Can Muscular Parameters Predict Symptoms of Anxiety and Depression?

Major depressive disorder and anxiety disorders are among the major public health issues. Therefore, identifying predictors of symptoms of depression and anxiety holds fundamental importance to avoid the aggravation of these conditions. Muscle strength and function (e.g., handgrip strength and timed-stands test) are widely recognized predictors of health outcomes; however, their association with symptoms of depression and anxiety is still not completely understood. This study investigated the associations between handgrip strength and timed-stands test scores with symptoms of depression and anxiety. In addition, we examined whether individuals exhibiting greater strength levels demonstrate reduced symptoms of anxiety and depression compared to those with lower levels of strength. This is a community-based, cross-sectional study. Participants were recruited through social media and underwent a semi-structured interview to record sociodemographic characteristics, comorbidities, use of tobacco and medication, and symptoms of anxiety (Beck's Anxiety Inventory [BAI]) and depression (Beck's Depressive Inventory [BDI]). Subsequently, anthropometric characteristics, handgrip strength, and functionality (i.e., timed-stands test) were assessed. In all, 216 individuals were evaluated. The adjusted regression model showed an inverse association between handgrip strength and anxiety (ß = -0.22; 95% CI [-0.38, -0.07]; R2 = 0.07, p = .005) and depression symptoms (ß = -0.25; 95% CI [-0.42, -0.07]; R2 = 0.05, p = .006). Similarly, timed-stands test scores were associated with anxiety (ß = -0.33; 95% CI [-0.54, -0.13]; R2 = 0.09, p = .002) and depression (ß = -0.32; 95% CI [-0.56, -0.09]; R2 = 0.06, p = .008). Furthermore, the low-strength group showed higher values on the BAI (9.5 vs. 5.9 arbitrary units; p = .0008) and BDI than the high-strength group (10.8 vs. 7.9 arbitrary units; p = .0214). When individuals were stratified by the timed-stands test, the low timed-stands group demonstrated higher values on the BAI (9.9 vs. 5.5 arbitrary units; p = .0030) and BDI than the high timed-stands group (11.2 vs. 7.5 arbitrary units; p < .0001). The results highlight muscular parameters as significant predictors associated with anxiety and depression symptoms.

Exercise training and DNA methylation profile in post-bariatric women: Results from an exploratory study.

Exercise training and bariatric surgery have been shown to independently modulate DNA methylation profile in clusters of genes related to metabolic and inflammatory pathways. This study aimed to investigate the effects of a 6-month exercise training program on DNA methylation profile in women who underwent bariatric surgery. In this exploratory, quasi-experimental study, we analyzed DNA methylation levels by array technology in eleven women who underwent Roux-en-Y Gastric Bypass and a 6-month, three-times-a-week, supervised exercise training program. Epigenome Wide Association Analysis showed 722 CpG sites with different methylation level equal to or greater than 5% (P < 0.01) after exercise training. Some of these CpGs sites were related to pathophysiological mechanisms of inflammation, specially Th17 cell differentiation (FDR value < 0.05 and P < 0.001). Our data showed epigenetic modification in specific CpG sites related to Th17 cell differentiation pathway in post-bariatric women following a 6-months exercise training program.

Exercise modifies hypothalamic connectivity and brain functional networks in women after bariatric surgery: a randomized clinical trial.

BACKGROUND: Obesity is a disease that may involve disrupted connectivity of brain networks. Bariatric surgery is an effective treatment for obesity, and the positive effects on obesity-related conditions may be enhanced by exercise. Herein, we aimed to investigate the possible synergistic effects of Roux-en-Y Gastric Bypass (RYGB) and exercise training on brain functional networks. METHODS: Thirty women eligible for bariatric surgery were randomly assigned to a Roux-en-Y gastric bypass (RYGB: n = 15, age = 41.0 ± 7.3 years) or RYGB plus Exercise Training (RYGB + ET: n = 15, age = 41.9 ± 7.2 years). Clinical, laboratory, and brain functional connectivity parameters were assessed at baseline, and 3 (POST3) and 9 months (POST9) after surgery. The 6-month, three-times-a-week, exercise intervention (resistance plus aerobic exercise) was initiated 3 months post-surgery (for RYGB + ET). RESULTS: Exercise superimposed on bariatric surgery (RYGB + ET) increased connectivity between hypothalamus and sensorial regions (seed-to-voxel analyses of hypothalamic connectivity), and decreased default mode network (DMN) and posterior salience (pSAL) network connectivity (ROI-to-ROI analyses of brain networks connectivity) when compared to RYGB alone (all p-FDR < 0.05). Increases in basal ganglia (BG) network connectivity were only observed in the exercised training group (within-group analyses). CONCLUSION: Exercise training is an important component in the management of post-bariatric patients and may improve the hypothalamic connectivity and brain functional networks that are involved in controlling food intake. TRIAL REGISTRATION: Clinicaltrial.gov: NCT02441361.

