The aims of this study were to investigate the mechanisms underlying (1) the ageing-related motor handicap at the whole muscle, cellular, contractile protein and myonuclear levels; and (2) ageing-related differences in muscle adaptability. In vivo muscles function was studied in the knee extensors. Decreases were observed in isokinetic and isometric torque outputs in old age in the sedentary men and women and elite master sprinters. A 20-week long specific sprint and resistance training successfully improved the maximal isometric force and rate of force development in a subgroup of master sprinters. In vitro measurements were performed in muscle biopsies from the vastus lateralis muscle. Immunocytochemical and contractile measurements in single membrane permeabilized muscle fibres demonstrated ageing- and gender-related changes at the myofibrillar level. In sedentary subjects, data showed a preferential decrease in the size of muscle fibres expressing type IIa MyHC in men, lower force generating capacity in muscle fibres expressing the type I MyHC isoform in both men and women and lower maximum velocity of unloaded shortening (V0) in fibres expressing types I and IIa MyHC isoforms in both men and women. The master sprinters also experienced the typical ageing-related reduction in the size of fast-twitch fibres, a shift toward a slower MyHC isoform profile and a lower V0 of type I MyHC fibres, which played a role in the decline in explosive force production capacity. The fast-twitch fibre area increased after the resistance training period. A model combining single muscle fibre confocal microscopy with a novel algorithm for 3D imaging of myonuclei in single muscle fibre segments was introduced to study the spatial organisation of myonuclei and the size of individual myonuclear domains (MNDs). Significant changes in the MND size variability and myonuclear organization were observed in old age, irrespective gender and fibre type. Those changes may influence the local quantity of specific proteins per muscle fibre volume by decreased and/or local cooperativity of myonuclei in a gender and muscle fibre specific manner. In conclusion, the ageing-related impairments in in vivo muscle function were related to significant changes in morphology, contractile protein expression and regulation at the muscle fibre level. It is suggested that the altered myonuclear organisation observed in old age impacts on muscle fibre protein synthesis and degradation with consequences for the ageing-related changes in skeletal muscle structure and function. However, the improved muscle function in response to a 20-week intense physical training regime in highly motivated physically active old subjects demonstrates that all ageing-related in muscle function are not immutable.

Carbon fibre reinforced ceramic composites (Cf/C-SiC) have been explored as lightweight and durable disc in a friction brake. This composite was manufactured through infiltration of liquid silicon into a Cf/C perform. It has heterogeneous microstructure, composed of three key phases, silicon carbide, Cf/C, and un-reacted residual silicon. The development of the transfer layer on the friction surface of Cf/C-SiC was studied through microstructural image registration of the surface after a range of braking stops on a laboratory-scale dynamometer test rig. When an organic pad was used as the counter face brake pad, it was found that a steady transfer layer was developed in silicon regions right after initial stops; in carbon-fibre/carbon (Cf/C) regions and most of the silicon carbide region, the friction surfaces were unsteady and any possible friction transfer layers were hardly built up. Large voids and cracks/crevices likely became pools to quickly and efficiently collect the transferred materials generated by the friction, but the compacts formed inside the pools were susceptible to be stripped off by further braking operation. Three types of friction surfaces were generalized: type I, the friction transfer layer had a steady relationship with the matrix and respectable longevity; type II, the transfer layer had an unstable relationship with the matrix and poor durability; type III, the friction transfer layer had a steady relationship with the matrix but short lifetime. After testing against organic pads under the laboratory scale dynamometer testing condition, the friction surface of each key phase in Cf/C-SiC composites disc was studied by transmission electron microscopy (TEM). It was found that the transfer layer developed on Si consists of fine particles of metal silicides, silicates and minerals. The substrate damage of Si was not observed, while the precipitates having high oxygen content were found in the substrate. Formation of an interfacial bonding between transfer layer and silicon substrate is believed to be the key factor for the formation of a stable transfer layer on Si. However, the interfacial bonding between transferred materials and SiC was not detected. Kinks are common features developed on the friction surface of SiC. The interface between carbon fibre and carbon matrix was experienced mechanical damage, in form of microcracks, and the transferred material was developed in the interface. Instead of transfer layer, a thin amorphous film, produced by friction induced amorphisation of carbon fibre, was developed on top of carbon fibre.

