When considering the array of terrestrial locomotor behaviors, bipedalism is a particularly rare way of moving about the landscape. In fact, humans are the only obligate terrestrial mammalian bipeds. Therefore, understanding both how and why it evolved is particularly intriguing. However, there is debate over why the evolution of bipedalism occurred and there is a large gap in knowledge for the mechanisms that underpin the evolution of these adaptive morphologies. One complicating factor for sorting out which models best explain how our hominin ancestors became bipedal is that they all rely on the same set of traits. Moreover, many of the traits that are thought to be diagnostic of bipedalism are only linked by association and have not been experimentally tested. That is, they do not appear in non-human primates and other quadrupeds. Therefore, addressing why the evolution of bipedalism occurred requires understanding the adaptive significance of traits linked with bipedalism. In this dissertation, I use an experimental approach employing both human and animal models to explore links between morphology and behavior and to tease apart the adaptive significance of particular traits. For the human portion of the dissertation, I use an inverse dynamics approach (estimating muscle forces from kinematic, kinetic, and anatomical data) to determine how modern human anatomy functions while walking using ape-like postures to clarify the links between morphology and energy costs in different mechanical regimes to determine the adaptive significance of postcranial anatomy. The results from this portion of the dissertation suggest that adopting different joint postures results in higher energy costs in humans due to an increase in active muscle volumes at the knee. These results lead to two conclusions important for understanding the evolution of human bipedalism. One is that human anatomy maintains low energy costs of walking in humans compared to chimpanzees regardless of lower limb postures. Second, the results suggest that erect trunk posture may be an important factor in reducing energy costs, therefore indicating that lumbar lordosis (the curvature of the lower spine) is important for reducing costs. For the animal portion of the dissertation, I use rats as a model for the quadrupedal-to-bipedal transition and experimentally induce bipedal posture and locomotion under a variety of loading conditions to determine if traits consistent with the evolution of bipedalism occur and under what conditions. This experimental design also has the ability to determine if there is a role for developmental plasticity in generating bipedal morphology to help answer the question how the evolution of bipedalism occurred. I find that inducing bipedal behaviors in a quadrupedal animal generates morphology consistent with human bipedal traits and that loading conditions have specific effects in different skeletal elements and at particular joints. I also find that there is a plausible role for developmental plasticity in generating adaptive bipedal morphology in the earliest hominins. Overall, the results from the experimental procedures in this dissertation were able to clarify links between behavior and bipedal morphology, demonstrate a plausible role for developmental plasticity in early adaptation to bipedal behavior in australopiths, determine the adaptive significance of human postcranial anatomy, and the ways in which postcranial anatomy reduces costs.

O suporte parcial de peso (SPP) define-se por algum grau de diminuição do peso corporal gerado por um aparato de suspensão, que acomoda as elevações e quedas corporais durante a realização da marcha em esteira. Trata-se de um método frequentemente indicado para indivíduos acometidos por disfunções do movimento, cujo programa de tratamento tenha como objetivo a diminuição da magnitude de cargas nos tecidos, gerando proteção articular e diminuição da dor. Contudo, ainda pouco se sabe sobre as reais repercussões geradas na marcha quando o suporte parcial de peso é utilizado. Desta forma, o presente trabalho teve como objetivo verificar o efeito da velocidade e do nível de suspensão corporal sobre variáveis cinemáticas e eletromiográficas de indivíduos saudáveis. Foram avaliados 49 sujeitos saudáveis, 18 do sexo feminino, 31 do sexo masculino, com idade de 28,7(±6,7), massa corporal de 76,9(±14,9) kg, altura de 173,3(±14,9) cm durante a realização de marcha em esteira sob 3 velocidades diferentes (2,0 Km/h, 4 km/h e velocidade auto selecionada), em 4 níveis de suspensão parcial de peso: 0%, 20%, 50% e 80%. Todos os voluntários passaram pelas 12 condições. Observou-se que, acima de 50% de sustentação em velocidades baixas e auto selecionadas, a cadência diminui gradativamente, e a porcentagem do tempo de balanço aumenta, com diminuição gradativa das amplitudes articulares e picos angulares de quadril, joelho e tornozelo. A atividade eletromiográfica também se mostrou diminuída em todas as fases da marcha para os músculos glúteo médio, reto femoral, vasto lateral, bíceps femoral, tibial anterior e gastrocnêmio lateral. Os resultados sugerem, portanto, que a suspensão influencia