Intramuscular adipose tissue, muscle area, and power as predictors of performance in breast cancer survivors.

PURPOSE: The decline in physical performance, assessed by physical tests such as the timed up and go (TUG) test, is a consequence of reduced physiological reserves at higher levels of a hierarchical process. This occurs due to changes in muscle architecture, including atrophy and fat infiltration into the muscles, which in turn lead to changes in muscle function, resulting in reduced muscle strength and power and, consequently, affecting physical performance. This study investigated predictive factors for physical performance in breast cancer survivor (BCS), focusing on intramuscular adipose tissue (IMAT), quadríceps muscle area (QMA), and muscular power. METHODS: This observational, analytical, and cross-sectional study included 23 women without a history of cancer (age, 58.5 ± 8.3 years; BMI, 27.2 ± 5.1 kg/m2) and 56 BCS (age, 58.5 ± 8.3 years; BMI, 27.2 ± 5.1 kg/m2). QMA and IMAT were assessed using computed tomography images. Muscular power and physical performance were measured using the 5-repetition sit-to-stand and TUG tests, respectively. RESULTS: IMAT (r = 0.4, P < 0.01) and muscular power (r = - 0.4, P < 0.01) were associated with TUG performance in BCS, whereas QMA (r = - 0.22, P = 0.10) showed no significant association. QMA (r = 0.55, P < 0.01) was associated with muscular power, while no significant association was found between IMAT and muscular power (r = - 0.05, P = 0.73). Age explained 19% (P < 0.01) of TUG performance variability. Adding muscular power increased explanatory power by 12% (P < 0.01), and including IMAT further increased it by 7% (P = 0.02) for TUG performance. Collectively, age, muscular power, and IMAT accounted for 38% of the performance variance in the TUG test (age, B = 0.06, P = 0.043; muscular power, B = - 0.01, P = 0.002; IMAT, B = - 0.05, P = 0.020). CONCLUSIONS: Our findings suggest that IMAT and muscular power predict the physical performance of BCS, while QMA does not have the same predictive capability.

Effect of resistance training volume on body adiposity, metabolic risk, and inflammation in postmenopausal and older females: Systematic review and meta-analysis of randomized controlled trials.

PURPOSE: This meta-analytical study aimed to explore the effects of resistance training (RT) volume on body adiposity, metabolic risk, and inflammation in postmenopausal and older females. METHODS: A systematic search was performed for randomized controlled trials in PubMed, Scopus, Web of Science, and SciELO. Randomized controlled trials with postmenopausal and older females that compared RT effects on body adiposity, metabolic risk, and inflammation with a control group (CG) were included. Independent reviewers selected the studies, extracted the data, and performed the risk of bias and certainty of the evidence (Grading of Recommendations, Assessment, Development, and Evaluation (GRADE)) evaluations. Total body and abdominal adiposity, blood lipids, glucose, and C-reactive protein were included for meta-analysis. A random-effects model, standardized mean difference (Hedges' g), and 95% confidence interval (95%CI) were used for meta-analysis. RESULTS: Twenty randomized controlled trials (overall risk of bias: some concerns; GRADE: low to very low) with overweight/obese postmenopausal and older females were included. RT groups were divided into low-volume RT (LVRT, ∼44 sets/week) and high-volume RT (HVRT, ∼77 sets/week). Both RT groups presented improved body adiposity, metabolic risk, and inflammation when compared to CG. However, HVRT demonstrated higher effect sizes than LVRT for glucose (HVRT = -1.19; 95%CI: -1.63 to -0.74; LVRT = -0.78; 95%CI:-1.15 to -0.41) and C-reactive protein (HVRT = -1.00; 95%CI: -1.32 to -0.67; LVRT = -0.34; 95%CI, -0.63 to -0.04)) when compared to CG. CONCLUSION: Compared to CG, HVRT protocols elicit greater improvements in metabolic risk and inflammation outcomes than LVRT in overweight/obese postmenopausal and older females.