Made available in DSpace on 2016-06-02T20:19:25Z (GMT). No. of bitstreams: 1 6272.pdf: 943725 bytes, checksum: fe22255b4e68c17bf799b7fcb6c4e5d4 (MD5) Previous issue date: 2014-02-26 / Financiadora de Estudos e Projetos / Traumatic anterior glenohumeral instability makes the humeral head unable to remain centered on the glenoid fossa and alters the arthrokinematics and the strength of the shoulder rotators. The rotator cuff muscles depend on a good performance of the scapular muscles and their strengthening has been recommended at different levels for subjects with traumatic anterior glenohumeral instability. On the other hand, poor scapular performance is not well described in this population. Therefore, the aim of this thesis was to investigate muscle performance during protraction and retraction of the scapula in the sagittal and scapular planes in subjects with traumatic anterior glenohumeral instability. The study included 40 volunteers of both sexes, divided into two groups: control group (n = 20) and patients with traumatic anterior glenohumeral instability (n = 20). Muscle performance during protraction and retraction was assessed using Biodex System III isokinetic dynamometer in the isometric mode, with three repetitions, and in the concentric isokinetic mode, at the speeds of 12.2 cm/s and 36.6 cm/s, with 5 and 10 repetitions, respectively. The evaluations were performed with the shoulder flexed at 90° in the sagittal plane and elevated at 90° in the scapular plane. The mean peak force, total work and the total range of motion (ROM) were the variables of interest. The variables were compared using analysis of variance with two factors (ANOVA - Two Way), considering plans as the withinsubject factor and group as the between-subject factor, at a significance level of 5%. There was difference between subjects in the average peak force at isometric protraction and retraction and also at protraction during isokinetic evaluation at 36 cm/s (p <0.05). For intra-subject analysis (scapular plane vs sagittal plane), differences were found for mean peak force during isometric protraction, isokinetic protraction at 12.2 cm/s and isokinetic protraction at 36.6 cm/s. There was an interaction for the total work in retraction at 12.2 cm / s, total work in retraction at 36.6 cm / s for ROM. This dissertation shows that subjects with traumatic anterior glenohumeral instability have decreased strength in protraction and in isometric retraction and also in isokinetic contraction. Average peak force, total work and ROM in the sagittal plane are higher than in the scapular plane. / A instabilidade glenoumeral traumática anterior torna a cabeça umeral incapaz de manter-se centralizada na fossa glenoidal. Essa disfunção altera a artrocinemática e a força dos rotadores do ombro. Os músculos do manguito rotador dependem de um bom desempenho dos músculos escapulares e, assim, seu fortalecimento tem sido recomendado em planos diferentes, em sujeitos com instabilidade glenoumeral traumática anterior. Por outro lado, o comprometimento do desempenho escapular não está claro nessa população. Diante disso, o objetivo desta dissertação foi investigar o desempenho muscular de protração e retração da escápula no plano sagital e escapular em sujeitos com instabilidade glenoumeral traumática anterior. Participaram deste estudo 40 voluntários de ambos os sexos, divididos em dois grupos: grupo controle (n=20) e grupo com instabilidade glenoumeral traumática anterior (n=20). O desempenho muscular de protração e retração foi avaliado por meio do dinamômetro isocinético Biodex System III, no modo isométrico, com 3 repetições, e no modo isocinético concêntrico, nas velocidades 12,2 cm/s e 36,6 cm/s, com 5 e 10 repetições, respectivamente. As avaliações foram realizadas com o ombro posicionado a 90° de flexão no plano sagital e a 90º de elevação no plano da escápula. A média dos picos de força, o trabalho total e a amplitude total de movimento (ADM) foram as variáveis de interesse. As variáveis foram comparadas, utilizando-se a análise de variância com dois fatores (ANOVA Two Way), com os planos como fator intrassujeitos e grupo como fator entressujeitos, a um nível de significância de 5%. Houve diferença entressujeitos para a média dos picos de força em protração e retração isométrica e também em protração durante a avaliação isocinética a 36 cm/s (p<0.05). Para a análise intrassujeitos (Plano escapular vs Plano sagital), as diferenças foram encontradas para a média dos picos de força durante a protração isométrica, protração isocinética a 12,2 cm/s e protração isocinética a 36,6 cm/s. Houve interação para o trabalho total em retração a 12,2 cm/s, trabalho total em retração a 36,6 cm/s e para a ADM. Esta dissertação permite concluir que sujeitos com instabilidade glenoumeral traumática anterior apresentam diminuição de força em protração e retração isométrica e em retração isocinética. A média dos picos de força, o trabalho total e a ADM no plano sagital são maiores do que no plano escapular.

