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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Adaptações morfofuncionais e respostas moleculares do músculo esquelético de ratos submetidos ao treinamento resistido

Aguiar, Andreo Fernando [UNESP] 28 February 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:30:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-28Bitstream added on 2014-06-13T19:19:46Z : No. of bitstreams: 1 aguiar_af_dr_botib.pdf: 679778 bytes, checksum: c5aff2254c12cb4b62de64431ebf700b (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Embora fortes evidências demonstrem que os fatores de regulação miogênica (MRFs) e o fator de crescimento semelhante à insulina (IGF-I) apresentem um importante papel na resposta hipertrófica após treinamento resistido (TR) agudo, permanece desconhecido se a resposta dos MRFs e IGF-I também ocorre durante a adaptação ao TR a longo-prazo. Portanto, o objetivo deste estudo foi testar a hipótese de que a resposta hipertrófica e modulação das fibras do músculo esquelético após TR a longo-prazo poderia estar associada ao aumento na expressão gênica dos MRFs e IGF-I. Ratos Wistar (80 dias de idade, 250-300 g) foram divididos em quatro grupos: Controle 8 semana (C8, n = 8), Treinado 8 semanas (T8, n = 8), Controle 12 semanas (C12, n = 8) e Treinado 12 semanas (T12, n = 8). Os grupos T8 e T12 foram submetidos a um programa de TR progressivo (3 dias/semana) durante 8 e 12 semanas, respectivamente. O protocolo de treinamento consistiu de quatro séries de 10-12 repetições, com um período de descanso de 40 segundos entre cada série, realizado a 65-75% de uma repetição máxima (1RM). Ao término do experimento, os animais foram sacrificados e o músculo plantar coletado para as análises morfológica e molecular. O TR durante 8 e 12 semanas não promoveu qualquer alteração (p > 0,05) significante no ganho de peso corporal e consumo alimentar dos grupos T8 e T12 em relação aos grupos C8 e C12, respectivamente. Após 8 e 12 semanas de TR, a força absoluta (T8: 69,7% and T12: 126,0%, p < 0,05) e relativa (T8: 36,1% and T12: 57,7%, p < 0,05) foi significantemente elevada nos grupos T8 e T12, em comparação aos seus respectivos controles. No entanto, houve um similar aumento da área de secção transversal (AST) das fibras musculares (T8: 29% vs. T12: 35%, p > 0,05) entre os grupos T8 e T12, comparados aos grupos C8 e C12, respectivamente... / Although strong evidence show that the myogenic regulatory factors (MRFs) and insulin-like growth factor (IGF-I) have important roles in the hypertrophy response after acute resistance training, it is still unclear if response of MRFs and IGF-I also occurs during the adaptation to prolonged periods of resistance training (RT). Therefore, the purpose of this study was to test the hypothesis that fiber-types transition and hypertrophy during long-term RT could be associated with increased MRFs and IGF-I mRNA expression in the skeletal muscle. Male Wistar rats (80 days old, 250-300 g) were divided into four groups: 8 weeks control (C8, n = 8), 8-weeks trained (T8, n = 8), 12-weeks control (C12, n = 8), 12-weeks trained (T12, n = 8). T8 and T12 groups were submitted to a progressive RT program (3 day/week) for 8 and 12 weeks, respectively. The training protocol consisted of four sets of 10–12 repetitions, with a 40 s rest period between each set, performed at 65–75% of one repetition maximum (1RM). At the end of the experiment, animals were sacrificed and the plantaris muscle collected for morphological and molecular analysis. The RT did not change (p > 0.05) in body weight gain and food intake in the T8 and T12 compared to the C8 and C12 groups, respectively. After 8 and 12 weeks of RT, the absolute (T8: 69.7% vs. T12: 126.0%; p < 0.05) and relative (T8: 36.1% vs. T12: 57.7%; p < 0.05) strength (relative 1RM) was significantly elevated in the T8 e T12 groups, compared to respective control groups. RT for 8 and 12 weeks induced similar increase in myogenin (T8: 44.8% vs. T12: 37.7%; p > 0.05), MyoD (T8: 22.9% vs. T12: 22.3%; p > 0.05) and muscle fiber crosssectional area (CSA) (T8: 29% vs. T12: 35%; p > 0.05) in the T8 and T12, compared to C8 and C12 groups, respectively. After 8 weeks of RT, IGF-I increased in 30.1% in the T8 compared to C8 group, but returned to baseline after 12 weeks... (Complete abstract click electronic access below)
2