A randomized clinical trial on the effects of exercise on muscle remodelling following bariatric surgery.

BACKGROUND: Muscle atrophy and strength loss are common adverse outcomes following bariatric surgery. This randomized, controlled trial investigated the effects of exercise training on bariatric surgery-induced loss of muscle mass and function. Additionally, we investigated the effects of the intervention on molecular and histological mediators of muscle remodelling. METHODS: Eighty women with obesity were randomly assigned to a Roux-en-Y gastric bypass (RYGB: n = 40, age = 42 ± 8 years) or RYGB plus exercise training group (RYGB + ET: n = 40, age = 38 ± 7 years). Clinical and laboratory parameters were assessed at baseline, and 3 (POST3) and 9 months (POST9) after surgery. The 6 month, three-times-a-week, exercise intervention (resistance plus aerobic exercise) was initiated 3 months post-surgery (for RYGB + ET). A healthy, lean, age-matched control group was recruited to provide reference values for selected variables. RESULTS: Surgery resulted in a similar (P = 0.66) reduction in lower-limb muscle strength in RYGB and RYGB+ET (-26% vs. -31%), which was rescued to baseline values in RYGB + ET (P = 0.21 vs. baseline) but not in RYGB (P < 0.01 vs. baseline). Patients in RYGB+ET had greater absolute (214 vs. 120 kg, P < 0.01) and relative (2.4 vs. 1.4 kg/body mass, P < 0.01) muscle strength compared with RYGB alone at POST9. Exercise resulted in better performance in timed-up-and-go (6.3 vs. 7.1 s, P = 0.05) and timed-stand-test (18 vs. 14 repetitions, P < 0.01) compared with RYGB. Fat-free mass was lower (POST9-PRE) after RYBG than RYGB + ET (total: -7.9 vs. -4.9 kg, P < 0.01; lower-limb: -3.8 vs. -2.7 kg, P = 0.02). Surgery reduced Types I (~ - 21%; P = 0.99 between-group comparison) and II fibre cross-sectional areas (~ - 27%; P = 0.88 between-group comparison), which were rescued to baseline values in RYGB+ET (P > 0.05 vs. baseline) but not RYGB (P > 0.01 vs. baseline). RYGB + ET showed greater Type I (5187 vs. 3898 µm2 , P < 0.01) and Type II (5165 vs. 3565 µm2 , P < 0.01) fCSA than RYGB at POST9. RYGB + ET also resulted in increased capillarization (P < 0.01) and satellite cell content (P < 0.01) than RYGB at POST9. Gene-set normalized enrichment scores for the muscle transcriptome revealed that the ubiquitin-mediated proteolysis pathway was suppressed in RYGB + ET at POST9 vs. PRE (NES: -1.7; P < 0.01), but not in RYGB. Atrogin-1 gene expression was lower in RYGB + ET vs. RYGB at POST9 (0.18 vs. 0.71-fold change, P < 0.01). From both genotypic and phenotypic perspectives, the muscle of exercised patients resembled that of healthy lean individuals. CONCLUSIONS: This study provides compelling evidence-from gene to function-that strongly supports the incorporation of exercise into the recovery algorithm for bariatric patients so as to counteract the post-surgical loss of muscle mass and function.

Muscle strength and muscle mass as predictors of hospital length of stay in patients with moderate to severe COVID-19: a prospective observational study.

