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Le complexe lombo-pelvi-fémoral est une zone charnière du corps humain. Son rôle d’équilibration a étédémontré à de nombreuses reprises alors que sa fonction motrice, lors de mouvements explosifs requérant uneextension totale de la chaine articulaire, a été peu étudiée. Ainsi, l’objectif de ce travail a été d’évaluer le rôle moteurdu complexe lombo-pelvi-fémoral lors d’un mouvement de squat jump. A cet effet, une approche expérimentale(cinématique, dynamique et électromyographique) couplée à un modèle de simulation du système musculo-squelettiqueont été appliqués à l’analyse du squat jump dans le plan sagittal. Les résultats montrent, dans un premier temps, que lesétudes ne prenant pas en compte le complexe lombo-pelvi-fémoral conduisent à des erreurs de surestimation du travailmécanique attribué à l’articulation de la hanche lors de squat jumps avec ou sans balancé de bras. Dans un secondtemps, il apparaît que l’extension du rachis lombaire permise par l’erector spinae participe à l’atteinte d’une hauteurmaximale de saut. Ceci confirme l’hypothèse du rôle moteur du complexe lombo-pelvi-fémoral, soulignant égalementla contribution effectrice du muscle erector spinae, qui est accrue avec l’augmentation de sa force maximale et lorsd’une flexion initiale du tronc importante. En conclusion, il semble pertinent d’intégrer le complexe lombo-pelvifémoraldans l’analyse du squat jump en vue d’ouvrir de nouvelles perspectives d’entrainement visant à l’améliorationde la détente verticale. / The lumbo-pelvic-hip complex is an important structure of the human body. Its function of balancing the bodyhas been pointed out in many studies. While its motor function has rarely been investigated, especially duringexplosive movements involving a global extension of the whole body. Thus, the purpose of this work was to evaluatethe role of the lumbo-pelvic-hip complex during squat jumping. To this end, an experimental approach (kinematics,kinetics and electromyographic) as well as a simulation model of the musculoskeletal system have been used to analyzethe squat jump in the sagittal plan. The results show, firstly that studies which do not take into consideration the lumbopelvic-hip complex, lead to an overestimation of the mechanical work attributed to the hip joint during maximal squatjumps performed arms akimbo or with an arm swing. Secondly, the extension of the lumbar spine enabled by theerector spinae activation contributes to achieve a maximal vertical jump height. This result confirms the assumptionsabout the motor function of the lumbo-pelvic-hip complex and the erector spinae. Moreover, the contribution of thismuscle is increased when its maximal strength is enhanced and when the trunk is initially flexed. In conclusion, itseems relevant to take into consideration the lumbo-pelvic-hip complex when maximal squat jumping is studied. Thiswould also contribute to new training perspectives in order to improve maximal vertical jump height.

