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Context: Low-load resistance training (LL) and neuromuscular electrostimulation (NES), both combined with blood flow restriction (BFR), emerge as effective strategies to maintain or increase muscle mass. It is well established that LL-BFR promotes similar increases in muscle cross-sectional area (CSA) and lower rating of perceived exertion (RPE) and pain compared with traditional resistance training protocols. On the other hand, only 2 studies with conflicting results have investigated the effects of NES-BFR on CSA, RPE, and pain. In addition, no study directly compared LL-BFR and NES-BFR. Objective: The aim of the study was to compare the effects of LL-BFR and NES-BFR on vastus lateralis CSA, RPE, and pain. Individual response for muscle hypertrophy was also compared between protocols. Design: Intrasubject longitudinal study. Setting: University research laboratory. Intervention: Fifteen healthy young males (age = 23 [5] y; weight = 77.6 [11.3] kg; height = 1.76 [0.08] m). Main outcome measures: Vastus lateralis CSA was measured through ultrasound at baseline (pre) and after 20 training sessions (post). The RPE and pain responses were obtained through modified 10-point scales, handled during all training sessions. Results: Both protocols demonstrated significant increases in muscle CSA (P < .0001). However, the LL-BFR demonstrated significantly greater CSA changes compared with NES-BFR (LL-BFR = 11.2%, NES-BFR = 4.6%; P < .0001). Comparing individual increases in CSA, 12 subjects (85.7% of the sample) presented greater muscle hypertrophy for LL-BFR than for the NES-BFR protocol. In addition, LL-BFR produced significantly lower RPE and pain responses (P < .0001). Conclusions: The LL-BFR produced significantly greater increases in CSA with significant less RPE and pain than NES-BFR. In addition, LL-BFR resulted in greater individual muscle hypertrophy responses for most subjects compared with NES-BFR. [ABSTRACT FROM AUTHOR]