Adaptações morfofuncionais e respostas moleculares do músculo esquelético de ratos submetidos ao treinamento resistido /

Aguiar, Andreo Fernando. January 2011 (has links)
Orientador: Maeli Dal Pai Silva / Banca: Claudio Alexandre Gobatto / Banca: Selma Maria Michelin Mateus / Banca: André Soares Leopoldo / Banca: Robson Francisco Carvalho / Resumo: Embora fortes evidências demonstrem que os fatores de regulação miogênica (MRFs) e o fator de crescimento semelhante à insulina (IGF-I) apresentem um importante papel na resposta hipertrófica após treinamento resistido (TR) agudo, permanece desconhecido se a resposta dos MRFs e IGF-I também ocorre durante a adaptação ao TR a longo-prazo. Portanto, o objetivo deste estudo foi testar a hipótese de que a resposta hipertrófica e modulação das fibras do músculo esquelético após TR a longo-prazo poderia estar associada ao aumento na expressão gênica dos MRFs e IGF-I. Ratos Wistar (80 dias de idade, 250-300 g) foram divididos em quatro grupos: Controle 8 semana (C8, n = 8), Treinado 8 semanas (T8, n = 8), Controle 12 semanas (C12, n = 8) e Treinado 12 semanas (T12, n = 8). Os grupos T8 e T12 foram submetidos a um programa de TR progressivo (3 dias/semana) durante 8 e 12 semanas, respectivamente. O protocolo de treinamento consistiu de quatro séries de 10-12 repetições, com um período de descanso de 40 segundos entre cada série, realizado a 65-75% de uma repetição máxima (1RM). Ao término do experimento, os animais foram sacrificados e o músculo plantar coletado para as análises morfológica e molecular. O TR durante 8 e 12 semanas não promoveu qualquer alteração (p > 0,05) significante no ganho de peso corporal e consumo alimentar dos grupos T8 e T12 em relação aos grupos C8 e C12, respectivamente. Após 8 e 12 semanas de TR, a força absoluta (T8: 69,7% and T12: 126,0%, p < 0,05) e relativa (T8: 36,1% and T12: 57,7%, p < 0,05) foi significantemente elevada nos grupos T8 e T12, em comparação aos seus respectivos controles. No entanto, houve um similar aumento da área de secção transversal (AST) das fibras musculares (T8: 29% vs. T12: 35%, p > 0,05) entre os grupos T8 e T12, comparados aos grupos C8 e C12, respectivamente... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Although strong evidence show that the myogenic regulatory factors (MRFs) and insulin-like growth factor (IGF-I) have important roles in the hypertrophy response after acute resistance training, it is still unclear if response of MRFs and IGF-I also occurs during the adaptation to prolonged periods of resistance training (RT). Therefore, the purpose of this study was to test the hypothesis that fiber-types transition and hypertrophy during long-term RT could be associated with increased MRFs and IGF-I mRNA expression in the skeletal muscle. Male Wistar rats (80 days old, 250-300 g) were divided into four groups: 8 weeks control (C8, n = 8), 8-weeks trained (T8, n = 8), 12-weeks control (C12, n = 8), 12-weeks trained (T12, n = 8). T8 and T12 groups were submitted to a progressive RT program (3 day/week) for 8 and 12 weeks, respectively. The training protocol consisted of four sets of 10-12 repetitions, with a 40 s rest period between each set, performed at 65-75% of one repetition maximum (1RM). At the end of the experiment, animals were sacrificed and the plantaris muscle collected for morphological and molecular analysis. The RT did not change (p > 0.05) in body weight gain and food intake in the T8 and T12 compared to the C8 and C12 groups, respectively. After 8 and 12 weeks of RT, the absolute (T8: 69.7% vs. T12: 126.0%; p < 0.05) and relative (T8: 36.1% vs. T12: 57.7%; p < 0.05) strength (relative 1RM) was significantly elevated in the T8 e T12 groups, compared to respective control groups. RT for 8 and 12 weeks induced similar increase in myogenin (T8: 44.8% vs. T12: 37.7%; p > 0.05), MyoD (T8: 22.9% vs. T12: 22.3%; p > 0.05) and muscle fiber crosssectional area (CSA) (T8: 29% vs. T12: 35%; p > 0.05) in the T8 and T12, compared to C8 and C12 groups, respectively. After 8 weeks of RT, IGF-I increased in 30.1% in the T8 compared to C8 group, but returned to baseline after 12 weeks... (Complete abstract click electronic access below) / Doutor
3

