Made available in DSpace on 2014-06-11T19:28:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-12-16Bitstream added on 2014-06-13T19:16:51Z : No. of bitstreams: 1 ribeiro_dg_me_arafo.pdf: 507473 bytes, checksum: 1c6ba03d7141c053da8a5a15fc65d0c1 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O uso do microondas tem sido indicado como um método efetivo na desinfecção de resinas acrílicas. Entretanto, há pouca informação sobre o efeito da irradiação do microondas nas propriedades mecânicas desses materiais. Considerando esses aspectos, o objetivo deste estudo foi avaliar o efeito da irradiação por microondas sobre as propriedades mecânicas de resistência à flexão e dureza de resinas acrílicas. Os corpos-de-prova para a realização dos testes mecânicos foram confeccionados com os seguintes materiais: Kooliner (K), Tokuso Rebase Fast (TR), Ufi Gel Hard C (UGH) e New Truliner (NT), todas resinas indicadas para reembasamento imediato, e Lucitone 550 (L), que é uma resina para base de prótese. Para cada material foram confeccionados 48 corpos-de-prova que foram divididos igualmente em seis grupos. As resinas autopolimerizáveis (K, TR, UGH e NT) foram submetidas à irradiação logo após a confecção, enquanto que os corpos-de-prova da resina termopolimerizável (L) permaneciam 50 l 2 horas em água a 37ºC l 1ºC antes da irradiação. Para o procedimento de irradiação, cada corpo-de-prova foi individualmente imerso em 200 mL de água destilada e submetido a dois ciclos de irradiação pelas microondas, para simular o envio da prótese ao laboratório e o retorno dela ao consultório odontológico. Cada corpo-de-prova foi irradiado a uma potência constante de 650 W, variando-se o tempo de exposição: 1 minuto (T1), 2 minutos (T2), 3 minutos (T3), 4 minutos (T4) ou 5 minutos (T5). O grupo controle (T0) foi submetido aos testes mecânicos sem ser irradiado pelas microondas. Os ensaios de resistência à flexão para todos os corpos-de-prova foram realizados em máquina MTS-810 Material Test System sob velocidade de 5 mm/minuto, utilizando o teste em três pontos a uma distância de 50 mm entre os apoios. Em seguida, um dos fragmentos do... / Microwave irradiation was previous suggested as an effective method for the disinfection of acrylic resins. However, little information is available concerning the effect of microwave irradiation on the mechanical properties of acrylic resins. The purpose of this study was to evaluate the effect of two cycles of a microwave disinfection procedure on the flexural strength and Vickers hardness of acrylic resins. Four autopolymerized resins (Kooliner- K, Tokuso Rebase Fast- TR, Ufi Gel Hard- UGH and New Truliner- NT) and one heat-cured resin (Lucitone 550- L) were used for preparing specimens. For each material, 48 specimens were made and equally divided into six groups. The relined specimens were submitted to disinfection procedures after polymerization and the denture base polymer specimens were stored in water for 50 l 2 hours at 37ºC l 1ºC prior to disinfection. The specimens were individually immersed in 200 mL of destilated water and microwaved twice, simulating when dentures come from the patient and before being returned to the patient. Each cycle of microwave disinfection was performed at 650 W for one of the following irradiation times: 1 minute (T1), 2 minutes (T2), 3 minutes (T3), 4 minutes (T4) or 5 minutes (T5). Control group (T0) specimens were subjected to mechanical tests without being disinfected. The flexural strength values of the materials were determined using a testing machine MTS-810 at a crosshead speed of 5 mm/minute using a three-point bending fixture with a span of 50 mm. Thereafter, one fragment of specimen was submitted to Vickers microhardness test. The values were determined by using a 25 gf load, after 30 seconds contact. Twelve hardness measurements were taken on each specimen and the average was then calculated. The flexural and hardness values were submitted to ANOVA and ...(Complete abstract, click electronic access below)

No description available.