Made available in DSpace on 2016-06-02T20:19:27Z (GMT). No. of bitstreams: 1 6773.pdf: 1423884 bytes, checksum: 7e9d34dd271eeaddbef853357ac2a926 (MD5) Previous issue date: 2015-02-27 / Financiadora de Estudos e Projetos / This study aimed to compare neuromuscular aspects, such as antagonist co-activation during knee extension (Coext) and flexion (Coflex), functional ratio of the maximum concentric hamstring strength to the maximum eccentric quadriceps strenght for knee flexion (Icon:Qexc), knee extensor torque in concentric (PTcon_ext) and eccentric (PTexc_ext) ways, the concentric knee flexor torque (PTcon_flex) and physical function, in different knee OA degrees. It was also objective of this dissertation investigate the center of pressure (COP) behavior (amplitude and velocity of the anterior-posterior and medial-lateral displacement) during a task involving eccentric quadriceps contraction, and the correlation between center of pressure and variables related to muscle performance and physical function. These objectives comprise two studies, with different methodologies. Study I: 20 subjects with knee OA (GOA) and 20 healthy subjects (GC) performed a postural stability evaluation, standing on two force platforms (Bertec Mod) with 45 degrees of knee flexion. PTcon_flex and PTexc_ext were evaluated in a speed of 90°/s. Subjects answered Physical Function and Stiffness subscales of the questionnaire Western Ontario MacMaster Universities Osteoarthritis Index (WOMAC). Intergroup statistical analysis shown that subjects of the GOA, compared to GC, had no difference in postural control parameters, had lower Icon: Qexc (p = 0.004) and poorer selfreported physical function (p = 0.00) and stiffness (p = 0.001). Antero-posterior COP displacement was moderately and negatively correlated with the physical function subscale (&#961; = -0.480, p = 0.02). Antero-posterior COP speed was moderately and negatively correlated with the physical function WOMAC subscale (&#961; =-0.52, p = 0,01) and stiffness WOMAC subscale (&#961; = -0.44, p = 0.03). Study II: 20 subjects with knee OA grade II (GOAII), 15 with knee OA grade III (GOAIII) and 19 healthy subjects (GC) performed isokinetic knee extension and flexion at 60 °/s, simultaneously to the electromyographic assessment of muscles quadriceps (vastus lateralis, rectus femoris, vastus) and hamstrings (biceps femoris and semitendinosus). Subjects answered Physical Function WOMAC subscale and performed functional tests 30-s chair-stand test (STS30s), 40mfast-paced walk test (Caminhada40m) and a stair-climb test (Escada). After intergroup analysis, GOAII showed higher Coflex (p = 0.001), higher Icon:Qexc (p = 0.000), &#931;emgflex_flex (p = 0.000), lower PTcon_ext (p = 0:02) and PTexc_ext (p = 0.008) and worse self reported physical function (p= 0.000). In GOAIII were identified greater Icon:Qexc (p = 0.000), lower PTcon_ext (p = 0.000), PTexc_ext (p = 0.000) and PTcon_flex (p = 0.04), worse self-reported Physical Function (p = 0.000) and worse performance in the functional tests: STS30s Caminhada40m e Escada (p = 0.017 p = 0.000 and p = 0.001, respectively). There was no difference between the GOAII and GOAIII for all variables (p &#8805; 0.05). Together, these results suggest a neuromuscular adaptation present in individuals with knee OA, justifies the need for intervention from the early degrees of the disease and highlight the importance of taking into account different forms of assessment of physical function. / Foi objetivo desta dissertação comparar aspectos neuromusculares, como coativação do antagonista durante a extensão (Coext) e flexão (Coflex) do joelho, relação funcional de força concêntrica de isquiotibiais e excêntrica de quadríceps para flexão de joelho (Icon:Qexc), torque extensor do joelho nos modos concêntrico (PTcon_ext) e excêntrico (PTexc_ext), o torque flexor do joelho no modo concêntrico (PTcon_flex) e a função física nos diferentes graus da OA do joelho. Também foi objetivo dessa dissertação investigar o comportamento do centro de pressão (amplitude e velocidade do deslocamento ântero-posterior e médio-lateral) durante uma tarefa envolvendo contração