O forehand e o backhand são as técnicas de movimentos mais utilizados no tênis. São golpes técnicos de complexa execução, pois dependem de uma perfeita sincronização temporal entre o movimento da raquete e a trajetória da bola. A literatura especializada demonstra que o posicionamento dos pés é fundamental para gerar potência nestes golpes e registra basicamente dois tipos de forehand quanto ao posicionamento dos pés: forehand open stance (FOS) e forehand square stance (FSS). A técnica de backhand, desde o início da prática da modalidade, apresenta duas maneiras de ser executada: com uma mão (BK1) ou com duas mãos (BK2) segurando o cabo da raquete. Pesquisas científicas específicas nesta modalidade esportiva têm se tornado razoavelmente freqüentes nas últimas duas décadas. O objetivo deste estudo é descrever as características biomecânicas a partir de parâmetros dinâmicos, cinemáticos e eletromiográficos segundo variáveis e músculos relacionados experimentalmente em função da utilização das quatro técnicas descritas acima. Através do conhecimento destas características biomecânicas, pretende-se ainda estabelecer uma relação de dependência quanto às influências no desempenho técnico esportivo. A amostra foi composta por dez indivíduos do sexo masculino, que possuíam domínio das técnicas analisadas. Ao analisarmos os resultados que reúnem as variáveis Biomecânicas estudadas, percebemos que é possível aceitar parcialmente a hipótese inicial de nosso estudo: as técnicas FOS e BK2 demandam maior ativação muscular quando comparadas com as técnicas FSS e BK1, respectivamente. Observando-se ainda os resultados de eletromiografia, verificamos a predominância de valores mais elevados de ativação muscular para as técnicas FOS e BK2 durante a fase pós-impacto, confirmando-se, portanto a hipótese inicial. Porém, durante a fase pré-impacto, os valores mais elevados de ativação muscular foram observados nas técnicas FSS e BK1, contrariando desta maneira a hipótese inicial. Concluímos, portanto, distintos comportamentos entre as duas técnicas de forehand e backhand, principalmente ao analisarmos as fases pré e pós-impacto, o que nos permitiu uma análise técnica detalhada dos gestos esportivos estudados, dada a complexidade estrutural dos mesmos / The forehand and the backhand are the most common movements in tennis. They are technical strokes of complex execution because they depend on perfect temporal synchronization between the racket\'s movement and the ball\'s trajectory. The tennis literature on the subject shows that the feet\'s positioning is crucial to generate power during these strokes. Two kinds of forehand are identified: the forehand open stance (FOS) and the forehand square stance (FSS). The backhand, since its origin, has appeared in two forms: the one-handed grip (BK1) and the two-handed grip (BK2). Scientific research on the subject has been conducted regularly during the two decades. Hence, the aim of this study is to describe the biomechanical characteristics within dynamic, kinematic and electromyographic parameters, and according to variables and experimentally related muscles in relation to the four different tennis techniques. In addition, through knowledge of these biomechanical characteristics, this thesis intends to identify the influences on technical sports performance. The sample was composed of males (n=10) that have mastery of the forehand and backhand strokes. After analyzing the results that evolve Biomechanics variables studied, we realized that it\'s possible to partially accept the initial hypothesis of our study: the forehand open stance and backhand strokes with both hands demand greater muscle activation when they are compared with forehand square stance and backhand stoke with just one hand, respectively. Still, observing the results of electromyography, we verified the predominance of the highest values of muscle activation for forehand open stance and backhand strokes with both hands during the post-impact phase, it\'s, thus, confirming the initial hypothesis. However, during the pre-impact phase, the highest values of muscle activation were observed in the forehand square stance and backhand strokes with one hand, counteracting, in this way, the initial hypothesis. We concluded, therefore, distinct behaviors between the two forehand and backhand strokes, mainly to analyze the pre and post-impact phase, which allowed us a detailed technical analysis of the sportive gestures studied, owing to its structural complexity