Strength training and anabolic steroids : a comparative study of the vastus lateralis, a thigh muscle and the trapezius, a shoulder muscle, of strength-trained athletes /

Eriksson, Anders, January 2006 (has links)
Diss. (sammanfattning) Umeå : Umeå universitet, 2006. / Härtill 5 uppsatser.
4

Creatine uptake and creatine transporter expression among rat skeletal muscle fiber types /

Brault, Jeffrey J. January 2003 (has links)
Thesis (Ph. D.)--University of Missouri--Columbia, 2003. / "May 2003." Typescript. Vita. Includes bibliographical references (leaves 102-113).
5

Characterization of the role and regulation of the RNA binding protein HuR in muscle cell differentiation

Van der Giessen, Kate. January 2007 (has links)
Differentiation is the process of regulated gene expression that gives rise to different phenotypes from a common genotype. Skeletal muscle differentiation, myogenesis, is a good example of this process. Skeletal muscle is susceptible to injury due to direct or indirect causes. If left unrepaired, these injuries may lead to a loss of muscle mass, locomotive deficiency, and even lethality. Thus, understanding the molecular mechanisms behind this process is an important first step in the design of treatment for muscle-related diseases. Once myogenesis is induced, the expression of MRF proteins, such as MyoD and myogenin, is maintained at high levels in myofibers without the need to increase their rates of transcription, suggesting a role for post-transcriptional regulatory mechanisms. HuR is a ubiquitously expressed member of the embryonic lethal, abnormal vision (ELAV) family of RNA binding proteins that is known to post-transcriptionally regulate its target messages. Here, I demonstrate that, in the C2C12 muscle cell line, HuR is a required factor for both the initiation and maintenance of the myogenic process. First in vitro RNA Electro-Mobility Shift Assays (REMSA) and immunoprecipitation experiments demonstrated that HuR specifically binds to the AU-rich elements (AREs) that are present in the 3' untranslated regions (3'UTRs) of the MyoD and myogenin mRNAs. In the absence of HuR at the time of differentiation induction, accomplished using the siRNA technology, the expression of the MyoD and myogenin messages is significantly reduced, leading to inhibition of myogenesis. At this early stage in the differentiation process, HuR, a shuttling protein, is predominantly nuclear; localization that is mediated by the import receptor Transportin2 (Trn2). Nuclear HuR was determined to be required for the negative regulation of nucleophosmin (NPM) translation. Forced overexpression of NPM, resulting in differentiation inhibition, shows that its downregulation is a requirement for induction of the differentiation process. Late in myogenesis, however, NPM RNA is no longer expressed, and HuR is seen to accumulate in the cytoplasm of myotubes. This cytoplasmic accumulation results from dissociation of HuR from Trn2 due to caspase-dependent cleavage within its HNS region. Specifically blocking HuR import through the use of cell-permeable peptides, as well as RNAi-mediated depletion of Trn2, leads to an increase in cytoplasmic HuR, as well as increased cytoplasmic localization and stabilization of the MyoD and myogenin messages, and a corresponding enhancement of differentiation. Overall, we conclude that HuR is required for myogenesis due to its ability to post-transcriptionally regulate genes required for the process, and that HuR itself is regulated at the level of its subcellular localization, mediated by the import receptor TRN2.
6

The effects of maternal dietary supplementation of cholecalciferol (vitamin D₃) in conjunction with 25(OH)D₃ on sow and pig performance