Rheumatoid arthritis-increased gene expressions in muscle atrophy are restored back to control as a response to acute resistance exercise / Estímulo agudo de musculação promove regulação de genes alterados pela atrofi a muscular

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)

The Short Physical Performance Battery is a discrimi-native tool for identifying low quality of life in gynecological postmenopausal cancer survivor / O Short Physical Performance Battery é uma ferramenta discriminativa para identificar baixa qualidade de vida em mulheres na pós-menopausa sobreviventes do câncer ginecológico

Adverse events due to cancer treatment (changes in weight, reduced muscle capacity and mobility) hinder the quality of life (QoL) of cancer survivors. Nevertheless, the identification of discriminative predictors of QoL in post-menopausal women (PW) survivors of gynecological cancer (PW-SGC) has been ignored. Objective: The purpose of the present study was to examine the role of muscle capacity, mobility and body mass index (BMI) on the deterioration of QoL in PW (n=35; 62.1±8.2 years) and PW-SGC (n=51; 60.8±11.4 years). Methods: The QoL questionnaire (SF-36), anthropometrical evaluation (BMI), hand-held dynamometry (HHD) and short physical performance battery (SPPB) were applied in all volunteers. Results: The participants had overweight, low SF-36 scores and normal HHD, and no significant differences were found between both groups, however the SPPB score was higher in the PW group (p<0.001). Linear regression analyses for QoL indicated the BMI (beta=-0.27) and the SPPB (beta=0.57) were the strongest and most significant predictors in PW and PW-SGC, respectively. The area under the curve (AUC) for the SPPB score was 0.74 (95% CI: 0.57-0.87; P=0.015) in the PW-SGC group and 0.62 (95% CI: 0.47-0.75; P = 0.181) in PW. Conclusion: The present study showed that the importance of BMI and mobility (SPPB) for QoL differ between PW and PW-SGC. For PW-SGC, the strongest independent predictor of QoL was mobility (SPPB), whereas BMI was the strongest contributor in PW. Moreover, the SPPB test is a discriminative predictor (or assessment tool) for identifying the low quality of life in postmenopausal women survivors of gynecological cancer.

Efeitos adversos do tratamento (modificações da massa corporal e reduções da capacidade muscular e mobilidade) podem modificar a qualidade de vida (QV) de sobreviventes de câncer. Semelhantemente, a menopausa e o envelhecimento podem promover alterações antropométricas e da função física. Portanto, torna-se necessário o levantamento de ferramentas para predizer, distintamente, a QV em mulheres na pós menopausa (PM) e em mulheres na pós menopausa sobreviventes de câncer ginecológico (PMSCG). Objetivo: Examinar a contribuição da força, mobilidade e do índice de massa corporal (IMC) sobre as alterações da QV em PM (n = 35; 62,1±8,2 anos) e PMSCG (n = 51; 60,8±11,4 anos). Métodos: Aplicou-se questionário de QV (SF-36), avaliação antropométrica (IMC), dinamometria de preensão manual (DPM) e short physical performance battery (SPPB). Resultados: Participantes apresentaram sobrepeso, baixo score em SF36 e DPM normal, sem diferenças entre os grupos. O score de SPPB foi maior em PM (p<0,001). Análise de regressão linear de QV, indicou IMC (beta = -0,27) e o SPPB (beta = 0,57), como os mais fortes preditores em PM e PMSCG, respectivamente. A área sob a curva para o score do SPPB foi 0,74 (95% CI: 0,57-0.87; P = 0,015) em PMSCG e 0,62 (95% CI: 0,47-0,75; P = 0,181) em PM. Conclusão: O presente estudo demonstrou que para PMSCG o principal preditor da QV foi a mobilidade (SPPB), enquanto o IMC foi o mais forte contribuidor em PM. Portanto, o SPPB é um teste específico para identificar reduções na QV pacientes sobreviventes de câncer ginecológico.

Maior índice de massa corporal e menor circunferência da cintura estão associados com maior desempenho físico (SPPB) somente em idosas dinapênicas / Higher body mass index and lower waist circumference are associated to higher physical performance (SPPB) solely in dynapenic elderly women