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 [V̇O2peak], 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 V̇O2peak 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Bergamasco, JGA, Gomes da Silva, D, Bittencourt, DF, Martins de Oliveira, R, Júnior, JCB, Caruso, FC, Godoi, D, Borghi-Silva, A, and Libardi, CA. Low-load resistance training performed to muscle failure or near muscle failure does not promote additional gains on muscle strength, hypertrophy, and functional performance of older adults. J Strength Cond Res 36(5): 1209–1215, 2022—The aim of the present study was to compare the effects of low-load resistance training (RT) protocols performed to failure (FAI), to voluntary interruption (VOL), and with a fixed low repetitions (FIX) on muscle strength, hypertrophy, and functional performance in older adults. Forty-one subjects (60–77 years) were randomized into one of the RT protocols (FAI, VOL, or FIX) and completed 12 weeks of RT at 40% of 1 repetition maximum (1RM), twice a week. The assessments included 1RM test, muscle cross-sectional area (CSA), rate of torque development (RTD), and functional performance (chair stand [CS], habitual gait speed [HGS], maximal gait speed [MGS], and timed up-and-go [TUG]). All protocols significantly increased 1RM values from Pre (FAI: 318.3 ± 116.3 kg; VOL: 342.9 ± 93.7 kg; FIX: 328.0 ± 107.2 kg) to Post (FAI: 393.0 ± 143.1 kg, 23.5%; VOL: 423.0 ± 114.5 kg, 23.3%; FIX: 397.8 ± 94.6 kg, 21.3%; p < 0.0001 for all groups). Regarding CS, all protocols showed significant improvements from Pre (FAI: 11.5 ± 2.4 seconds; VOL: 12.1 ± 2.5 seconds; FIX: 11.3 ± 1.1 seconds) to Post (FAI: 10.5 ± 1.1 seconds, −8.5%, p = 0.001; VOL: 10.3 ± 1.5 seconds, −15.1%, p = 0.001; FIX: 11.0 ± 1.1, −3.2%, p = 0.001). Habitual gait speed values increased significantly from Pre (FAI: 1.3 ± 0.2 m·s−1; VOL: 1.3 ± 0.1 m·s−1; FIX: 1.3 ± 0.1 m·s−1) to Post (FAI: 1.4 ± 0.2 m·s−1, 2.5%, p = 0.03; VOL: 1.4 ± 0.2 m·s−1, 5.2%, p = 0.036; FIX: 1.4 ± 0.1 m·s−1, 5.7%, p = 0.03). No significant differences between protocols were found (p > 0.05). In addition, there were no significant changes in CSA, RTD, MGS, and TUG for any protocols (p > 0.05). In conclusion, low-load RT performed without muscle failure promotes significant improvements in muscle strength and some parameters of functional performance in older adults. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Using a within-subject design we compared the individual responses between drop-set (DS) vs. traditional resistance training (TRAD) (n=16) and crescent pyramid (CP) vs. TRAD (n=15). Muscle cross-sectional area (CSA), leg press and leg extension 1 repetition maximum (1-RM) were assessed pre and post training. At group level, CSA increased from pre to post (DS: 7.8% vs. TRAD: 7.5%, P =0.02; CP: 7.5% vs. TRAD: 7.8%, P =0.02). All protocols increased the 1-RM from pre to post for leg press (DS: 24.9% vs. TRAD: 26.8%, P < 0.0001; CP: 27.3% vs. TRAD:2 6.3%, P < 0.0001) and leg extension (DS: 17.1% vs. TRAD: 17.3%, P < 0.0001; CP: 17.0% vs. TRAD: 16.6%, P < 0.0001). Individual analysis for CSA demonstrated no differences between protocols in 15 subjects. For leg press 1-RM, 5 subjects responded more to TRAD, 2 to DS and 9 similarly between protocols. In TRAD vs. CP, 4 subjects responded more to CP, 1 to TRAD and 10 similarly between protocols. For leg extension 1-RM 2 subjects responded more to DS, 3 to TRAD and 11 similarly between protocols. Additionally, 2 subjects responded more to CP, 2 to TRAD and 11 similarly between protocols. In conclusion, all protocols induced similar individual responses for CSA. For 1-RM, some subjects experience greater gains for the protocol performed with higher loads, such as CP. [ABSTRACT FROM AUTHOR]

The purpose was to compare the effects of protein (whey protein) and carbohydrate supplementation and protein alone both combined with resistance training on muscle strength, muscle mass and total training volume progression in untrained young men. Resistance training was performed using the leg press and knee extension until concentric failure (8−12 repetition maximum), three times a week for eight weeks. Muscle strength and muscle cross-sectional area were assessed before and after training. Total training volume progression was calculated considering the first and eighth week. Seventeen men completed the study (protein and carbohydrate, n=9, age 23.44 ± 4.56 years, weight: 62.13±6.17 kg, height: 1.75±0.02 m, body mass index: 20.29±2.08 kg/m2 ; protein, n=8, age 24.63±2.39 years, weight: 69.01±5.57 kg, height: 1.77±0.07 m; body mass index: 21.64±1.05 kg/m2. Both protocols showed similar increases in muscle strength (effect size: protein and carbohydrate=1.28; protein=0.97; p<0.001), muscle cross sectional area (effect size: protein and carbohydrate=0.66; protein=0.47; p<0.001) and total training volume progression (effect size: protein and carbohydrate=2.68; protein=1.63; p<0.001) after training. No differences were found between groups p>0.05). Protein and carbohydrate supplementation combined with resistance training does not induce greater gains in muscle strength, hypertrophy and total training volume compared to resistance training combined with protein alone in untrained individuals. [ABSTRACT FROM AUTHOR]

