O Sistema Nervoso é capaz de organizar, controlar e adequar respostas motoras diante de mudanças repentinas no ambiente. No esporte tal capacidade é solicitada frequentemente. A cobrança do pênalti no futebol é um exemplo interessante deste tipo de situação, pois exige do atleta a tomada de decisão do lado para o qual chutar. Porém, muitas vezes esta decisão é executada sobre a influência de vários fatores que afetam o desempenho no decorrer de uma partida no futebol, entre eles a fadiga. Com o objetivo de estudar o efeito de fadiga sobre o desempenho em uma tarefa de computador que simula alguns aspectos da cobrança de um pênalti no futebol, foram comparadas duas situações: controle e de fadiga muscular promovida por um sistema de alavanca com sobrecarga. Os voluntários permaneciam sentados em frente ao monitor de um computador que apresentava três pontos que representavam o cobrador, a bola e o goleiro. O goleiro poderia deslocar-se tanto para a direita como para a esquerda (aleatoriamente) em momentos diferentes. A tarefa do voluntário era a de inclinar uma alavanca no exato momento em que o cobrador, se deslocando em direção a bola, coincidisse com este último, e se possível a alavanca deveria ser inclinada na direção oposta ao movimento do goleiro. Os resultados indicaram um melhor desempenho no percentual de respostas com lateralidade correta e uma menor variabilidade (respostas demasiadamente antecipadas ou atrasadas) dos voluntários na condição controle do que em condição de fadiga. / The Nervous System is capable of organizing, controlling and adjusting motor responses to sudden changes on the environment. In sports this ability is often tested. The penalty kick in soccer is an interesting example of this type of situation, because it requires of the kicker quick decision making as to which side to kick, depending on the last minute actions of the goalkeeper. However, often this decision influencedd by several factors which affect the performance during a soccer game, such as fatigue..In order to study the effect of fatigue on performance in a computer task which simulates some aspects of the penalty kick in soccer, two situations were compared: control and with fatigue, induced by a lever system with weights. Volunteers remained seated in front of a computer screen that presented three small circles, vertically aligned, which represented the kicker, the ball and the goalkeeper. At the beginning of each trial the kicker (lower circle) moved vertically up, at contant speed, toward the ball (middle circle) and at different times before kicker-ball contact the goalkeeper (upper circle) might move to the right or to the left, randomly. The task of participants was to incline a lever at the instant of kicker-ball superposition, and, if possible, to the side opposite to that of the goalkeeper\'s movement. Results indicated a slightly better performance in the percentage of trials with correct laterally, and lower temporal variability, with fewer delays or anticipations when participants were in the control rather than the fatigue condition.

Durante diferentes atividades cotidianas ou esportivas o ser humano é submetido a desafios unilaterais que podem estar relacionados à performance de uma tarefa específica ou a própria manutenção de sua postura. Portanto, é natural o desenvolvimento motor de um membro em relação ao outro para tarefas específicas, desde que estas sejam repetidas de forma não simétrica. Desta forma, pode-se supor que sujeitos que possuam maiores estresses físicos unilaterais apresentem maior probabilidade em desenvolver assimetrias funcionais e morfológicas. O presente trabalho apresenta três diferentes experimentos visando investigar as assimetrias funcionais e morfológicas relacionadas ao controle de movimento para tarefas dinâmicas e estáticas em diferentes condições e grupos. O primeiro experimento visou investigar as diferenças, entre os membros inferiores, no controle de movimento entre sedentários e atletas, utilizando para isto a postura ereta quieta e o salto com contra-movimento nas condições bipedais e unipedais. O segundo experimento visou investigar o efeito da fadiga neuromuscular unilateral e bilateral no controle de movimento, entre membros, durante o salto com contra-movimento e a postura ereta quieta bipedal. O terceiro experimento objetivou investigar o efeito prolongado da temporada esportiva no controle de movimento, entre membros, de atletas, utilizando o salto com contra-movimento e a postura ereta quieta nas condições unipedal e bipedal. Inicialmente, o presente trabalho concluiu que não parece existir relação entre as diferenças antropométricas e funcionais. Indivíduos sedentários e atletas possuem diferenças entre os membros inferiores, entretanto supõe-se que os mecanismos relacionados à tais