excêntrica do quadríceps e correlaciona-lo às variáveis relacionadas ao desempenho muscular e função física. Estes objetivos compõem dois estudos, com metodologias distintas. Estudo I: 20 indivíduos com OA de joelhos (GOA) e 20 sujeitos saudáveis (GC) realizaram avaliação da estabilidade postural, em pé sobre duas plataformas de força (Bertec Mod) e flexão de joelhos de 45 graus. Também foram avaliados PTcon_flex e PTexc_ext na velocidade de 90°/s e os sujeitos responderam às seções função física e rigidez do questionário Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC). Após análise estatística intergrupo, não foi observada diferença estatística para as variáveis do controle postural entre os sujeitos com OA e o GC. No entanto, foram identificados menor PTexc_ext (p=0.01), menor Icon:Qexc (p=0.004), pior auto-relato de função física (p=0,00) e rigidez (p=0,001). A análise de correlação indicou correlação entre o controle postural e função física e rigidez. Estudo II: Vinte indivíduos com OA do joelho grau II (GOAII), 15 com OA do joelho grau III (GOAIII) e 19 saudáveis (GC) realizaram teste isocinético de extensão do joelho a 60°/s, simultaneamente à avaliação eletromiográfica dos músculos do quadríceps (vasto lateral, reto femural e vasto medial) e isquiotibiais (bíceps femural e semitendíneo). Os sujeitos responderam à seção Função Física do qustionário WOMAC e realizaram testes funcionais de sentar e levantar de uma cadeira por 30 segundos (STS30s), caminhada de 40 metros (Caminhada40m) e subida e descida de escada (Escada). Após análise intergrupo, o GOAII apresentou maior Coflex (p = 0.001), maior Icon:Qexc (p = 0.000), &#425;emgflex_flex (p = 0.000), menores PTcon_ext (p = 0.02) e PTexc_ext (p = 0.008) e pior auto-relato de função física (p = 0.000 ). No GOAIII foram identificados maior Icon:Qexc (p = 0.000), menores PTcon_ext (p = 0.000), PTexc_ext (p = 0.000) e PTcon_flex (p = 0.04), pior auto-relato de função física (p = 0.000) e pior desempenho nos testes STS30s, Caminhada40m e Escada (p = 0.017 p = 0.000 e p = 0.001, respectivamente). Não houve diferença entre o GOAII e GOAIII para nenhuma das variáveis (p &#8805; 0.05). Em conjunto, os resultados sugerem uma adaptação neuromuscular presente nos indivíduos com OA do joelho, necessidade de intervenção desde os graus iniciais da doença e destacam a importância de levar em conta diferentes formas de avaliação da função física.

Made available in DSpace on 2014-12-17T14:55:21Z (GMT). No. of bitstreams: 1 FabioSL_TESE.pdf: 5888891 bytes, checksum: cd954df5e4af671c3361060293cc5710 (MD5) Previous issue date: 2014-05-30 / Universidade Federal do Rio Grande do Norte / The precision and the fast identification of abnormalities of bottom hole are essential to prevent damage and increase production in the oil industry. This work presents a study about a new automatic approach to the detection and the classification of operation mode in the Sucker-rod Pumping through dynamometric cards of bottom hole. The main idea is the recognition of the well production status through the image processing of the bottom s hole dynamometric card (Boundary Descriptors) and statistics and similarity mathematics tools, like Fourier Descriptor, Principal Components Analysis (PCA) and Euclidean Distance. In order to validate the proposal, the Sucker-Rod Pumping system real data are used / A identifica??o r?pida e precisa de anormalidades de fundo de po?o ? essencial para evitar danos e aumentar a produ??o na ind?stria do petr?leo. Esta tese apresenta um estudo sobre uma nova abordagem autom?tica para a detec??o e classifica??o de modos de opera??o no sistema de Bombeio Mec?nico atrav?s de carta de dinamom?tricas de fundo de po?o. A id?ia principal ? o reconhecimento das condi??es de produ??o do sistema atrav?s do processamento de imagem do carta dinamom?trica de fundo de po?o (Descritores de Fourier) e ferramentas matem?ticas estat?sticas (An?lise de Componentes Principais - PCA) e de similaridade (Dist?ncia Euclidiana). Para validar a proposta, s?o utilizados dados provenientes de sistemas de Bombeio Mec?nico reais

