Effects of walk training with self-selected intensity on biochemical markers and anthropometric variables in women with obesity.

To evaluate the effects of 12-weeks of walk training with self-selected intensity on lipid profile and anthropometric variables in women with obesity. Forty-eight women volunteers with obesity were randomly assigned into two training groups: self-selected walking group (SSWG; n=25) and control group (CG; n=23). There was improvement in biochemical markers only in the SSWG post-intervention (p<0.05), however no changes were verified in anthropometric variables (p>0.05). This study demonstrates that walking at self-selected intensity improved the lipid profile in women with obesity.

Energy System Contributions in Upper and Lower Body Wingate Tests in Highly Trained Athletes.

PURPOSE: This study compared the energy system contributions and relationship between mechanical and energy system variables in upper and lower body Wingate tests (WAnT) in judo athletes. METHOD: Eleven male judo athletes (18 ± 1 years, 174.3 ± 5.3 cm, 72.6 ± 9.9 kg, 11.8 ± 1.7% body fat) attended two laboratory sessions to perform two WAnT (upper and lower body) and two incremental tests (upper and lower body). The energy contributions of the oxidative, glycolytic, and phosphagen (ATP-PCr) systems were estimated based on oxygen consumption ( V˙O2 ) during WAnT, delta of lactate, and the fast phase of excess V˙O2 , respectively. RESULTS: The upper and lower body presented similar results of oxidative (21 ± 4% vs 23 ± 3%) and ATP-PCr system contributions (29 ± 6% vs 32 ± 5%). The glycolytic system contribution (50 ± 5% vs 45 ± 4%) was higher in the upper body. The variance of mechanical variables in upper body was explained by glycolytic (R2 = 0.49-0.62) and oxidative systems (R2 = 0.44-0.49), whereas the variance of mechanical variables in lower body was explained by ATP-PCr (R2 = 0.41-0.55) and glycolytic systems (R2 = 0.62-0.94). CONCLUSIONS: During WAnT, the glycolytic system presented the major energy contribution, being higher in the upper body. Moreover, mechanical and energy system variables presented a distinct relationship when comparing upper and lower body WAnT.

Diabetes induces tri-methylation at lysine 9 of histone 3 at Slc2a4 gene in skeletal muscle: A new target to improve glycemic control.

Expression of the glucose transporter GLUT4, encoded by Slc2a4 gene, is reduced in both type 1 and type 2 diabetes (T1D and T2D), contributing to glycemic impairment. The present study investigated epigenetic regulations at the Slc2a4 promoter in skeletal muscle of T1D- and T2D-like experimental models. Slc2a4/GLUT4 repression was observed in T1D and T2D and that was reversed by insulin and resveratrol treatments, respectively. In both T1D-like and T2D-like animals, tri-methylation at lysine 9 of histone 3 (H3K9me3) increased in the Slc2a4 enhancer segment, whereas MEF2A/D binding into this segment was reduced; all effects were reversed by respective treatments. This study reveals that increased H3K9me3 in the Slc2a4 promoter enhancer segment contributes to reduce GLUT4 expression in skeletal muscle and to worse glycemic control in diabetes, pointing to the H3K9me3 of Slc2a4 promoter as a potential target for development of new approaches for treating diabetes.

Diabetes Modulates MicroRNAs 29b-3p, 29c-3p, 199a-5p and 532-3p Expression in Muscle: Possible Role in GLUT4 and HK2 Repression.