A limitação na capacidade física, definida como dificuldades em realizar tarefas físicas, é crítica para independência funcional de idosos. A capacidade física limitada é associada fortemente com o aumento de quedas, hospitalizações, doenças cardíacas e cerebrovasculares e mortalidade em idosos. O impacto do status da massa corporal e da baixa força muscular (dinapenia) sobre a capacidade física de idosos é bem documentado. Contudo, a interação desses fatores (força muscular e status da massa corporal) sobre a capacidade física de idosos ainda não é clara. Objetivo: Verificar o poder preditivo do índice de massa corpórea (IMC) associada com a circunferência da cintura (CC) na capacidade física de mulheres idosas com ou sem dinapenia (baixa força muscular). Método: Foram avaliadas 142 idosas atendidas na especialidade de Geriatria e Gerontologia. Foram realizadas as seguintes medidas: antropométricas (IMC e CC), força de preensão manual (FPM) e capacidade física (SPPB). As idosas foram classificadas em dinapênicas (FPM < 20 kg) ou não dinapênicas (FPM ≥ 20 kg). Resultados: A análise de regressão linear múltipla indicou que o IMC e a CC, analisados separadamente, não se associaram com SPPB em nenhum dos grupos. Porém, quando analisados concomitantemente, o IMC (associação positiva) e a CC (associação negativa) foram significantemente associados com SPPB somente no grupo dinapenia. Conclusão: Os principais achados deste estudo sugerem que a CC e IMC aplicados conjuntamente, mas não separados, são preditores da capacidade física em mulheres idosas com dinapenia. Esses resultados são importantes para a prática ambulatorial devido à fácil aplicabilidade e baixo custo das medidas

Physical performance limitation is defined as difficulties in performing physical tasks. It is critical for the functional independence of the elderly. Limited physical performance is strongly associated with increased falls, hospitalizations, cardio and cerebrovascular diseases, and mortality in the elderly. The impact of body mass status and low muscle strength (dynapenia) on elderly physical performance is well documented. However, the interaction of these factors (muscle strength and body mass status) on the physical performance of the elderly is not yet clear. Objective: To assess the predictive power of body mass index (BMI) associated with waist circumference (WC) in determining the physical performance of older women classified as dynapenic (low muscle strength) or non-dynapenic. Method: One hundred forty-two older women were evaluated according to: anthropometry (BMI and WC), handgrip (HG) and physical performance (SPPB). The elderly were classified in dynapenic (HG < 20 kg) or non-dynapenic (HG ≥ 20 kg). Results: In both groups, multiple linear regression analysis indicated that BMI and WC were not associated with SPPB when they were analyzed separately. However, when BMI and WC were analyzed concomitantly, both were significantly associated with SPPB only for the dynapenic group. Conclusion: The main findings of this study suggest that WC and BMI applied together, but not separate, are predictors of physical performance in older women with dynapenia. These results are important for clinical practice because of easy application and low cost of measures

Predicting Functional Capacity From Measures of Muscle Mass in Postmenopausal Women.

BACKGROUND: Menopause increases body fat and decreases muscle mass and strength, which contribute to sarcopenia. The amount of appendicular muscle mass has been frequently used to diagnose sarcopenia. Different measures of appendicular muscle mass have been proposed. However, no studies have compared the most salient measure (appendicular muscle mass corrected by body fat) of the appendicular muscle mass to physical function in postmenopausal women. OBJECTIVE: To examine the association of 3 different measurements of appendicular muscle mass (absolute, corrected by stature, and corrected by body fat) with physical function in postmenopausal women. DESIGN: Cross-sectional descriptive study. SETTING: Outpatient geriatric and gynecological clinic. PARTICIPANTS: Forty-eight postmenopausal women with a mean age (standard deviation [SD]) of 62.1 ± 8.2 years, with mean (SD) length of menopause of 15.7 ± 9.8 years and mean (SD) body fat of 43.6% ± 9.8%. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Appendicular muscle mass measure was measured with dual-energy x-ray absorptiometry. Physical function was measured by a functional capacity questionnaire, a short physical performance battery, and a 6 minute-walk test. Muscle quality (leg extensor strength to lower-body mineral-free lean mass ratio) and sum of z scores (sum of each physical function tests z score) were performed to provide a global index of physical function. RESULTS: The regression analysis showed that appendicular muscle mass corrected by body fat was the strongest predictor of physical function. Each increase in the standard deviation of appendicular muscle mass corrected by body fat was associated with a mean sum of z score increase of 59% (standard deviation), whereas each increase in absolute appendicular muscle mass and appendicular muscle mass corrected by stature were associated with a mean sum of z scores decrease of 23% and 36%, respectively. Muscle quality was associated with appendicular muscle mass corrected by body fat. CONCLUSION: These findings indicate that appendicular muscle mass corrected by body fat is a better predictor of physical function than the other measures of appendicular muscle mass in postmenopausal women. LEVEL OF EVIDENCE: I.