fenômenos não sejam os mesmos, como no caso dos sedentários, onde as assimetrias poderiam estar relacionadas ao pobre controle de força, sinergismo e padrão de coordenação.. Analisando as diferenças entre sedentários e atletas foram observadas semelhanças em relação ao nível de assimetria para algumas variáveis analisadas. Deve-se considerar que os atletas analisados estavam no início da temporada esportiva, e possivelmente sem grande influência dos efeitos do treinamento prolongado. Para testar a hipótese do efeito prolongado, o terceiro experimento foi realizado e observou-se que a temporada esportiva não afetou todas as variáveis relacionadas ao controle de movimento estático e dinâmico em atletas e os maiores efeitos foram verificados durante as tarefas bipedais. Além disto, a fadiga neuromuscular também influenciou o controle de movimento em sedentários, produzindo ajustes compensatórios em algumas variáveis, principalmente nos ângulos articulares. Entretanto, as assimetrias previamente observadas não parecem serem alteradas durante as diferentes condições de fadiga neuromuscular. Para a tarefa dinâmica bipedal, observou-se que para todas as variáveis analisadas (ângulos articulares, parâmetros de desempenho e atividade muscular) apresentaram assimetrias. Curiosamente, se observa tendência à maior ativação do membro contra-lateral em função do membro fatigado. Portanto, o presente estudo ressalta o efeito do nível de condicionamento, o efeito da fadiga e do treinamento prolongado no controle de movimento dos membros inferiores em tarefas com diferentes demandas motoras bipedais e unipedais / The human body is exposed to different unilateral challenges during different daily and sportive tasks. These challenges may either be related to specific-task performance or posture maintenance. Thus, it is natural the increase of motor control in one limb related to another during specific tasks and movements. It can be assumed that individuals exposed to higher physical unilateral stress show greater probability to develop functional and morphological asymmetries. The present study shows three different experiments in order to investigate the functional and morphological asymmetries related to the motor control for dynamic and static tasks in different conditions and groups. The first experiment aimed to investigate the differences between the lower limbs, related to the motor control between sedentary and athletes during two tasks: quiet stance and countermovement jump in bi- and unipedal conditions. The second experiment aimed to investigate the effect of neuromuscular fatigue on uni- and bilateral tasks related to the motor control between lower limbs during both double-leg tasks: countermovement jump and quiet stance. The third experiment aimed to investigate the effect of prolonged sportive season in motor control, between lower limbs, during two tasks: quiet stance and countermovement jump in bi- and unipedal conditions. We concluded that there was no correlation between the anthropometric and functional asymmetries. Both sedentary and athlete groups had differences between the lower limbs in several variables, however it is assumed that the mechanisms related to such phenomena are not the same. There were similarities between sedentary and athlete groups related to the level of asymmetry for some variables. We must consider that the athletes were analyzed at the beginning of the sportive season, without the training influence. To verify the prolonged effect hypothesis, the third experiment was conducted and it was observed that the sportive season did not affect all the variables related to the motor control and the greatest effects were observed during the bipedal tasks. In addition to that, the neuromuscular fatigue influenced the control of movement in the sedentary group, showing compensatory adjustments in some variables, especially in the maximal joint angles. However, we observed that the asymmetries did not change during different neuromuscular fatigue conditions. During the bipedal dynamic task it was observed asymmetries in all variables (joint angles, performance parameters and muscle activity). Interestingly, it was also observed the trend to higher activation of the contra-lateral lower limb during the fatigued limb. So, this study highlights the effect of the conditioning levels, the neuromuscular fatigue effect and the prolonged training to the motor control of the lower limbs in different tasks and conditions

