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1.
Trials ; 21(1): 171, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32051025

RESUMO

BACKGROUND: Patients with rheumatoid arthritis spend most of their daily hours in sedentary behavior (sitting), a predisposing factor to poor health-related outcomes and all-cause mortality. Interventions focused on reducing sedentary time could be of novel therapeutic relevance. However, studies addressing this topic remain scarce. We aim to investigate the feasibility and efficacy of a newly developed intervention focused on reducing sedentary time, and potential clinical, physiological, metabolic and molecular effects in rheumatoid arthritis. METHODS: The Take a STAND for Health study is a 4-month, parallel-group, randomized controlled trial, in which postmenopausal patients with rheumatoid arthritis will set individually tailored, progressive goals to replace their sedentary time with standing and light-intensity activities. Patients will be recruited from the Clinical Hospital (School of Medicine, University of Sao Paulo) and will be assessed at baseline and after a 4-month follow up. Outcomes will include objectively measured sedentary behavior (primary outcome) and physical activity levels, clinical parameters, anthropometric parameters and body composition; aerobic fitness, muscle function, blood pressure, cardiovascular autonomic function, vascular function and structure, health-related quality of life, and food intake. Blood and muscle samples will be collected for assessing potential mechanisms, through targeted and non-targeted approaches. DISCUSSION: Findings will be of scientific and clinical relevance with the potential to inform new prescriptions focused on reducing sedentary behavior, a modifiable risk factor that thus far has been overlooked in patients with rheumatoid arthritis. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03186924. Registered on 14 June 2017.

2.
Med Sci Sports Exerc ; 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-32079916

RESUMO

INTRODUCTION: Several acute studies have suggested that leucine is a key amino acid to drive muscle protein synthesis. However, there are very few studies on the long-term effects of leucine supplementation on resistance training-induced gains in muscle mass and strength. We sought to determine the impact of 10 grams of leucine on muscle mass and strength in response to resistance training (RT) in healthy young men. METHODS: Twenty-five, resistance-trained men (27 ± 5 y; 78.4 ± 11.6 kg; 24.8 ± 3.0 kg/m) consuming 1.8 ± 0.4 g protein·kg·d, were randomly assigned to receive 2 x 5 g·d supplementation of either free leucine (LEU n=12) or alanine (PLA n= 13), while undergoing a supervised 12-week, twice- weekly lower-limb RT program. One-repetition maximum (leg-press 1RM) and muscle cross-sectional area (mCSA) of the vastus lateralis were determined before (PRE) and after (POST) the intervention. Additionally, three 24-hour dietary recalls were also performed at PRE and POST. RESULTS: Protein intake was roughly double that of the RDA in both groups and remained unchanged across time with no differences detected between groups. Similar increases were observed between groups in leg-press 1RM (LEU: 19.0 ± 9.4% and PLA: 21.0 ± 10.4%, p=0.31) and mCSA (LEU: 8.0 ± 5.6% and PLA: 8.4 ± 5.1%, p=0.77). CONCLUSION: high-dose leucine supplementation did not enhance gains in muscle strength and mass after a 12-week resistance training program in young resistance-trained males consuming adequate amounts of dietary protein.

3.
Clin Rheumatol ; 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31902026

RESUMO

To investigate the association between food consumption stratified by processing level and cardiovascular risk factors in rheumatoid arthritis. In this cross-sectional study, 56 patients (age: 62.5 ± 7.9 years, BMI: 28.4 ± 5.1 kg/m2) had food consumption evaluated according to the processing level (e.g., unprocessed or minimally processed foods, processed foods, and ultra-processed foods) and associated with cardiovascular risk factors. The most prevalent food processing level was unprocessed or minimally processed foods (42.6 ± 12.6% of total energy intake [TEI]), followed by processed (24.2 ± 11.9%TEI), ultra-processed (18.1 ± 11.8%TEI), and culinary ingredients (15.1 ± 6.4%TEI). Adjusted regression models showed that higher consumption of ultra-processed foods was positively associated with Framingham risk score (ß = 0.06, CI: 95% 0.001, 0.11, p = 0.045) and glycated hemoglobin (ß = 0.04, CI: 95% 0.01, 0.08, p = 0.021). In contrast, higher consumption of unprocessed or minimally processed foods was associated with lower 10-year risk of developing cardiovascular diseases (ß = -0.05, CI: 95% - 0.09, -0.003, p = 0.021) and LDL (ß = -1.09, CI: 95% - 1.94, -0.24, p = 0.013). Patients with rheumatoid arthritis consuming more ultra-processed foods showed worse metabolic profile, whereas those consuming more unprocessed or minimally processed foods had lower cardiovascular risks. A food pattern characterized by a high ultra-processed food consumption appears to emerge as a novel, modifiable risk factor for cardiovascular diseases in rheumatoid arthritis. Key-Points • Higher ultra-processed food consumption was associated with worse metabolic profile and increased cardiovascular risk, whereas higher unprocessed or minimally processed food consumption was associated with lower 10-year risk of developing cardiovascular diseases. • A food pattern characterized by a high ultra-processed food consumption appears to emerge as a novel, modifiable risk factor for cardiovascular diseases in rheumatoid arthritis.

