Interrelated but Not Time-Aligned Response in Myogenic Regulatory Factors Demethylation and mRNA Expression after Divergent Exercise Bouts.

INTRODUCTION: DNA methylation regulates exercise-induced changes in the skeletal muscle transcriptome. However, the specificity and the time course responses in the myogenic regulatory factors DNA methylation and mRNA expression after divergent exercise modes are unknown. PURPOSE: This study aimed to compare the time course changes in DNA methylation and mRNA expression for selected myogenic regulatory factors ( MYOD1 , MYF5 , and MYF6 ) immediately after, 4 h after, and 8 h after a single bout of resistance exercise (RE), high-intensity interval exercise (HIIE), and concurrent exercise (CE). METHODS: Nine healthy but untrained males (age, 23.9 ± 2.8 yr; body mass, 70.1 ± 14.9 kg; peak oxygen uptake [V̇O 2peak ], 41.4 ± 5.2 mL·kg -1 ·min -1 ; mean ± SD) performed a counterbalanced, randomized order of RE (4 × 8-12 repetition maximum), HIIE (12 × 1 min sprints at V̇O 2peak running velocity), and CE (RE followed by HIIE). Skeletal muscle biopsies (vastus lateralis) were taken before (REST) immediately (0 h), 4 h, and 8 h after each exercise bout. RESULTS: Compared with REST, MYOD1 , MYF5 , and MYF6 , mean methylation across all CpGs analyzed was reduced after 4 and 8 h in response to all exercise protocols ( P < 0.05). Reduced levels of MYOD1 methylation were observed after HIIE and CE compared with RE ( P < 0.05). Compared with REST, all exercise bouts increased mRNA expression over time ( MYOD1 at 4 and 8 h, and MYF6 at 4 h; P < 0.05). MYF5 mRNA expression was lower after 4 h compared with 0 h and higher at 8 h compared with 4 h ( P < 0.05). CONCLUSIONS: We observed an interrelated but not time-aligned response between the exercise-induced changes in myogenic regulatory factors demethylation and mRNA expression after divergent exercise modes. Despite divergent contractile stimuli, changes in DNA methylation and mRNA expression in skeletal muscle were largely confined to the late (4-8 h) recovery period and similar between the different exercise challenges.

Exercise-Induced Circulating microRNAs: Potential Key Factors in the Control of Breast Cancer.

Losses in skeletal muscle mass, strength, and metabolic function are harmful in the pathophysiology of serious diseases, including breast cancer. Physical exercise training is an effective non-pharmacological strategy to improve health and quality of life in patients with breast cancer, mainly through positive effects on skeletal muscle mass, strength, and metabolic function. Emerging evidence has also highlighted the potential of exercise-induced crosstalk between skeletal muscle and cancer cells as one of the mechanisms controlling breast cancer progression. This intercellular communication seems to be mediated by a group of skeletal muscle molecules released in the bloodstream known as myokines. Among the myokines, exercise-induced circulating microRNAs (c-miRNAs) are deemed to mediate the antitumoral effects produced by exercise training through the control of key cellular processes, such as proliferation, metabolism, and signal transduction. However, there are still many open questions regarding the molecular basis of the exercise-induced effects on c-miRNA on human breast cancer cells. Here, we present evidence regarding the effect of exercise training on c-miRNA expression in breast cancer, along with the current gaps in the literature and future perspectives.

Resistance training variable manipulations are less relevant than intrinsic biology in affecting muscle fiber hypertrophy.