Made available in DSpace on 2014-12-17T14:58:06Z (GMT). No. of bitstreams: 1 GilCL_DISSERT.pdf: 1771464 bytes, checksum: 92ddc93639f74d5c2bbc96617815f7ed (MD5) Previous issue date: 2010-12-18 / Flex-fuel vehicles are equipped with Otto Cycle internal combustion engines and have the capability of functioning with more than one type of fuel, mixed at the same tank and burned in the combustion chamber simultaneously. This sort of motorization is a world pattern due to the scarcity of petroleum, the trade of several types of fuels, technology advances and the restriction imposed to gas emissions to the atmosphere. In Brazil, the Flexfuel vehicles are a reality, specially the ones using fuel with 20 to 25% anhydrous alcohol mixed with gasoline and those that use natural gas or original liquid fuel (gasoline or hydrated ethanol). The Brazilian model Fiat Siena, the object of this present scientific investigation, is equipped with a unique electronic central capable of managing the liquid or gaseous fuels. The purpose of this research was to perform a comparative analysis in terms of performance (in terms of both potency and consumption) of a tetra-fuel vehicle - using a chassis dynamometer, operating with different fuels: common gasoline, premium gasoline, Podium gasoline, ethanol or natural gas. It became necessary to develop a bench of tests and trials procedures, as well as to know the functioning of the electronic management of the vehicle under analysis. The experiments were performed at the automotive laboratory in CTGAS-ER (Center of Gas Technologies and Renewable energies) at the light of Brazilian standard ABNT, NBR 7024: Light on-road vehicles - measurement of fuel consumption. The essay results on specific fuel consumption using common gasoline, premium gasoline and Podium gasoline have shown similar results, both for urban and road driving cycles / Os ve?culos flex s?o equipados com um motor de combust?o interna do ciclo Otto e t?m como caracter?stica a capacidade de funcionar com mais de um tipo de combust?vel, misturados no mesmo tanque e queimados na c?mara de combust?o simultaneamente. Este tipo de motoriza??o ? uma tend?ncia mundial devido ? escassez do petr?leo, a comercializa??o de v?rios tipos de combust?veis, aos avan?os tecnol?gicos dos sistemas de gerenciamento eletr?nico de combust?vel e ?s restri??es as emiss?es de gases poluentes na atmosfera. No Brasil, os ve?culos flex s?o uma realidade, com destaque para os ve?culos alimentados com 20 a 25% do ?lcool anidro misturado com gasolina e os que utilizam g?s natural ou o combust?vel l?quido original (gasolina ou etanol hidratado). O FIAT SIENA TETRAFUEL, objeto da presente investiga??o, ? equipado com uma ?nica central eletr?nica capaz de gerenciar os combust?veis l?quidos ou gasoso. A pesquisa em tela teve como prop?sito a an?lise comparativa de desempenho (pot?ncia e consumo) de um ve?culo tetracombust?vel simulando ciclos de condu??o urbano e de estrada em um dinam?metro de chassi, operando com os combust?veis: gasolina comum (tipo C), gasolina aditivada (tipo C), gasolina Podium (Premium), etanol (AEHC) ou g?s natural (GNV). Foi necess?rio desenvolver bancada de testes e procedimentos de ensaios, como tamb?m conhecer o funcionamento do gerenciamento eletr?nico do ve?culo em quest?o. Os ensaios foram realizados no Laborat?rio do Centro de Tecnologias do G?s e Energias Renov?veis de acordo com a norma ABNT NBR 7024 - Ve?culos rodovi?rios leves Medi??o do consumo de combust?vel. Os resultados dos ensaios de consumo espec?fico com as gasolinas comum, aditivada e Podium resultaram em valores pr?ximos, tanto no ciclo de condu??o urbano como tamb?m no ciclo de condu??o de estrada