O desenvolvimento da potência muscular e das habilidades motoras como salto vertical, velocidade de corrida e agilidade é fundamental para um bom desempenho nas modalidades esportivas coletivas, dentre elas o handebol. Os exercícios do levantamento de peso olímpico (LPO), dentre eles o hang power clean (HPC), têm sido comumente utilizados para esta finalidade; porém, pouco se sabe a respeito do efeito de diferentes intensidades de treinamento com o HPC sobre o desempenho motor de atletas. Desta forma, o objetivo do estudo foi investigar o efeito de dois protocolos de treinamento com 50% e 90% 1RM no exercício HPC nos ganhos de potência muscular dos membros inferiores, na altura do salto vertical, na velocidade de corrida, na mudança de direção e na força dinâmica máxima de jogadoras de handebol. Dezesseis atletas das categorias júnior e adulto foram divididas em dois grupos (LPO50 e LPO90; 50% e 90% 1RM, respectivamente) e submetidas a 15 sessões de treinamento durante sete semanas. Testes de potência muscular dos membros inferiores, altura do salto vertical sem e com contra-movimento (SJ e CMJ, respectivamente), velocidade de corrida, mudança de direção e força dinâmica máxima (1RM) nos exercícios meio-agachamento e HPC foram realizados pré- e pós-treinamento. Após o período de treinamento foi observado aumento significante da potência de membros inferiores no CMJ com 40% da massa corporal (MC) somente para o grupo LPO90, enquanto nenhuma alteração significante ocorreu no CMJ 60% e 80% MC para ambos os grupos. Não foram observadas alterações significantes na altura dos saltos verticais (SJ, CMJ e CMJ com diferentes sobrecargas externas) para os dois grupos; porém, a velocidade de corrida nas distâncias 0-5, 0-20 e 0-30m aumentou de forma significante e semelhante entre LPO50 e LPO90. Houve diminuição significante no desempenho da mudança de direção no teste T-40 para ambos os grupos. A 1RM no exercício HPC aumentou para os dois grupos enquanto nenhuma alteração significante foi observada para o exercício meio-agachamento. Assim, após 15 sessões de treinamento com HPC em diferentes intensidades (50% vs. 90% 1RM), pode-se afirmar que a utilização de menores intensidades promoveu adaptações positivas muito similares à utilização de maiores intensidades na velocidade de corrida e na força dinâmica máxima no exercício HPC, em jogadoras de handebol / The development of muscle power and motor skills such as vertical jump, running speed and agility is fundamental for a good performance in several team sports, among them handball. Olympic weightlifting (OWL) exercises such as the hang power clean (HPC) have been commonly used for this purpose; however, little is known about the effect of different training intensities with HPC on athletes\' motor performance. Thus, the objective of the study was to investigate the effect of two training protocols with 50% and 90% 1RM of the HPC exercise on lower limbs muscle power, vertical jump height, running speed, agility, and maximum dynamic strength of female handball players. Sixteen junior and adult athletes were divided into two groups (OWL50 and OWL90, 50% and 90% 1RM, respectively) and underwent 15 training sessions for seven weeks. Test for lower limbs muscle power, squat jump and countermovement jump height (SJ and CMJ, respectively), running velocity, agility, and maximal dynamic strength (1RM) in half-squat and HPC exercises were performed pre- and post-training. After the training period, a significant increase in lower limbs power in the CMJ was observed with 40% of body mass (BM) only for the OWL90 group, while no significant alteration occurred in the CMJ 60% and 80% BM for both groups. No significant changes were observed in vertical jumps height (SJ, CMJ and CMJ with different external loads) for both groups; however, running speed at 0-5, 0-20 and 0-30m increased significantly and similarly between OWL50 and OWL90. There was a significant decrease in agility performance for both groups. The 1RM in the HPC exercise increased for both groups while no significant change was observed for the half-squat exercise. Thus, after 15 training sessions with HPC at different intensities (50% vs. 90% 1RM), it can be stated that the use of lower intensities promoted positive adaptations in running speed and maximum dynamic strength in the HPC exercise similar to the use of higher intensities, in handball players

O presente estudo teve como objetivo investigar o desempenho do salto em distância de atletas com deficiência visual em razão do tipo de comando de transição, da localização do atleta-guia e da localização em que o saltador se encontrava no momento do comando de transição. Participaram do estudo oito atletas, homens e mulheres adultos, saltadores de nível internacional, com deficiência visual \"classe 11\", e seus respectivos atletas-guia. Os atletas executaram saltos considerando a interação de duas condições: (1) o atleta-guia se comunicava de quatro locais distintos (à frente, atrás, ao lado direito e do lado esquerdo da tábua de impulsão); (2) o atleta-guia fornecia comandos de transição da corrida para a impulsão via voz ou palma. A distância do salto foi considerada como principal variável dependente. Os resultados mostraram que: (1) os comandos por