Orientador: Nilson Cristiano da Cruz / Banca: Roberto Martins de Souza / Banca: Maria Eliziane Pires de Souza / O programa de Pós graduação em Ciencia e Tecnologia de Materiais, PosMat, tem carater institucional e integra as atividades de pesquisa em materiais de diversos campi da UNESP / Resumo: Apesar da excelente relação resitência/peso das ligas de alumínio, a aplicação tecnológica destas ligas é limitada pela baixa resistência ao desgaste. Neste trabalho, amostras de uma liga de alumínio (AA 5052) foram tratadas pelo processo de oxidação por plasma eletrolítico, com tempo de exposição variando de 150 a 900 s. A composição e a estrutura química dos revestimentos assim produzidos foram analisadas por espectroscopia de absorção no infravermelho. Um método baseado na medida de correntes parasitas e a perfilometria foram usados, respectivamente, na determinação da espessura e da rugosidade das camadas depositadas. O revestimento formado porssui espessura de até 9,2um. Análises da morfologia dos revestimentos foram feitas com microscopia eletrônica de varredura enquanto a resistência a desgastte das superfícies foi avaliada com um sistema pino-sobre-disco. Os resultados revelaram a deposição de um revestimento cerâmico, que conferiu expressivo aumento à resistência a desgaste da liga, o qual mostrou que as amostras tratadas suportaram uma carga aplicada de 13,44 vezes em comparação com amostras sem tratamento / Abstract: Despiste the excellent strengh/weight ratio, technological applications of aluminum aloys are limited by their low wear resistance. In this work, samples of AA 5052 aluminum alloy have been modified by plasma electrolytic oxidation, with exposure time ranging from 150 s to 900 soconds. Compositional characterization has been performed by fourier transform infrared spectroscopy. Eddy current and profilometry have been used, respectively, to evaluate thickness and roughness of the deposited layers. The coating formed has a thickness of up to 9,2 micrometers. Morphological investigations have been performed with scanning electron microscopy while wear resitance has been assessed using a pin-on-disk devide. The results have revealed the deposition of ceramic layers with significant enhancement of wear resistance, which showed that the treated samples resistance, which showed that the treated samples resist an applied load 13.44 times more compared with untreated samples / Mestre

No description available.

Muscle function after exercise-induced muscle damage has traditionally been evaluated by measures of isometric strength at a single joint angle or muscle length. The thesis investigates the effect of muscle damage on other muscle function parameters such as, isometric strength as a function of muscle length, concentric strength as a function of angular velocity, strength across muscle actions, the stretch-shortening cycle, power output, and fatigability. Study 1 The first part of this study aimed to determine how the muscle length at which strength is measured affects reductions in isometric strength following eccentric exercise-induced muscle damage. The damaging exercise protocol consisted of 100 maximal voluntary eccentric actions of the knee extensors, performed in the prone position through a range of motion from 40° to 140° (0° = full extension) at an angular velocity of 90 deg's-1. Isometric strength of the knee extensors was measured at short muscle length (10° knee flexion) and optimal length (80°). A significantly greater relative loss of strength was observed at short versus optimal muscle length (76.3 ± 2.5% vs. 82.1 ± 2.7% of pre-exercise values, P<0.05) over the seven day testing period following eccentric exercise. The second part of the study investigated isometric strength at optimal length and concentric strength at slow (30 deg's 1) and fast (180 deg's 1) angular velocities of movement. No differences were apparent in the magnitude and rate of recovery of strength across isometric (82.1 ± 2.7%) and slow (86.6 ± 2.0%) and fast (84.3 ± 1.5%) concentric muscle actions. Both the popping sarcomere hypothesis of 2 muscle damage and a failure in excitation-contraction coupling are possible explanations for the reduction in strength being affected by the muscle length at which it is measured. Both would be expected to affect strength to a greater extent at short versus optimal muscle