We aimed to investigate whether muscle fiber cross-sectional area (fCSA) and associated molecular processes could be differently affected at the group and individual level by manipulating resistance training (RT) variables. Twenty resistance-trained subjects had each leg randomly allocated to either a standard RT (RT-CON: without specific variables manipulations) or a variable RT (RT-VAR: manipulation of load, volume, muscle action, and rest interval at each RT session). Muscle fCSA, satellite cell (SC) pool, myonuclei content, and gene expression were assessed before and after training (chronic effect). Gene expression was assessed 24 h after the last training session (acute effect). RT-CON and RT-VAR increased fCSA and myonuclei domain in type I and II fibers after training (p < 0.05). SC and myonuclei content did not change for both conditions (p > 0.05). Pax-7, MyoD, MMP-2 and COL3A1 (chronic) and MGF, Pax-7, and MMP-9 (acute) increased similar for RT-CON and RT-VAR (p < 0.05). The increase in acute MyoG expression was significantly higher for the RT-VAR than RT-CON (p < 0.05). We found significant correlation between RT-CON and RT-VAR for the fCSA changes (r = 0.89). fCSA changes were also correlated to satellite cells (r = 0.42) and myonuclei (r = 0.50) changes. Heatmap analyses showed coupled changes in fCSA, SC, and myonuclei responses at the individual level, regardless of the RT protocol. The high between and low within-subject variability regardless of RT protocol suggests that the intrinsic biological factors seem to be more important to explain the magnitude of fCSA gains in resistance-trained subjects.

Maintenance of Muscle Mass and Cardiorespiratory Fitness to Cancer Patients During COVID-19 Era and After SARS-CoV-2 Vaccine.

There is emerging evidence that decreased muscle mass and cardiorespiratory fitness (CRF) are associated with increased risk of cancer-related mortality. This paper aimed to present recommendations to prescribe effective and safe exercise protocols to minimize losses, maintain or even improve muscle mass, strength, and CRF of the cancer patients who are undergoing or beyond treatment during the COVID-19 era. Overall, we recommend performing exercises with bodyweight, elastic bands, or suspension bands to voluntary interruption (i.e., interrupt the exercise set voluntarily, according to their perception of fatigue, before concentric muscular failure) to maintain or increase muscle strength and mass and CRF during COVID-19 physical distancing. Additionally, rest intervals between sets and exercises (i.e., long or short) should favor maintaining exercise intensities between 50 and 80% of maxHR and/or RPE of 12. In an exercise program with these characteristics, the progression of the stimulus must be carried out by increasing exercise complexity, number of sets, and weekly frequency. With feasible exercises attainable anywhere, modulating only the work-to-rest ratio and using voluntary interruption, it is possible to prescribe exercise for a wide range of patients with cancer as well as training goals. Exercise must be encouraged; however, exercise professionals must be aware of the patient's health condition even at a physical distance to provide a safe and efficient exercise program. Exercise professionals should adjust the exercise prescription throughout home confinement whenever necessary, keeping in mind that minimal exercise stimuli are beneficial to patients in poor physical condition.

Time Course of Skeletal Muscle miRNA Expression after Resistance, High-Intensity Interval, and Concurrent Exercise.

INTRODUCTION: Exercise-induced microRNA (miRNA) expression has been implicated in the regulation of skeletal muscle plasticity. However, the specificity and acute time course in miRNA expression after divergent exercise modes are unknown. In a randomized crossover design, we compared the acute expression profile of eight skeletal muscle miRNAs previously reported to be involved in skeletal muscle development, growth, and maintenance after a bout of either resistance exercise (RE), high-intensity interval exercise (HIIE), and concurrent resistance and high-intensity interval exercises (CE). METHODS: Nine untrained young men (23.9 ± 2.8 yr, 70.1 ± 14.9 kg, 177.2 ± 3.0 cm, 41.4 ± 5.2 mL·kg-1·min-1) underwent a counterbalanced crossover design in which they performed bouts of RE (2 × 10 repetitions maximum 45° leg press and leg extension exercises), HIEE (12 × 1-min sprints at V˙O2peak with 1-min rest intervals between sprints), and CE (RE followed by HIIE), separated by 1 wk. Vastus lateralis biopsies were harvested immediately before (Pre) and immediately (0 h), 4 h, and 8 h after each exercise bout. RESULTS: There were similar increases (main effect of time; P < 0.05) in miR-1-3p, miR-133a-3p, miR-133b, miR-181a-3p, and miR-486 expression at 8 h from Pre with all exercise modes. Besides a main effect of time, miR-23a-3p and miR-206 presented a main effect of condition with lower expression after HIIE compared with RE and CE. CONCLUSIONS: Select miRNAs (miR-1-3p, miR-133a-3p, miR-133b, miR-23a-3p, miR-181a-3p, miR-206, miR-486) do not exhibit an expression specificity in the acute recovery period after a single bout of RE, HIIE, or CE in skeletal muscle. Our data also indicate that RE has a higher effect on the expression of miR-23a-3p and miR-206 than HIIE. As upregulation of these miRNAs seems to be confined to the 8-h period after exercise, this may subsequently affect the expression patterns of target mRNAs forming the basis of exercise-induced adaptive responses.