Effect of resistance training on muscular strength and indicators of abdominal adiposity, metabolic risk, and inflammation in postmenopausal women: controlled and randomized clinical trial of efficacy of training volume.

This study evaluated the effect of resistance training (RT) volume on muscular strength and on indicators of abdominal adiposity, metabolic risk, and inflammation in post-menopausal women (PW). Thirty-two volunteers were randomly allocated into the following three groups: control (CT, no exercise, n = 11), low-volume RT (LV, three sets/exercise, n = 10), and high-volume RT (HV, six sets/exercise, n = 11). The LV and HV groups performed eight exercises at 70 % of one maximal repetition, three times a week, for 16 weeks. Muscular strength and indicators of abdominal adiposity, metabolic risk, and inflammation were measured at baseline and after 16 weeks. No differences were found in baseline measures between the groups. The PW showed excess weight and fat percentage (F%), large waist circumference (WC), high waist-hip ratio (WHR), and hypercholesterolemia and borderline values of glycated hemoglobin (HbA1c%). Following the RT, a similar increase in muscle strength and reduction in F% from baseline were found in both trained groups. In HV, a decrease in total cholesterol, LDL-c, WC, and WHR was noted. Moreover, the HV showed a lower change (delta%) of interleukin-6 (IL-6) when compared to CT (HV = 11.2 %, P 25-75 = -7.6-28.4 % vs. CT = 99.55 %, P 25-75 = 18.5-377.0 %, p = 0.049). In LV, a decrease was noted for HbA1c%. There were positive correlations (delta%) between WHR and IL-6 and between IL-6 and TC. These results suggest that while a low-volume RT improves HbA1c%, F%, and muscular strength, a high-volume RT is necessary to improve indicators of abdominal adiposity and lipid metabolism and also prevent IL-6 increases in PW.

Loss of Ovarian Function Results in Increased Loss of Skeletal Muscle in Arthritic Rats.

OBJECTIVE: We studied the effects of loss of ovarian function (ovariectomy) on muscle mass of gastrocnemius and the mRNA levels of IGF-1, atrogin-1, MuRF-1, and myostatin in an experimental model of rheumatoid arthritis in rats. METHODS: We randomly allocated 24 female Wistar rats (9 weeks, 195.3 ± 17.4 grams) into four groups: control (CT-Sham; n = 6); rheumatoid arthritis (RA; n = 6); ovariectomy without rheumatoid arthritis (OV; n = 6); ovariectomy with rheumatoid arthritis (RAOV; n = 6). We performed the ovariectomy (OV and RAOV) or Sham (CT-Sham or RA) procedures at the same time, fifteen days before the rheumatoid arthritis induction. The RA and RAOV groups were immunized and then were injected with Met-BSA in the tibiotarsal joint. After 15 days of intra-articular injections the animals were euthanized. We evaluated the external manifestations of rheumatoid arthritis (perimeter joint) as well as animal weight, and food intake throughout the study. We also analyzed the cross-sectional areas (CSA) of gastrocnemius muscle fibers in 200 fibers (H&E method). In the gastrocnemius muscle, we analyzed mRNA expression by quantitative real time PCR followed by the Livak method (ΔΔCT). RESULTS: The rheumatoid arthritis induced reduction in CSA of gastrocnemius muscle fibers. The RAOV group showed a lower CSA of gastrocnemius muscle fibers compared to RA and CT-Sham groups. Skeletal muscle IGF-1 mRNA increased in arthritics and ovariectomized rats. The increased IGF-1 mRNA was higher in OV groups than in the RA and RAOV groups. Antrogin-1 mRNA also increased in the gastrocnemius muscle of arthritic and ovariectomized rats. However, the increased atrogin-1 mRNA was higher in RAOV groups than in the RA and OV groups. Gastrocnemius muscle MuRF-1 mRNA increased in the OV and RAOV groups, but not in the RA and Sham groups. However, the RAOV group showed higher MuRF-1 mRNA than the OV group. The myostatin gene expression was similar in all groups. CONCLUSION: Loss of ovarian function results in increased loss of skeletal muscle-related ubiquitin ligases atrogin-1 and MuRF-1 in arthritic rats.