lengths. Study 2 The second study investigated knee extensor muscle strength during isometric, concentric and eccentric muscle actions and vertical jump performance under conditions of squat jump (SJ), countermovement jump (CMJ) and drop jump (DJ). These measures were taken before, 1 hour after, and on days 1,2,3,4 and 7 following a damaging exercise protocol consisting of 100 barbell squats (10 sets x 10 reps @ 70% body mass load). Strength was significantly reduced for four days, however, no differences were observed in the magnitude or rate of recovery of isometric strength at 80° knee flexion and concentric and eccentric strength at 90 deg's'. Vertical jump performance was significantly reduced for three days and was dependent on the type of jump being performed. The relative decline in SJ performance was significantly greater than that in CMJ performance (91.6 ± 1.1% vs. 95.2 ± 1.3% of pre-exercise values, P<0.05) and the relative decline in SJ was significantly greater than that in DJ performance (91.6 ± 1.1% vs. 95.2 ± 1.4%, P<0.05). No differences were observed in the relative decline in CMJ and DJ performance (95.2 ± 1.3% vs. 95.2 ± 1.4%, P> 0.05). The stretch-shortening cycle (SSC) of muscle function is utilised in CMJ and DJ but not in SJ. The SSC has a clear purpose: to allow the final phase (concentric action) to take place with greater force or power output, as compared to the condition where the movement is initiated by a concentric action alone. 3 Utilisation of the SSC in performance seems to attenuate the detrimental performance effects of exercise-induced muscle damage. Study 3 The third and final study investigated the effects of exercise-induced muscle damage on maximal power output and knee extensor fatigability under isometric and dynamic conditions. Under isometric conditions, strength was assessed at 40° and 80° knee flexion and fatigability was assessed by a sustained 60s maximum voluntary contraction (MVC) at each joint angle. For dynamic conditions, maximum power output and fatigue were assessed during a maximal 30s cycle ergometer test. These measures were taken before, 1 hour after, and on days 1,2,3, and 7 following a damaging exercise protocol consisting of 100 eccentric squats (10 sets x 10 reps @ 80% concentric 1 RM). Isometric strength was significantly reduced (P < 0.05) for seven days but no significant differences were observed in the magnitude of strength loss and the pattern of recovery between the two joint angles. Fatigability was quantified as the slope (b) of a linear regression line fitted to the torque and power decay during the 60s MVC and the 30s cycle test, respectively. Prior to muscle damage, subjects were significantly less fatigable (P < 0.05) at 40° (b = -2.39 ± 0.26) versus 80° (b = -5.50 ± 0.72). After muscle damage, subjects became significantly less fatigable at both 40° and 80° with recovery taking three days at 401 and seven days at 80°. Before damaging exercise, a greater rate of fatigue was observed under dynamic (b = -12.75 ± 2.3) versus isometric (80°) conditions (b = -5.50 ± 0.72). Isometric and dynamic fatigue 4 followed a similar temporal pattern after damaging exercise. When the effects of muscle damage on strength at 801 and maximal power output were compared, differences in the extent of performance loss and the time course of recovery were observed. At 1 hour post-exercise, strength was affected to a greater extent (30% reduction) than power (13% reduction) and whereas strength followed a linear recovery pattern, power suffered further decrements at day 1 (18%) and day 2 (16%) before starting to recover. The results indicate that under conditions of voluntary activation muscle becomes weaker but less fatigable under isometric and dynamic conditions following exercise-induced muscle damage. The lower starting torque / power output and the slower rate of decline in torque / power output observed in post-damage fatigue curves may be a phenomenon of selective type II fibre damage. Evidence suggests that type II fibres are selectively damaged during eccentric exercise and therefore post-damage fatigue curves may be missing their contribution to performance. The different recovery patterns observed for isometric and dynamic performance may indicate an inability to maintain central motor drive during complex dynamic tasks when damage is present.