BACKGROUND: Strength and muscle mass are predictors of relevant clinical outcomes in critically ill patients, but in hospitalized patients with COVID-19, it remains to be determined. In this prospective observational study, we investigated whether muscle strength or muscle mass are predictive of hospital length of stay (LOS) in patients with moderate to severe COVID-19 patients. METHODS: We evaluated prospectively 196 patients at hospital admission for muscle mass and strength. Ten patients did not test positive for SARS-CoV-2 during hospitalization and were excluded from the analyses. RESULTS: The sample comprised patients of both sexes (50% male) with a mean age (SD) of 59 (±15) years, body mass index of 29.5 (±6.9) kg/m2 . The prevalence of current smoking patients was 24.7%, and more prevalent coexisting conditions were hypertension (67.7%), obesity (40.9%), and type 2 diabetes (36.0%). Mean (SD) LOS was 8.6 days (7.7); 17.0% of the patients required intensive care; 3.8% used invasive mechanical ventilation; and 6.6% died during the hospitalization period. The crude hazard ratio (HR) for LOS was greatest for handgrip strength comparing the strongest versus other patients (1.47 [95% CI: 1.07-2.03; P = 0.019]). Evidence of an association between increased handgrip strength and shorter hospital stay was also identified when handgrip strength was standardized according to the sex-specific mean and standard deviation (1.23 [95% CI: 1.06-1.43; P = 0.007]). Mean LOS was shorter for the strongest patients (7.5 ± 6.1 days) versus others (9.2 ± 8.4 days). Evidence of associations were also present for vastus lateralis cross-sectional area. The crude HR identified shorter hospital stay for patients with greater sex-specific standardized values (1.20 [95% CI: 1.03-1.39; P = 0.016]). Evidence was also obtained associating longer hospital stays for patients with the lowest values for vastus lateralis cross-sectional area (0.63 [95% CI: 0.46-0.88; P = 0.006). Mean LOS for the patients with the lowest muscle cross-sectional area was longer (10.8 ± 8.8 days) versus others (7.7 ± 7.2 days). The magnitude of associations for handgrip strength and vastus lateralis cross-sectional area remained consistent and statistically significant after adjusting for other covariates. CONCLUSIONS: Muscle strength and mass assessed upon hospital admission are predictors of LOS in patients with moderate to severe COVID-19, which stresses the value of muscle health in prognosis of this disease.

Constraints of Weight Loss as a Marker of Bariatric Surgery Success: An Exploratory Study.

PURPOSE: The aim of this exploratory study was to investigate whether the degree of weight loss properly reflects improvements in cardiometabolic health among patients who underwent Roux-en-Y gastric bypass. METHODS: In this ancillary analysis from a clinical trial, patients were clustered into tertiles according to the magnitude of the percentage weight loss (1st tertile: "higher weight loss": -37.1 ± 5.8%; 2nd tertile: "moderate weight loss": -29.7 ± 1.4%; 3rd tertile: "lower weight loss": -24.2 ± 2.3%). Delta changes (9 months after surgery-baseline) in clustered cardiometabolic risk (i.e., blood pressure index, fasting glucose, high-density lipoprotein [HDL] and triglycerides [TG]), glycated hemoglobin (HbA1c), homeostasis model assessment (HOMA-IR), and C-reactive protein (CRP) were calculated. RESULTS: A total of 42 patients who had complete bodyweight data (age = 40 ± 8 year; BMI = 47.8 ± 7.1 kg/m2) were included. Surgery led to substantial weight loss (-37.9 ± 11.3 kg, P < 0,001), and clinically significant improvements in blood pressure index (-17.7 ± 8.2 mmHg, P < 0.001), fasting glucose (-36.6 ± 52.5 mg/dL, P < 0.001), HDL (9.4 ± 7.1 mg/dL, P < 0.001), TG (-35.8 ± 44.1 mg/dL P < 0,001), HbA1c (-1.2 ± 1.6%, P < 0.001), HOMA-IR (-4.7 ± 3.9 mg/dL, P < 0.001) and CRP (-8.5 ± 6.7 µg/mL P < 0.001). Comparisons across tertiles revealed no differences for cardiometabolic risk score, fasting glucose, HbAc1, HOMA-IR, blood pressure index, CRP, HDL, and TG (P > 0.05 for all). Individual variable analysis confirmed cardiometabolic improvements across the spectrum on weight-loss. There were no associations between weight loss and any dependent variable. CONCLUSION: Weight loss following bariatric surgery does not correlate with improvements in cardiovascular risk factors. These findings suggest that weight loss alone may be insufficient to assess the cardiometabolic success of bariatric surgery, and the search for alternate proxies that better predict surgery success are needed.

Exercise Enhances the Effect of Bariatric Surgery in Markers of Cardiac Autonomic Function.