Thayer, Morgan Taylor January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Jim Nelssen / A thorough literature review on feeding vitamin D₃ and 25(OH)D₃ revealed a large amount of research conducted in swine and poultry. In general, increasing vitamin D₃ concentrations or adding 25(OH)D₃ to the maternal diet increases the vitamin D₃ status of the dam and often the progeny as well. Varying results have been reported on the practical and valuable impacts of this elevated status with some topics including improved sow performance, changes in muscle fiber morphometrics, and growth performance to market. The first experiment used a total of 69 sows and the progeny from one group of 22 sows to determine the effects of feeding a combination of vitamin D₃ and 25(OH)D₃ to the sow. Differences in sow productivity and growth performance of progeny due to dietary treatment were not observed (P > 0.05). When pigs were sacrificed at birth, there were no treatment effects for all fiber morphometric measures (P > 0.170), except primary fiber number and the ratio of secondary to primary muscle fibers (P < 0.014). Pigs from the CON and DL fed sows had less primary fibers than pigs from sows fed the DH treatment (P < 0.046), but did not differ from each other (P = 0.732). These results suggest progeny went through a longer prenatal period of primary myogenesis which delayed the onset of secondary myogenesis. Pigs from DL fed sows had a smaller secondary to primary muscle fiber ratio compared to pigs from sows fed the CON treatment (P = 0.016), with pigs from sows fed DL treatment not differing from either (P > 0.057). There were treatment x time interactions for all sow and pig serum metabolites (P < 0.001). Therefore, we chose to compare treatment means within time period. At all time periods, sow serum 25(OH)D₃ concentrations differed for all treatments with the magnitude of difference largest at weaning (P < 0.011). The second and third experiment investigated the impact of adding benzoic acid and an essential oil blend to diets and creep feed. When these additives were included in growing pig diets in a 28-d trial, a main effect of time (P < 0.001) was detected where there was no evidence of difference during the first 3 weeks for ADG and G:F, however both responses decreased during the final week of the experiment (P < 0.001) and average pen BW increased (P < 0.001) for all time points. There was a treatment x time interaction (P = 0.003) for ADFI where during the first 3 weeks, there was no evidence of difference due to dietary treatment, but during the final week of the study, pigs consumed more (P = 0.007) of the control diet (2.38 kg/d control vs. 2.24 kg/d benzoic acid paired and essential oil blend). Fecal samples collected provided no evidence of differences (P > 0.05) in fecal pathogens due to dietary treatment. When these additives were included in the maternal diet and in the creep feed, they did not (P > 0.05) affect sow performance or preweaned piglet performance. Fecal swabbing of pigs the day before weaning showed they did not eat the creep feed and, therefore, no (P > 0.05) improvements in growth performance were observed in the nursery. In conclusion, adding benzoic acid and an essential oil blend to diets and creep feed did not affect growth performance and combining vitamin D₃ and 25(OH)D₃ in the maternal diet improved the vitamin D₃ status of the dam and progeny and increased primary muscle fibers at birth.
7

Characterization of the role and regulation of the RNA binding protein HuR in muscle cell differentiation

Van der Giessen, Kate. January 2007 (has links)
No description available.
8

Fiber Type-specific Desmin Content in Human Single Muscle Fibers

Ghent, Heidi 23 March 2006 (has links) (PDF)
Contractile and cytoskeletal protein concentrations have been shown to differ on the basis of fiber type in whole muscle homogenates. The purpose of this study was to compare the content of the intermediate filament protein, desmin, between type I and type IIa single muscle fibers from a mixed muscle in human subjects. Biopsies were taken from the vastus lateralis of six recreationally active males. Approximately 150 single muscle fibers were dissected from each sample and analyzed using SDS-PAGE to determine myosin heavy chain (MHC) composition. Following identification, muscle fibers were pooled into two groups (MHC I and MHC IIa). Desmin and actin content within the pooled samples was determined via immunoblotting. On average, muscle samples were composed of 51 ± 7 % type I, 2 ± 1% type I/IIa, 27 ± 5% type IIa, 19 ± 4% type IIa/IIx and 1 ± 1% type IIx MHC single fibers. Desmin and actin contents were 40% and 34% higher in type I fibers compared to type IIa fibers, respectively (P < 0.05). However the desmin to actin ratio was similar between pooled type I and IIa single muscle fibers within the vastus lateralis. These data suggest that desmin and actin content is a function of muscle fiber type. These differences in cytoskeletal protein content may have implications for differences in contractile function and eccentric damage characteristics between fiber types.
9