Made available in DSpace on 2014-06-11T19:34:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-11-30Bitstream added on 2014-06-13T20:05:58Z : No. of bitstreams: 1 cunha_mgs_dr_guara.pdf: 2456684 bytes, checksum: 35c3e64f73a4469232f7849a6e313dfa (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os músculos estriados esqueléticos, através de suas propriedades de contratilidade, extensibilidade e elasticidade, formam o principal motor das articulações nos seres humanos, através da tração exercida no tendão ou na aponeurose. Os músculos controlam, coordenam e realizam os movimentos articulares. A força produzida pelos músculos pode ser estimada através das alavancas realizadas pelo membro, considerando-se o torque de cada força, quando o músculo se contrai, parte da energia desta contração será dissipada na forma de som. A presente pesquisa tem como objetivo principal desenvolver um sistema para avaliar o sinal acústico muscular e comparar com a força produzida em uma célula de carga pela alavanca do membro superior. Os músculos selecionados para esta pesquisa foram os flexores do cotovelo, pela facilidade de acesso e de posicionamento. Foram coletados os sinais acústicos e do esforço realizado de 16 indivíduos de ambos os sexos, sendo 9 do sexo masculino e 7 do sexo feminino, saudáveis, com idade entre 18 e 35 anos, sem histórico de doenças neurológicas, cardiovasculares, não praticantes de atividade física que produzisse a hipertrofia dos músculos flexores do cotovelo. Foi desenvolvido um sistema para avaliação do sinal acústico muscular utilizando como sensor um estetoscópio adaptado com um microfone, simultaneamente à aquisição do torque produzido pelos flexores do cotovelo e avaliado por uma célula de carga. A presente pesquisa permitiu identificar que as principais freqüências acústicas da contração dos flexores do cotovelo estão na faixa de 10 a 15 Hz quando a contração equivale de 75 a 100% da força máxima para o sexo feminino e de 50 a 100 % da força máxima para o sexo masculino e na faixa de 5 a 10 Hz quando a contração equivale de 25 a 50 % da força máxima para o sexo feminino e 25 % da força máxima para o sexo masculino... / Striated skeletal muscles, through their properties of contractility, extensibility and elasticity, are the main driver of the joints in humans, through the traction exerted on the tendon or aponeurosis, muscle control, coordinate and carry out joint movements. The force produced by muscles can be estimated using from the levers held by the member, considering the torque of each force when the muscle contracts, this contraction of the energy is dissipated in the form of sound. The main objective of this research is to develop a system to evaluate the acustic signal and compare it with the muscular force produced in a load cell by the lever of the upper limb. The muscles selected for this research were elbow flexors, because of the easy access and positioning. Acoustic signals were collected and the effort made to 16 individuals of both sexes. We analyzed 9 male and 7 female, healthy and aged between 18 and 35 years old with no history of neurological and cardiovascular disease and not engaged in physical activity that could develop hypertrophy of the elbow flexor muscles. A system was developed for evaluation of the acoustic signal using muscle as a sensor adapted stethoscope with a microphone, simultaneously with the aquisition of the torque produced by the elbow flexor and evaluated by a load cell. This research has identified that the main acoustic frequencies of contraction of the elbow flexors are in the range of 10 to 15 Hz when the contraction equals 75 to 100% of maximum force for females and 50 to 100% of maximum force to males and in the range 50 to 10 Hz when the contraction equals 25 to 50% of maximum force for females and 25% of maximum force for males, as well as the correlation of the acoustic signals of males female with a coefficient less than 4. It was concluded that the acoustic signal muscle has specific characteristics for different levels of intensity of muscle... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:22:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-06-15Bitstream added on 2014-06-13T20:49:25Z : No. of bitstreams: 1 ruas_vda_me_rcla.pdf: 912357 bytes, checksum: 39029679087dd76e4d8e693443be7ed4 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Em muitos programas de condicionamento físico ou de treinamento esportivo, os indivíduos têm de realizar exercícios aeróbios e de força na mesma sessão. No entanto, o treinamento concorrente demanda adaptações específicas para a melhora do rendimento aeróbio e do rendimento de força, e pode, dependendo das condições que forem realizados, comprometerem o rendimento da força. Portanto, os objetivos deste estudo foram: a) Analisar o efeito do exercício aeróbio realizado no ciclismo sobre a força muscular subseqüente, e; b) Verificar se o efeito do exercício aeróbio prévio é