The reduced expression of solute carrier family 2, facilitated glucose transporter member 4 (GLUT4) and hexokinase-2 (HK2) in skeletal muscle participates in insulin resistance of diabetes mellitus (DM). MicroRNAs (miRNAs) have emerged as important modulators of mRNA/protein expression, but their role in DM is unclear. We investigated miRNAs hypothetically involved in GLUT4/HK2 expression in soleus muscle of type 1 diabetes-like rats. In silico analysis revealed 651 miRNAs predicted to regulate solute carrier family 2 member 4 (Slc2a4) mRNA, several of them also predicted to regulate Hk2 mRNA, and 16 miRNAs were selected for quantification. Diabetes reduced Slc2a4/GLUT4 and Hk2/HK2 expression (50-77%), upregulated miR-29b-3p and miR-29c-3p (50-100%), and downregulated miR-93-5p, miR-150-5p, miR-199a-5p, miR-345-3p, and miR-532-3p (~30%) expression. Besides, GLUT4 and HK2 proteins correlated (P < 0.05) negatively with miR-29b-3p and miR-29c-3p and positively with miR-199a-5p and miR-532-3p, suggesting that these miRNAs could be markers of alterations in GLUT4 and HK2 expression. Additionally, diabetes increased the nuclear factor kappa B subunit 1 protein (p50) expression, a repressor of Slc2a4, which was also predicted as a target for miR-199a-5p and miR-532-3p. Correlations were also detected between these miRNAs and blood glucose, 24-h glycosuria and plasma fructosamine, and insulin therapy reversed most of the alterations. In sum, we report that diabetes altered miR-29b-3p, miR-29c-3p, miR-199a-5p and miR-532-3p expression in muscle of male rats, where their predicted targets Slc2a4/GLUT4 and Hk2/HK2 are repressed. These data shed light on these miRNAs as a markers of impaired skeletal muscle glucose disposal, and, consequently, glycemic control in diabetes.

Advanced glycation end products-induced insulin resistance involves repression of skeletal muscle GLUT4 expression.

Little is known about advanced glycation end products (AGEs) participation in glucose homeostasis, a process in which skeletal muscle glucose transporter GLUT4 (Scl2a4 gene) plays a key role. This study investigated (1) the in vivo and in vitro effects of AGEs on Slc2a4/GLUT4 expression in skeletal muscle of healthy rats, and (2) the potential involvement of endoplasmic reticulum and inflammatory stress in the observed regulations. For in vivo analysis, rats were treated with advanced glycated rat albumin (AGE-albumin) for 12 weeks; for in vitro analysis, soleus muscles from normal rats were incubated with bovine AGE-albumin for 2.5 to 7.5 hours. In vivo, AGE-albumin induced whole-body insulin resistance; decreased (~30%) Slc2a4 mRNA and GLUT4 protein content; and increased (~30%) the nuclear content of nuclear factor NF-kappa-B p50 subunit (NFKB1), and cellular content of 78 kDa glucose-regulated protein (GRP78). In vitro, incubation with AGE-albumin decreased (~50%) the Slc2a4/GLUT4 content; and increased cellular content of GRP78/94, phosphorylated-IKK-alpha/beta, nuclear content of NFKB1 and RELA, and the nuclear protein binding into Slc2a4 promoter NFKB-binding site. The data reveal that AGEs impair glucose homeostasis in non-diabetic states of increased AGEs concentration; an effect that involves activation of endoplasmic reticulum- and inflammatory-stress and repression of Slc2a4/GLUT4 expression.

Resveratrol Improves Glycemic Control in Type 2 Diabetic Obese Mice by Regulating Glucose Transporter Expression in Skeletal Muscle and Liver.