Attenuated PGC-1α Isoforms following Endurance Exercise with Blood Flow Restriction.

INTRODUCTION: Exercise performed with blood flow restriction simultaneously enhances the acute responses to both myogenic and mitochondrial pathways with roles in training adaptation. We investigated isoform-specific gene expression of the peroxisome proliferator-activated receptor gamma coactivator 1 and selected target genes and proteins regulating skeletal muscle training adaptation. METHODS: Nine healthy, untrained males participated in a randomized, counterbalanced, crossover design in which each subject completed a bout of low-intensity endurance exercise performed with blood flow restriction (15 min cycling at 40% of V˙O2peak, BFR-EE), endurance exercise (30 min cycling at 70% of V˙O2peak, EE), or resistance exercise (4 × 10 repetitions of leg press at 70% of one-repetition maximum) separated by at least 1 wk of recovery. A single resting muscle biopsy (vastus lateralis) was obtained 2 wk before the first exercise trial (rest) and 3 h after each bout. RESULTS: Total PGC-1α mRNA abundance, along with all four isoforms, increased above rest with EE only (P < 0.05) being higher than BFR-EE (P < 0.05). PGC-1α1, 2, and 4 were higher after EE compared with resistance exercise (P < 0.05). EE also increased vascular endothelial growth factor, Hif-1α, and MuRF-1 mRNA abundance above rest (P < 0.05), whereas COXIV mRNA expression increased with EE compared with BFR-EE (P < 0.05). CONCLUSION: The attenuated expression of all four PGC-1α isoforms when EE is performed with blood flow restriction suggests this type of exercise provides an insufficient stimulus to activate the signaling pathways governing mitochondrial and angiogenesis responses observed with moderate- to high-intensity EE.

A review of resistance training-induced changes in skeletal muscle protein synthesis and their contribution to hypertrophy.

Muscle protein synthesis (MPS) is stimulated by resistance exercise (RE) and is further stimulated by protein ingestion. The summation of periods of RE-induced increases in MPS can induce hypertrophy chronically. As such, studying the response of MPS with resistance training (RT) is informative, as adaptations in this process can modulate muscle mass gain. Previous studies have shown that the amplitude and duration of increases in MPS after an acute bout of RE are modulated by an individual's training status. Nevertheless, it has been shown that the initial responses of MPS to RE and nutrition are not correlated with subsequent hypertrophy. Thus, early acute responses of MPS in the hours after RE, in an untrained state, do not capture how MPS can affect RE-induced muscle hypertrophy. The purpose of this review is provide an in-depth understanding of the dynamic process of muscle hypertrophy throughout RT by examining all of the available data on MPS after RE and in different phases of an RT programme. Analysis of the time course and the overall response of MPS is critical to determine the potential protein accretion after an RE bout. Exercise-induced increases in MPS are shorter lived and peak earlier in the trained state than in the untrained state, resulting in a smaller overall muscle protein synthetic response in the trained state. Thus, RT induces a dampening of the MPS response, potentially limiting protein accretion, but when this occurs remains unknown.