dependente do tipo de exercício de força realizado. Doze indivíduos do gênero masculino fisicamente ativos (23 l 3,7 anos, 77,2 l 8,9 kg, 179,3 l 4 cm, 14,34 l 2,99% gordura) executaram 2 testes incrementais até a exaustão em diferentes cadências de pedalada (50 rev.min-1 e 100 rev.min-1) para determinação do LAn, e um protocolo para a determinação da carga equivalente a 10 repetições máximas (10RM) em um aparelho leg-press 45°. Após a realização destes, os mesmos executaram três séries de repetições máximas com a carga de 10RM no leg-press (L) ou três séries de 10 saltos máximos em uma plataforma de saltos (S), nas seguintes condições: 1) Controle (LC e SC); 2) L50 e S50 após a realização de um exercício de 30 minutos no LAn na cadência de 50 rev.min-1; 3) L100 e S100 após a realização de um exercício de 30 minutos no LAn na cadência de 100 rev.min-1. Houve uma redução significante do número de repetições na primeira série nas condições L50 (10 l 1) e L100 (9 l 2) em relação à LC (12 l 2), e na terceira série na condição L100 (6 l 2) comparada à LC (9 l 1). Houve uma redução significante na altura média de saltos... / In several physical conditioning and sports training programs, individuals have to perform aerobic and strength exercises in the same training session. However, the concurrent training demands specific adaptations to the improvement of aerobic and strength performance and, depending of the conditions which they are performed, the strength performance can be compromised. Thus, the purposes of this study were: a) To analyze the effect of aerobic exercise performed in cycling on subsequent muscular strength, and; b) To analyze if the effect of previous aerobic exercise is dependent on the type of the strength exercise. Twelve active males (23 l 3.7 years, 77.17 l 8.86 kg, 179.33 l 4.03 cm, 14.34 l 2.99% body fat) performed 2 incremental tests until exhaustion in different pedal cadences (50 rev.min-1 and 100 rev.min-1) to in order to determine the anaerobic threshold (AT), and a protocol to determine the workload corresponding to 10 maximal repetitions (10RM) in leg press 45°. Then, they performed 3 sets of maximal repetitions with workload of 10RM in leg press (L) or 3 sets of 10 maximal countermovement jumps in a contact plate (S), in the following conditions: 1) Control (LC and SC); 2) L50 and S50 after 30 minutes of cycling at AT and pedal cadence of 50 rev.min-1; 3) L100 and S100 after 30 minutes of cycling at AT and pedal cadence of 100 rev.min-1. There was a significant reduction on the number of repetitions performed in the first set at the conditions L50 (10 l 1) and L100 (9 l 2) in relation to LC (12 l 2), and in the third set at the condition L100 (6 l 2) compared to LC (9 l 1). There was a significant reduction in the mean jump height in the first (29.0 l 4.1 cm) and third (29.1 l 2.9 cm) sets at S50 in relation to SC (32.0 l 3.3 cm and 31.8 l 2.9 cm, respectively). Thus, at these... (Complete abstract click electronic access below)

Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2006. / Welded joints are major causes for concern in the engineering arena for two basic reasons. In the first instance the weld is known to be a region of weakness within a structure and is caused by residual and applied stress concentrations. Secondly, the behaviour of the stress patterns is somewhat difficult to predict accurately due to the difficulty of conforming to the geometry and process parameters. The experimental procedure in this work commenced with specimens being welded with a technique very commonly used in industry. The residual stresses generated by thermal fluctuations from the welding process cannot be predicted easily and is viewed as a problem as increased stress levels promotes failure. Residual stresses were then determined with the use of an ultrasonic stress measuring device. Strain gauges were used to measure strains in the welded specimens and these strains converted to stresses. The results of the two methods were compared and analysed. Compact tensile specimens were used to perform fatigue testing. The results confirmed findings from earlier research such as the proportion of cyclic life spent on initiating the crack. Hardness tests were performed to determine if any relationship existed between fatigue failure, yield strength and hardness. Finally metallurgical analysis revealed the phases and structures of the weld and heat-affected zones. The findings of this research indicate that close relationships exist between the cycles to crack initiation and ultimate fracture, the hardness, yield stress and the fatigue life of the weld as well as between the grain diameter and the yield stress. Furthermore it is shown that there was not enough information gathered in this research to conclude that the life expectancy of 300WA welded steel can be predicted. However recommendations are made for future research in the prediction of failure of the 300WA welded steel.