Orientador: Tamotsu Hirata / Banca: José Elias Tomazini / Banca: Rubens Alexandre da Silva Júnior / Banca: Fabiano Politti / Banca: Daniela Aparecida Biasotto Gonzalez / Resumo: O controle postural é um fator determinante na execução de gestos funcionais que necessitam de um alto desempenho da coordenação motora, como por exemplo, nas atividades esportivas. Neste presente trabalho foi abordada a modalidade esportiva do futebol, e de forma mais específica, o gesto técnico do chute. Neste sentido, o objetivo deste trabalho foi de investigar o equilíbrio dinâmico durante o chute futebolístico por meio de um sistema de análise com uma tarefa controlada. O sistema proposto foi constituído por um dispositivo disparador vertical de bola, alvo de acerto, sistema de aquisição de sinais com eletromiografia, acelerômetria, registro do instante do acionamento do disparador, e por uma plataforma de força. A amostra foi constituída por 11 atletas profissionais de futsal, os quais realizaram a tarefa de vinte e cinco chutes ao alvo com a bola em movimento vertical. Para análise dos dados foi proposta a identificação e análise do comportamento dos sinais dos músculos Glúteo média (GM), Tibial anterior (TA), Fibular longo (FL) e Vasto lateral (VL), em relação às variáveis estabilométricas do equilíbrio postural no pré-chute, durante o chute e após-chute. Foram apresentados os gráficos das médias das variáveis estabilométricas: posição média, desvio padrão, deslocamento total, amplitude, velocidades, freqüências médias e freqüências medianas na direção ântero-posterior (AP) e médio-lateral (ML), centro de pressão (COP) e respectiva direção de oscilação, desenvolvidas durante a execução da tarefa controlada do chute. Os resultados apresentaram o comportamento das médias dos valores RMS (root mean square) dos músculos glúteo médio (GL), tibial anterior (TA), fibular longo (FL) e vasto lateral (VL) no pré-chute, durante o chute e pós-chute em relação a análise postural através do COP... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Postural control is a determining factor in the execution of functional movements that require a high performance of the motor control coordination, such as sporting activities. In this study the soccer sports activity was chosen, and more specifically, the technical movement of the kick. The objective this study was to investigate the postural sway through the kick's movement control. A vertical ball shooting machine (VBS) with an active target was especially developed to measure the effectiveness of the kick. This system was synchronized with electromyographic signal, accelerometer and force platform in order to recognize the movement. Eleven professional athletes of soccer kicked the ball twenty-five times on target using the VBS system by EMG System do Brasil. Data analysis was proposed for identification and correlation of the signal behavior of the middle gluteus muscle (GM), tibialis anterior (TA), peroneus longus (FL) and vastus lateralis (VL) in relation stabilometric variables of postural sway before the kick, during the kick and after the kick. It was analysed of stabilometric variables: the mean position, standard deviation, total displacement, amplitude, speed, median frequencies in the anteroposterior (AP) and mediolateral (ML) of the center of pressure (COP ) and direction of oscillation during the controlled kick. The results showed the same trends in the behavior of the RMS (root mean square) of the gluteus medius muscle (LG), tibialis anterior (TA), peroneus longus (FL) and vastus lateralis (VL) before the kick during the kick and after the kick. This was also observed in the analysis of the variables stabilometric, standard deviation, speed, median frequency in anteroposterior (AP) and mediolateral (ML). Considering the results of this study, analysis of the behavior of EMG signals of the muscles involved in... (Complete abstract click eletronic access below) / Doutor

A análise do chute através de técnicas biomecânicas pode auxiliar na compreensão do comportamento e organização do sistema motor. Ao identificar a predominância, emergência ou variabilidade de um padrão de movimento, deve-se considerar a interação de elementos internos e externos ao indivíduo, seja o ambiente onde está sendo executada a ação, as características que envolvem a tarefa ou as particularidades do organismo do executante. O objetivo deste trabalho foi analisar e comparar o padrão de movimento e o desempenho da habilidade motora chutar, a um alvo, em duas condições: bola parada e bola em movimento. Com o propósito de detectar a influência da faixa etária na execução desta tarefa, participaram deste estudo 10 crianças divididas em dois grupos: G1 (8 a 9 anos) e o G2 (12 a 13 anos). Cada criança realizou 10 chutes a um alvo em ambas as condições. As tentativas foram capturadas por duas câmeras de alta velocidade e foram obtidos dados referentes ao desempenho, variabilidade, coordenação e amplitude do movimento. A análise estatística detectou ajustes na coordenação e amplitude do movimento além de um aumento da variabilidade na condição da bola em movimento. Em