Introdução: Embora a migrânea seja considerada uma desordem primariamente da função cerebral, seu quadro é frequentemente acompanhado de dor e disfunções cervicais associadas, como diminuição da amplitude de movimento, pontos-gatilhos em cabeça e pescoço, diminuição do limiar de dor à pressão, bem como diminuição da força muscular e padrões alterados de atividade dos músculos da cervical. Um protocolo de fortalecimento para os flexores e extensores da cervical demonstra resultados positivos para a dor cervical crônica e melhora da atividade eletromiográfica, porém não está estabelecido se este mesmo protocolo teria efeitos em pacientes com migrânea. Objetivo: Investigar os efeitos de um protocolo de exercícios específicos para os músculos flexores e extensores da coluna cervical na força e atividade eletromiográfica em indivíduos com migrânea. Materiais e Métodos: 23 indivíduos do sexo feminino, entre 18 a 55 anos, com diagnóstico de migrânea passaram por um avaliação inicial contendo os questionários Neck Disability Index (NDI), 12 itemAllodynia Symptom Checklist (ASC-12), TAMPA questionário de Cinesiofobia e Migraine Disability Assesment (MIDAS). Após os questionários, foi avaliada a força da contração isométrica voluntária máxima (CIVM) dos flexores e extensores cervicais, tempo de pico necessário para atingir a contração, e concomitantemente, avaliada as variáveis eletromiográficas para os músculos esternocleidomastóideo, escaleno anterior, esplênio da cabeça e trapézio superior de frequência mediana e slope, além da coativação dos antagonistas. Os pacientes realizaram um protocolo de fortalecimento de oito semanas para os flexores e extensores cervicais e na nona semana, foram reavaliados.. Resultados: Não houve diferença na pontuação dos questionários NDI, ASC-12/Brasil e TAMPA pré e pós intervenção, porém houve diminuição da incapacidade gerada pela migrânea avaliado pelo questionário MIDAS (p=0,017). Foi observado aumento da força dos músculos extensores cervicais (p=0,001) e não houve diferença na força dos músculos flexores e no pico da força pré e pós intervenção. Em relação às variáveis eletromiográficas, os valores da frequência mediana foram diferentes apenas no músculo escaleno anterior pós intervenção na atividade de flexão(p=0,004). Não houve diferença para o slope em ambas as atividades de flexão e10 extensão, porém houve diminuição da coativação antagonista na tarefa de flexão (p=0,001). Conclusão: Um protocolo de fortalecimento dos flexores e extensores cervicais de oito semanas parece ter efeito na diminuição da incapacidade gerada pela migrânea, no ganho de força dos músculos extensores cervicais e na diminuição da coativação antagonista em flexão, resultando em menor atividade antagonista pós treinamento. / Introduction: Although migraine is considered a disorder primarily of brain function, its condition is often accompanied by pain and associated cervical dysfunctions, such as decreased range of motion, trigger points in the head and neck, decreased pressure pain threshold, and such as decreased muscle strength and altered patterns of cervical muscle activity. A strengthening protocol for cervical flexors and extensors demonstrates positive results for chronic neck pain and improved electromyographic activity, but it is not established whether this protocol would have effects in patients with migraine. Objective: To investigate the effects of a specific exercise protocol for the cervical spine flexor and extensor muscles on the force and electromyographic activity in individuals with migraine. Materials and methods: Twenty-three female subjects aged 18 to 55 years with a diagnosis of migraine underwent an initial evaluation containing the Neck Disability Index (NDI) questionnaire, 12 item-Allodynia Symptom Checklist (ASC-12), TAMPA questionnaire Kinesiophobia and Migraine Disability Assesment (MIDAS). After the questionnaires, the strength of the maximal voluntary isometric contraction (MVIC) of the cervical flexors and extensors, the peak time required to achieve the contraction, and the electromyographic variables for the sternocleidomastoid, anterior scalene, splenius and upper trapezoid of medium frequency and slope, besides the coactivation of the antagonists. The patients underwent an eight-week strengthening protocol for flexors and cervical extensors and in the ninth week, they were reevaluated. Results: There was no difference in the scores of the NDI, ASC-12/Brasil and TAMPA questionnaires before and after intervention, but there was a decrease in disability generated by the MIDAS questionnaire (p = 0.017). Increased cervical extensor muscle strength (p = 0.001) was observed and there was no difference in flexor muscle strength and peak pre and post intervention force. Regarding the electromyographic variables, the median frequency values were different only in the anterior scalene muscle post intervention in the flexion activity (p = 0.004). There was no difference for the slope in both flexion and extension activities, but there was decrease of the antagonistic coactivation in the flexion task (p = 0.001). Conclusion: An eight-week protocol for strengthening cervical flexors and12 extensors seems to have an effect on the decrease in the disability generated by migraine, on increase in strenght of the cervical extensor muscles and on the decrease of the antagonist coactivation in flexion, resulting in less antagonist activity post-intervention.