BACKGROUND: Bariatric surgery improves cardiovascular health, which might be partly ascribed to beneficial alterations in the autonomic nervous system. However, it is currently unknown whether benefits from surgery on cardiac autonomic regulation in post-bariatric patients can be further improved by adjuvant therapies, namely exercise. We investigated the effects of a 6-month exercise training program on cardiac autonomic responses in women undergoing bariatric surgery. METHODS: Sixty-two women eligible for bariatric surgery were randomly allocated to either standard of care (control) or an exercise training intervention. At baseline (PRE) and 3 (POST3) and 9 (POST9) months after surgery, we assessed chronotropic response to exercise (CR%; i.e., percentage change in heart rate from rest to peak exercise) and heart rate recovery (HRR30s, HRR60s, and HRR120s; i.e., decay of heart rate at 30, 60, and 120 s post exercise) after a maximal exercise test. RESULTS: Between-group absolute changes revealed higher CR% (Δ = 8.56%, CI95% 0.22-19.90, P = 0.04), HRR30s (Δ = 12.98 beat/min, CI95% 4.29-21.67, P = 0.01), HRR60s (Δ = 22.95 beat/min, CI95% 11.72-34.18, P = 0.01), and HRR120s (Δ = 34.54 beat/min, CI95% 19.91-49.17, P < 0.01) in the exercised vs. non-exercised group. CONCLUSIONS: Our findings demonstrate that exercise training enhanced the benefits of bariatric surgery on cardiac autonomic regulation. These results highlight the relevance of exercise training as a treatment for post-bariatric patients, ensuring optimal cardiovascular outcomes.

Self-selected Rest Interval Improves Vertical Jump Postactivation Potentiation.

ABSTRACT: do Carmo, EC, De Souza, EO, Roschel, H, Kobal, R, Ramos, H, Gil, S, and Tricoli, V. Self-selected rest interval improves vertical jump postactivation potentiation. J Strength Cond Res 35(1): 91-96, 2021-This study compared the effects of self-selected rest interval (SSRI) and fixed rest interval (FRI) strategies on postactivation potentiation (PAP) in countermovement jump (CMJ) performance. Twelve strength-trained men (age: 25.4 ± 3.6 years; body mass: 78.8 ± 10.5 kg; height: 175 ± 7.0 cm; half-squat 1 repetition maximum: 188.7 ± 33.4 kg) performed 3 experimental conditions: (a) FRI: CMJ test; 4-minute rest interval; 5 repetition maximum (5RM) back squat; 4-minute rest interval; and CMJ test, (b) SSRI: CMJ test; 4-minute rest interval; 5RM back squat; SSRI; and CMJ test, and (c) control: CMJ test; 8-minute rest interval and CMJ test. In SSRI, subjects were instructed to rest until they felt fully recovered and able to exercise at maximal intensity based on the perceived readiness scale. Significant changes in pre-post CMJ performance were observed in the SSRI condition (38.2 ± 4.6 cm vs. 40.5 ± 4.4 cm; p = 0.08; confidence interval [CI]: 0.72-3.82 cm; effect size [ES] = 0.93). There were significant differences in post-CMJ performance when SSRI was compared with FRI (40.5 ± 4.4 cm vs. 37.7 ± 5.1 cm; p = 0.02; CI: 0.43-5.08; ES = 1.13) and control (40.5 ± 4.4 cm vs. 37.4 ± 5.7 cm; p = 0.01; CI: 0.66-5.61; ES = 1.35). The average rest interval length for the SSRI condition was 5:57 ± 2:44 min:sec (CI: 4:24-7:30). Our results suggest that the use of SSRI was an efficient and practical strategy to elicit PAP on CMJ height in strength-trained individuals.

Exercise-Induced Increases in Insulin Sensitivity After Bariatric Surgery Are Mediated By Muscle Extracellular Matrix Remodeling.