palma e voz, as localizações do atleta-guia (à frente, atrás, do lado direito e do lado esquerdo da tábua de impulsão), e a localização em que o saltador se encontrava no momento do comando de transição afetaram semelhantemente o desempenho do salto em distância de atletas com deficiência visual; (2) os comandos fornecidos quando o saltador encontrava-se mais distante da tábua de impulsão foram aqueles com ele estava em menor velocidade; (3) nos últimos cinco metros os atletas aumentaram a amplitude das passadas e a velocidade em comparação com os dez metros anteriores; (4) as preferências dos saltadores e atletas-guia pelo tipo de comando de transição e local de posicionamento tiveram os mesmos efeitos / The aim of this study was to investigate the long jump performance by athletes with the visual impairment based on the type of transition command, jumper location, and athlete-guide. Participants were 8 athletes, men and women, international level jumpers, class 11 visual impairment, and their respective athletes-guide. The athletes performed jumps considering the interaction of two conditions: (1) athlete-guide communicated from four distinct locations (front, back, right side and left side of the board); (2) athlete-guide provided commands for transitioning from the running to impulsion phase by voice or palms. The distance of the jump was considered as the main dependent variable. The results showed that: (1) palm and voice commands, locations of the guide-athlete (front, back, right side and left side of the board), and the location where the jumper was at the time of the transition command similarly affected the performance of distance jumping of visually impaired athletes; (2) commands provided when the jumper was further from the impulsion board were those with his/her was at a slower speed; (3) in the last five meters athletes increased the steps amplitude and running speed in comparison with the previous ten meters; (4) preferences of jumpers and athletes-guide by the type of transition command and positioning location had the same effects

Thesis advisor: Ronnie Sadka / This dissertation is comprised of three essays which examine the ramifications of executive compensation incentive structures on corporate outcomes. In the first essay, I present evidence which suggests that executive compensation convexity, measured as the sensitivity of managerial equity compensation portfolios to stock volatility, predicts firm-specific crashes. I find that a bottom-to-top decile change in compensation convexity results in a 21% increase in a firm's unconditional ex-post idiosyncratic crash risk. In contrast, I do not find robust evidence of a symmetric relation between compensation convexity and a firm's idiosyncratic positive jump risk. Finally, I exploit exogenous variation in compensation convexity, arising from a change in the expensing treatment of executive stock options, in buttressing my interpretations within a natural experiment setting. My results suggest that managerial equity compensation portfolios do not augment a firm's future idiosyncratic crash risk because they link managerial wealth to equity prices, but rather because they tie managerial wealth to the volatility of a firm's equity. In the second essay, I exploit an exogenous negative shock to CEO compensation convexity in examining the differential ramifications of option pay and risk-taking incentives on the systematic and idiosyncratic volatility of the firm. I find new evidence that is largely consistent with the notion that compensation convexity, stemming from option convexity, predominantly incentivizes under-diversified risk-averse CEOs to increase the value of their option portfolios by increasing the systematic volatility of the firms they manage. I hypothesize that this effect manifests as systematic volatility is readily more hedgeable than idiosyncratic volatility from the perspective of risk-averse executives who are overexposed to the idiosyncratic risk of their firms. If managers use options as a conduit through which they can gamble with shareholder wealth by overexposing them to suboptimal systematic volatility, options are not serving their intended contracting function. Instead of decreasing agency costs of risk, by encouraging CEOs to adopt innovative positive NPV projects that may be primarily characterized by idiosyncratic risk, option pay may have contributed to the same frictions it was intended to reduce. In the third essay, I present evidence that is consistent with the notion that certain managerial debt-like remuneration structures decrease the likelihood of firm-specific positive stock-price jumps. Namely, I find that a bottom-to-top decile increase in the present value of CEO pension pay leads to a roughly 25\% decrease in a firm's unconditional ex-post jump probability. However, I do not find that CEO deferred compensation decreases firm jump risk. Finally, I find that information in option-implied volatility smirks does not appear to reflect these dynamics. Together, these results suggest that not all debt-like compensation mechanisms decrease managerial risk-taking equally. / Thesis (PhD) — Boston College, 2015. / Submitted to: Boston College. Carroll School of Management. / Discipline: Finance.