Insulin resistance participates in the glycaemic control disruption in type 2 diabetes mellitus (T2DM), by reducing muscle glucose influx and increasing liver glucose efflux. GLUT4 (Slc2a4 gene) and GLUT2 (Slc2a2 gene) proteins play a fundamental role in the muscle and liver glucose fluxes, respectively. Resveratrol is a polyphenol suggested to have an insulin sensitizer effect; however, this effect, and related mechanisms, have not been clearly demonstrated in T2DM. We hypothesized that resveratrol can improve glycaemic control by restoring GLUT4 and GLUT2 expression in muscle and liver. Mice were rendered obese T2DM in adult life by neonatal injection of monosodium glutamate. Then, T2DM mice were treated with resveratrol for 60 days or not. Glycaemic homeostasis, GLUT4, GLUT2, and SIRT1 (sirtuin 1) proteins (Western blotting); Slc2a4, Slc2a2, and Pck1 (key gluconeogenic enzyme codifier) mRNAs (RT-qPCR); and hepatic glucose efflux were analysed. T2DM mice revealed: high plasma concentration of glucose, fructosamine, and insulin; insulin resistance (insulin tolerance test); decreased Slc2a4/GLUT4 content in gastrocnemius and increased Slc2a2/GLUT2 content in liver; and increased Pck1 mRNA and gluconeogenic activity (pyruvate tolerance test) in liver. All alterations were restored by resveratrol treatment. Additionally, in both muscle and liver, resveratrol increased SIRT1 nuclear content, which must participate in gene expression regulations. In sum, the results indisputably reveals that resveratrol improves glycaemic control in T2DM, and that involves an increase in muscle Slc2a4/GLUT4 and a decrease in liver Slc2a2/GLUT2 expression. This study contributes to our understanding how resveratrol might be prescribed for T2DM according to the principles of evidence-based medicine.

Energy-System Contributions to Simulated Judo Matches.

PURPOSE: To estimate the contribution of the 3 energy systems to simulated judo matches. METHODS: Twelve judo athletes (18 ± 1 y, 175.1 ± 5.3 cm, 74.3 ± 10.5 kg, 11.7% ± 1.5% body fat, 8 ± 2 y of practice) performed 5 combats with different durations (1, 2, 3, 4, and 5 min), against the same opponent, on different days and blinded to the duration. The estimated energy contributions for the oxidative, glycolytic, and ATP-PCr systems were calculated based on oxygen uptake (V̇O2) during activity, Delta of lactate, and the fast phase of excess V ̇ O2, respectively. Analysis of mixed models for repeated measures was used to compare the contribution of the 3 energy systems and different durations of judo matches, followed by a post hoc Bonferroni test. RESULTS: The oxidative system's contribution (70%) was higher than those of the glycolytic (8%; P < .001) and ATP-PCr (21%; P < .001) energy systems (in all durations), and the ATP-PCr contribution was higher than that of the glycolytic energy system (up to 3 min). In addition, during the match there was an increase in the oxidative (from 50% to 81%; P < .001), a decrease in the ATP-PCr (from 40% to 12%; P < .001), and maintenance of the glycolytic contributions (between 6% and 10%). CONCLUSIONS: There is a predominance of the oxidative system to supply the energy cost of judo matches from the first minute of combat up to the end, compared with the anaerobic systems.

Brazilian Jiu-Jitsu Simulated Competition Part I: Metabolic, Hormonal, Cellular Damage, and Heart Rate Responses.

The aim of this study was to analyze physiological responses in Brazilian jiu-jitsu athletes during simulated competition. To this end, 10 athletes (age: 28 ± 4 years, body mass: 81.8 ± 7.4 kg, body fat: 13.0 ± 4.8%, systematic practice: 11 ± 4 years) were analyzed in simulated competition (4 matches of 10 minutes). Blood samples were taken to assess energy demand, hormonal responses, and cell damage. Additionally, the heart rate variability (HRV) response was analyzed. The main results show that in simulated competition, during the last matches, athletes had lower lactate (p < 0.001), epinephrine (p < 0.001), norepinephrine (p < 0.001), and insulin (p = 0.002) concentrations. Increases observed in creatine kinase (p < 0.001), aspartate aminotransferase (p < 0.001), alanine aminotransferase (p = 0.007), and creatinine (p < 0.001) seen, especially, in the last matches are indicative of possible cell damage. The HRV reflected a decrease in the RR medium (average of the normal R-R intervals) (p = 0.001) during the competition. Thus, it is concluded that successive matches from competition generate a gradual decrease of adrenergic and glycolytic activities, which is accompanied by a gradual increase in cell damage markers and decrease in the RR medium of the HRV.