Exercise seems to enhance the beneficial effect of bariatric (Roux-en-Y gastric bypass [RYGB]) surgery on insulin resistance. We hypothesized that skeletal muscle extracellular matrix (ECM) remodeling may underlie these benefits. Women were randomized to either a combined aerobic and resistance exercise training program following RYGB (RYGB + ET) or standard of care (RYGB). Insulin sensitivity was assessed by oral glucose tolerance test. Muscle biopsy specimens were obtained at baseline and 3 and 9 months after surgery and subjected to comprehensive phenotyping, transcriptome profiling, molecular pathway identification, and validation in vitro. Exercise training improved insulin sensitivity beyond surgery alone (e.g., Matsuda index: RYGB 123% vs. RYGB + ET 325%; P ≤ 0.0001). ECM remodeling was reduced by surgery alone, with an additive benefit of surgery and exercise training (e.g., collagen I: RYGB -41% vs. RYGB + ET -76%; P ≤ 0.0001). Exercise and RYGB had an additive effect on enhancing insulin sensitivity, but surgery alone did not resolve insulin resistance and ECM remodeling. We identified candidates modulated by exercise training that may become therapeutic targets for treating insulin resistance, in particular, the transforming growth factor-ß1/SMAD 2/3 pathway and its antagonist follistatin. Exercise-induced increases in insulin sensitivity after bariatric surgery are at least partially mediated by muscle ECM remodeling.

Exercise Mitigates Bone Loss in Women With Severe Obesity After Roux-en-Y Gastric Bypass: A Randomized Controlled Trial.

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.

Exercise-induced anti-inflammatory effects in overweight/obese women with polycystic ovary syndrome.

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.

Risco de fadiga prematura, percepção subjetiva de esforço e estratégia de prova durante uma corrida de 10 km / Hazard score, rating of perceived exertion and pacing strategy during a 10 km running

O objetivo do estudo foi verificar as modificações na estratégia de prova frente às alterações do risco de fadiga prematura e da percepção subjetiva de esforço (PSE) em corredores durante uma corrida de 10 km. Participaram do estudo 55 corredores com tempo nos 10 km de 41:39 ± 3:52 min:s. A estratégia de prova e a PSE foram avaliadas a cada quilômetro. O risco de fadiga prematura foi determinado pelo produto entre a PSE e a distância restante de prova e a estratégia de prova foi determinada pela curva da velocidade e distância. A ANOVA de um caminho para medidas repetidas foi utilizada para determinar as diferenças na velocidade, PSE e risco de fadiga a cada quilômetro e entre a velocidade a cada quilômetro e a velocidade média da prova. O coeficiente de correlação de Pearson foi calculado entre a PSE e o risco de fadiga prematura com a velocidade. A velocidade do primeiro quilômetro foi 8,1% maior do que a média (p ≤ 0,001). A velocidade diminuiu gradualmente ao longo da prova, ocorrendo um novo aumento no décimo quilômetro. A PSE aumentou linearmente ao longo da prova e o risco de fadiga diminuiu significantemente após o terceiro quilômetro. Houve forte correlação negativa entre a PSE e a velocidade desenvolvida durante a prova (r = -0,80; p = 0,006). Foi observada uma correlação moderada negativa entre o risco de fadiga prematura e a velocidade (r = -0,57; p = 0,04). Com isso, os achados do presente estudo sugerem que a PSE parece ter importante papel sobre os ajustes da velocidade ao longo da prova, sendo que o aumento da velocidade observado no último quilômetro pode estar associado ao baixo risco de fadiga prematura

The aim of the study was to verify the modifications on pacing strategy induced by the hazard score of premature fatigue and rated perceived exertion (RPE) in amateur runners during a simulated 10-km running. Fifty five amateur runners with the 10-km run time of 41:39 ± 3:52 min:s participated in the study. The pacing strategy and the RPE were analyzed each kilometer. The hazard score of premature fatigue was expressed as the product of RPE by the remaining distance of the running. An ANOVA one-way for repeated measures was applied to determine possible statistical differences in speed, RPE and hazard score at each kilometer or the running speed differences at each kilometer and the average running speed. Pearson's product moment correlations were calculated between RPE and hazard of premature fatigue and running speed. The speed in the first kilometer was 8.1% higher than the average speed (p ≤ 0.001). There was a progressive decrease in speed during the running with an increment near the last kilometer. The RPE increased linearly until the end of the running and the hazard score of premature fatigue significantly decreased after the third kilometer. During the running there was a strong negative correlation between speed and RPE (r = -0.80; p = 0.006). It was also observed a moderate negative correlation between speed and hazard score of premature fatigue (r = -0.57; p = 0.04). Thus, our results suggested the important role of RPE on speed adjustment during a 10-km running and the increase of running speed near the end of the race seems to be associated to the lower score of hazard of premature fatigue