Made available in DSpace on 2014-12-17T15:16:03Z (GMT). No. of bitstreams: 1 MariaINN.pdf: 1641471 bytes, checksum: 418fb1ddb8d49afec9041cfbd9871221 (MD5) Previous issue date: 2009-03-18 / Background: Several studies emphasize the importance of assessing the knee function after anterior cruciate ligament (ACL) reconstruction. The influence of several variables on the function of these patients has been analyzed, but there is no consensus in the science literature. Purpose: To evaluate the correlation between the torque and balance on the knee function after ACL reconstruction. Methods: 23 males patients with ACL reconstruction were tested. The procedures of the study included analysis of concentric peak torque at 60o/s and 180o/s of quadriceps femoris and hamstring muscle with a isokinetic dynamometer. The balance in single-limb stance was measured with stabilometry. The functional performance were performed by two hop tests. To estimate the subjective function of the patients was applied Lysholm Knee Scoring Scale and a Global Rating scale. Results: The analysis of data showed a moderate positive correlation between knee extensor torque and functional performance tests (r= 0,48; p=0,02). A moderate negative correlation was found between the two variables of the stabilometry center of pressure and average speed of centre of pressure and the Global Rating scale (r = -0.4, p = 0,04 and r = -0,49, p = 0 ,02, respectively). No correlation was found between peak torque and balance in single-limb stance. Conclusion: The results of the present study suggest that knee extensor strength and postural balance have some influence on knee function in patients after ACL reconstruction / Introdu??o: Diversos estudos ressaltam a import?ncia de avaliar a fun??o do joelho ap?s a reconstru??o do Ligamento Cruzado Anterior (LCA). A influ?ncia de diversas vari?veis sobre a fun??o desses pacientes tem sido analisada, por?m ainda n?o ? encontrado um consenso na literatura. Objetivo: avaliar correla??o entre o torque e o equil?brio postural sobre a fun??o do joelho ap?s a reconstru??o do LCA. M?todos: Foram avaliados 23 pacientes do sexo masculino. Os procedimentos do estudo inclu?ram an?lise do torque conc?ntrico a 60o/s 180 o/s dos m?sculos quadr?ceps e ?squiostibiais no dinam?metro isocin?tico. O equil?brio est?tico em apoio unipodal foi avaliado sobre um baropod?metro computadorizado. A avalia??o do desempenho funcional foi feita por dois testes de salto e para estimar a fun??o subjetiva dos pacientes foi aplicado o question?rio Lysholm e uma escala de avalia??o global. Resultados: A an?lise dos dados mostrou uma correla??o positiva moderada entre o pico de torque extensor e os testes de desempenho funcional (r= 0,48; p= 0,02) e uma correla??o negativa moderada entre as vari?veis do equil?brio oscila??o do centro de press?o e velocidade m?dia do centro de press?o e a escala de avalia??o global (r= - 0,4; p= 0,04 e r= -0,49; p= 0,02, respectivamente). Nenhuma correla??o foi encontrada entre pico de torque e equil?brio em apoio unipodal. Conclus?o: Os resultados encontrados no presente estudo sugerem que a for?a extensora e o equil?brio postural t?m alguma influ?ncia na fun??o do joelho de pacientes ap?s reconstru??o de LCA

Made available in DSpace on 2014-12-17T15:16:05Z (GMT). No. of bitstreams: 1 JailsonOF.pdf: 1523651 bytes, checksum: 41f8b0fd700f378ae21791704785f8b3 (MD5) Previous issue date: 2009-04-02 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / PURPOSE: To examine the acute effects caused by three techniques for stretching the hamstrings muscle on the active concentric peak torque (PT), passive PT and electromyographic activity (EMG). METHODS: Sixty volunteers (mean ? SD age, 22.6 ? 3 years), height 1.64 ? 0.07m and body weight of 58 ? 8.6kg, were randomly allocated into 4 groups of 15 subjects: Control Group (CG) - 5 minutes at rest, Static Stretching Group (SG) - 2 x 30s; Hold-Relax Group (HRG) - 3 x 6s of isometric contraction of hamstrings interspersed by 10s of hamstrings stretching and agonist Hold-Relax Group (AHRG) - 3 x 6s of isometric contraction of the quadriceps interspersed by 10s of hamstrings stretching. Evaluation has been conducted preand post-intervention, which verified the active concentric PT, passive PT EMG activity of IT. The statistical inference was performed by testing intra and inter, significance level at 5%. RESULTS: After intervention, there was a reduction in passive PT on CG, accompanied by a reduction of EMG activity, and an increase in passive PT on SG and AHRG. There was no change in the active concentric PT, or change in EMG activity. CG showed an increase in angle of the PT active, while the other groups showed no change. CONCLUSION: The results suggest that the shortterm stretching: 1) causes acute increase in passive torque, since the muscle does not perform sub-maximal contraction, 2) does not change in electromyographic activity and active torque, ind ependent of the technique / OBJETIVO: Examinar os efeitos agudos provocados por tr?s t?cnicas de alongamento muscular sobre os isquiotibiais (IT) quanto ao pico de torque (PT) ativo conc?ntrico, PT passivo e atividade eletromiogr?fica (EMG). M?TODOS: Sessenta volunt?rias (idade m?dia ? DP, 22,6 ? 