Loss of Ovarian Function Results in Increased Loss of Skeletal Muscle in Arthritic Rats / Perda da função ovariana resulta em perda de músculo esquelético aumentada em ratos artríticos

Objective We studied the effects of loss of ovarian function (ovariectomy) onmuscle mass of gastrocnemius and themRNA levels of IGF-1, atrogin-1, MuRF-1, andmyostatin in an experimental model of rheumatoid arthritis in rats. Methods We randomly allocated 24 female Wistar rats (9 weeks, 195.3±17.4 grams) into four groups: control (CT-Sham; n = 6); rheumatoid arthritis (RA; n = 6); ovariectomy without rheumatoid arthritis (OV; n = 6); ovariectomy with rheumatoid arthritis (RAOV; n = 6). We performed the ovariectomy (OV and RAOV) or Sham (CTSham or RA) procedures at the same time, fifteen days before the rheumatoid arthritis induction. The RA and RAOV groups were immunized and then were injected with Met- BSA in the tibiotarsal joint. After 15 days of intra-articular injections the animals were euthanized. We evaluated the external manifestations of rheumatoid arthritis (perimeter joint) as well as animal weight, and food intake throughout the study. We also analyzed the cross-sectional areas (CSA) of gastrocnemius muscle fibers in 200 fibers (H&E method). In the gastrocnemius muscle, we analyzed mRNA expression by quantitative real time PCR followed by the Livak method (ΔΔCT). Results The rheumatoid arthritis induced reduction in CSA of gastrocnemius muscle fibers. The RAOV group showed a lower CSA of gastrocnemius muscle fibers compared to RA and CT-Sham groups. Skeletal muscle IGF-1 mRNA increased in arthritics and ovariectomized rats. The increased IGF-1 mRNA was higher in OV groups than in the RA and RAOV groups. Antrogin-1 mRNA also increased in the gastrocnemius muscle of arthritic and ovariectomized rats. However, the increased atrogin-1 mRNA was higher in RAOV groups than in the RA and OV groups. Gastrocnemius muscle MuRF-1 mRNA increased in the OVand RAOVgroups, but not in the RA and Shamgroups. However, the RAOV group showed higher MuRF-1 mRNA than the OV group. The myostatin gene expression was similar in all groups. Conclusion Loss of ovarian function results in increased loss of skeletal musclerelated ubiquitin ligases atrogin-1 and MuRF-1 in arthritic rats.

Objetivo Foram estudados os efeitos da perda da função ovariana (ovariectomia) sobre músculo esquelético e os níveis de RNAm de IGF-1, atrogina-1, MuRF-1, e de miostatina em modelo experimental de artrite reumatóide em ratos. Métodos 24 ratos Wistar (9 semanas, 195,3±17,4 gramas) foram distribuídos aleatoriamente em quatro grupos: controle (CT-Sham, n = 6); artrite reumatóide (RA, n = 6); ovariectomia sem artrite reumatóide (OV; n = 6); ovariectomia com artrite reumatóide (RAOV; n = 6). Os procedimentos da ovariectomia (OV e RAOV) ou simulação da ovariectomia (CT-Shamou RA) foramrealizados aomesmo tempo, quinze dias antes da indução da artrite reumatóide. Os grupos RA e RAOV foramimunizados e, em seguida, foram injetados com Met-BSA na articulação tibiotársica. Após 15 dias das injeções intra-articulares, os animais foram eutanasiados. Foram avaliadas as manifestações externas da artrite reumatóide (perimetria articular), bem como o peso dos animais e a ingestão de alimentos ao longo do estudo. Além disso, as áreas de secção transversa (CSA) do músculo gastrocnêmio foram analisadas em 200 fibras (método H & E). No músculo gastrocnêmio, a expressão de RNAm foi analisada por PCR quantitativo em tempo real, seguido pelo método Livak (ΔΔCT). Resultados A artrite reumatoide reduziu a CSA das fibras do músculo gastrocnêmio. O grupo RAOV mostrou uma CSA menor nas fibras do músculo gastrocnêmio em comparação com os grupos RA e CT-Sham. O RNAm do IGF-1 do músculo esquelético aumentou nos ratos artríticos e ovariectomizados. O RNAm do IGF-1 foi maior nos grupos OV do que nos grupos RA e RAOV. A expressão de antrogina-1 também aumentou no músculo gastrocnêmio dos ratos artríticos e ovariectomizados. No entanto, o aumento do RNAm da atrogina-1 foi maior no grupo RAOV do que nos grupos RA e OV. O RNAm da MuRF-1 aumentou nos grupos OV e RAOV, mas não nos grupos RA e CT-Sham. Porém, o grupo RAOV apresentou maior expressão gênica de MuRF-1 do que o grupo OV. A expressão do gene da miostatina foi semelhante em todos os grupos. Conclusão A perda de função ovariana resulta em perda de músculo esquelético associado às ubiquitina-ligases atrogina-1 e MuRF-1 em ratos artríticos.