by So Chi-hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 155-167). / Abstracts in English and Chinese. / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter Chapter 2 --- Physiological Characteristics of Elite Windsurfers --- p.7 / Abstract --- p.8 / Chapter 2.1 --- Introduction --- p.9 / Chapter 2.2 --- Literature Review --- p.11 / Chapter 2.3 --- Method --- p.20 / Chapter 2.4 --- Result --- p.23 / Chapter 2.5 --- Discussion --- p.25 / Chapter 2.6 --- Conclusion --- p.36 / Chapter Chapter 3 --- An evaluation of a windsurfing pumping simulator for objective assessment of windsurfing pumping performance --- p.37 / Abstract --- p.38 / Chapter 3.1 --- Introduction --- p.39 / Chapter 3.2 --- Method --- p.44 / Chapter 3.3 --- Result --- p.48 / Chapter 3.4 --- Discussion --- p.49 / Chapter 3.5 --- Conclusion --- p.50 / Chapter Chapter 4 --- Kinesiological Analysis of Joints' Movement Pattern in Windsurfing Pumping and Its Change with Muscle Fatigue --- p.52 / Abstract --- p.53 / Chapter 4.1 --- Introduction --- p.55 / Chapter 4.2 --- Literature Review --- p.57 / Chapter 4.3 --- Method --- p.65 / Chapter 4.4 --- Result --- p.72 / Chapter 4.5 --- Discussion --- p.77 / Chapter 4.6 --- Conclusion --- p.82 / Chapter Chapter 5 --- The Use of Electromyography in the Study of Windsurfing Pumping --- p.83 / Abstract --- p.84 / Chapter 5.1 --- Introduction --- p.86 / Chapter 5.2 --- Literature Review --- p.89 / Chapter Part 1. --- Frequency Spectrum Analysis During Repeated Isokinetic Knee Extension and Elbow Flexion --- p.106 / Chapter 5.3 --- Method --- p.106 / Chapter 5.4 --- Result --- p.112 / Chapter 5.5 --- Discussion --- p.129 / Chapter 5.6 --- Conclusion --- p.133 / Chapter Part 2. --- Application of Surface EMG in Assessing Muscle Fatigue Pattern in Repetitive Dynamic Windsurfing Pumping Action --- p.134 / Chapter 5.7 --- Method --- p.134 / Chapter 5.8 --- Result --- p.135 / Chapter 5.9 --- Discussion --- p.145 / Chapter 5.10 --- Conclusion --- p.149 / Chapter Chapter 6 --- Conclusion --- p.151 / Chapter Chapter 7 --- References --- p.155 / Chapter Chapter 8 --- Reference Photos --- p.168 / Chapter Chapter 9 --- Appendix --- p.183

by Luk tze Chung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 105-111). / Text in English; abstract also in Chinese. / by Luk tze Chung. / Chapter Chapter One --- Introduction / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Work station design --- p.2 / Chapter 1.3 --- Method of study --- p.4 / Chapter 1.4 --- Purpose of study --- p.5 / Chapter 1.5 --- Variables definition --- p.5 / Chapter 1.6 --- Hypotheses --- p.6 / Chapter 1.7 --- Significance of study --- p.6 / Chapter Chapter Two --- Literature Review / Chapter 2.1 --- Biomechanical study on ergonomics problems --- p.7 / Chapter 2.1.1 --- Ergonomics --- p.7 / Chapter 2.1.2 --- Biomechanics --- p.7 / Chapter 2.1.3 --- Force and torque --- p.8 / Chapter 2.1.3.1 --- Lever systems --- p.8 / Chapter 2.1.3.2 --- Torque and moment --- p.8 / Chapter 2.1.4 --- Biomechanics of the back --- p.9 / Chapter 2.1.5 --- Shoulder biomechanics --- p.10 / Chapter 2.2 --- Manual lifting --- p.12 / Chapter 2.2.1 --- Manual handling and musculoskeletal problems --- p.12 / Chapter 2.2.2 --- Strategies for reducing manual handling injuries --- p.13 / Chapter 2.3 --- Method of analysis in ergonomics problems --- p.13 / Chapter 2.3.1 --- Electromyography --- p.13 / Chapter 2.3.1.1 --- Neurophysiology --- p.13 / Chapter 2.3.1.2 --- Electromyography in biomechanics --- p.14 / Chapter 2.3.2 --- Motion analysis --- p.16 / Chapter 2.3.2.1 --- Direct measurement techniques --- p.16 / Chapter 2.3.2.2 --- Indirect measurement using imaging techniques --- p.17 / Chapter 2.4 --- Summary --- p.18 / Chapter Chapter Three --- Method / Chapter 3.1 --- Subjects --- p.19 / Chapter 3.2 --- Position of EMG electrodes --- p.20 / Chapter 3.3 --- Electromyography (EMG) --- p.23 / Chapter 3.4 --- Normalization of EMG --- p.24 / Chapter 3.5 --- Force platform --- p.31 / Chapter 3.6 --- Motion analysis system --- p.33 / Chapter 3.7 --- Calibration of instrument --- p.39 / Chapter 3.7.1 --- EMG --- p.39 / Chapter 3.7.2 --- Force platform --- p.40 / Chapter 3.7.3 --- Motion analysis system --- p.40 / Chapter 3.7.3.1 --- Calibration of displacement and velocity --- p.40 / Chapter 2.7.3.2 --- Calibration of acceleration --- p.40 / Chapter 3.8 --- Work station design --- p.41 / Chapter 3.9 --- Procedure --- p.42 / Chapter 3.10 --- Data