relação à idade, foram encontradas diferenças estatisticamente significantes na velocidade do pé. Os resultados demonstraram que os grupos etários estudados apresentaram ajustes similares na coodenação do movimento. A condição da bola provocou adaptações no padrão de movimento, entretanto, apesar do aumento nos níveis de variabilidade, não exerceu influência no desempenho do chutar / The analysis of kicking through biomechanics techniques can help the comprehension of behavior and motor system organization. In order to identify the predominance, emergence, or variability of a moving pattern, is imperative to consider the interactions between internal and external elements to the individual, such as the environment where the action is executed, characteristics that are intrinsic to the task or any individual particularity. The aim of the present work was to analyze and compare the performance and movement pattern of the kick realized by children to a target, in two different conditions: stationary and moving ball. To enable us to detect the age influence on the execution of the given task, the experimental group comprised 10 children from different ages: group 1 (G1) children from 8 to 9 years old and group 2 (G2) children from 12 to 13 years old. Each participant performed 10 kicks to the target in both conditions. Attempts were captured by two high speed cameras and were obtained data to analyze performance, variability, coordination and range of motion. Statistical analysis showed adjustments in coordination and range of motion, besides an increase of variability in the condition of moving ball in relation to the stationary ball condition. Regarding the age, it was found differences statistically significant only in the foot velocity. The results showed that the age groups studied had similar adjustments in movement coordination. The moving ball condition led to adjustments in the movement pattern, however, despite the increase in the variability, the performance was not different in relation to the stationary ball condition

A variabilidade da força muscular, geralmente em uma tarefa de força constante e isométrica, tem sido estudada tanto de forma experimental quanto com o uso de ferramentas computacionais. No entanto, a maioria dos estudos utilizando simulações computacionais tem sido feita em tarefas que utilizam apenas um músculo, geralmente da mão. Até onde se tem conhecimento, não foi feito um estudo, nem experimental nem teórico, abrangendo o comportamento da variabilidade do torque durante a flexão plantar de uma forma geral. Considerando isso, esse trabalho tem como objetivo estudar a variabilidade do torque de flexão plantar por meio de simulações e de modelos matemáticos, comparando os resultados com os obtidos em experimentos realizados localmente. Uma primeira tentativa foi feita utilizando um modelo de contração muscular do tipo Hill ativado pela envoltória dos sinais de eletromiograma captados de cada um dos três músculos do tríceps sural. Essa abordagem não foi bem sucedida em termos da reprodução dos resultados experimentais obtidos de variabilidade do torque em humanos, embora tenha reproduzido bem o valor médio do torque da flexão plantar. Essa impossibilidade em reproduzir os dados experimentais de variabilidade do torque com um modelo ativado por envoltória do eletromiograma provavelmente deveu-se à perda de informação no eletromiograma sobre os disparos dos motoneurônios. Em uma segunda tentativa, os disparos individuais dos motoneurônios foram obtidos de um simulador desenvolvido localmente, chamado de ReMoto, capaz de fornecer os instantes de disparos de todos os modelos de motoneurônios que ativam cada músculo, além de ser capaz de fornecer a força produzida por esse músculo, calculada a partir da força produzida pelas unidades motoras individualmente. No entanto, a versão original do ReMoto foi parametrizada quase que totalmente utilizando dados de gatos e, por isso, foi necessário modificar diversos parâmetros (como amplitude dos abalos e amplitude do potencial de ação da unidade motora) e modelos (como limiar de recrutamento e saturação da força) antes de utilizar o simulador para o estudo da variabilidade do torque. Também foi adicionado um segundo modelo de gerador de força, que consegue reproduzir melhor as características temporais dos abalos das unidades motoras. Adicionalmente, um modelo do tipo Hill também foi modificado para ser ativado pelo conjunto de motoneurônios do simulador ReMoto. Novas simulações foram feitas com a nova versão do simulador (adaptada a dados de humanos) e os resultados foram condizentes com os dados experimentais (variabilidade do torque e do eletromiograma), indicando que os modelos no simulador são uma representação razoável do que acontece no ser humano. / The muscle force