Orientador: Camila Coelho Greco / Banca: Emerson Franchini / Banca: Mauro Gonçalves / Resumo: Em muitos programas de condicionamento físico ou de treinamento esportivo, os indivíduos têm de realizar exercícios aeróbios e de força na mesma sessão. No entanto, o treinamento concorrente demanda adaptações específicas para a melhora do rendimento aeróbio e do rendimento de força, e pode, dependendo das condições que forem realizados, comprometerem o rendimento da força. Portanto, os objetivos deste estudo foram: a) Analisar o efeito do exercício aeróbio realizado no ciclismo sobre a força muscular subseqüente, e; b) Verificar se o efeito do exercício aeróbio prévio é dependente do tipo de exercício de força realizado. Doze indivíduos do gênero masculino fisicamente ativos (23 l 3,7 anos, 77,2 l 8,9 kg, 179,3 l 4 cm, 14,34 l 2,99% gordura) executaram 2 testes incrementais até a exaustão em diferentes cadências de pedalada (50 rev.min-1 e 100 rev.min-1) para determinação do LAn, e um protocolo para a determinação da carga equivalente a 10 repetições máximas (10RM) em um aparelho leg-press 45°. Após a realização destes, os mesmos executaram três séries de repetições máximas com a carga de 10RM no leg-press (L) ou três séries de 10 saltos máximos em uma plataforma de saltos (S), nas seguintes condições: 1) Controle (LC e SC); 2) L50 e S50 após a realização de um exercício de 30 minutos no LAn na cadência de 50 rev.min-1; 3) L100 e S100 após a realização de um exercício de 30 minutos no LAn na cadência de 100 rev.min-1. Houve uma redução significante do número de repetições na primeira série nas condições L50 (10 l 1) e L100 (9 l 2) em relação à LC (12 l 2), e na terceira série na condição L100 (6 l 2) comparada à LC (9 l 1). Houve uma redução significante na altura média de saltos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In several physical conditioning and sports training programs, individuals have to perform aerobic and strength exercises in the same training session. However, the concurrent training demands specific adaptations to the improvement of aerobic and strength performance and, depending of the conditions which they are performed, the strength performance can be compromised. Thus, the purposes of this study were: a) To analyze the effect of aerobic exercise performed in cycling on subsequent muscular strength, and; b) To analyze if the effect of previous aerobic exercise is dependent on the type of the strength exercise. Twelve active males (23 l 3.7 years, 77.17 l 8.86 kg, 179.33 l 4.03 cm, 14.34 l 2.99% body fat) performed 2 incremental tests until exhaustion in different pedal cadences (50 rev.min-1 and 100 rev.min-1) to in order to determine the anaerobic threshold (AT), and a protocol to determine the workload corresponding to 10 maximal repetitions (10RM) in leg press 45°. Then, they performed 3 sets of maximal repetitions with workload of 10RM in leg press (L) or 3 sets of 10 maximal countermovement jumps in a contact plate (S), in the following conditions: 1) Control (LC and SC); 2) L50 and S50 after 30 minutes of cycling at AT and pedal cadence of 50 rev.min-1; 3) L100 and S100 after 30 minutes of cycling at AT and pedal cadence of 100 rev.min-1. There was a significant reduction on the number of repetitions performed in the first set at the conditions L50 (10 l 1) and L100 (9 l 2) in relation to LC (12 l 2), and in the third set at the condition L100 (6 l 2) compared to LC (9 l 1). There was a significant reduction in the mean jump height in the first (29.0 l 4.1 cm) and third (29.1 l 2.9 cm) sets at S50 in relation to SC (32.0 l 3.3 cm and 31.8 l 2.9 cm, respectively). Thus, at these... (Complete abstract click electronic access below) / Mestre