4.
Am J Physiol Heart Circ Physiol ; 318(1): H90-H109, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31702969

RESUMO

Blood flow restriction training (BFRT) is an increasingly widespread method of exercise that involves imposed restriction of blood flow to the exercising muscle. Blood flow restriction is achieved by inflating a pneumatic pressure cuff (or a tourniquet) positioned proximal to the exercising muscle before, and during, the bout of exercise (i.e., ischemic exercise). Low-intensity BFRT with resistance training promotes comparable increases in muscle mass and strength observed during high-intensity exercise without blood flow restriction. BFRT has expanded into the clinical research setting as a potential therapeutic approach to treat functionally impaired individuals, such as the elderly, and patients with orthopedic and cardiovascular disease/conditions. However, questions regarding the safety of BFRT must be fully examined and addressed before the implementation of this exercise methodology in the clinical setting. In this respect, there is a general concern that BFRT may generate abnormal reflex-mediated cardiovascular responses. Indeed, the muscle metaboreflex is an ischemia-induced, sympathoexcitatory pressor reflex originating in skeletal muscle, and the present review synthesizes evidence that BFRT may elicit abnormal cardiovascular responses resulting from increased metaboreflex activation. Importantly, abnormal cardiovascular responses are more clearly evidenced in populations with increased cardiovascular risk (e.g., elderly and individuals with cardiovascular disease). The evidence provided in the present review draws into question the cardiovascular safety of BFRT, which clearly needs to be further investigated in future studies. This information will be paramount for the consideration of BFRT exercise implementation in clinical populations.

6.
Eur J Nutr ; 59(1): 57-65, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30552505

RESUMO

PURPOSE: To investigate the effects of chronic beta-alanine (BA) supplementation on muscle taurine content, blood clinical markers and sensory side-effects. METHODS: Twenty-five healthy male participants (age 27 ± 4 years, height 1.75 ± 0.09 m, body mass 78.9 ± 11.7 kg) were supplemented with 6.4 g day-1 of sustained-release BA (N = 16; CarnoSyn™, NAI, USA) or placebo (PL; N = 9; maltodextrin) for 24 weeks. Resting muscle biopsies of the m. vastus lateralis were taken at 0, 12 and 24 weeks and analysed for taurine content (BA, N = 12; PL, N = 6) using high-performance liquid chromatography. Resting venous blood samples were taken every 4 weeks and analysed for markers of renal, hepatic and muscle function (BA, N = 15; PL, N = 8; aspartate transaminase; alanine aminotransferase; alkaline phosphatase; lactate dehydrogenase; albumin; globulin; creatinine; estimated glomerular filtration rate and creatine kinase). RESULTS: There was a significant main effect of group (p = 0.04) on muscle taurine, with overall lower values in PL, although there was no main effect of time or interaction effect (both p > 0.05) and no differences between specific timepoints (week 0, BA: 33.67 ± 8.18 mmol kg-1 dm, PL: 27.75 ± 4.86 mmol kg-1 dm; week 12, BA: 35.93 ± 8.79 mmol kg-1 dm, PL: 27.67 ± 4.75 mmol kg-1 dm; week 24, BA: 35.42 ± 6.16 mmol kg-1 dm, PL: 31.99 ± 5.60 mmol kg-1 dm). There was no effect of treatment, time or any interaction effects on any blood marker (all p > 0.05) and no self-reported side-effects in these participants throughout the study. CONCLUSIONS: The current study showed that 24 weeks of BA supplementation at 6.4 g day-1 did not significantly affect muscle taurine content, clinical markers of renal, hepatic and muscle function, nor did it result in chronic sensory side-effects, in healthy individuals. Since athletes are likely to engage in chronic supplementation, these data provide important evidence to suggest that supplementation with BA at these doses for up to 24 weeks is safe for healthy individuals.