analysis --- p.46 / Chapter Chapter Four --- Results / Chapter 4.1 --- EMG data analysis --- p.47 / Chapter 4.1.1 --- MVC testing results --- p.47 / Chapter 4.1.2 --- Results of ANOVA test --- p.48 / Chapter 4.1.2.1 --- Class level information --- p.48 / Chapter 4.1.2.2 --- ANOVA results --- p.49 / Chapter 4.1.2.3 --- Post Hoc test --- p.53 / Chapter 4.2 --- Motion analysis --- p.63 / Chapter 4.2.1 --- Parameters in motion analysis --- p.63 / Chapter 4.2.2 --- Results of ANOVA test --- p.63 / Chapter 4.2.2.1 --- Post Hoc test --- p.68 / Chapter 4.3 --- Force platform data analysis --- p.84 / Chapter 4.3.1 --- Parameters in force platform data analysis --- p.84 / Chapter 4.3.2 --- Result of ANOVA test --- p.84 / Chapter 4.3.2.1 --- Post Hoc test --- p.85 / Chapter 4.4 --- Results of correlation --- p.89 / Chapter Chapter Five --- Discussion and Conclusions / Chapter 5.1 --- EMG signal --- p.90 / Chapter 5.1.1 --- MVC test --- p.90 / Chapter 5.1.2 --- Results of ANOVA in EMG signal --- p.91 / Chapter 5.1.2.1 --- Cervical erector spinae --- p.91 / Chapter 5.1.2.2 --- Trapezius pars descendens --- p.92 / Chapter 5.1.2.3 --- Infraspinatus --- p.93 / Chapter 5.1.2.4 --- Lumbar erector spinae --- p.94 / Chapter 5.2 --- Motion analysis --- p.95 / Chapter 5.2.1 --- Posture --- p.95 / Chapter 5.2.1.1 --- Absolute thigh angle --- p.96 / Chapter 5.2.1.2 --- Absolute arm angle --- p.96 / Chapter 5.2.1.3 --- Absolute chest and abdomen angle --- p.97 / Chapter 5.2.1.4 --- Absolute neck angle --- p.97 / Chapter 5.2.2 --- Force produced by spinae muscle --- p.98 / Chapter 5.3 --- Ground reaction force analysis --- p.99 / Chapter 5.4 --- Correlation analysis --- p.99 / Chapter 5.5 --- Differences between workers and students --- p.100 / Chapter 5.5.1 --- Muscle activity --- p.100 / Chapter 5.5.2 --- Posture . --- p.100 / Chapter 5.6 --- Conclusions --- p.101 / Chapter 5.7 --- Recommendations --- p.102 / References --- p.105 / Appendix --- p.112

The electrical activity of skeletal muscle¡ªthe electromyogram (EMG)¡ªis of value to many different application areas, including ergonomics, clinical biomechanics and prosthesis control. For many applications the EMG is related to muscular tension, joint torque and/or applied forces. In these cases, a goal is for an EMG-torque model to emulate the natural relationship between the central nervous system and peripheral joints and muscles. This thesis mainly describes an experimental study which relates the simultaneous biceps/triceps surface EMG of 12 subjects to elbow torque at seven joint angles (ranging from 45¡ÃƒÂ£to 135¡ÃƒÂ£) during constant-posture, quasi-constant-torque contractions. The contractions ranged between 50% maximum voluntary contractions (MVC) extension and 50% MVC flexion. Advanced EMG amplitude (EMG¦Ãƒâ€™) estimation processors were investigated, and three nonlinear EMG¦Ãƒâ€™-torque models were evaluated. Results show that advanced (i.e., whitened, multiple-channel) EMG¦Ãƒâ€™ processors lead to improved joint torque estimation, compared to unwhitened, single-channel EMG¦Ãƒâ€™ processors. Depending on the joint angle, use of the multiple-channel whitened EMG¦Ãƒâ€™ processor with higher polynomial degrees produced a median error that was 50%-66% that found when using the single-channel, unwhitened EMG¦Ãƒâ€™ processor with a polynomial degree of 1. The best angle-specific model achieved a minimum error of 3.39% MVCF90 (i.e., error referenced to MVC at 90¢X flexion), yet it does not allow interpolation across angles. The best model which parameterizes the angle dependence achieved an error of 3.55% MVCF90. This thesis also summarizes other collaborative research contributions performed as part of this thesis. (1) Decomposition of needle EMG data was performed as part of a study to characterize motor unit behavior in patients with amyotrophic lateral sclerosis (ALS) [with Spaulding Rehabilitation Hospital, Boston, MA]. (2) EMG-force modeling of force produced at the finger tips was studied with the purpose of assessing the ability to determine two or more independent, continuous degrees of freedom of control from the muscles of the forearm [with WPI and Sherbrooke University]. (3) Identification of a nonlinear, dynamic EMG-torque relationship about the elbow was studied [WPI]. (4) Signal whitening preprocessing for improved classification accuracies in myoelectric control of a prosthesis was studied [with WPI and the University of New Brunswick].