The aging process is associated with several changes in the elderly such as the decrease in cardiorespiratory fitness, strength and muscle mass, in addition to chronic low-grade inflammation. Concurrent training with blood flow restriction can be an interesting alternative to improve functional capacity with low mechanical stress in the elderly. The purpose of this study was to compare the inflammatory effects in older individuals submitted to two different protocols of concurrent training. Twenty-two healthy older adults (63.7 ± 3.8 years; 69.8 ± 8.9 kg; 1.6 ± 0.1 m) performed 12 weeks of concurrent training (CT) or concurrent training with blood flow restriction (CTBFR) and the effects on inflammatory markers were analyzed. We found inflammatory behavior for the CTBFR group with a significant difference in serum concentration of C-reactive protein between pre- and post-moment (0.96 ± 0.37 to 1.71 ± 1.45, p = 0.049), with no difference between groups, and a time effect in interleukin-6 (pre = 0.86 ± 0.43; post = 1.02 ± 0.46, p = 0.016). We conclude that the CTBFR showed a pro-inflammatory profile after the period of intervention whereas the CT showed the opposite. [ABSTRACT FROM AUTHOR]

Introduction: Physical inactivity is considered as one of the factors to increase the risk of developing cardiovascular diseases (CVDs) and decrease aerobic fitness mainly in middle-age. Increased habitual physical activity (HPA) is one of the strategies recommended to reduce physical inactivity. However, it is not known whether middle-age individuals who exclusively perform greater amount of HPA have greater aerobic fitness and / or a lower risk of CVDs. Objective: Verify the association between HPA with the risk of CVDs and aerobic fitness in individuals who only perform HPA. Method: We selected 89 male volunteers, age: 47.4 ± 5.06 years, who did not practice systemized physical training. Our measurements were: HPA by the International Physical Activity Questionnaire and Baecke questionnaires, the aerobic fitness by direct assessment of maximal oxygen consumption (VO2máx) and the risk of developing cardiovascular disease by the score calculation of General Cardiovascular Risk Profile from Framingham Study. Results: There was no correlation of the HPA level with cardiovascular risk factors, general cardiovascular disease risk and VO2máx. Moreover, no difference was found between the categorical groups of the IPAQ questionnaire and between the groups, "clusters", calculated from the Baecke questionnaire scores for the variables of cardiovascular risk, general cardiovascular disease risk and VO2máx. Conclusion: This study have found that the HPA level of middle-aged men is not associated with lower cardiovascular risk profile or higher aerobic fitness, suggesting that only increase HPA may not be enough to promote beneficial adaptations in aerobic fitness and improve risk profile for CVDs. These results may be related to low volume and intensity of HPA, which reinforces the importance of performing physical training with control of these variables for health promotion. [ABSTRACT FROM AUTHOR]

The article reports on research which was conducted to evaluate the effects 16 weeks of resistance training (RT), endurance training (ET) and concurrent training (CT) had on inflammatory markers, C-reactive protein (CRP), and functional capacity in sedentary middle-age men. Researchers evaluated 47 men who performed three weekly sessions lasting about 60 minutes for 16 weeks. They found that 16 weeks of RT, ET, or CT in middle-age healthy men did not effect low and moderate IL-6, TNF-a, and CRP levels but that CT performed in the same weekly frequency and session duration of ET and RT was effective in increasing both maximal strength and oxygen uptake peak, in addition to fostering improvements in lipid profile.

Purpose: Manual reconstruction (MR) of the vastus lateralis (VL) muscle cross-sectional area (CSA) from sequential ultrasound (US) images is accessible, is reproducible, and has concurrent validity with magnetic resonance imaging. However, this technique requires numerous controls and procedures during image acquisition and reconstruction, making it laborious and time-consuming. The aim of this study was to determine the concurrent validity of VL CSA assessments between MR and computer vision--based automated reconstruction (AR) of CSA from sequential images of the VL obtained by US. Methods: The images from each sequence were manually rotated to align the fascia between images and thus visualize the VL CSA. For the AR, an artificial neural network model was utilized to segment areas of interest in the image, such as skin, fascia, deep aponeurosis, and femur. This segmentation was crucial to impose necessary constraints for the main assembly phase. At this stage, an image registration application, combined with differential evolution, was employed to achieve appropriate adjustments between the images. Next, the VL CSA obtained from the MR (n = 488) and AR (n = 488) techniques was used to determine their concurrent validity. Results: Our findings demonstrated a low coefficient of variation (CV) (1.51%) for AR compared with MR. The Bland--Altman plot showed low bias and close limits of agreement (+1.18 cm², -1.19 cm²), containing more than 95% of the data points. Conclusions: The AR technique is valid compared with MR when measuring VL CSA in a heterogeneous sample. [ABSTRACT FROM AUTHOR]