7.
J Hum Kinet ; 69: 239-247, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31666906

RESUMO

The aim of this study was to compare the acute effects of performing half squats (HSs) with different loading intensities (1, 3, and 5 repetitions maximum [RM], and 60% 1RM) and a different number of sets (1, 2, and 3) on the countermovement jump (CMJ) performance of 18 highly-trained male subjects. Participants were submitted to four experimental conditions (1RM, 3RM, 5RM, and 60% 1RM) in randomized order. The CMJ was assessed before and after each set. Differences in CMJ performance between the distinct experimental conditions and individual responses in CMJ performance induced by the different protocols were analyzed via the magnitude-based inference method. Overall, significant improvements were detected in individual CMJ heights after each activation protocol. It can be concluded that the use of 1 to 3 sets of HSs performed at moderate-to-high loads may be an effective strategy to improve jump performance in highly-trained subjects. Nonetheless, despite the high efficiency of the protocols tested here, coaches and researchers are strongly encouraged to perform individualized assessments within the proposed range of loads and sets, to find optimal and tailored post-activation potentiation protocols.

9.
J Clin Endocrinol Metab ; 104(10): 4639-4650, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31322672

RESUMO

CONTEXT: Bone loss after bariatric surgery potentially could be mitigated by exercise. OBJECTIVE: To investigate the role of exercise training (ET) in attenuating bariatric surgery-induced bone loss. DESIGN: Randomized, controlled trial. SETTING: Referral center for bariatric surgery. PATIENTS: Seventy women with severe obesity, aged 25 to 55 years, who underwent Roux-en-Y gastric bypass (RYGB). INTERVENTION: Supervised, 6-month, ET program after RYGB vs. standard of care (RYGB only). OUTCOMES: Areal bone mineral density (aBMD) was the primary outcome. Bone microarchitecture, bone turnover, and biochemical markers were secondary outcomes. RESULTS: Surgery significantly decreased femoral neck, total hip, distal radius, and whole body aBMD (P < 0.001); and increased bone turnover markers, including collagen type I C-telopeptide (CTX), procollagen type I N-propeptide (P1NP), sclerostin, and osteopontin (P < 0.05). Compared with RYGB only, exercise mitigated the percent loss of aBMD at femoral neck [estimated mean difference (EMD), -2.91%; P = 0.007;], total hip (EMD, -2.26%; P = 0.009), distal radius (EMD, -1.87%; P = 0.038), and cortical volumetric bone mineral density at distal radius (EMD, -2.09%; P = 0.024). Exercise also attenuated CTX (EMD, -0.20 ng/mL; P = 0.002), P1NP (EMD, -17.59 ng/mL; P = 0.024), and sclerostin levels (EMD, -610 pg/mL; P = 0.046) in comparison with RYGB. Exercise did not affect biochemical markers (e.g., 25(OH)D, calcium, intact PTH, phosphorus, and magnesium). CONCLUSION: Exercise mitigated bariatric surgery-induced bone loss, possibly through mechanisms involving suppression in bone turnover and sclerostin. Exercise should be incorporated in postsurgery care to preserve bone mass.

