Ballistic movements have been shown to be controlled differently by the central nervous system than slow, ramp actions. It has been suggested that the cerebellum is involved primarily with ballistic actions, while the basal ganglia primarily control slower movements. These command and control differences have been shown to manifest in unique ways at the neuromuscular level. Ballistic actions evidence high firing rates, brief contraction times, and high rates of force development. A characteristic triphasic agonistantagonist-agonist burst pattern presents itself during ballistic movement, wherein the amount and intensity of antagonist co-activation is variable. In conditions of low-grade tonic muscular activity, a premovement depression (P:MD; or silent period, PMS) can occur in both agonist and antagonist muscles prior to ballistic contraction. The agonist P:MD period may serve to potentiate the force and velocity of the following contraction A selective activation of fast twitch motor units may occur in ballistic contractions under certain movement conditions. Finally, high velocity, ballistic training induces specific neuromuscular adaptations that are representative of the underlying neurophysiological mechanisms that sub serve ballistic movement. / Thesis / Master of Science (MS)

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A utilização da eletroestimulação muscular é uma estratégia utilizada para investigação da fadiga neuromuscular. Entretanto, esta técnica é pouco aplicada na musculatura extensora do cotovelo em função de limitações biomecâncias (atuação de músculos sinergistas), neurais (influência de reflexo neural) e fisiológicas (facilidade em atingir estados de potencialização pós-ativação e fadiga). Portanto, o objetivo deste estudo foi padronizar procedimentos para avaliação neuromuscular da musculatura extensora do cotovelo. Para isso, foram realizados três estudos que envolveram a adequação da técnica de eletroestimulação e um \"estudo principal\" para validar um novo protocolo de avaliação neuromuscular. Após resultados positivos em estudos complementares, a presente dissertação propôs a validação de um protocolo para análise neuromuscular com contrações submáximas para a musculatura extensora do cotovelo. Vinte participantes com idade de 25,1 ± 6,8 anos foram submetidos, em dias diferentes, a dois esforços, um a fim de promover fadiga central e fadiga periférica respectivamente. Antes e após os esforços envolvendo fadiga (periférica ou central) foram realizadas avaliações de fadiga neuromuscular para musculatura extensora do joelho (protocolo já validado) e musculatura extensora do cotovelo (protocolo proposto). Verificou-se que: (i.) o modelo de análise proposto não promove nenhum tipo de fadiga ou potencialização pós-ativação; (ii) a resposta de um pulso controle no início e no fim do modelo de análise proposto promovem respostas diferentes; (iii) o modelo proposto foi capaz de identificar redução da resposta neuromuscular; (iv) o esforço envolvendo fadiga central não promoveu fadiga central significante; (v) a utilização de um modelo matemático para investigação de fadiga neuromuscular (coeficientes resultantes de uma regressão linear) com os valores de estimulação em contrações submáximas foi sensível a fadiga mas não foi capaz de discriminar fadiga central e periférica. É possível concluir que o modelo de análise proposto para a musculatura extensora do cotovelo apresentou sensibilidade para verificar a fadiga neuromuscular. Entretanto, este não foi capaz de discriminar fadiga central e periférica. A utilização da regressão linear parece ser uma boa estratégia para diferenciar os dois modelos de fadiga e deve ser estudada com mais profundidade futuramente. / Muscular electrostimulation is a strategy used to investigate neuromuscular fatigue. However, this technique is poorly applied in the elbow extensor muscles due to the limitations of biomechanics (acting of synergistic muscles), neural (influence of neural reflex) and physiological (easiness to achieve post-activation and fatigue states of potentiation). Therefore, the purpose of this study was to standardize a neuromuscular evaluation strategy for the elbow extensor musculature. Thus, three complementary studies aimed at adjusting the electrostimulation technique and one \"main study\" to validate a new neuromuscular assessment protocol were realized. After positive results in complementary studies, the present dissertation proposed a protocol validation for neuromuscular analysis with submaximal contractions on the elbow extensor musculature. Twenty participants with 25.1 ± 6.8 years old performed, on different days, two efforts, one to promote central fatigue and peripheral fatigue respectively. Before and after the exercise involving fatigue (peripheral or central) there were realized neuromuscular fatigue evaluations for knee extensor muscles (protocol already validated) and elbow extensor musculature (protocol). The results indicate that: (i) the proposed analysis model does not promote any type of fatigue or post-activation potentiation; (ii) the response of a control pulse at the beginning and end of the proposed analysis model promotes different responses; (iii) the proposed model was able to identify reduction of neuromuscular response; (iv) the effort involving central fatigue did not promote significant central fatigue; (v) the use of a mathematical model to investigate neuromuscular fatigue (coefficients resulting from a linear regression) with the values of stimulation in submaximal contractions was sensitive after fatigue but was not able to discriminate central and peripheral fatigue. It is possible to conclude that the proposed analysis model for the elbow extensor musculature presented sensitivity to verify the neuromuscular fatigue. However, it was not able to discriminate central and peripheral fatigue. The use of linear regression seems to be a good strategy to differentiate the two models of fatigue and should be studied in more depth in the future.

Title: The influence of kinematic factors on shooting velocity and accuracy in team handball. Goals: The main goal of this thesis is to find the influence of kinematic factors of throwing arm on shooting velocity and accuracy in team handball. Methods: The relationship between velocity and accuracy is based on practical measurement of group of team handballers. The measurement itself consists of three chosen types of shooting. We focused on movement and reciprocal position of reference points (ball, wrist, elbow and shoulder joint) and their influence on velocity and accuracy of hitting a target in goal. For measuring velocity is used a radar device Stalker. Measured values were elaborated in TEMA motion program which is appropriate for detail 3D analysis of throwing motion. Results: The results of this thesis demostrate the proximal-to-distal sequence in both types of throwing. An absolute velocities in this sequence were higher at Vmax shots than in accurate shots. There was found a significal difference between elbow extension angle of shots on upper and lower targets but exception. Higher elbow extension angle was found at Vmax shots than at accurate shots. This shows the influence of angle size on shooting velocity. A movement of the arm relative to vertical axis of a goal reflected an...