variability, usually in a constant and isometric force task, has been studied both experimentally and using computational tools. However, most studies using computer simulations have been made on tasks that use only one muscle, usually in the hand. As far as is known, no study has analyzed, either theoretically or experimentally, the overall behavior of the torque variability during plantar flexion. Therefore, this work aims to study the plantar flexion torque variability by means of mathematical models and simulations, comparing the results with those obtained in human experiments carried out locally. A first attempt was made using a Hill-type muscle contraction model activated by the electromyogram obtained from each of the three triceps surae muscles. This approach was not successful in terms of reproducing the torque variability results obtained from humans, although it estimated well the average value of plantar flexion torque. This inability to reproduce the torque variability found in experimental data was probably due to the information loss in the electromyogram of the spike times of motoneurons. In a second approach, the firing of individual motoneuron were obtained from a neuromuscular simulator developed locally, called ReMoto, capable of providing the spike times of all motoneuron models that activate each muscle and the respective muscle force. The latter is generated in the simulator from the forces generated by each motor unit that composes the muscle. However, the ReMoto original version was almost completely parameterized using data from cats and, hence, it was necessary to modify various parameter values (such as motor unit twitchs and action potential amplitudes) and models (such as the recruitment threshold and force saturation) before using the simulator to study torque variability in humans. Besides the second order twitch model already implemented in the original version of the simulator, two other models were implemented in this work. One was a more refined twitch model and the second was a Hill-type model modified to be activated by the ReMoto simulator motoneuron pool. New simulations were run with the new version of the simulator (adapted to human data) and the fittings to the experimental data (torque and electomyogram envelope variability) were good, suggesting that the models in the simulator are a reasonable representation of what occurs in the living human being.

The ability to successfully switch hit, or hit a baseball from both sides of the plate, requires a great amount of practice and coordination bilaterally. This study used three-dimensional kinematic and kinetic data to examine the swing patterns of skilled switch hitters in baseball. Three male minor league and division I collegiate switch hitters participated. Subjects stood on force plates and hit baseballs off a tee while their swings were recorded with a three-dimensional optical motion capture system. Each subject performed twenty total swings, ten from the right and ten from the left. The swings were digitally analyzed and the dependent measures were compared side-to-side. The swing was broken down into specific events and temporal phase parameters were obtained. Peak vertical ground reaction force of each foot and stride length of each swing were also obtained. All variables were statistically analyzed using paired t-tests. The subjects displayed surface swing characteristics side-to-side that appeared identical and statistically there were no significant differences in the swing variables side-to-side. However, each subject had slight internal pattern differences side-to-side that are reported and discussed. Switch hitters are an excellent example of skilled practitioners that can provide insight into questions pertaining to dominance and motor control. Further research is needed with more subjects to explore side-to-side similarities and differences in well-established patterns.

Over the past decade it has become increasingly clear that to understand the brain, we must study not only its biochemical and biophysical mechanisms and its outward perceptual and physical behavior. We also must study the brain at a theoretical level that investigated the computations that are necessary to perform its functions. The control of movements such as reaching, grasping and manipulating objects requires complex mechanisms that elaborate information form many sensors and control the forces generated by a large number of muscles. The act of seeing, which intuitively seems so simple and effortless, requires information processing whose complexity we are just beginning to grasp. A computational approach to the study of vision and motor tasks. This paper discusses a particular view of the computational approach and its relevance to experimental neuroscience.