3 anos), altura de 1,64 ? 0,07 m, e peso corporal de 58 ? 8,6 Kg, foram alocadas aleatoriamente em 4 grupos de 15 sujeitos: Grupo Controle (GC) 5 minutos em repouso; Grupo Alongamento Est?tico (GE) 2 x 30s; Grupo Manter-Relaxar (GMR) 3 x 6s de contra??o isom?trica dos IT intercaladas por 10s de alongamento dos IT; e Grupo Agonista Manter-Relaxar (GAMR) 3 x 6s de contra??o isom?trica do quadr?ceps intercaladas por 10s de alongamento dos IT. Foi realizada uma avalia??o antes e ap?s a interven??o, na qual foi verificado o PT ativo conc?ntrico, PT passivo e atividade EMG dos IT. A estat?stica inferencial foi realizada por meio de testes intra e intergrupos, atribuindose o n?vel de signific?ncia de 5%. RESULTADOS: Foi constatada uma redu??o no PT passivo do GC, acompanhada de uma redu??o da atividade EMG de repouso, e um aumento do PT passivo do GE e do GAMR. N?o houve altera??o no PT ativo conc?ntrico, nem altera??o na atividade EMG. O GC apresentou aumento no ?ngulo do PT ativo, enquanto os demais grupos n?o apresentaram altera??o. CONCLUS?O: Os resultados sugerem que o alongamento de curta-dura??o: 1) provoca aumento agudo do torque passivo, desde que o m?sculo n?o realize contra??o sub-m?xima; 2) n?o provoca altera??o da atividade eletromiogr?fica nem do torque ativo, indepentente da t?cnica utilizada.

Made available in DSpace on 2014-12-17T15:16:06Z (GMT). No. of bitstreams: 1 RobsonAS.pdf: 4092657 bytes, checksum: bfcb1dfee12e404a9e060942b5799125 (MD5) Previous issue date: 2009-07-31 / The Patellofemoral pain syndrome is defined as a fore or retro patellar pain and it has multifactorial etiology, where the bad patellar alignment is the most acceptable hypothesis. However proximal factors to the knee, as the debility of the muscles of the hip, have been demonstrated as a contributing factor to the appearing of that syndrome. Purpose: To evaluate if exists a relation between the hip muscles performance and the development of the SDPF. Methods: Thirty women took part in this study. They were divided in two groups; a control group (fifteen asymptomatic subjects) and an experimental group (fifteen subjects with the diagnosis of SDPF). The muscle performance was evaluated in an isokinetic dynamometer, where it was verified the peak torque (PT), PT to body weight, PT time and the agonist/antagonist relation. It was also analyzed the electromyographic activity of the middle gluteus. The data was analyzed by the not paired t test at a significance level of 5%. Results:. Didn t have significant difference to the PT of the abductor muscles (p = 0,46) and lateral rotators of the hip (p = 0,17) between groups. Also didn t have significant difference to the PT values by the body weight, to these muscle groups either (p = 0,10 e p = 0,11, respectively). Didn t have significant difference between the amplitude of the signal (p = 0,05) and the onset of medium gluteus (p = 0,25) between the groups. Conclusion: In the experimental conditions realized, the study didn t demonstrate a relation between performance the hip muscles behavior and the development of the SDPF / A S?ndrome da Dor Patelofemural (SDPF) ? definida como uma dor anterior ou retropatelar e possui etiologia multifatorial, onde o mau-alinhamento patelar ? a hip?tese mais comumente aceita. Entretanto fatores proximais ao joelho, como a debilidade dos m?sculos do quadril, t?m sido sugerido como um fator contribuinte ao surgimento desta s?ndrome. Objetivo: Avaliar se existe rela??o entre a performance dos m?sculos do quadril e o desenvolvimento da SDPF. M?todos: Participaram do estudo 30 mulheres