diretamente no comportamento da marcha de indivíduos saudáveis diminuindo a solicitação muscular e articular, e provavelmente, diminuindo a solicitação mecânica da tarefa, sem contudo alterar por demais as características principais, o que possibilita a utilização de tal estratégia para a proteção articular e o retorno precoce à locomoção, caso haja esta necessidade / Partial weight support (PWS) is an intervention method that allows a decrease in body weight by a suspension apparatus, which accommodates elevations and body falls during treadmill walking. It is frequently prescribed for individuals with movement disorders whose treatment programs aims to decrease the loads in the tissues, promoting joint protection and pain relieve. However, little is known about the actual repercussions generated in gait when partial weight support is used. Thus, the present study aimed to verify the effect of speed and PWS on kinematic and electromyographic variables of healthy individuals. Forty nine healthy subjects (18 women), with 28.7 (± 6.7) years of age, body mass of 76.9 (± 14.9) kg, height of 173.3 (± 14.9) took part of the study. They walked in a treadmill at 3 different velocities (2.0 km/h, 4 km/h and at a self-selected pace), and under 4 levels of partial weight suspension: 0%, 20%, 50% and 80%. All volunteers went through the 12 conditions. We found that PWS above 50% at low velocities and at self-selected pace the gait cadence decreases, the balance phase increases, articular amplitudes and hip, knee and ankle peaks decrease. Higher PWS induced a decrease in the electromyographic activity in gluteus medius, rectus femoris, vastus lateralis, biceps femoris, tibialis anterior and lateral gastrocnemius muscles in all gait phases. These results suggest that the suspension has a direct influence in the gait behavior of healthy individuals. It decreases muscle and joint demands without changing its main characteristics, allowing the use of this strategy for joint protection and early return to independent locomotion

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A Lesão Medular (LM) afeta a funcionalidade do indivíduo e pode reduzir drasticamente a independência. A restauração da mobilidade e do andar, é uma das principais metas das intervenções na população com LM, e nesse contexto o treinamento locomotor (TLSP) é uma intervenção utilizada com objetivo de fornecer estímulos sensoriais específicos ao sistema nervoso danificado para estimular as redes e circuitos preservados da medula. A velocidade é uma aferência sensorial importante durante o TLSP em esteira. Objetivo: investigar o efeito da variação de velocidade sobre as respostas motoras de indivíduos com lesões medulares durante TLSP em esteira. Método: 20 sujeitos sem LM denominado de grupo controle (GC) e 13 com LM completa (GLM) foram submetidos ao protocolo TLSP em esteira nas velocidades 2, 3 e 4 km/h. Foi realizada uma análise de EMG para avaliar atividade muscular de vasto lateral (VL), bíceps femural (BF), tibial anterior (TA) e gastrocnêmio lateral (GL) ao longo do ciclo do passo. Resultados: O GC apresentou maior atividade muscular distal TA e GL quando comparado ao GLM com maior atividade proximal VL e BF durante todas as fases da marcha. A velocidade que apresentou maior atividade muscular foi a intermediária (3km/h), quando comparado as velocidades 2Km/h e 4km/h. O aumento da velocidade resultou em maior influência nos músculos distais. Conclusão: a velocidade pode influenciar nas respostas motoras locomotoras de indivíduos com LM. O aumento da velocidade teve um papel importante no aumento da atividade muscular, contudo a atividade muscular foi maior na velocidade intermediária (3km/h) / Spinal Cord Injury (SCI) affects the individual\'s functionality and can gradually reduce independence. The restoration of mobility and walking, is one of the main goals of the interventions in SCI population. In this context body weight support treadmill training (BWSTT) is an intervention used to provide specific sensory stimuli to the damaged nervous system to stimulate the networks and circuits preserved in the spinal cord. Velocity is an important sensory afferment during the BWSTT. Objective: to investigate the effect of speed variation on motor responses of use with spinal cord injuries BWSTTl. Method: 20 healthy subjects composed the control group (CG) and 13 with complete SCI (SCIG) were submitted to BWSTT at speeds 2, 3 and 4 km/h. An EMG analysis was performed to evaluate the muscle activity of lateral vastus (LV), biceps femorales (BF), tibial anterior (TA) and gastrocnemius lateral (GL) throughout the cycle of the step. Results: The CG had greater distal muscle activity TA and GL when compared to GLM with greater proximal activity, VL and BF, during all gait phases. The velocity that presented greater muscular activity was the intermediate (3km/h), when compared as speeds 2Km/h and 4km/h. Increased speed resulted in greater influence on the distal muscles. Conclusion: the velocity can influence motor responses. Increased speed had an important role in increasing muscle activity, however, muscle activity was greater at intermediate velocity (3km / h)