Dor muscular e atividade de creatina quinase após ações excêntricas: uma análise de cluster / Muscle soreness and creatine kinase activity after eccentric actions: a cluster analysis / Dolor muscular y actividad de creatina kinasa tras acciones excéntricas: un análisis de cluster

INTRODUÇÃO: O exercício excêntrico máximo promove queda da capacidade de geração de força, aumento de dor muscular de início tardio (DMIT) e extravasamento de creatina quinase (CK) no sangue. No entanto, essas respostas ao exercício excêntrico demonstram alta variabilidade interindivíduos. OBJETIVOS: Classificar e analisar essas respostas segundo a vulnerabilidade individual, por meio da magnitude da redução dos níveis de força após exercício excêntrico. MÉTODOS: Dezoito sujeitos (11 homens e sete mulheres com idade entre 18 e 71 anos) saudáveis realizaram cinco séries de seis ações excêntricas máximas para flexores do cotovelo em dinamômetro isocinético (90°s- 1, amplitude de movimento de 80 a 20°). Foram analisadas contração voluntária muscular concêntrica máxima (CVM), DMIT e CK pré, pós (exceto CK), 24 h, 48 h, 72 h e 96 h após o protocolo. Os indivíduos foram classificados como "baixos" (BR) e "altos" respondedores (AR) ao pico de queda de CVM pós-exercício seguindo-se uma análise de cluster e comparação entre grupos para CVM, DMIT e CK com teste-t independente. RESULTADOS: A comparação entre BR e AR indicou maiores valores de queda de CVM para o grupo AR (AR: -30,7 ± 3,3%; BR: -14,1 ± 2,2%, p < 0,001) e maior DMIT também para o grupo AR (AR: 33,0 ± 8,6 mm; BR: 10,2 ± 2,5 mm, p = 0,033); no entanto, os valores de pico de atividade de CK não diferiram entre os grupos (AR: 232,1 ± 54,8 UI.L- 1; BR: 306,1 ± 82,3 UI.L- 1, p = 0,490). CONCLUSÃO: A classificação dos indivíduos em grupos de baixos e altos respondedores foi importante para demonstrar que o grupo mais responsivo à queda de força após exercício excêntrico ...

INTRODUCTION: Maximal eccentric exercise promotes decreases in muscular strength, increases in delayed-onset muscle soreness (DMIT) and leakage of creatine kinase (CK) in the blood. However, these responses to eccentric exercise demonstrated large inter-individual variability. OBJECTIVES: To classify and analyze these responses according to individual vulnerability through the magnitude of the reduction of strength following eccentric exercise. METHODS: Eighteen healthy subjects (11 men and seven women aged 18 to 71 years) performed five sets of six maximal isokinetic eccentric actions of the elbow flexors using an isokinetic dynamometer (90°s- 1, range of motion 80-20°). Maximum voluntary concentric muscle contraction (CVM), DMIT and CK pre-, post (except CK), 24h, 48h, 72h and 96h were analyzed after the protocol. Individuals were classified as "low" (BR) and "high" (AR) responders at the peak of CVM decrease post-exercise using a k-means cluster analysis and compared between groups for CVM, DMIT and CK with independent t-test. RESULTS: The comparison between BR and AR showed higher CVM decrease for AR (AR: -30.7±3.3%, BR: -14.1±2.2%, p<0.001) and higher DMIT also for AR group (AR: 33.0±8.6 mm; BR: 10.2±2.5 mm, p=0.033) however, the peak values of CK activity did not differ between groups (AR: 232.1±54.8 UI.L- 1, BR: 306.1±82.3 UI.L- 1, p=0.490). CONCLUSION: The classification of the subjects into low and high responders groups was important to demonstrate that the most responsive group to strength decrease after eccentric exercise also shows higher DMIT levels; notwithstanding, for creatine kinase this relation could not be established. .