Esta tese trata da estimativa de torque e rigidez do paciente dirigida por EMG e sua utilização para adaptar a rigidez do robô durante a reabilitação assistida por robôs. Os sinais eletromiográficos (EMG), obtidos de músculos que atuam durante os movimentos de flexão e extensão de um usuário utilizando uma órtese de joelho ativa, são processados para obter as ativações dos músculos. Inicialmente, um modelo musculoesquelético simplificado e otimizado é usado para calcular as estimativas de torque e rigidez da junta do paciente. A otimização do modelo é realizada comparando o torque estimado com o torque gerado pela ferramenta de dinâmica inversa do software OpenSim, considerando um modelo musculoesquelético escalonado. Como uma solução complementar, é proposta uma rede neural perceptron multicamada (NN) para mapear os sinais EMG para o torque do paciente. Também é apresentado um Ambiente de Estimativa de Torque Gerado por EMG criado para analisar os dados obtidos a partir da aplicação das abordagens propostas considerando a aplicação de um protocolo criado para a análise de interação usuário-exoesqueleto. Um banco de dados de indivíduos saudáveis também foi disponibilizado neste trabalho. Além disso, uma estratégia de controle de impedância adaptativa é proposta para ajustar a rigidez do robô com base na estimativa de rigidez do paciente por EMG. A estratégia inclui uma solução ideal para a interação paciente-robô. Finalmente, são apresentados os resultados obtidos aplicando o controle de impedância adaptativo proposto durante os movimentos de flexão e extensão do usuário que usa a órtese ativa. / This thesis deals with EMG-driven patient torque and stiffness estimation and its use to adapt the robot stiffness during robot-aided rehabilitation. Electromyographic (EMG) signals, taken from selected muscles acting during flexion and extension movements of an user wearing an active knee orthosis, are processed to get the muscles activations. First, a simplified and optimized musculoskeletal model is used to compute the estimate of patient joint torque and stiffness. The model optimization is performed by comparing the estimate torque with the torque generated by the inverse dynamics tool of the OpenSim software, considering a scaled musculoskeletal model. As a complementary solution, a multilayer perceptron neural network (NN) is proposed to map the EMG signals to the patient torque. It is also presented an EMG-driven Torque Estimation Environment created to analyze the data obtained from the application of the proposed approaches considering a protocol created for user-exoskeleton interaction analysis. A database with data from 5 healthy subjects is also made available in this work. Additionally, an adaptive impedance control strategy is proposed to adjust the robot stiffness based on the EMG-driven patient stiffness estimation. The strategy includes an optimal solution for the patient-robot interaction. Finally, the results obtained by applying the proposed adaptive impedance control during flexion and extension movements of the user wearing the active orthosis are presented.