Este trabalho estuda a observabilidade e controlabilidade para uma classe de sistema dinâmico markoviano com saltos nos parâmetros, e uma coleção de matrizes de observabilidade e controlabilidade associadas. São explorados alguns resultados de invariância, bem como certas propriedades envolvendo essas matrizes. Uma dessas propriedades, relacionada com a coleção de matrizes de observabilidade é conhecida na literatura desta classe de sistemas, mas não há uma prova disponível. Esses resultados de invariancia foram estendidos para o estudo da controlabilidade e sua respectiva coleção de matrizes associada, obtendo assim uma propriedade análoga ao caso da observabilidade. Os resultados obtidos são importantes para validar outros resultados existentes que se baseiam na propriedade referida / This work studies observability and controlability of a class of Markov systems with jumping parameters, and associated set of observability and controlability matrices. We explore some invariance results regarding the state trajectory and certain properties involving those matrices. One of these properties, related with the collection of observability matrices, is employed in the literature of this class of systems, but there is no available proof. The invariance results are extended similarly to the context of controlability leading to a property that is analogous to the observability case. The obtained results are important to validate other existing results that rely on that property

Este trabalho estuda a observabilidade e controlabilidade para uma classe de sistema dinâmico markoviano com saltos nos parâmetros, e uma coleção de matrizes de observabilidade e controlabilidade associadas. São explorados alguns resultados de invariância, bem como certas propriedades envolvendo essas matrizes. Uma dessas propriedades, relacionada com a coleção de matrizes de observabilidade é conhecida na literatura desta classe de sistemas, mas não há uma prova disponível. Esses resultados de invariancia foram estendidos para o estudo da controlabilidade e sua respectiva coleção de matrizes associada, obtendo assim uma propriedade análoga ao caso da observabilidade. Os resultados obtidos são importantes para validar outros resultados existentes que se baseiam na propriedade referida / This work studies observability and controlability of a class of Markov systems with jumping parameters, and associated set of observability and controlability matrices. We explore some invariance results regarding the state trajectory and certain properties involving those matrices. One of these properties, related with the collection of observability matrices, is employed in the literature of this class of systems, but there is no available proof. The invariance results are extended similarly to the context of controlability leading to a property that is analogous to the observability case. The obtained results are important to validate other existing results that rely on that property

O objetivo do presente trabalho foi descrever as características cinemáticas do salto de cavalos da raça Brasileiro de Hipismo, avaliar o julgamento realizado pelos juízes durante uma competição de salto em liberdade e comparar essas avaliações. Foram utilizados 13 equinos da raça Brasileiro de Hipismo, machos não castrados (40,15±4,24 meses, 491,1±40,89 kg). Os animais foram filmados saltando um obstáculo oxer durante uma competição de saltos em liberdade. Trajetórias do centro de massa corporal (CM) foram calculadas através da posição de pontos anatômicos que foram rastreados manualmente desde a decolagem até o pouso. Dessa trajetória, variáveis biomecânicas foram calculadas: velocidade vertical e horizontal, ângulos da velocidade e do deslocamento do CM na decolagem, altura máxima, deslocamento vertical e horizontal do CM, altura e fração de encurtamento dos membros sobre o obstáculo. Um polinômio de segunda ordem foi calculado através da trajetória do CM para obter três constantes com base na equação resultante. Os cavalos foram avaliados por três juízes: medidas zoométricas, funcionalidade, morfologia, salto, genealogia e modelo de garanhão. As notas de julgamento são consistentes entre si, mas são tendenciosas. As variáveis biomecânicas apresentaram alta repetibilidade e baixo erro. Nenhuma das notas de funcionalidade, genealogia e salto se correlacionam com as variáveis biomecânicas de salto. O julgamento do salto realizado não apresenta relação com as variáveis biomecânicas medidas. A análise cinemática não apresentou viés e foi muito consistente, podendo ser uma ferramenta para tornar o julgamento mais objetivo. / The objective of this study was to describe the jump kinematic characteristics of Brazilian Sport horses, evaluate the judgment conducted during a free jump competition and compare these assessments. Thirteen Brazilian Sport Horses stallions (40.15 ± 4.24 months, 491.1 ± 40.89 kg) were filmed jumping an obstacle during a competition. Body center of mass (CM) trajectories were calculated by the position of anatomical landmarks that were manually tracked from takeoff to landing. From this trajectory, biomechanical variables were calculated: vertical and horizontal velocities, angles of the velocity and of the displacement of the CM at takeoff, maximum height, vertical and horizontal displacement of the CM, height and shortening rate of the limbs over the obstacle. A second order polynomial was calculated to obtain three coefficients. All horses were evaluated by three judges: body measures, functionality, morphology, jumping, genealogy and stallion model. Judges are consistent with each other, but they are biased. The biomechanical variables showed high repeatability and low error. None of the functionality, genealogy and jumping scores correlate with jumping biomechanical variables. The judgement is not associated with the jumping biomechanical variables measured. Kinematic analysis showed no bias and was very consistent therefore being helpful for future sport horses judgement.