INTRODUCCIÓN: El ejercicio excéntrico máximo promueve reducciones de capacidad de generación de energía, aumento de dolor muscular de aparición tardía (DMIT), y escape de creatina kinasa (CK) en la sangre. Sin embargo, estas respuestas al ejercicio excéntrico demostraron una gran variabilidad interindividual. OBJETIVOS: Clasificar y analizar las respuestas de acuerdo a la vulnerabilidad individual al grado de disminución de la fuerza después del ejercicio excéntrico. MÉTODOS: Dieciocho sujetos sanos (11 hombres y siete mujeres de entre 18 a 71 años) han realizado cinco series de seis acciones excéntricas isocinéticas máximas de los flexores del codo utilizando un dinamómetro isocinético (90º s- 1, rango de movimiento 80-20°). La contracción concéntrica muscular voluntaria máxima (CVM), DMIT y CK pre-, inmediatamente después (excepto CK), 24h, 48h, 72h y 96h fue analizada después del protocolo. Los individuos fueron clasificados en "bajos" (BR) y "altos" (AR) respondedores, conforme el pico de declinación en la CVM después del ejercicio mediante un análisis de cluster y comparados entre los grupos para la CVM, DMIT y CK con pruebas t-independientes. RESULTADOS: La comparación entre BR y AR indicó mayor disminución de la CVM para AR (AR: -30,7 ± 3,3%, BR: -14,1 ± 2,2%, p < 0,001) y mayor DMIT también para AR (AR: 33,0 ± 8,6 mm; BR : 10,2 ± 2,5 mm, p = 0,033), sin embargo, los valores de pico de actividad de la CK no difirieron entre los grupos (AR: 232,1 ± 54,8 UI.L-1, BR: 306,1 ± 82,3 UI.L-1, p = 0,490). CONCLUSIÓN: La clasificación de los sujetos en los grupos bajos y altos respondedores fue importante para demostrar que el grupo más sensible a la disminución de la fuerza después del ejercicio excéntrico ...

Comparison in responses to maximal eccentric exercise between elbow flexors and knee extensors of older adults.

OBJECTIVES: To compare the susceptibility of elbow flexors (EF) and knee extensors (KE) to eccentric exercise-induced muscle damage in older individuals, since ageing could modulate the difference in the susceptibility to muscle damage between muscles. DESIGN: Cross-sectional and cross-over study design. METHODS: Eight older (61.6 ± 1.8 years) adults performed 5 sets of 6 maximal isokinetic (90° s(-1)) eccentric contractions of the EF (range of motion: 80-20°) and KE (30-90°) with the non-dominant limb in a randomised, counterbalanced order with 2 weeks between bouts. Maximal voluntary isometric (MVC-ISO) and concentric contraction torque, optimum angle, range of motion (ROM), muscle soreness and serum creatine kinase (CK) activity were measured before, immediately after (except CK), and 24, 48, 72 and 96 h following exercise. Normalised changes in the variables following exercise were compared between EF and KE by a mixed model analysis of variance. RESULTS: Only MVC-ISO and ROM demonstrated significant group effects (p<0.05) for the comparison between EF and KE. Additionally, no significant group vs. time interactions (p>0.05) were found between EF and KE for any of the dependent variables changes. CONCLUSIONS: These results suggest that the KE of older adults are relatively as susceptible to muscle damage as their EF, or at the very least, the difference between EF and KE are small for older adults.

Sixteen weeks of resistance training can decrease the risk of metabolic syndrome in healthy postmenopausal women.

