comportamento das variáveis amplitude e freqüência do sinal eletromiográfico (EMG) dos músculos bíceps do braço (BB), braquiorradial (BR), tríceps do braço (TB) e multifido (MT) em exercícios isotônicos resistidos de flexão do cotovelo, e avaliar o efeito de um treinamento de oito semanas nos valores de limiar de fadiga eletromiográfico (EMGLF), nas variáveis de amplitude e freqüência eletromiográfica, na frequência cardíaca (FC) e na percepção de esforço (PE). Participaram deste estudo 20 voluntários do gênero masculino, divididos em um grupo controle (GC) e um grupo treinamento (GT). Inicialmente, determinou-se a carga máxima isotônica (CMI) para os exercícios rosca bíceps (RB) e rosca Scott (RS). Na semana seguinte, em três dias diferentes, foram realizados os exercícios rosca bíceps, rosca bíceps adaptado (RBA) e rosca Scott, com intensidades de 25%, 30%, 35% e 40% da CMI pelo período de um minuto, um exercício por dia. A partir dos valores de coeficiente de inclinação (slope) das intensidades de carga foram calculados os valores de EMGLF. Antes e após a execução dos exercícios isotônicos foram realizadas contrações isométricas voluntárias máximas (CIVM) e submáximas (50% da CIVM). Durante a realização dos exercícios isotônicos foram registrados valores de FC e de PE. viii Com os valores de EMGLF do músculo BB foi realizado o treinamento do exercício RBA (8 semanas, 2 sessões semanais, 3 séries até a exaustão com 2 minutos de intervalo entre as séries). Foram analisados os valores de FC, PE, força isométrica máxima, bem como a amplitude e frequência da EMG em contrações isométricas máximas, submáximas e isotônicas. / The aim of this study was to analyze the behaviour of electromyographic (EMG) amplitude and frequency of the biceps brachii (BB), brachioradialis (BR), triceps brachii (TB) and multifidus (MT) in different isotonic resistance elbow flexion exercises, and to evaluate the 8 weeks training effect based in the EMG fatigue threshold (EMGFT) in the EMG variables, heart rate (HR), and perceived exertion (PE). 20 healthy males subjects was divided in a control group (CG, n=10) and a training group (TG, n=10). Initially, the one repetition maximum (1RM) isotonic force for biceps curl (BC) and Scott preacher curl (SC), was obtained. On the next week, in three different days, they was perform the BC, adapted biceps curl (ABC) and SC, with 25%, 30%, 35% e 40% of 1RM for one minute, one exercise per day. With the slope values of each load level, the EMGFT was calculated. Before and after the isotonic exercises, was performed isometric maximum voluntary contractions (IMVC) and submaximal (50% of IMVC). During the isotonic exercises, HR and PE was record. Once the BB EMGFT values were obtained, the TG performs training in the ABC exercise (8 weeks, 2 sessions, 3 exhaustive sets with 2 minutes rest). The HR, PE, isometric and isotonic force, as well as the EMG amplitude and frequency in maxima and submaximal isometric and isotonic contractions. Isotonic 166 contractions were analysed by slope and intercept values so linear regressions pre and post training. The results showed after 1 minute rest, there was recovery for BB muscle in EMG amplitude and frequency during the BC (except for total power). There was load level effect for all exercises, mainly for EMG amplitude (root mean square RMS) for BB and BR, with fatigue-induced immediately after the protocol.

When a muscle contracts it produces vibrations. The origin of these vibrations is not known in detail. The purpose of this study was to determine the mechanism associated with muscle vibrations. Mechanisms which have been proposed in the literature were described as theories (cross-bridge cycling, vibrating string and unfused motor unit theories). Specific predictions were derived from each theory, and tested in three conceptually different studies. In the first study, the influence of recruitment strategies of motor units (MUs) on the vibromyographic (VMG) signal was studied in the in-situ cat soleus using electrical stimulation of the soleus nerve. VMG signals increased with increasing recruitment and decreased with increasing firing rates of MUs. Similar results were obtained for the human rectus femoris (RF) muscle using percutaneous electrical stimulation of the femoral nerve. The influence of MU activation on muscle vibrations was studied in RF by analyzing VMG signals at different percentages (0-100%) of the maximal voluntary contraction (MVC). In our second study, we tested the effects of changing the material properties of the in-situ cat soleus (through muscle length changes) on the VMG signal. The magnitude of the VMG signal was higher for intermediate muscle lengths compared to the longest and the shortest muscle lengths. The decreased magnitude of the VMG signal at the longest and at the shortest muscle lengths was associated with increased passive stiffness and with decreased force transients during unfused contractions, respectively. In the third study, the effect of fatigue on muscle vibrations was studied in human RF and vastus lateralis (VL) musc1es during isometric voluntary contractions at a leveI of 70% MVC. A decrease in the VMG signal magnitude was observed in RF (presumably due to derecruitment of MUs) and an increase in VL (probably related to the enhancement of physiological tremor, which may have occurred predorninantly in a mediolateral direction) with fatigue. The unfused MU theory, which is based on the idea that force transients produced by MUs during unfused tetanic contraction is the mechanism for muscle vibrations, was supported by the results obtained in the above three studies.