Brazilian Jiu-Jitsu Simulated Competition Part II: Physical Performance, Time-Motion, Technical-Tactical Analyses, and Perceptual Responses.

The aim of this study was to analyze performance, time structure, technical actions, and perceptual responses in Brazilian jiu-jitsu athletes during a simulated competition. For this purpose, 10 athletes were analyzed in a simulated competition (4 matches of 10 minutes). Physical tests and scales of the perception of effort and recovery were applied. The matches were recorded for the purpose of technical-tactical analysis and to determine the time structure. The main results show that in the simulated competition, reaction time (F(2.5,17.6) = 2.7; p = 0.087; η² = 0.28) and flexibility (F(7,63) = 1.5; p = 0.172; η² = 0.15) were unchanged across the matches. An analysis of variance showed a significant difference for grip endurance using the kimono (F(2.0,15.9) = 8.1; p = 0.004; η² = 0.50), which was not confirmed by the Bonferroni test. Jump height indicated postactivation potentiation after match 2 (F(7,63) = 3.5; p = 0.003; η² = 0.28). The maximal isometric handgrip strength in the dominant hand (F(3.2,28.6) = 2.9; p = 0.049; η² = 0.24) and in the nondominant hand (F(7,63) = 3.8; p = 0.002; η² = 0.30) showed a decline after matches 3 and 4. Although these data indicate the onset of fatigue, the effort/pause ratio of the matches was not altered (F(3,12) = 0.6; p = 0.624; η² = 0.13). The perceptions of effort (F(3,27) = 0.9; p = 0.469; η² = 0.09) and recovery (F(1.9,17.0) = 2.4; p = 0.125; η² = 0.21) and the degree of fatigue reported (F(1.5,13.8) = 0.5; p = 0.588; η² = 0.05) did not change during the simulated competition. Thus, it may be concluded that the execution of successive matches causes a decline in maximal isometric handgrip strength. No changes in the time structure of the matches or in the perceptual responses were observed.

Physiological and Technical-tactical Analysis in Brazilian Jiu-jitsu Competition.

PURPOSE: The present study aims at investigating the physiological response and technical-tactical parameters in Brazilian jiu-jitsu competition. METHODS: The study included 35 male Brazilian jiu-jitsu athletes (adult category, body mass: 80.2 ± 13.0 kg), graded from white to brown belt, during combats fought at regional level. Twenty-two fights were analyzed in terms of technique and time structure. Blood glucose, lactate and maximal isometric grip strength were determined before and after the fights. The rate of perceived exertion was also assessed after the fight, using the 6-20 Borg rating. The fights were recorded and the following variables were determined: the exertion/pause ratio and subjective intensity of actions, categorized between low and high intensity. RESULTS: The results indicated that during Brazilian jiu-jitsu fights, the glycolytic pathway is only moderately activated (lactate before: 4.4 (4.0 - 4.6) mmol/L, after: 10.1 (8.0 - 11.3) mmol/L; glucose before: 112.4 ± 22.3 mg/dL, after: 130.5 ± 31.0 mg/dL). The exertion during the fight resulted in significant reductions in handgrip strength (right hand grip before: 45.9 ± 10.3 kgf, after: 40.1 ± 9.5 kgf; left hand grip before: 44.2 ± 11.1 kgf, after: 37.0 ± 10.2 kgf). The athletes rated the fight as hard: 15 (13 - 15). Effort/pause ratio was 6:1, while high-intensity actions lasted approximately 4 s, resulting in a low/high intensity? ratio of 8:1. CONCLUSION: It is recommended that coaches direct the training loads to simulate the energy demand imposed by the competitive matches, activating moderately the glycolytic pathway. Moreover, the time structure of combats can be used to prescribe both physical and technical-tactical training.