alocadas em um grupo controle (15 sujeitos assintom?ticos) e um grupo experimental (15 sujeitos com diagn?stico de SDPF). A performance muscular foi avaliada em um dinam?metro isocin?tico, onde verificou-se o Pico de Torque (PT), PT pelo peso corporal, tempo do PT e a rela??o agonista/antagonista. Tamb?m foi analisada a atividade eletromiogr?fica do gl?teo m?dio. Os dados foram analisados atrav?s do teste t n?o pareado com um n?vel de signific?ncia de 5%. Resultados: N?o houve diferen?a significativa entre o PT dos m?sculos abdutores (p = 0,46) e rotadores laterais do quadril (p = 0,17) entre os grupos. Tamb?m n?o foi encontrada diferen?a significativa no PT pelo peso corporal, para esses grupos musculares (p = 0,10 e p = 0,11, respectivamente). N?o houve diferen?a entre a amplitude do sinal eletromiogr?fico (p = 0,05) e o onset do gl?teo m?dio (p = 0,25) entre os grupos. Conclus?o: Nas condi??es experimentais realizadas, o estudo n?o demonstrou rela??o entre a performance dos m?sculos do quadril e o desenvolvimento da SDPF

Made available in DSpace on 2014-12-17T15:16:10Z (GMT). No. of bitstreams: 1 IvyMA_DISSERT.pdf: 2126733 bytes, checksum: aea8af9b37264ffb195f4cd5cb711294 (MD5) Previous issue date: 2010-12-01 / To evaluate the effects of warm-up and stretching, singly or combined, on isokinetic performance and electromyographic activity of the biceps femoris. Materials and methods: Sixty-four volunteers of both sexes, with mean age of 23,1 ? 3,5 years and mean body mass index of 23,5 ? 2,5 Kg/m2 were randomly assigned into 4 groups: control, warm-up (stationary bicycle for 10 minutes), stretching (4 sets of 30 seconds of hamstring muscles static stretching) and warm-up + stretching. All the volunteers were submitted to evaluation pre and post-intervention of the muscle latency time and biceps femoris RMS and the passive torque, peak torque and power of the hamstring muscles. Results: The warm-up + stretching group had reduction of muscle latency time. There was a reduction of RMS during passive torque evaluation in stretching group. The RMS during isometric evaluation was reduced in all experimental groups. The RMS during eccentric evaluation showed reduction in control and warm-up + stretching groups. The passive torque and the eccentric peak torque had no significant differences pre to post-intervention in any group. There was reduction in isometric peak torque in all groups. Conclusion: The warm-up and stretching, when applied in combination can reduce the muscle latency time; stretching protocol promoted neural changes; the protocols used did not alter the muscle viscoelastic properties / Avaliar os efeitos do aquecimento e do alongamento, isolados ou associados, no desempenho isocin?tico e na atividade eletromiogr?fica do m?sculo b?ceps femoral. Materiais e m?todos: Sessenta e quatro volunt?rios de ambos os sexos, com idade m?dia de 23,1 ? 3,5 anos e ?ndice de massa corporal m?dio de 23,5 ? 2,5 Kg/m2 foram aleatoriamente distribu?dos em 4 grupos: controle, aquecimento (bicicleta estacion?ria por 10 min.), alongamento (4 s?ries de 30s de auto alongamento est?tico dos m?sculos isquiotibiais) e aquecimento + alongamento. Todos foram submetidos ? avalia??o pr? e p?s-interven??o do tempo de lat?ncia muscular e da RMS do m?sculo b?ceps femoral e do torque passivo, pico de torque e pot?ncia dos m?sculos isquiotibiais. Resultados: No grupo aquecimento + alongamento houve redu??o do tempo de lat?ncia muscular. Houve redu??o da RMS durante a avalia??o do torque passivo no grupo alongamento. A RMS durante a avalia??o isom?trica foi reduzida em todos os grupos experimentais. A RMS na avalia??o exc?ntrica apresentou redu??o nos grupos controle e aquecimento + alongamento. O torque passivo e o pico de torque exc?ntrico n?o apresentaram diferen?as significativas pr? e p?s-interven??o em nenhum grupo. Houve redu??o do pico de torque isom?trico em todos os grupos. Conclus?o: O aquecimento e o alongamento, quando aplicados em associa??o podem reduzir o tempo de lat?ncia muscular; o protocolo de alongamento promoveu altera??es neurais; os protocolos empregados n?o alteraram as propriedades viscoel?sticas do m?sculo