10.
Artigo em Inglês | MEDLINE | ID: mdl-31033228

RESUMO

OBJECTIVE: To evaluate the effects of a low-load resistance training program associated with partial blood flow restriction in patients with rheumatoid arthritis (RA). METHODS: Forty-eight women with RA were randomized into one of the three groups: high-load resistance training (HL-RT: 70% one repetition maximum [1RM]); low-load resistance training (30% 1RM) with partial blood flow restriction (BFRT) and control group. Patients completed a 12-week supervised training program and were assessed for lower-limb 1RM, quadriceps cross-sectional area (CSA), physical function (timed-stands test [TST], timed-up-and-go test [TUG], Health Assessment Questionnaire [HAQ]) and quality of life (Short Form Health Survey [SF-36]) at baseline and after the intervention. RESULTS: BFRT and HL-RT were similarly effective in increasing maximal dynamic strength in both leg press (+22.8% and +24.2%, all p<0.0001) and knee extension (+19.7% and +23.8%; all p<0.0001). Quadriceps CSA was also significantly increased in both BFRT and HL-RT (+9.5% and +10.8%; all p<0.0001, respectively). Comparable improvements in TST (+11.2% and +14.7%; all p<0.0001) and TUG (-6.8%, p<0.0053 and -8.7%, p<0.0001) were also observed in BFRT and HL-RT, respectively. Improvements in both groups were significantly greater than those of CG (all p<0.05). SF-36 role physical, bodily pain and HAQ scores were improved only in BFRT (+45.7%, +22.5% and -55.9%, respectively; all p<0.05). HL-RT resulted in one case of withdrawal and several cases of exercise-induced pain, which did not occur in BFRT. CONCLUSION: BFRT was effective in improving muscle strength, mass, function and health-related quality of life in patients with RA, emerging as a viable therapeutic modality in RA management. This article is protected by copyright. All rights reserved.

11.
J Hum Kinet ; 66: 195-203, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30988853

RESUMO

The aim of this study was to compare the acute effects of performing half squats (HSs) with different loading intensities (1, 3, and 5 repetitions maximum [RM], and 60% 1RM) and a different number of sets (1, 2, and 3) on the countermovement jump (CMJ) performance of 18 highly-trained male subjects. Participants were submitted to four experimental conditions (1RM, 3RM, 5RM, and 60% 1RM) in randomized order. The CMJ was assessed before and after each set. Differences in CMJ performance between the distinct experimental conditions and individual responses in CMJ performance induced by the different protocols were analyzed via the magnitude-based inference method. Overall, significant improvements were detected in individual CMJ heights after each activation protocol. It can be concluded that the use of 1 to 3 sets of HSs performed at moderate-to-high loads may be an effective strategy to improve jump performance in highly-trained subjects. Nevertheless, despite the high efficiency of the protocols tested here, coaches and researchers are strongly encouraged to perform individualized assessments within the proposed range of loads and sets, to find optimal and tailored post-activation potentiation protocols.

12.
Cytokine ; 120: 66-70, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31005728

RESUMO

Polycystic ovary syndrome (PCOS) is characterized by exacerbated inflammation, which is implicated in cardiometabolic dysfunction. This study aimed to examine the potential effects of acute exercise on inflammatory responses in obese/overweight PCOS women and their controls. Participants underwent a single bout of moderate-intensity aerobic exercise (30 min at ∼65% of VO2peak). Blood and muscle samples were collected immediately before (PRE) and 60 min after the exercise session. Cytokines (i.e., IL-1ß, IL-6, IL-4, IL-10, TNF-α) were measured both in plasma and in skeletal muscle, and proteins related to inflammatory signaling (IKKα/ß and JNK) were assessed in skeletal muscle. At PRE, PCOS showed elevated muscle TNF-α (+62%, p = 0.0012) and plasma IL-1ß (+76%, p = 0.0010) compared to controls. In PCOS, exercise decreased plasma and muscle TNF-α (-14%, p = 0.0003 and -46%, p = 0.0003), as well as increased plasma and muscle IL-4 (+147%, p = 0.0018 and +62%, p = 0.0474) and plasma IL-10 (+38%, p = 0.0029). Additionally, IKKα/ß and JNK phosphorylation in skeletal muscle, which was higher in PCOS at PRE, was significantly reduced by exercise (-58%, p < 0.0001 and -46%, p < 0.0001, respectively), approaching control levels. Person's correlations between PRE values and delta changes (i.e., exercise effect) showed significant, negative associations for plasma IL-1ß (r = -0.92, p < 0.0001), TNF-α (r = -0.72, p = 0.0100) and IL-6 (r = -0.58, p = 0.05), and muscle TNF-α (r = -0.95, p < 0.0001), IKKα/ß (r = -0.75, p = 0.005), and JNK (r = -0.94, p < 0.0001) in PCOS. In conclusion, exercise can mitigate the inflammatory milieu in women with PCOS. The anti-inflammatory role of exercise could underlie its cardiometabolic protection in PCOS.