Efeito do número e intensidade das ações excêntricas nos indicadores de dano muscular / Effect of the number and the intensity of eccentric muscle actions on muscle damage markers

A realização de uma sessão de treinamento de força, especialmente de ações excêntricas, provoca danos à estrutura muscular. Algumas características da realização das ações excêntricas parecem agravar a ocorrência do dano. O número de contrações realizadas e o grau de tensão desenvolvida em cada uma delas parecem afetar a magnitude o dano. Dessa maneira, o objetivo deste estudo foi investigar se o número e a intensidade das ações excêntricas contribuem para o aumento do dano muscular, avaliado através das alterações de marcadores indiretos. Vinte e quatro jovens adultos do sexo masculino foram divididos aleatoriamente em três grupos. Um dos grupos realizou 30 ações excêntricas para os flexores do cotovelo com 70 por cento de 1RM (EXC30-70, n = 8). Outro grupo realizou o mesmo número de repetições, porém com 110 por cento de 1RM (EXC30110, n = 8). Um terceiro grupo realizou um número maior de repetições (60) com 70 por cento de 1RM (EXC60-70, n = 8). A amplitude de movimento, a circunferência do braço, a força máxima (1RM) e a dor muscular tardia foram avaliadas antes, imediatamente, 48 e 96 horas após o exercício. Os resultados foram analisados através de análise de variância com dois fatores e revelaram que as alterações foram maiores no grupo EXC30-110 comparadas com EXC30-70 e EXC60-70. Esses dados sugerem que a intensidade das ações excêntricas afeta mais a ocorrência de dano do que o número de contrações.

A single bout of resistance training, especially with eccentric actions, induces damage to the muscle structure. Characteristics of eccentric actions may increase muscle damage. The number and intensity of contractions seem to affect the magnitude of muscle damage. Thus, the aim of this study was to investigate if the number and the intensity of contraction increase muscle damage, evaluated through alterations in indirect markers of muscle damage. Twenty-four young male adults were randomly placed into three groups. One of the groups performed 30 eccentric actions of the elbow flexors at 70 percent of 1RM (EXC30-70, n = 8). Another group performed the same number of repetitions, but at 110 percent of 1RM (EXC30-110, n = 8). A third group performed a higher number of repetitions (60) at 70 percent of 1RM (EXC60-70, n = 8). Range of motion, limb girth, maximal dynamic strength (1RM) and muscle soreness were assessed before, immediately after, 48h and 96h post exercise. Results were analyzed by a 2-way ANOVA and showed that alterations were more remarkable larger in EXC30-110 compared to EXC30-70 and EXC60-70. These data suggest that eccentric action intensity affects the magnitude of muscle damage more than the number of contractions.

Número de repetições e intensidade relativa em membros superiores e inferiores: implicações para o treinamento / Number of repetitions and relative intensity in upper and lower limbs: implications to training

Tradicionalmente, as recomendações para a prescrição do treinamento de força podem ser baseadas tanto na intensidade relativa ao 1RM quanto no número de repetições máximas. Entretanto, sabe se que o número máximo de repetições realizadas com a mesma carga relativa varia de acordo com o exercício e o tamanho do grupo muscular envolvido. Além disso, considerando tal diferença nas respostas musculares a diferentes cargas, é possível especular que o número máximo de repetições em cada série de exercício em uma sessão tradicional de treinamento de força (com múltiplas séries) pode também ser diferentemente afetado ao compararmos os membros superiores e superiores. Isto se torna particularmente importante, ao considerarmos as sugestões recentes de que o número total de repetições realizadas em um treinamento de força pode afetar as adaptações oriundas do mesmo. Assim, o presente trabalho teve o objetivo de comparar o número de repetições realizadas com uma mesma intensidade relativa tradicionalmente recomendada para hipertrofia muscular em séries múltiplas de exercícios para os membros superiores e inferiores. Doze homens jovens treinados foram testados para força dinâmica máxima (1RM) nos exercícios leg-press e supino reto. Uma semana depois, os participantes realizaram três séries até a falha concêntrica com carga igual a 80% de 1RM com dois minutos de intervalo entre séries. O número máximo de repetições realizadas em cada série foi anotado e utilizado para análise estatística. A análise por modelos mistos revelou que o número de repetições realizadas no leg-press foi maior do que no supino reto (p<0,05). Além disso, o número de repetições diminui ao longo das três séries sem diferença entre os exercícios. Assim, é possível sugerir que as recomendações para o treino de força que visa hipertrofia devem ser revistas e possivelmente incluir recomendações diferenciadas para exercícios distintos.