Acute resistance exercise reduces increased gene expression in muscle atrophy of ovariectomised arthritic rats.

OBJECTIVE: We studied the effect of resistance exercise (RE) on mRNA levels of atrogin-1, MuRF-1, and myostatin in the gastrocnemius muscle of arthritic rats after loss of ovarian function (LOF). MATERIAL AND METHODS: Thirty female Wistar rats (nine weeks old, 195.3 ±17.4 grams) were randomly allocated into five groups: control group (CT-Sham; n = 6); group with rheumatoid arthritis (RA; n = 6); group with rheumatoid arthritis subjected to RE (RAEX; n = 6); ovariectomy group with rheumatoid arthritis (RAOV; n = 6); and an ovariectomy group with rheumatoid arthritis subjected to RE (RAOVEX; n = 6). After 15 days of intra-articular injections with Met-BSA the animals were subjected to RE and six hours after workout were euthanised. RESULTS: The rheumatoid arthritis provoked reduction in the cross-sectional area (CSA) of muscle fibres, but the CSA was lower in the RAOV when compared to the RA groups. Skeletal muscle atrogin-1 mRNA level was increased in arthritic rats (RA and RAOV), but the atrogin-1 level was higher in RAOV group when compared to other arthritic groups. The Muscle MuRF-1 mRNA level was also increased in the RAOV group. The increased atrogin-1 and MuRF-1 mRNA levels were lower in the RAOVEX group than in the RAOV group. The myostatin mRNA level was similar in all groups, except for the RAOVEX group, in which it was lower than the other groups. CONCLUSIONS: LOF results in increased loss of skeletal muscle-related ubiquitin ligases (atrogin-1 and MuRF-1). However, the RE reduces the atrogin-1, MuRF-1, and myostatin mRNA levels in muscle of arthritic rats affected by LOF.

Low-load resistance training promotes muscular adaptation regardless of vascular occlusion, load, or volume.

PURPOSE: This study investigates the impact of two different intensities and different volumes of low-load resistance training (LLRT) with and without blood flow restriction on the adaptation of muscle strength and size. METHODS: The sample was divided into five groups: one set of 20 % of one repetition maximum (1RM), three sets of 20 % of 1RM, one set of 50 % of 1RM, three sets of 50 % of 1RM, or control. LLRT was performed with (OC) or without (NOC) vascular occlusion, which was selected randomly for each subject. The maximal muscle strength (leg extension; 1RM) and the cross-sectional area (quadriceps; CSA) were assessed at baseline and after 8 weeks of LLRT. RESULTS: 1RM performance was increased in both groups after 8 weeks of training: OC (1 × 50 % = 20.6 %; 3 × 50 % = 20.9 %; 1 × 20 % = 26.6 %; 3 × 20 % = 21.6 %) and NOC (1 × 50 % = 18.6 %; 3 × 50 % = 26.8 %; 1 × 20 % = 18.5 %; 3 × 20 % = 21.6 %; 3 × 20 % = 24.7 %) compared with the control group (-1.7 %). Additionally, the CSA was increased in both groups: OC (1 × 50 % = 2.4 %; 3 × 50 % = 3.8 %; 1 × 20 % = 4.6 %; 3 × 20 % = 4.8 %) and NOC (1 × 50 % = 2.4 %; 3 × 50 % = 1.5 %; 1 × 20 % = 4.3 %; 3 × 20 % = 3.8 %) compared with the control group (-0.7 %). There were no significant differences between the OC and NOC groups. CONCLUSION: We conclude that 8 weeks of LLRT until failure in novice young lifters, regardless of occlusion, load or volume, produces similar magnitudes of muscular hypertrophy and strength.