Avaliação do sinal eletromiografico e da histomorfometria do musculo vasto lateral em diferentes posicionamentos de eletrodos, intensidades de contração e generos / Evaluation of the electromyographic signal and the histomorphometry of vastus lateralis muscle in different electrodes placement, intensities of contraction and genders

Sakabe, Fabiana Forti 15 August 2018 (has links)
Orientador: Fausto Berzin / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-15T03:24:24Z (GMT). No. of bitstreams: 1 Sakabe_FabianaForti_D.pdf: 2084817 bytes, checksum: b0340d79b05862a9990b4042a871cf3b (MD5) Previous issue date: 2010 / Resumo: Tem sido demonstrado que os sinais eletromiográficos e a histomorfometria diferem ao longo do ventre muscular e entre os gêneros, porém a relação entre esses parâmetros não está bem estabelecida. O objetivo deste trabalho foi avaliar a eletromiografia (EMG) em diferentes intensidades de contração (IC) isométrica voluntária (10 a 100%) e posicionamentos de eletrodos (PE) sobre o músculo vasto lateral proximal (VLP) e distal (VLD), assim como a histomorfometria em ambos os gêneros. Participaram 11 mulheres e 7 homens (22,0+2,1 e 23,3+2,5 anos, respectivamente), sem lesões nos membros inferiores. Inicialmente foi obtida uma linha de base para determinação da força máxima de extensão da perna (célula de carga MM-100 (KRATOS®)). Para a coleta da EMG foi utilizado o módulo de aquisição EMG-1000 da Lynx® (16 bits de resolução, filtro passa-banda de 20-1000 Hz e freqüência de amostragem 2000 Hz). Dois eletrodos de superfície ativos simples diferencial (Lynx®, ganho 20x) com distância intereletrodo de 10mm foram posicionados sobre o VLP e VLD. O eletrodo de referência foi fixado à tuberosidade da tíbia. O sinal foi coletado simultaneamente nos eletrodos e na célula de carga em diferentes IC por 5 segundos, repetida por 3 vezes e com intervalo de 1 minuto. A EMG foi processada no software Matlab® 6.5.1, sendo determinados o RMS e a freqüência mediana (FM). Após a EMG, foi realizada a biópsia do VLP e VLD com agulha de Bergström. Os cortes (12um) foram realizados em criostato (MICRON HM 505E a -25°C). Os principais tipos de fibras (TF) musculares (I, IIA e IID) foram delineados pela técnica dxa mATPase e a área das fibras (um2) foi analisada no software Image Manager (Leica Microsystems®). Foram utilizados os testes ANOVA com post-hoc de Tukey, o teste T de Student pareado e não pareado e a correlação de Pearson. Com o aumento da IC (10100% CIVM) houve elevação significativa do RMS (em ambos os PE e gêneros). Para a FM, de maneira geral, não houve variação com o aumento da IC (nos PE e gêneros). A força e o RMS bruto foram maiores nos homens em relação às mulheres para os dois eletrodos. A FM não diferiu entre os gêneros. Para a distribuição (%) dos TF, não houve variação tanto nos gêneros quanto nos PE. Entretanto, a área dos diferentes TF foi maior nos homens do que nas mulheres e de maneira geral, não houve variação entre os PE. Verificou-se correlação positiva entre força x área I e área II, RMS x área I e área II. Não houve correlação entre área das fibras e FM, nem entre força e FM. De acordo com os resultados obtidos, pode-se verificar que o percentual de fibras não variou entre os PE e gêneros, porém os homens apresentaram os TF, a força e o RMS maiores do que as mulheres. A FM não diferiu entre os gêneros. Deste modo, a área das