Made available in DSpace on 2014-06-11T19:30:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-09-15Bitstream added on 2014-06-13T20:21:20Z : No. of bitstreams: 1 melo_sg_dr_rcla.pdf: 609577 bytes, checksum: a9d51fbcdf884c8d8bd0fca73bb98fef (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A fadiga muscular é definida como a incapacidade que o músculo esquelético tem de gerar ou manter elevados níveis de força e potência muscular durante determinado tempo. Ela pode está associada a exercícios submáximos e/ou máximos, respondendo com diminuição da velocidade de contração das fibras musculares e aumento do tempo de relaxamento da musculatura trabalhada. Muitos estudos têm utilizado a eletromiografia de superfície (EMGs) para caracterizar a fadiga pelo aumento induzido da amplitude do sinal EMG, assim como investigar os mecanismos fisiológicos e biomecânicos associados ao processo de instalação da fadiga neuromuscular. O objetivo desse estudo foi analisar metodologias empregadas na determinação do limiar eletromiográfico na fadiga muscular (LFEMG), visando a comparação entre os métodos quanto a capacidade de determinar um índice de limiar anaeróbio eletromiográfico fidedigno. Participaram da pesquisa 10 jogadores amadores de futsal com médias de idade 20,8 anos, massa corpórea de 67,3kg e estatura de 1,75m. Executaram um protocolo incremental de corrida em esteira para análise do LFEMG. Foi utilizada a eletromiografia de superfície para músculos do membro inferior e coletados dados como amplitude do sinal e frequência mediana. Posteriormente os dados relativos à eletromiografia foram verificados quanto à normalidade (Shapiro-Wilk) e analisados (ANOVA) através do software SPSS. Os resultados confirmam a proposta de que o limiar de fadiga neuromuscular pode ser identificado por meio da análise do comportamento do sinal eletromiográfico durante o protocolo incremental de corrida, como observado em estudos anteriores, e que os métodos pesquisados não apresentam diferenças estatisticamente significativas entre eles, contudo necessitam-se padrões metodológicos mais confiáveis e reprodutíveis para determinação de índices de fadiga neuromuscular através da análise do sinal EMG / Muscle fatigue is defined as the inability the skeletal muscle has to generate or maintain high levels of muscle strength and power during a given time. It can submaximal exercise be associated with and / or maximum response with a decrease in speed of contraction of muscle fibers and increased time of relaxation of the muscles worked. Many studies have used surface electromyography (EMG) to characterize the fatigue induced by the increase of the amplitude of the EMG signal as well as investigate the physiological and biomechanical mechanisms associated with the installation process of neuromuscular fatigue. The aim of this study was to analyze the methodologies used in determining the electromyographic fatigue threshold (FTEMG) in order to compare the methods for their ability to determine an reliable index of anaerobic threshold electromyographic. 10 players of amateur soccer participated in the research with average age 20.8 years, body mass index of 67.3 kg and height 1.75 m. They performed an incremental protocol of treadmill running for FTEMG analysis. We used surface electromyography to lower limb muscles and collected as signal amplitude and median frequency. Subsequently, data were normalized relative to the electromyography (Shapiro-Wilk) analyzed (ANOVA) by SPSS software. The results confirm the proposal that the neuromuscular fatigue threshold can be identified by analyzing the behavior of electromyographic signals during incremental running protocol, as observed in previous studies, and that the methods surveyed have no statistically significant differences between them, however, more reliable and methodological standards for reproducible determination of indices of neuromuscular fatigue by EMG signal analysis are required