A Lesão Medular (LM) afeta a funcionalidade do indivíduo e pode reduzir drasticamente a independência. A restauração da mobilidade e do andar, é uma das principais metas das intervenções na população com LM, e nesse contexto o treinamento locomotor (TLSP) é uma intervenção utilizada com objetivo de fornecer estímulos sensoriais específicos ao sistema nervoso danificado para estimular as redes e circuitos preservados da medula. A velocidade é uma aferência sensorial importante durante o TLSP em esteira. Objetivo: investigar o efeito da variação de velocidade sobre as respostas motoras de indivíduos com lesões medulares durante TLSP em esteira. Método: 20 sujeitos sem LM denominado de grupo controle (GC) e 13 com LM completa (GLM) foram submetidos ao protocolo TLSP em esteira nas velocidades 2, 3 e 4 km/h. Foi realizada uma análise de EMG para avaliar atividade muscular de vasto lateral (VL), bíceps femural (BF), tibial anterior (TA) e gastrocnêmio lateral (GL) ao longo do ciclo do passo. Resultados: O GC apresentou maior atividade muscular distal TA e GL quando comparado ao GLM com maior atividade proximal VL e BF durante todas as fases da marcha. A velocidade que apresentou maior atividade muscular foi a intermediária (3km/h), quando comparado as velocidades 2Km/h e 4km/h. O aumento da velocidade resultou em maior influência nos músculos distais. Conclusão: a velocidade pode influenciar nas respostas motoras locomotoras de indivíduos com LM. O aumento da velocidade teve um papel importante no aumento da atividade muscular, contudo a atividade muscular foi maior na velocidade intermediária (3km/h) / Spinal Cord Injury (SCI) affects the individual\'s functionality and can gradually reduce independence. The restoration of mobility and walking, is one of the main goals of the interventions in SCI population. In this context body weight support treadmill training (BWSTT) is an intervention used to provide specific sensory stimuli to the damaged nervous system to stimulate the networks and circuits preserved in the spinal cord. Velocity is an important sensory afferment during the BWSTT. Objective: to investigate the effect of speed variation on motor responses of use with spinal cord injuries BWSTTl. Method: 20 healthy subjects composed the control group (CG) and 13 with complete SCI (SCIG) were submitted to BWSTT at speeds 2, 3 and 4 km/h. An EMG analysis was performed to evaluate the muscle activity of lateral vastus (LV), biceps femorales (BF), tibial anterior (TA) and gastrocnemius lateral (GL) throughout the cycle of the step. Results: The CG had greater distal muscle activity TA and GL when compared to GLM with greater proximal activity, VL and BF, during all gait phases. The velocity that presented greater muscular activity was the intermediate (3km/h), when compared as speeds 2Km/h and 4km/h. Increased speed resulted in greater influence on the distal muscles. Conclusion: the velocity can influence motor responses. Increased speed had an important role in increasing muscle activity, however, muscle activity was greater at intermediate velocity (3km / h)

Introduction: Maximum running acceleration essential components in many sports. The identification of specific training protocols to maximize sprint speed would be useful knowledge for soccer coaches and players. Purpose: The purpose of this study was to determine the effect of a high-speed treadmill with the use of a body-weight support system in a 6-week sport acceleration program on: 40-yard sprint time, maximal isometric knee flexor and extensor strength. Methods: 32 female soccer players (age 16 ± 1.19 yrs) participated in two treatment groups and one control group. Both treatment groups participated in a 12-session sport acceleration program. The first treatment group utilized a body-weight support system while on a high-speed treadmill; the second group used a standard treadmill with no body weight support system. The control group, NT, did not participate in a sports acceleration program and did not alter their exercise routines outside of the study. Results: For each variable an Analysis of Covariance (ANCOVA) was performed. 40-yard sprint times for treatment groups were shown to improve significantly as compared to the control group (p = 0.0007 for high-speed treadmill with body-weight support system, p= < 0.0001 for standard treadmill without body-weight support system). Isometric flexor and extensor strengths did not show significant differences between treatment groups and control group. P-values for the high-speed with body-weight support system were (p = 0.53) for flexors and (p = 0.51) for extensors as compared to the control group. P-values for the standard treadmill with no body-weight support system were (p = 0.19) for extensors and (p = 0.0263) for flexors. It is noted that the extensor muscles were nearly significant for the standard treadmill with no body-weight support system. Discussion: These results can help high school coaches and athletes determine the optimal treadmill training regime. The current study shows that a high-speed treadmill with body-weight support system is just as beneficial as standard treadmill training.