Neste trabalho estudamos as equações de Riccati para a filtragem de sistemas lineares com saltos Markovianos a tempo discreto. Obtemos uma condição geral para estabilidade do filtro ótimo obtido pela equação algébrica de filtragem, e que também é válida para que não haja multiplicidade de soluções. Revisitamos também a questão da existência, chegando a uma condição em termos da sequência de ganhos de um observador de Luenberger. Estes resultados usaram cadeias de Markov em escala reversa de tempo, inspirando a explorar a dualidade entre filtragem e controle em sistemas com reversão na cadeia, chegando a uma relação simples de dualidade. / In this work, we studied Riccati equations for filtering Markovian jump linear systems in discrete time. We found a general condition for the stability of the optimal filter obtained via the coupled algebraic Riccati equation, and it is also valid for uniqueness of solutions. We revisit the topic of existence of solutions of the Riccati and obtain a condition in terms of the sequence of gains of a Luenberger observer. These results used Markov chains in reverse time scale, inspiring us to explore the duality between filtering and control in systems with chain reversion, arriving at a simple relation of duality.

"The goal of this project was to investigate the dynamic effects of incipient separation of industrial cam-follower systems. Typical industrial cam-follower systems include a force closed cam joint and a follower train containing both substantial mass and stiffness. Providing the cam and follower remain in contact, this is a one degree-of-freedom (DOF) system. It becomes a two-DOF system once the cam and follower separate or jump, creating two new natural frequencies, which bracket the original. The dynamic performance of the system as it passed through the lower of the two post-separation modes while on the verge of jump was investigated. A study was conducted to determine whether imperfections in the cam surface, while the contact force is on the brink of incipient separation, may cause a spontaneous switch to the two-DOF mode and begin vibration at resonance. A force-closed translating cam-follower train was designed for the investigation. The fixture is a physical realization of the two-mass mathematical model. Pro/Engineer was used to design the follower train, Mathcad and TK Solver were used to analyze the linkage and DYNACAM & Mathcad were used to dynamically model the system. The system is designed to be on the cusp of incipient separation when run. Experiments were carried out by bringing the system up to jump speed and then backing off the preload to get the system on the cusp of separation. Data were collected at the prejump, slight jump, and violently jumping stages. The time traces show the acceleration amplitudes grow to large peaks when the system is jumping. The frequency spectrum shows the two new natural frequencies growing in amplitude from non-existant in the prejump stage, to higher values in the violently jumping stage. The peak amplitudes of the phenomenon are small in magnitude compared to the harmonic content of the cam. It is concluded that the contribution of the two-DOF system natural frequencies is not a significant factor from a practical aspect. Although the actual jump phenomenon is of concern in high-speed applications, calculations show that if the follower system is designed sufficiently stiff then the two-DOF situation will not occur."