13.
Int J Sport Nutr Exerc Metab ; 29(5): 505-511, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30859862

RESUMO

This study evaluated the effects of ß-hydroxy-ß-methylbutyrate free acid (HMB-FA) and calcium salt (HMB-Ca) on strength, hypertrophy, and markers of muscle damage. In this randomized, double-blind, placebo-controlled study, 44 resistance-trained men (age: 26 ± 4 years; body mass: 84.9 ± 12.0 kg) consuming ≥1.7 g·kg-1·day-1 of protein received HMB-FA (3 g/day; n = 14), HMB-Ca (3 g/day; n = 15), or placebo (PL; cornstarch, 3 g/day; n = 15) for 12 weeks, while performing a periodized resistance training program. Before and after intervention, lean body mass (measured with dual X-ray absorptiometry), maximal dynamic strength (one-repetition maximum), knee extension maximal isometric strength (maximal voluntary isometric contraction [MVIC]), cross-sectional area (measured with ultrasound), and muscle soreness were assessed. MVIC was also measured 48 hr after the first and the last training sessions. All groups increased lean body mass (main time effect: p < .0001; HMB-FA: 1.8 ± 1.8 kg; HMB-Ca: 0.8 ± 1.4 kg; PL: 0.9 ± 1.4 kg), cross-sectional area (main time effect: p < .0001; HMB-FA: 6.6 ± 3.8%; HMB-Ca: 4.7 ± 4.4%; PL: 6.9 ± 3.8%), one-repetition maximum bench press (main time effect: p < .0001; HMB-FA: 14.8 ± 8.4 kg; HMB-Ca: 11.8 ± 7.4 kg; PL: 11.2 ± 6.6 kg), MVIC (main time effect: p < .0001; HMB-FA: 34.4 ± 39.3%; HMB-Ca: 32.3 ± 27.4%; PL: 17.7 ± 20.9%) after the intervention, but no differences between groups were shown. HMB-FA group showed greater leg press strength after the intervention than HMB-Ca and PL groups (Group × Time interaction: p < .05; HMB-FA: 47.7 ± 31.2 kg; HMB-Ca: 43.8 ± 31.7 kg; PL: 30.2 ± 20.9 kg). MVIC measured 48 hr after the first and the last sessions showed no attenuation of force decline with supplementation. Muscle soreness following the first and last sessions was not different between groups. The authors concluded that neither HMB-Ca nor HMB-FA improved hypertrophy or reduced muscle damage in resistance-trained men undergoing resistance training ingesting optimal amounts of protein. HMB-FA but not HMB-Ca resulted in a statistically significant yet minor improvement on leg press one-repetition maximum.


Assuntos
Cálcio/administração & dosagem , Força Muscular , Músculo Esquelético/crescimento & desenvolvimento , Treinamento de Resistência , Fenômenos Fisiológicos da Nutrição Esportiva , Valeratos/administração & dosagem , Adulto , Composição Corporal , Método Duplo-Cego , Humanos , Contração Isométrica , Masculino , Mialgia , Adulto Jovem
14.
Appl Physiol Nutr Metab ; 44(2): 216-220, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30001503

RESUMO

We aimed to investigate the mechanisms underlying muscle growth after 12 weeks of resistance training performed with blood flow restriction (RT-BFR) and high-intensity resistance training (HRT) in older individuals. Participants were allocated into the following groups: HRT, RT-BFR, or a control group. High-throughput transcriptome sequencing was performed by the Illumina HiSeq 2500 platform. HRT and RT-BFR presented similar increases in the quadriceps femoris cross-sectional area, and few genes were differently expressed between interventions. The small differences in gene expression between interventions suggest that similar mechanisms may underpin training-induced muscle growth.


Assuntos
Envelhecimento/fisiologia , Músculo Esquelético/metabolismo , Educação Física e Treinamento , Fluxo Sanguíneo Regional/fisiologia , Treinamento de Resistência , Transcriptoma/fisiologia , Idoso , DNA/biossíntese , DNA/genética , Dieta , Feminino , Regulação da Expressão Gênica/fisiologia , Humanos , Perna (Membro)/anatomia & histologia , Perna (Membro)/fisiologia , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/irrigação sanguínea , Músculo Quadríceps/fisiologia , RNA/biossíntese , RNA/genética
15.
Clin Exp Rheumatol ; 37(2): 235-241, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30148431