Introdução: a paralisia facial periférica (PFP) é caracterizada por lesão geralmente unilateral do nervo facial em qualquer parte de seu trajeto. Na paralisia total há perda dos movimentos de todos os segmentos da hemiface ipsilateral à lesão. Clinicamente observa-se que a maioria dos pacientes com PFP em fase flácida apresenta dificuldade para mastigar do lado paralisado, pois a manutenção dos alimentos entre as arcadas dentárias está comprometida pela falta de participação do músculo bucinador. Aliada a isso pode ocorrer incompetência labial devido à flacidez da hemiface afetada em conseqüência à queda da comissura labial ipsilateral. Objetivo: verificar as conseqüências da PFP unilateral na fase flácida, com duração de pelo menos seis meses, na função mastigatória quanto a preferência clínica mastigatória e diferença eletromiográfica entre os masseteres.Casuística e Método: foram selecionados 27 indivíduos de ambos os gêneros, com PFP em fase flácida com pelo menos seis meses de paralisia, com idade entre 16 anos e 67 anos, com dentição natural permanente, selecionados por um protocolo específico, complementado com exame clínico miofuncional e avaliação eletromiográfica de superfície nos músculos masseteres nas provas de aperto dentário e mastigação habitual. Resultados: de acordo com as respostas da anamnese, 77,8% dos pacientes referiram mastigar preferencialmente do lado sadio. Clinicamente, 70% apresentaram preferência mastigatória. A atividade muscular dos bucinadores e orbicular da boca foi estatisticamente significante (p = 0,025) entre os lados sadio e paralisado. Apenas, 22,2% dos pacientes apresentou diminuição de massa do masseter do lado paralisado. Não houve diferença eletromiográfica estatisticamente significante entre os lados sadio e paralisado nos masseteres. Conclusão: no presente estudo, pacientes com PFP unilateral na fase flácida, com duração de pelo menos seis meses, apresentaram preferência clínica mastigatória pelo lado sadio. Não houve diferença clínica e eletromiográfica entre os lados paralisado e sadio nos músculos masseteres / Introduction: peripheral facial paralysis (PFP) usually affects the facial nerve in part or in whole on one side of the face. Most patients with PFP find it difficult to chew on the paralyzed side, especially due to compromised buccinator function. In addition, the sagging of the ipsilateral lip commissure tends to compromise lip competence. In spite of the importance of these associations, the literature on mastication difficulties in PFP patients is scarce, perhaps because the facial nerve has conventionally been considered to be responsible primarily for facial expression. Objective: to evaluate the impact of long-standing peripheral facial nerve paralysis upon mastication, regarding to clinical mastication preference besides clinical and electromyographic activity of the masseters. Method: the study included 27 male and female subjects aged 1669 years with permanent natural dentition and long-standing PFP. Patients answered questions on their mastication habits before and after onset of PFP and were submitted to clinical myofunctional examination and electromyographical tests of the masseters during clenching and habitual mastication. Results: according to the anamnesis, 77.8% claimed to prefer chewing on the unaffected side. Clinically, 70% presented a lateral preference in mastication. In the clinical evaluation, the buccinators and orbicularis oris activity differed significantly (p = 0.025) between the healthy and the paralyzed side. Only 22.2% of the patients presented increased thickness of the contralateral masseters. No statistical significant electromyographic difference was observed between the affected and unaffected masseters. Conclusion: in general, subjects with flaccid-stage PFP for 6 months or longer preferred to masticate on the unaffected side. No significant clinical or electromyographic differences were found between the affected and unaffected side masseter in this patient population

Força máxima (TF) e potência (TP) são métodos de treinamento considerados distintos, na prática profissional e em diversos designs experimentais. O presente estudo testou a capacidade destes métodos promoverem o aumento do desempenho, assim como a similaridade das adaptações entre os métodos. Trinta e sete sujeitos foram divididos nos grupos: força (TF), potência (TP) e controle (C), sendo submetidos a oito semanas de treinamento nas seguintes zonas: TF (4-10 RM) e TP (30-60% 1RM). Os resultados significantes foram: força dinâmica máxima TF de 145,3 (±17,1) para 178,5 (±18,8) kg, TP de 147,2 (±16,8) para 171,6 (±19,9) kg; pico de força na contração voluntária isométrica máxima (CVIM) TF de 2240,52 (±448,76) para 2651,82 (±700,22) N, TP de 2249,86 (±427,95) para 2674,80 (±507,68) N; salto vertical a partir da posição de semi-agachamento (SJ) TF de 31,35 (±4,63) para 37,18 (±4,74) cm, TP de 34,44 (±3,90) para 39,61 (±4,70) cm. Apenas o TP gerou aumento no salto com contra-movimento (CMJ) de 35,52 (±4,43) para 38,50 (±4,34) cm. Nenhum dos protocolos promoveu o aumento do sinal eletromiográfico, seja na CVIM ou nos saltos. Verificou-se efeito principal para deslocamento do centro de gravidade, torque de joelho e quadril no SJ, assim como para o deslocamento excêntrico no CMJ. Observou-se similaridade entre os grupos em diversas variáveis analisadas, assim