The goal of this thesis is to apply the computational approach to motor learning, i.e., describe the constraints that enable performance improvement with experience and also the constraints that must be satisfied by a motor learning system, describe what is being computed in order to achieve learning, and why it is being computed. The particular tasks used to assess motor learning are loaded and unloaded free arm movement, and the thesis includes work on rigid body load estimation, arm model estimation, optimal filtering for model parameter estimation, and trajectory learning from practice. Learning algorithms have been developed and implemented in the context of robot arm control. The thesis demonstrates some of the roles of knowledge in learning. Powerful generalizations can be made on the basis of knowledge of system structure, as is demonstrated in the load and arm model estimation algorithms. Improving the performance of parameter estimation algorithms used in learning involves knowledge of the measurement noise characteristics, as is shown in the derivation of optimal filters. Using trajectory errors to correct commands requires knowledge of how command errors are transformed into performance errors, i.e., an accurate model of the dynamics of the controlled system, as is demonstrated in the trajectory learning work. The performance demonstrated by the algorithms developed in this thesis should be compared with algorithms that use less knowledge, such as table based schemes to learn arm dynamics, previous single trajectory learning algorithms, and much of traditional adaptive control.

Saab has an analogue solution which is used to drive small motors in aircrafts. The motor is a brushless DC-motor and uses a resolver and hall sensors to control it. As sensorless control is something that has been expanding and attracting more interest over the last decade, Saab is considering the possibility of using a digital sensorless system depending on its performance on the control compared to their analogue system. There is little documentation of performance for a digital sensorless solution compared to an analogue solution. Therefore the question to be answered in this research is: How is the performance of the digital solution compared to the existing analogue solution? It was answered by finding a complete sensorless system on the market and then compare its performance to a digital system with sensors that resembles the analogue solution. Performance wise, InstaSPIN does not perform as well as EPOS2 which represent the sensorless system respective the system with sensors. InstaSPIN needs a startup sequence, can not run at the same low velocities, has a longer rise time, settling time and greater ripple. An examination of the software should be done before using the disadvantages that was found as a reason for not considering a sensorless system. Especially the startup sequence in the software should be examined as it is InstaSPINs greatest weakness compared to EPOS2. / Saab använder idag ett analogt system för att driva små motorer i deras flygfarkoster. Det analoga systemet använder en borstlös DC-motor och en resolver för styrning av motorn. Motorstyrning med system som är oberoende av givare är ett område som vuxit och fått ett ökat intresse det senaste decenniet. Saab överväger möjligheten att använda ett givarlöst digitalt system beroende på dess styrprestanda jämfört med deras analoga system. Eftersom det finns lite dokumentation om prestandan så är frågan som ska besvaras i denna rapport: Hur förhåller sig det givarlösa digitala systemet prestandamässigt jämfört med det existerande analoga systemet? Detta besvarades genom att leta upp ett komplett system på marknaden och sedan jämföra dess prestanda mot ett digitalt system som liknar det analoga systemet.  Prestandamässigt så fungerar InstaSPIN som representerar det givarlösa systemet inte lika effektivt som EPOS2 som representerar systemet som använder givare. Nackdelarna med InstaSPIN är att den behöver en startsekvens, inte kan köra på lika låga hastigheter, har längre stigtid, insvängningstid och större rippel. Man bör undersöka mjukvaran innan nackdelarna används som en anledning till att inte använda ett givarlöst system. Speciellt startsekvensen bör undersökas eftersom det är IntaSPINs största svaghet jämfört mot EPOS2.

This study investigated the effect of palate morphology and anthropometric measures of the head and face on lingual consonant target (positional) variability of twenty one adult speakers (eleven male, ten female). An electromagnetic tracking system (WAVE, NDI, Canada) was used to collect tongue movements while each speaker produced a series of VCV syllables containing a combination of consonants /t, d, s, z, ʃ, tʃ, k, g, j/ and three corner vowel /i, ɑ, u/. Distributions of x, y, and z coordinates representing maximum tongue elevation during the consonants were used to represent target variability across contexts. Palate and anthropometric measures were obtained for each participant. A correlational analysis showed that target variability of the consonants produced in the front of the mouth (e.g. alveolar and palatal) was explained, to a degree, by palate morphology. The variability of velar consonants was not explained by the structural measures.