RESUMO

OBJECTIVES: To evaluate the feasibility, safety and efficacy of exercise training in patients with immune-mediated necrotising myopathies (IMNM). METHODS: Eight consecutive sedentary patients with IMNM (5 anti-signal recognition particle and 3 anti-hydroxy-methyl-glutaryl coenzyme A reductase) were engaged in this study. Disease status was based on International Myositis Assessment and Clinical Studies Group (IMACS) core set measures. Physical performance was evaluated by cardiopulmonary exercise test, repetition maximum (RM) protocol, handgrip dynamometry, sit-to-stand (STS) and timed up-and-go (TUG) tests. All these parameters were measured at baseline and after a 12-week, twice-a-week, supervised exercise training comprising aerobic and strength exercises. RESULTS: Patients (aged 61 years on average) were very disabled at the beginning of the disease (mean duration of 17.7 months), but after being aggressively treated with a treat-to-target approach, they presented only mild symptoms that were well-controlled with oral immunosuppression and low disease status scores by the time of the exercise intervention. No disease relapsing, worsening of the IMACS set scores or adverse events were observed throughout the training period. Patients also increased aerobic capacity (e.g. time to achieve anaerobic threshold and time to achieve exhaustion), muscle strength (e.g. 1RM bench press) and function (e.g. STS test). CONCLUSIONS: Supervised exercise training did not impair disease status and seemed to be feasible, safe and effective in patients with IMNM. Moreover, exercise training increased aerobic capacity, muscle strength and function, suggesting that this could be a novel potential coadjuvant therapy in IMNM.


Assuntos
Terapia por Exercício , Miosite , Treinamento de Resistência , Exercício , Estudos de Viabilidade , Força da Mão , Humanos , Pessoa de Meia-Idade , Força Muscular , Miosite/terapia , Estudos Prospectivos
16.
J Sport Rehabil ; 28(7): 706-710, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30040033

RESUMO

CONTEXT: Given the comparable muscle hypertrophy constantly observed between blood-flow restriction exercise (BFR-RE) and conventional resistance exercise, understanding their particular rating of perceived exertion (RPE) and pain may help to better prescribe exercise at a low-discomfort level, thus increasing its feasibility. DESIGN: Randomized crossover study. OBJECTIVE: To compare the RPE and pain response between conventional high- (HI-RE) and low-intensity resistance exercise (LI-RE) protocols to failure with a nonmuscular failure LI-RE associated with BFR-RE. PARTICIPANTS: A total of 12 men (age: 20 [3] y; body mass: 73.5 [9] kg; height: 174 [6] cm). INTERVENTIONS: Four sets of 45° leg-press exercises in 3 different conditions: (1) BFR-RE (15 repetitions; 30% 1-repetition maximum), (2) HI-RE (80% 1-repetition maximum to muscular failure), and (3) LI-RE (30% 1-repetition maximum to muscular failure). MAIN OUTCOME MEASURES: RPE and pain were assessed immediately before exercise session and after the end of each of the 4 sets. RESULTS: RPE and pain levels increased throughout the exercise sets for all RE protocols (all, Ps < .05). HI-RE and LI-RE protocols showed similar increase in RPE and pain levels during all exercise sets (P < .05); however, both protocols demonstrated higher RPE and pain response compared with BFR-RE after each of the 4 sets (all Ps < .05 between-group comparisons). CONCLUSIONS: Our results demonstrated that both HI-RE and LI-RE to muscular failure resulted in similar and significant increases in RPE and pain levels, regardless of exercise intensity. In addition, nonmuscular failure BFR-RE also increased RPE and pain response, however, to a lower extent compared with either HI-RE or LI-RE.


Assuntos
Hemodinâmica , Músculo Esquelético/fisiologia , Dor , Esforço Físico , Treinamento de Resistência , Constrição , Estudos Cross-Over , Humanos , Masculino , Força Muscular , Músculo Esquelético/irrigação sanguínea , Medição da Dor , Fluxo Sanguíneo Regional , Adulto Jovem
17.
Amino Acids ; 51(1): 27-37, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29905904