Orientador: Marilza Vieira Cunha Rudge / Resumo: Objetivo - Determinar a influência da via de parto na força muscular do assoalho pélvico (AP) de primíparas, 4 a 6 meses pósparto. Sujeitos e Métodos - Estudo clínico, de corte transversal, para avaliar a função da musculatura do AP pelo teste da AFA e perineômetro pneumático e classificada em: zero - ausência de contração muscular, um - contração leve, dois - contração moderada não sustentada por 6 segundos e, três - contração normal sustentada por 6 segundos. As 94 mulheres, tinham entre 20 e 30 anos, foram divididas em 3 grupos de acordo com a via de parto: I com 32 primíparas pós-parto vaginal; II com 32 primíparas pós-parto cesárea e III com 30 nulíparas que serviram como grupo controle. A variável independente foi a via de parto e a dependente a força muscular do AP(1). Resultados e conclusões - A mediana e o 1º e 3º quartís da força muscular do AP foram menores (p=0.01) pós-parto vaginal (2.0;1-2) e intermediária pós-parto cesárea (2.0; 2-3) em relação as nulíparas (3.0;2-3) pelo AFA e perineômetro. Aumentou o risco relativo(RR) de exame alterado da força da musculatura do AP pós-parto vaginal (RR=2.579 IC 95%=1.32-5.04 p=0.002); (RR=2.31 IC 95%=1.24- 4.32 p=0.005) e pós-cesárea (RR=1.56 IC 95% = 0.94-2.57 p=0.12); (RR=1.38 IC 95%=0.85-2.23 p=0.29) pela AFA e perineômetro. O parto vaginal diminuiu a força muscular do AP de primíparas e comparando com a cesárea e as nulíparas. / Abstract: Objective - To evaluate the influence of the route of delivery on pelvic floor (PF) muscle strength, in primiparous patients at 4 to 6 months after delivery. Subjects and methods - A cross-sectional study was undertaken among primiparous women at 4 to 6 months postpartum to evaluate the PF muscle strength by AFA test and pneumatic perineometer, classified in: zero - lack of muscle contraction; one - weak contraction; two - moderate contraction not sustained for 6 seconds and three - normal contraction sustained for 6 seconds. 94 enrolled patients were divided in three groups based upon prior delivery route: I) 32 vaginal delivery with singleton cephalic presentation; II) 32 cesarean delivery; and III) 30 nuliparous patients served as a control group. The independent variable was the route of delivery and the dependent one was the muscle strength of the PF. Data were subjected to Student t test to estimate the relative risk and the Kappa test(1). Results and conclusions - The three subgroups were comparable with respect to maternal age, weight, gestational age and newborn weight. The 1st and the 3rd quartiles of the route of delivery on PF muscle strength were lower (p=0.01) for vaginal delivery (n=32) (2.0;1- 2) and intermediate for cesarean (n=32) (2.0; 2-3) comparing to the nuliparous (3.0; 2-3) by AFA test and pneumatic perineometer. The altered PF muscle strength in primiparous were significantly lower in the vaginal delivery group (RR=2.58, CI 95%=1.32-5.04, p=0.002); (RR=2.31, CI 95%=1.24-4.32, p=0.005); and postcesarean (RR=1.56, CI 95% = 0.94- 2.57, p= 0.12); (RR=1.38, CI 95%=0.85-2.23, p=0.29). Vaginal delivery decreases PF muscle strength when compared with caesarean delivery and control. / Mestre