Background: The current study examined the acute effects of a lower body resistance training (RT) session on physiological and thermoregulatory measures during a sub-maximal running protocol in the heat in heat-acclimatized men. Ten resistance-untrained men (age 27.4 ± 4.1 years; height 1.78 ± 0.06 m; body mass 76.8 ± 9.9 kg; peak oxygen uptake 48.2 ± 7.0 mL kg−1 min−1) undertook a high-intensity RT session at six-repetition maximum. Indirect muscle damage markers (i.e., creatine kinase [CK], delayed-onset muscle soreness [DOMS], and countermovement jump [CMJ]) were collected prior to, immediately post and 24 and 48 h after the RT session. The sub-maximal running protocol was performed at 70% of the ventilatory threshold, which was conducted prior to and 24 and 48 h following the RT session to obtain physiological and thermoregulatory measures. Results: The RT session exhibited significant increases in DOMS (p < 0.05; effect size [ES]: 1.41–10.53), whilst reduced CMJ (p < 0.05; ES: − 0.79–1.41) for 48 h post-exercise. There were no differences in CK (p > 0.05), although increased with moderate to large ES (0.71–1.12) for 48 h post-exercise. The physiological cost of running was increased for up to 48 h post-exercise (p < 0.05) with moderate to large ES (0.50–0.84), although no differences were shown in thermoregulatory measures (p > 0.05) with small ES (0.33). Conclusion: These results demonstrate that a RT session impairs sub-maximal running performance for several days post-exercise, although thermoregulatory measures are unperturbed despite elevated muscle damage indicators in heat-acclimatized, resistance untrained men. Accordingly, whilst a RT session may not increase susceptibility to heat-related injuries in heat-acclimatized men during sub-maximal running in the heat, endurance sessions should be undertaken with caution for at least 48 h post-exercise following the initial RT session in resistance untrained men. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the effects of 24 wk of combined training on proinflammatory and anti-inflammatory markers associated with obesity in obese middle-age men. Methods: Thirty obese men (48.73 ± 1.04 yr; body mass index, 31.00 ± 0.29 kg·m-2) underwent 24 wk of combined training [CT (N = 17), aerobic (50%-85% of ...O2peak) and resistance (6-10 maximum repetition [RM]) training)] three times per week, 60 min per session, or a control group (N = 13). Anthropometric measures, maximal strength for leg press and bench press, peak oxygen uptake (...O2peak) and serum concentrations of C-reactive protein (CRP), tumor necrosis factor > (TNF-α), interleukin-6 (IL-6), IL-10, IL-15, resistin, leptin, and adiponectin were determined before (M1) and after 8 (M2), 16 (M3), and 24 (M4) wk of the experimental design. Results: Significant increases were observed in the maximal strength for bench press and leg press, ...O2peak, and serum concentrations of adiponectin and IL-15 for CT. Concomitantly, significant decreases were observed in percentage body fat and serum concentrations of CRP, resistin, and leptin for CT after the experimental period. Conclusion: Twenty-four weeks of moderate- to high-intensity CT reduced markers of subclinical inflammation associated with obesity and improved insulin resistance and functional capabilities of obese middle-age men, regardless of dietary intervention and weight loss. [ABSTRACT FROM AUTHOR]