RESUMO

ß-Alanine (BA) supplementation may be ergogenic during high-intensity exercise, primarily due to the buffering of hydrogen cations, although the effects of beta-alanine supplementation on strength endurance are equivocal. The aim of the study was to determine the effects of 4 weeks of beta-alanine supplementation on skeletal muscle endurance using a battery of performance tests. This study employed a parallel group, repeated measures, randomised, double-blinded and placebo-controlled design. Twenty recreationally strength-trained healthy males completed tests of isotonic strength endurance (repeated bench and leg press), along with tests of isometric and isokinetic endurance conducted using an isokinetic dynamometer. Tests were performed before and after a 4 week intervention, comprising an intake of 6.4 g day-1 of BA (n = 9) or placebo (maltodextrin, n = 11). Time-to-exhaustion during the isometric endurance test improved by ~ 17% in the BA group (p < 0.01), while PL remained unchanged. No significant within-group differences (p > 0.1) were shown for any of the performance variables in the isokinetic test (peak torque, fatigue index, total work) nor for the total number of repetitions performed in the isotonic endurance tests (leg or bench press). Four weeks of BA supplementation (6.4 g day-1) improved isometric, but not isokinetic or isotonic endurance performance.


Assuntos
Suplementos Nutricionais , Contração Isométrica/efeitos dos fármacos , Contração Isotônica/efeitos dos fármacos , Substâncias para Melhoria do Desempenho/administração & dosagem , Resistência Física/efeitos dos fármacos , beta-Alanina/administração & dosagem , Adulto , Exercício , Humanos , Masculino , Dinamômetro de Força Muscular , Músculo Esquelético/metabolismo , Substâncias para Melhoria do Desempenho/farmacologia , Adulto Jovem , beta-Alanina/farmacologia
18.
Biol Sport ; 35(2): 111-119, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30455539

RESUMO

The aim of this study was to investigate the effects of an acute bout of eccentric actions, performed at fast velocity (210º.s-1) and at slow velocity (20º.s-1), on the gene expression of regulatory components of the myostatin (MSTN) signalling pathway. Participants performed an acute bout of eccentric actions at either a slow or a fast velocity. Muscle biopsy samples were taken before, immediately after, and 2 h after the exercise bout. The gene expression of the components of the MSTN pathway was assessed by real-time PCR. No change was observed in MSTN, ACTRIIB, GASP-1 or FOXO-3a gene expression after either slow or fast eccentric actions (p > 0.05). However, the MSTN inhibitors follistatin (FST), FST-like-3 (FSTL3) and SMAD-7 were significantly increased 2 h after both eccentric actions (p < 0.05). No significant difference between bouts was found before, immediately after, or 2 h after the eccentric actions (slow and fast velocities, p > 0.05). The current findings indicate that a bout of eccentric actions activates the expression of MSTN inhibitors. However, no difference was observed in MSTN inhibitors' gene expression when comparing slow and fast eccentric actions. It is possible that the greater time under tension induced by slow eccentric (SE) actions might compensate the effect of the greater velocity of fast eccentric (FE) actions. Additional studies are required to address the effect of eccentric action (EA) velocities on the pathways related to muscle hypertrophy.

20.
Eur J Appl Physiol ; 118(12): 2607-2616, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30196447

RESUMO

BACKGROUND: Gene expression is an important process underpinning the acute and chronic adaptive response to resistance exercise (RE) training. PURPOSE: To investigate the effect of training status on vastus lateralis muscle global transcriptome at rest and following acute RE. METHODS: Muscle biopsies of nine young men (age: 26(2) years; body mass: 69(9) kg; height 172(6) cm) who undertook RE training for 10 weeks were collected pre and 24 h post-RE in the untrained (W1) and trained (W10) states and analysed using microarray. Tests of differential expression were conducted for rested and after RE contrasts in both training states. To control for false discovery rate (FDR), multiple testing correction was performed at a cut-off of FDR < 0.05. RESULTS: Unaccustomed RE (at W1) upregulated muscle gene transcripts related to stress (e.g., heat shock proteins), damage and inflammation, structural remodelling, protein turnover and increased translational capacity. Trained muscles (at W10) showed changes in the transcriptome signature regarding the regulation of energy metabolism, favouring a more oxidative one, upregulated antioxidant- and immune-related genes/terms, and gene transcripts related to the cytoskeleton and extracellular matrix, muscle contraction, development and growth. CONCLUSIONS: These results highlight that chronic repetition of RE changes muscle transcriptome response towards a more refined response to RE-induced stress.


Assuntos
Músculo Esquelético/metabolismo , Treinamento de Resistência , Estresse Fisiológico , Transcriptoma , Adulto , Humanos , Masculino , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/fisiologia
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