como a possível transferência coordenativa do TP para o CMJ. Assim, força máxima e potência parecem constituir estímulos de treinamento equivalentes em muitos aspectos e por isso, os padrões de especificidade atribuídos a ambos devem ser reconsiderados / Strength and power are considered different training methods in promoting neuromuscular adaptations in practice and in several research designs as well. In the present research, the efficacy of these methods in improving performance and resultant neural adaptations in some motor tasks was investigated. Thirty sevens subjects were divided in groups: strength (TF), power (TP) and control (C) and submited to eight weeks of training in different zones: TF (4-10 RM) and TP (30%-60% 1RM). Results that reached significance were the following, pre and pos-test, respectively: Maximum dynamic strength TF:145,3 (±17,1) and 178,5(±18,8), TP:147,2 (±16,8) and 171,6 (±19,9). Peak force in maximum isometric voluntary contraction (MIVC) TF: 2240,52 (±448,76) and 2651,82 (±700,22), TP: 2249,86 (±427,95) and 2674,80 (±507,68). Squat jump (SJ) TF: 31,35 (±4,63) and 37,18 (±4,74), TP: 34,44 (±3,90) and 39,61 (±4,70). In countermovement jump (CMJ) only TP improved: 35,52 (±4,43) and 38,50 (±4,34). No method could improve electromiographical signal. A main effect was noticed for center of mass displacement, knee and hip moments in SJ and eccentric displacement in CMJ. Similar results for many parameters analysed could be observed. The results indicate a possible transference from TP to CMJ as well. This way, strength and power can be considered equivalent in promoting performance in many tasks. Therefore, specificity patterns between strength and power should be reconsidered

Introdução: Atletas de Powerlifting utilizam habitualmente em sua preparação física o Agachamento (AT) e o Box-Squat (BS). Conhecer as variáveis cinemáticas e eletromiográficas destes exercícios é relevante para sua prescrição. Objetivo: Comparar os efeitos agudos da utilização do Agachamento e do Box-Squat, em três diferentes amplitudes de movimento, sobre variáveis de desempenho neuromuscular, em atletas de Powerlifting. Materiais e Métodos: Dez atletas de Powerlifing (31,7±5,05 anos) participaram de duas sessões de avaliação: i) aplicação de questionário, realização de medidas antropométricas e testes de 1RM para Agachamento e Box-Squat nas condições Completo, Paralelo e Parcial; ii) Coleta do sinal eletromiográfico dos músculos Reto Femoral; Vasto Lateral; Vasto Medial; Bíceps Femoral; Glúteo Máximo; Gastrocnêmio Lateral e Eretores da Coluna, durante AT e BS com as cargas de 1RM previamente aferidas. Coleta de dados de cinemetria 2D para o cálculo da Potência Absoluta e Relativa. Resultados: A carga de 1RM (252±55 Kg) e o Índice de Força Relativa (2,66±0,43) do BS Parcial foram significativamente maiores que nas outras cinco variações de exercício. Potência Absoluta (613,25±194,80 W) e Relativa (6,48±1,86) foram maiores no AT Parcial quando comparado a BS Completo, AT Completo, AT Paralelo e BS Paralelo. A ativação EMG do Reto Femoral foi maior no BS Completo (95,48±46,82 %CIVM) comparada à AT Parcial e BS Parcial. O Glúteo Máximo foi mais ativado no AT Paralelo (175,36±101,79 %CIVM) comparado ao BS Completo (143,51±79,00 %CIVM). A ativação dos Eretores da Coluna no AT Paralelo (132,27±77,31 %CIVM) foi superior à do AT Parcial (92,09±38,28 %CIVM). Conclusão: As cargas de 1RM foram maiores em excursões articulares reduzidas, com vantagem do BS Parcial. O AT Parcial apresentou maiores valores de Potência Absoluta e Relativa. AT e BS mostraram-se equivalentes do ponto de vista da ativação muscular. / Introduction: Powerlifters commonly use Squats and Box-Squats in their training process. Knowing kinetics and kinematics of these exercises can help trainers when planning a training program. Objective: To compare kinetic and kinematics of full, parallel and partial Squats and Box-Squats performed by Powerlifters. Material and Methods: Ten Powerlifters (31,7±5,05 years) participated in two sessions of data collection: i) Survey about training and injury, Anthropometrical measures, 1RM testing for the full, parallel and partial Squats and Box-Squats; ii) Muscle activity of rectus femoris, vastus lateralis, vastus medialis, biceps femoris, gluteus maximus, lateral gastrocnemius and erector spinae over the six conditions at 100% of 1RM. Sagital plane video was recorded for power output measures. Results: Significantly higher loads were observed in Partial Box-Squat (252±55 Kg) compared to the other five situations. Overall (613,25±194,80 W) and Relative (6,48±1,86) Power Output were higher at Partial Squat when compared to Parallel and Full Squats and Box-Squats. Muscle activation of rectus femoris was significantly higher in Full Box-Squat (95,48±46,82 %MVC) compared to Partial Squats and Box-Squats. Gluteus maximus activation was higher at the Parallel Squat (175,36±101,79 %MVC) when compared to the Full Box-Squat (143,51±79,00 %MVC). Erector Spinae muscle activation was significantly higher in Parallel Squat (132,27±77,31 %MVC) in comparison to the Partial Squat (92,09±38,28 %MVC). Conclusion: Higher 1RM loads were found in Partial Range of Motion, especially in Box-Squat. Overall and Relative Power Output were higher at Partial Squats. Squats and Box-Squats showed similar muscle activation patterns.