fibras musculares influenciou o RMS e a força do músculo vasto lateral, sendo a diferença entre os gêneros provavelmente devido a essa variável. / Abstract: It has been shown that electromyography signal (EMGs) and histomorphometry are different along the muscle belly and between genders, although the relationship between these parameters is not clear. The aim of this study was to evaluate the EMGs in different intensities of volunteer isometric muscle contraction (10-100%) and electrodes positions over the belly of vastus lateralis muscle [proximal (VLP) and distal (VLD) portions], as well as the histomorphometry for both genders. Eleven women (22,0 ± 2,1 years) and seven men (23,3 ± 2,5 years), took part in the study. All subjects had no lesions in lower limbs. At first a baseline was made to determine the maximum force of leg extension [MM-100 load cell (KRATOS®)]. For EMG recording an EMG-1000 acquisition module (Lynx®) was used (16 bits of resolution, band-pass filter of 201000Hz and sampling frequency of 2000Hz). Two simple differential surface active electrodes (Lynx®, 20 times gain) separated by 10mm were placed over VLP and VLD muscles bellies. Reference electrode was attached to the anterior tibial tuberosity of the evaluated leg. EMGs was recorded simultaneously in both electrodes in different intensities of contraction for 5 seconds, repeated for 3 times and with one-minute intervals among contractions. Load cell signals were also recorded. EMGs were analyzed in Matlab® 6.5.1 software and RMS and median frequency (MF) values were obtained. After EMGs recordings, the muscle biopsies of VLP and VLD were performed using a Bergström needle. Histological sections (12um) were performed in cryostat (MICRON HM 505E at -25°C). The main types of muscle fibers (I, IIA and IID) were identified by mATPase technique and fibers' area (um2) was analyzed in Image Manager software (Leica Microsystems®). ANOVA test and Tukey post-hoc test, paired and non-paired Student t test, paired Student t test and Pearson test (correlations). A significant elevation of RMS was observed with the rise of contraction intensity (10-100% maximum voluntary isometric contraction - MVIC) for both genders and electrodes positions. In general, there were no variations in MF with the rise of contraction intensity (for both genders and electrodes positions). Force and absolute RMS values were higher in men compared to women for both electrodes. MF was not different between genders. For fiber types distribution (%) there was no difference between genders and between electrodes positions. However, male's fibers' areas were greater than women's and, as a general matter, there was no difference between the electrodes. A positive correlation was observed between force x type I and II fiber areas, RMS x type I and II fiber areas. There was no significant correlation between fibers' area and MF and between force and MF. According to our results the fiber type's distribution was not different between genders and electrodes; nevertheless, higher RMS and force values, as well as greater fibers' areas, were found in male group. MF was not different between genders. Finally, muscle fibers' area did influence RMS and force of vastus lateralis muscle and we suggest that this could be the reason of the observed differences between genders. / Doutorado / Anatomia / Doutor em Biologia Buco-Dental
10