BACKGROUND: The postmenopausal phase has been considered an aggravating factor for developing metabolic syndrome. Notwithstanding, no studies have as yet investigated the effects of resistance training on metabolic syndrome in postmenopausal women. Thus, the purpose of this study was to verify whether resistance training could reduce the risk of metabolic syndrome in postmenopausal women. METHODS: Twenty postmenopausal women were randomly assigned to a resistance training protocol (n = 10, 53.40 ± 3.95 years, 64.58 ± 9.22 kg) or a control group (n = 10, 53.0 ± 5.7 years, 64.03 ± 5.03 kg). In the resistance training protocol, ten exercises were performed, with 3 × 8-10 maximal repetitions three times per week, and the load was increased every week. Two-way analysis of variance was used to evaluate specific metabolic syndrome Z-score, high density lipoprotein cholesterol, fasting blood glucose, triglycerides, waist circumference, blood pressure, strength, and body composition. The level of statistical significance was set at P < 0.05. RESULTS: The main results demonstrated a significant decrease of metabolic syndrome Z-score when the postmenopausal women performed resistance training (P = 0.0162). Moreover, we observed decreases in fasting blood glucose for the resistance training group (P = 0.001), and also significant improvements in lean body mass (P = 0.042, 2.46%), reduction of body fat percentage (P = 0.001, -6.75%) and noticeable increases in muscle strength after resistance training to leg press (P = 0.004, 41.29%) and bench press (P = 0.0001, 27.23%). CONCLUSION: It was concluded that resistance training performed three times a week may reduce the metabolic syndrome Z-score with concomitant decreases in fasting blood glucose, improvements in body composition, and muscle strength in postmenopausal women.

Comparison of maximal muscle strength of elbow flexors and knee extensors between younger and older men with the same level of daily activity.

BACKGROUND: Aging promotes neuromuscular loss, significantly reducing muscle strength. The magnitude of loss of strength seems to be different between the limbs, probably because of differences in activities of daily living (ADL). Therefore, the present study compared the muscle strength of the elbow flexors and knee extensors in younger (n = 7, mean age 23.3 ± 1.2 years) and older (n = 5, mean age 61.8 ± 2.6 years) men matched by ADL level. METHODS: The study participants performed maximal concentric, isometric, and eccentric contractions of the elbow flexors and knee extensors using an isokinetic dynamometer following a crossover study design. Changes in the dependent variables were compared using mixed model analysis (limb versus age). RESULTS: The main results demonstrated that concentric, eccentric, and mean contraction torques for knee extensors were significantly (P < 0.05) higher for younger men than for elderly men. On the other hand, no statistically significant difference (P > 0.05) was found in concentric, isometric, eccentric, and mean torques for elbow flexors between younger and older individuals. CONCLUSION: These results show that elbow flexors maintain better strength than knee extensors through aging, even when comparing individuals with similar ADL levels.

Efeito do treinamento concorrente sobre a força e área de secção transversa muscular / Effects of concurrent training on strength and muscle cross sectional area

O treinamento de força (TF) induz aumentos na força e hipertrofia muscular. Por outro lado, o treinamento aeróbio (TA) é capaz de elevar a potência aeróbia (VO2pico). Porém a associação entre o TF e TA, conhecido como treinamento concorrente (TC), parece diminuir os ganhos de força e hipertrofia muscular quando comparado ao TF isolado. Dessa forma, esse estudo comparou os efeitos de 16 semanas de TF, TA e TC na área de secção transversa de coxa (ASTC) e força muscular em 49 homens de meia-idade idade não ativos fisicamente. Para tanto os sujeitos foram randomizados em TF (n=12), TA (n=12), TC (n=12) e grupo controle (GC, n=13). Os protocolos de treinamento foram compostos de duas etapas (E1 e E2) com duração de oito semanas cada, e frequência de três sessões/semana (TF: 10 exercícios 3 x 8 10RM; TA: 60 min de caminhada ou corrida a 55-85%VO2pico; TC: 6 exercícios 3 x 8-10RM somados de 30 min de caminhada ou corrida a 55-85%VO2pico; GC não realizou nenhum protocolo de treinamento durante o período do estudo). A ASTC foi mensurada pela equação de Knapik; força máxima por teste de 1-RM; VO2pico por meio de teste ergométrico em esteira. Os principais resultados demonstraram que o TF e TC obtiveram aumentos similares da ASTC (5,7 e 5,6%; respectivamente) e concomitante aumento da força máxima no exercício leg press após 16 semanas de intervenção (48,6 e 54,8%; respectivamente). Os resultados referentes ao VO2pico evidenciaram aumentos similares apenas para os grupos TC (14,8%) e TA (21,7%) após a intervenção. Dessa forma, concluímos que o protocolo de TC utilizado no presente estudo, não promove o efeito de interferência na ASTC e força muscular de membros inferiores de homens de meia-idade.

