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1.
Rev. bras. ciênc. mov ; 26(2): 24-33, abr.-jun. 2018.
Artigo em Inglês | LILACS | ID: biblio-910720

RESUMO

This study had as objective to analyze the acute eff ects of resistance exercise (RE) on the mRNA levels of the following genes (MyoD, myogenin, IGF-1, atrogin-1, MuRF-1, and myostatin) in rheumatoid arthritis (experimental arthritis). Therefore, 26 females rats were randomly allocated into four groups, control (CT, n=7), exercise (Ex, n=6), rheumatoid arthritis (RA, n=6) and RA with exercise (RAEx, n=7). Met-BSA was injected into the tibiotarsal joint in the RA and RAEx groups. After 15 days from injection, the animals were submitted to an acute bout of RE and six hours post protocol the animals were euthanized. We evaluated the joint thickness, infl ammation score, cross-sectional area (CSA) of gastrocnemius muscle fi bers and mRNA expression of the IGF-1, MyoD, myogenin, myostatin, MuRF-1, atrogin-1 and GAPDH. It was observed that the joint thickness and score strongly increased in arthritic rats (p <0.001) while the CSA decreased (p ≤ 0.05). Increased mRNA levels of IGF-1 (2.0 fold), myostatin (4.5 fold), atrogin-1 (2.5 fold), MyoD (3.7-fold) and myogenin (5 fold) were observed in muscle of arthritic rats. The mRNA expression of myostatin, atrogin-1, MyoD and myogenin decreased in the RAEx group. In this way, we can conclude that experimental arthritis-increased gene expressions in muscle atrophy myostatin, atrogin-1, MyoD and myogenin) are restored back to control as a response to acute RE....(AU)


O presente estudo teve como objetivo analisar o efeito agudo do Exercício com pesos sobre os níves de mRNA de genes envolvidos no anabolismo ou catabolismo muscular em um modelo experimental de Artrite Reumatóide. Para tanto, 26 ratas fêmeas foram randomicamente alocadas em quatro grupos, controle (CT, n=7), Exercício (Ex, n=6), Artrite Reumatóide (AR, n=6) e Artrite Reumatóide com exercício (AREx, n=7). Uma substância contendo Albumina bovina metilada foi injetada na articulação tíbio-tarsal nos grupos AR e AREx para indução da Artrite Reumatóide. Após 15 dias da injeção, os animais foram submetidos a um estímulo agudo de treinamento com pesos e 6 horas após o exercício os animais foram eutanasiados. Nós avaliamos a espessura da articulação, escore de infl amação, a área de secção transversa (AST) das fi bras do músculo Gastrocnêmio e a mRNA de IGF-1, MyoD, Myogenina (genes envolvidos no anabolismo muscular), e MuRF-1, atrogina-1 (genes envolvidos no catabolismo muscular), além do gene controle , GAPDH. Foi observado que a espessura articular e o escore de infl amação aumentaram fortemente nas ratas induzidas a Artrite Reumatóide (p <0,001), enquanto a AST reduziu (p ≤ 0,05). Um aumento nos níveis de mRNA de IGF-1 (2,0 vezes), miostatina (4,5 vezes), atrogina-1 (2,5 vezes), MyoD (3,7 vezes) e miogenina (5 vezes) foi observado no músculo das ratas induzidas a Artrite Reumatóide. mRNA de miostatina, atrogina-1, MyoD e miogenina reduziu no grupo RAEx. Desta forma, podemos concluir, que o modelo experimental de Artrite Reumatóide induziu um aumento da expressão de genes durante a atrofi a muscular (myostatin, atrogin-1, MyoD and myogenin) e que estas alterações foram reguladas pelo Exercício com peso....(AU)


Assuntos
Animais , Ratos , Caquexia , Proteína MyoD , Miogenina , Miostatina , Educação Física e Treinamento
2.
J Strength Cond Res ; 2018 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-29489727

RESUMO

We studied the effects of two different weekly frequency resistance training (RT) protocols over eight weeks on muscle strength and muscle hypertrophy in well-trained men. Twenty-three subjects (age: 26.2±4.2 years; RT experience: 6.9±3.1 years) were randomly allocated into the two groups: low frequency (LFRT, n = 12) or high frequency (HFRT, n = 11). The LFRT performed a split-body routine, training each specific muscle group once a week. The HFRT performed a total-body routine, training all muscle groups every session. Both groups performed the same number of sets (10-15 sets) and exercises (1-2 exercise) per week, 8-12 repetitions maximum (70-80% of 1RM), five times per week. Muscle strength (bench press and squat 1RM) and lean tissue mass (dual-energy x-ray absorptiometry) were assessed prior to and at the end of the study. Results showed that both groups improved (p<0.001) muscle strength [LFRT and HFRT: bench press = 5.6 kg (95% Confidence Interval (CI): 1.9 - 9.4) and 9.7 kg (95%CI: 4.6 - 14.9) and squat = 8.0 kg (95%CI: 2.7 - 13.2) and 12.0 kg (95%CI: 5.1 - 18.1), respectively] and lean tissue mass (p = 0.007) [LFRT and HFRT: total body lean mass = 0.5 kg (95%CI: 0.0 - 1.1) and 0.8 kg (95%CI: 0.0 - 1.6), respectively] with no difference between groups (bench press, p = 0.168; squat, p = 0.312 and total body lean mass, p = 0.619). Thus, HFRT and LFRT are similar overload strategies for promoting muscular adaptation in well-trained subjects when the sets and intensity are equated per week.

3.
J Strength Cond Res ; 2017 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-28135215

RESUMO

We studied the effects of two different resistance training (RT) multiple-set protocols (three and six sets) on muscle strength and basal hormones concentrations in postmenopausal women (PW). Thirty-four PW were randomly allocated into three groups: control (CT, n=12), low RT volume (LV = three sets for each exercise, n=10) and high RT volume (HV = six sets for each exercise, n=12). The LV and HV groups performed eight exercises of a total body RT protocol three times a week, at 70 % of one repetition maximum (1RM) for 16 weeks. The muscle strength and basal hormones concentration were measured before and after the RT. Our findings show that three sets or six sets at 70% of 1RM protocol increased muscular strength similarly after 16 weeks (sum of all exercises, LV: 37.7% and HV: 34.1% vs. CT: 2.1%, p < 0.001). Moreover, the RT volume does not affect basal levels of testosterone (TT) (LV: 0.02%, HV: -0.12% and CT: 0.006%, p = 0.233), cortisol (C) (LV: 72.4%, HV: 36.8% and CT: 16.8%, p = 0.892), insulin-like growth factor-1 (LV: 6.7%, HV: 7.3% and CT: 4.1%, p = 0.802), dehydroepiandrosterone sulfate (LV: 0.1%, HV: -4.5% and CT: -6.7%, p = 0.885) and TT:C ratio (LV: -0.9%, HV: -1.6% and CT: -0.4%, p = 0.429). Our results suggest that three sets and six sets at 70% of 1RM seem to promote similar muscle strength gain. Thus, three set RT is a time efficient protocol for strength gain after 16 weeks in PW.

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