Efeitos do treinamento de força de baixa intensidade associado à restrição parcial do fluxo sanguíneo na força, hipertrofia e modulação das células satélites musculares em idosos / Effects of low load resistance training with partial blood flow restriction in the strength and hypertrophy gains as well as in the muscle satellite cells content in elderly

Vechin, Felipe Cassaro 15 December 2014 (has links)
O treinamento de força de baixa intensidade com restrição parcial do fluxo sanguíneo (TFR) emergiu como uma alternativa ao treinamento de força tradicional, com intensidades variando entre moderada a alta, principalmente para idosos que possam apresentar alguma limitação ou dificuldade na realização do treinamento mais intenso. Assim, o presente estudo objetivou analisar a efetividade do TFR na modulação dos níveis de força, área de secção transversa muscular (ASTM) e dos diferentes tipos de fibra (ASTF) bem como da quantidade de células satélites (CS) e mionúcleos (MIO) presentes nas células musculares de indivíduos idosos e comparar os ganhos proporcionados por esse treinamento com os ganhos do treinamento de força tradicional. Trinta sujeitos foram alocados de maneira aleatória e balanceada, pela área de secção transversa muscular do quadríceps, nos seguintes grupos: grupo controle (GC), treinamento de força de baixa intensidade com restrição parcial do fluxo sanguíneo (TFR) e treinamento de força de alta intensidade (TFAI). Após 12 semanas de treinamento, realizados duas vezes na semana, com o exercício Leg Press ambos os grupos, TFR e TFAI apresentaram aumentos nos níveis de força muscular (17% P = 0,067 e 54% P < 0,001 respectivamente) e na ASTM do quadríceps (P < 0,001; 6,6% e 7,9% respectivamente). O grupo controle não apresentou nenhuma alteração significativa dessas variáveis. Após o período de intervenção, a ASTF bem como a quantidade de CS e MIO presentes nas fibras musculares não apresentaram alterações estatisticamente significantes para nenhum dos grupos. Entretanto, no grupo controle foi observada uma queda na ASTF (tipo I = -10%; tipo II = -1%) e também na quantidade de CS e MIO presentes nas fibras (CS = -29,2%; MIO = -9,7%). Para o grupo TFR foi observado um aumento na ASTF tipo II de 13%, contudo um decréscimo de 6% na ASTF do tipo I. Na quantidade de CS o grupo TFR apresentou uma queda de 5% enquanto que para quantidade de MIO foi apresentado um acréscimo de 14,6%. Já o grupo TFAI apresentou uma elevação de 15% na ASTF para ambos os tipos de fibra, I e II. A quantidade de CS aumentou em 32,6% enquanto que a quantidade de MIO presente nas fibras musculares aumentou 3,6%. Os achados do presente estudo mostram adaptações similares nos ganhos de força e hipertrofia muscular entre o TFR e o TFAI, sendo ambos efetivos em reverter os efeitos deletérios do envelhecimento nessas variáveis, consolidando assim o TFR como uma possível alternativa ao TFAI. Quanto à modulação da ASTF bem como da quantidade de CS e MIO por fibra muscular, se comparado ao controle, que apresentou queda nos níveis dessas variáveis, ambos os treinos TFR e TFAI foram capazes de retardar o efeito do envelhecimento sobre essas variáveis, sendo o TFAI mais efetivo em modular a ASTF do tipo I e a quantidade de CS por fibra em dozes semanas de treinamento, realizados duas vezes na semana. Já para modulação da quantidade de MIO por fibra, o TFR apresentou uma ligeira vantagem frente ao TFAI. Dessa forma, em nível celular, no que diz respeito à ASTF, CS e MIO ambos os treinos, após 12 semanas com uma frequência de treinamento baixa, parecem capazes de preservar os níveis dessas variáveis frente ao processo de envelhecimento / The low load resistance training with blood flow restriction (BFR) emerged as an alternative training mode to traditional resistance training (RT), with moderate to high intensities, mainly to elderly, with some limitations or losses, unable to exercise the traditional RT. Thus, the aim of the present study was comparing the effectiveness of BFR to promote strength gains, increases in the muscle and fibers cross sectional area (CSAm and CSAf in that order) as well as an augment in the muscle satellite cells (SC) and myonucleous (MYO) contents in elderly with RT results in these variables. Thirty elderly individuals were ranked in quartiles according to their initial quadriceps CSA and then randomly allocated into one of the following groups: control (CG), low-intensity resistance training with blood flow restriction group (BFR) and high-intensity resistance training (HRT). After 12 weeks of training, twice a week, using the Leg Press exercise, both groups, BFR and HRT presented increases to muscle strength (17% P = 0,067 e 54% P < 0,001 respectively) and CSAm (P < 0,001; 6,6% e 7,9% respectively). The CG did not present any significantly alteration in these variables. After the intervention, the CSAf as well as the SC and MYO contents did not show any significantly alteration for the three groups. However in the CG was observed a CSAf decreases (type I = -16%; type II = -12%) even as in the SC and MYO (CS= -29,2; MYO = -9,7%). To the BFR group was observed an increase of 13% in the type II CSAf while type I presented a decrease of 6%. The CS content decreases 5% whereas MYO content show a increase of 14,6%. To the HRT, both fibers type, I and II, presented an increase in the CSAf (type I = 1%; type II = 12%). To CS and MYO contents HRT showed an augment of 32,6% and 3,6 % respectively. These finds indicate similar strength and hypertrophy gains between BFR and HRT, being both training capable to offset age-related loss in muscle strength and mass, placing the BFR as a surrogate approach to HRT. Comparing the CSAf as well as SC and MYO modulation after intervention in both groups with the control group, BFR and HRT seems capable to break the aging impact on these variables, being the HRT slightly more effective to increase the type I CSA and CS contents while BFR seems slight more effective to increase MYO contents after 12 weeks of training twice a week. On this way both training, BFR and HRT, showed able to preserve CSAf levels even as CS and MYO content during aging

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