Made available in DSpace on 2016-06-02T20:18:13Z (GMT). No. of bitstreams: 1 3132.pdf: 3107997 bytes, checksum: 1b931ab55a545210b8e98eae0eee3ce1 (MD5) Previous issue date: 2010-05-10 / Universidade Federal de Sao Carlos / This work is composed of three distinct studies. In the first one, we compared the muscle coactivation of tibialis anterior (TA) and gastrocunemius medialis (GM) during quiet stance and the also during the stance phase of gait in hemiparetic subjects (hemiparetic group, HG, n=12) and in subjects with no neurologic injuries (control group, CG, n=10). We evaluated the TA and GM electromyographic signal and calculated their overlapping ratio (OR). We concluded that these individuals do not present significant coactivation alterations in the stance phase of gait, but in quiet stance they seem to use the coactivation of the non-paretic limb to maintain postural stability. In the second study we investigated the effects of the association of treadmill training with body weight support (TTBWS) associated with strength training of ankle muscles on the motor control in chronic hemiparetic subjects. Fifteen volunteers were distributed into 2 treatment groups: 1) TTBWS (G1; n=7); and 2) TTBWS associated with resistance training for dorsi and plantar flexors (G2; n=8). We evaluated muscle performance of plantar flexion and dorsiflexion in an isokinetic dynamometer through peak torque (PT), total work (TW) and acceleration time (AT) at the speeds of 60°/s and 120°/s. For gait analysis we assessed the ground reaction forces (GRF). There was an increase in PT and TT of plantar flexion at 60°/s in the paretic side, and an increase in the positive peak of the anterior-posterior GRF component in both sides of G2. We suggested that the proposed intervention leads to improvements in the components related to propulsion of gait. In the third study, we evaluated the effect of the robot assisted gait training (RAGT) in children with spastic diplegia. Twenty children (12 male, 5-13 years old) were evaluated for functional outcomes and spatial-temporal patterns of gait before, after and 3 months after the end of the intervention. Comparisons revealed significant improvements on functional outcomes and in gait mechanics. We concluded that RAGT promotes better gait patterns, and that the learning of this new task is retained even after the end of the intervention. / Este trabalho é composto por três estudos distintos. Inicialmente comparamos a coativação dos músculos tibial anterior (TA) e gastrocnêmio medial (GM) em postura ortostática e durante a fase de apoio da marcha de indivíduos hemiparéticos (grupo hemiparético, GH; n = 12) e de indivíduos sem lesões neurológicas (grupo controle, GC; n = 10). Avaliamos o sinal eletromiográfico do TA e do GM e calculamos a taxa de sobreposição dos mesmos (ICoa). Em atividade estática observamos maior ICoa no membro não parético do GH quando comparado com o membro dominante do GC. Concluímos que hemiparéticos não apresentam alterações significativas da coativação na fase de apoio da marcha, mas em atividade estática parecem utilizar o aumento da coativação do lado não parético para a manutenção da estabilidade. No segundo estudo investigamos os efeitos da associação do treino de marcha em esteira com suporte parcial do peso corporal (TMESPP) ao treinamento de força para a musculatura do tornozelo sobre o controle motor em indivíduos hemiparéticos crônicos. Quinze voluntários foram distribuídos em 2 grupos de tratamento: 1) TMESPP (G1; n=7) e 2) TMESPP associado ao fortalecimento da musculatura do tornozelo (G2; n=8). Avaliamos o desempenho muscular nos movimentos de plantiflexão e dorsiflexão em dinamômetro isocinético nas velocidades de 60°/s e 120°/s, através dos valores de pico de torque (PT), trabalho total (TT) e tempo de aceleração (TA). Para avaliação da marcha analisamos as forças de reação do solo (FRS). Houve aumento do PT e do TT da plantiflexão a 60°/s do lado parético, e aumento dos picos positivos do componente ântero-posterior das FRS em ambos os lados do G2. Sugerimos que a intervenção proposta provoca melhora nos componentes da propulsão da marcha. O terceiro estudo avaliou o efeito do treino de marcha assistido por robô (TMAR) em 20 crianças com diparesia espástica (12 sexo masculino, 5-13 anos). Avaliamos medidas funcionais e padrões espaço-temporais da marcha antes, após e três meses depois do término da intervenção. As comparações revelaram melhora significativa nas medidas funcionais e na mecânica da marcha. Concluímos que o TMAR promove melhoras nos padrões da marcha, e que a aprendizagem dessa nova tarefa é retida mesmo após a interrupção do treino.

The work treats the static recalculation of an existing roof structure of a construction for social purposes and proposes two variants of the design of a new roof structure. The construction has a rectangular ground plan of 30 m x 47 m and the roof structure is placed on the load bearing circumference concrete walls. Except for the load constituted by the function of the construction and by the climatic area, an extra load of 2 tons suspended at any place of the structure is considered because of the special requirement of working and technological equipment. The variant no. 1 is designed from the steel S355. The variant no. 2 is designed as a combination of the wood GL24h and the aluminium EN-AW 5083. Both of the variants have 11 transverse load bearing girders. The purlins are perpendicular to the girders and are placed on them. Stiffness is secured by roof stiffeners.