Strength training (TF) promotes muscle hypertrophy and enhances muscle strength. On the other hand, endurance training (TA) raises the peak oxygen uptake (VO2peak). However, the association between TF and TA, known as concurrent training (TC), might impair gains of muscle hypertrophy and strength compared to isolated TF. Therefore, this study analyzed the effects of 16 weeks of TF, TA and TC in muscle strength and thigh cross sectional area (AST) in 49 non-physically active middle-aged men. Subjects were randomized in TF (n=12), TA (n=12), TC (n=12) and control group (GC, n=13). Trainings were composed of two periods (E1 and E2) of 8 weeks each and frequency of 3 days/week (TF: 10 exercises-3x8-10RM; TA: 60 min of walking or running; TC: 6 exercises-3x8-10RM followed by 30 min of walking or running at 55-85%VO2peak; GC did not performed any training during study period). Thigh AST was analyzed through the equation of Knapik; muscle strength through 1-RM test; VO2peak through a cardiorespiratory treadmill test. Main results showed that TF and TC enhanced similarly muscle strength in leg press (5,7 e 5,6%; respectively) and thigh AST (48,6 e 54,8%; respectively) following 16 weeks of intervention. The results regarding VO2peak demonstrated similar increases for TC (14,8%) and TA (21,7%) after intervention. We concluded that 16 weeks of TC did not produce the interference effect either for thigh AST or lower limbs muscle strength in middle-aged men.

Efeito do treinamento com pesos sobre a flexibilidade de homens de meia-idade / Effect of weight training on the flexibility of middle-aged men

O presente estudo teve como objetivo investigar o efeito de 12 semanas de treinamento com pesos (TP) na flexibilidade de homens de meia-idade. Possivelmente, indivíduos na meia-idade sedentários apresentem melhoras na flexibilidade somente com a realização de TP. Foram selecionados 16 indivíduos de meia-idade (48,8 ± 5,0 anos) divididos aleatoriamente em dois grupos: grupo controle (GC, n=8) e grupo treinamento (GT, n=8). O GT realizou TP duas vezes por semana, em dias não consecutivos (3 séries de 15 repetições, 1 minuto de pausa). A flexibilidade de ombro, tronco, quadril e joelhos foram aferidas bilateralmente (com exceção do tronco) antes e após o período experimental. Não foi verificado efeito do tempo para nenhuma das variáveis analisadas (p>0,05). O TP de baixa intensidade não reduz a flexibilidade de homens de meia-idade.

The aim of the present study was to investigate the effect of 12 weeks of resistance training on flexibility levels of middle-aged men. Possibly, middle-aged sedentary subjects might show flexibility improvements only performing resistance training. Sixteen middle-aged men (48.8 ± 5.0 years) were selected for the present study. They were randomly divided in two groups: control group (GC, n=8) and training group (GT, n=8). The GT performed resistance training twice a week, in alternate days (3 sets of 15 repetitions, with 1 minute rest between sets). Shoulder, trunk, hips and knees flexibility were assessed bilaterally (with the exception of trunk) pre- and post- study period. No significant time interaction was found for any variable (p>0.05). Low-intensity resistance training does not reduce middle-aged men flexibility.