A presente pesquisa teve como objetivo investigar o potencial mastigatório em crianças com mordida aberta anterior dentoalveolar e com mordida aberta anterior esquelética, comparativamente à crianças com oclusão normal e analisar a associação da espessura e largura desses músculos com a idade, a atividade EMG e o padrão de crescimento facial. Participaram 56 crianças de ambos os sexos, de 6 a 12 anos de idade, distribuídas em três grupos: 23 com mordida aberta anterior dentoalveolar (grupo OB), 20 com mordida aberta anterior esquelética (grupo Hyper-OB) e 13 portadoras de oclusão normal (Grupo Controle), selecionadas nas Clínicas de Odontopediatria e de Ortodontia da Faculdade de Odontologia de Ribeirão Preto-USP. Todas as crianças realizaram a avaliação clínica odontológica, o exame cefalométrico, o exame miofuncional orofacial e as análises eletromiográfica (EMG) e ultrassonográfica dos músculos masseteres e temporais. Durante a EMG, todas as crianças realizaram apertamento dos dentes em Contração Voluntária Máxima, mastigação de alimentos naturais (amendoim, biscoito recheado, barra de cereais, chocolate e damasco) e artificial (chiclete). O modelo de análise adotado para a comparação dos grupos mordida aberta anterior esquelética, mordida aberta anterior dentoalveolar e controle foi Análise de Covariância (4-Way Ancova), tendo a idade como covariável. Não houve diferença entre os grupos OB e Hyper-OB (p>0,05). As medidas ultrassonográficas foram menores para ambos os grupos com mordida aberta em comparação com o grupo controle (p<0,01). Houveram diferenças entre os grupos Hyper-OB e C (p<0,05) na eletromiografia, em testes estáticos e dinâmicos. A capacidade mastigatória funcional foi semelhante para as crianças com mordida aberta dentoalveolar e esquelética e ambos os grupos diferiram do grupo controle. Esses resultados demonstram a importância da oclusão para a função muscular. / This study aimed to investigate the potential of chewing in children with dentoalveolar open bite and skeletal anterior open bite compared to children with normal occlusion and analyze the association between thickness and width of these muscles with age, and the pattern of EMG activity facial growth. Participants 56 children of both sexes, 6-12 years of age, divided into three groups: 23 with dentoalveolar anterior open bite, 20 with skeletal anterior open bite and 13 women with normal occlusion in selected clinics of Pediatric Dentistry and Orthodontics Faculty of Dentistry of Ribeirão Preto-USP. All children underwent clinical dental cephalometric examination, examination and analysis miofunctional electromyographic (EMG) and ultrasound of the masseter and temporal muscles. During the EMG, all children had teeth clenching at maximum voluntary contraction, mastication of natural foods (peanuts, crackers, cereal bars, chocolate and apricot) and artificial flavor (bubblegum). The analytical model adopted for the comparison group skeletal anterior open bite, anterior open bite was dentoalveolar control and analysis of covariance (4-Way Ancova), with age as covariate. There was no difference between groups OB and Hyper-OB (p> 0,05). The ultrasound measurements were lower for both groups with open bite compared with the control group (p <0,01). There were differences between the groups Hyper-OB and C (p<0,05) in EMG in static and dynamic testing. The ability masticatory function was similar for children with dentoalveolar and skeletal open bite and both groups differed from the control group. These results demonstrate the importance of occlusion in muscle function.