Traditionally, the recommendations to resistance training prescription are based on the relative intensity or on the number of repetition maximum. However, it is well known that the maximal number of repetitions performed with the same relative intensity varies according to both the exercise and the muscle size. Besides, considering the different muscle response to different loads, it is plausible to speculate that the maximal number of repetitions performed in each set of a traditional bout of resistance exercise (multiple-set scenario) may also differ between upper- and lower-limbs. This is of particular interest if we take into account the recent suggestions that the total number of repetitions may play an important role in the adaptations to strength training. Hence, the aim of this study was to compare the number of repetitions performed in multiple sets of exercises performed with the traditionally recommended hypertrophy-oriented intensity in upper- and lower-limb exercises. Twelve trained male adults were tested for one repetition maximum (1RM) in the leg-press and bench press exercises. After one week, participants performed three sets to concentric failure with 80% 1RM with 2-min interval between sets. The maximal number of repetition was recorded and used for statistical analyses. Mixed model analyses showed that number of repetitions performed on the leg-press was higher than on the bench press (p<0.05). In addition, the number of repetitions decreased similarly in both exercises along the three sets. Therefore, it is possible to suggest that hypertrophy oriented resistance training recommendation should be revised, and possibly include distinct recommendation to different exercises.

Efeito da ordem dos exercícios no número de repetições e na percepção subjetiva de esforço em homens treinados em força / The effect of the exercises order on number of repetitions and rate of perceived effort in resistance trained men

A ordem dos exercícios refere-se à sequência de execução durante uma sessão de treinamento. Evidências demonstram que essa ordem pode afetar o número de repetições realizadas nos exercícios. A percepção subjetiva de esforço (PSE), assim como o número de repetições realizadas, depende da sobrecarga utilizada. Assim, alterações no número de repetições podem afetar a PSE. O volume total de trabalho (VTT) influencia nas adaptações crônicas ao treinamento e também pode ser afetado pela ordem dos exercícios. O objetivo foi verificar o efeito da ordem dos exercícios para membros inferiores no número de repetições realizadas, na PSE e no VTT. Doze homens treinados (19,3 ± 2,1 anos, 71,1 ± 9,8 kg, 172,4 ± 6,1 cm, 23,3 ± 11,5 meses/treino) realizaram duas sessões com os exercícios "leg-press" (L), mesa flexora (F) e cadeira extensora (E) em diferentes ordens (LFE ou EFL). Foram utilizados testes t de "Student" pareados com ajuste de Bonferroni para comparações múltiplas. O número de repetições em L e E diminuiu quando realizados no final da sessão. As repetições realizadas em F diminuíram na LFE. A PSE de E foi maior quando realizada no final da sessão, porém de L e de F não foram afetadas pelas diferentes ordens. O volume de trabalho total de LFE foi maior. Em conclusão, a ordem dos exercícios envolvendo membros inferiores afeta o número de repetições e a PSE de um exercício além do VTT, ressaltando a importância da ordem dos exercícios como uma importante variável na prescrição do treinamento.

The order of exercises refers to the sequence during a training bout. Some evidence shows that the number of repetitions may be affected by the order of exercises. Both the number of repetitions and the rate of perceived effort (PSE) are influenced by exercise load. Thus, changes in the number of repetitions may affect PSE. Additionally, total work volume influences long term training adaptations and can be affected by the order of exercises. The aim of this study was to evaluate the effect of order of lower limb exercises on the number of repetitions, RPE and total work volume. Twelve resistance trained male (19.3 ± 2.1 years, 71.1 ± 9.8 kg, 172.4 ± 6.1 cm, 23.3 ± 11.5 months of training) performed leg-press (L), leg extension (E) and leg curl (F) exercises, in different orders (LFE or EFL). Number of repetitions, PSE and total work volume were compared by paired t-test with Bonferroni adjustment. Number of repetitions on both L and E decreased when they were performed last in the bout. The number of repetitions on F also decreased, when F was preceded by L. PSE for E was greater when performed at the end of the bout. However, PSE after L and F were not affected by the order. Total work volume was greater in LFE. In conclusion, the order of lower limb exercises affects the number of repetitions, PSE and total work performed, supporting the importance of the order of exercises as an important variable in training prescription.