Muscle Resistance Research Articles

Taurine Enhances Stretch Reflex Excitability.

The purpose of this study was to characterize the effects of taurine (supplementation and acute injection) on the stretch reflex in the ankle muscles, and in particular to compare the effects of chronic taurine supplementation versus acute injection on the muscle tension, amplitude of electromyogram and velocity of muscle response. Stretch reflex responses were evoked using a specialized stretching device designed for mice. The triceps surae muscle of an awake mouse was stretched at various speeds ranging from 500 to 500,000° per second. A transducer recorded the muscle resistance at each velocity and the corresponding EMG. We found that at each velocity, the taurine-fed mice generated more tension and exhibited a higher EMG response. Acute taurine injection did not affect the tension but significantly reduced the EMG. To evaluate if the enhances response was due to neuronal excitability of changes in the passive properties of the muscles, we anesthetize the mice to eliminate the central component of the reflex. Under these conditions, taurine-fed mice still exhibited an enhanced stretch reflex response. We have previously shown that taurine-fed mice have reduced expression of GABAA receptors and other biochemical changes in the GABAergic system that are consistent with hyper-excitability. GABAA receptor is a major component of the inhibitory (GABAergic) system and its reduced expression probably contributes to the enhanced stretch reflex in these mice through biochemical mechanisms that involve alterations not only at the spinal level but also at the cortical level.

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Objective: The objective of this study was to evaluate the physical growth, biological maturation and motorperformance of children and adolescents in the mid-west baseball team (Atibaia, Campinas and Indaiatuba) Brazil; in the Pre-Junior category, runner-up of the Inter-seleccoes tournament of the year 2018. The specific objectives were: a) to compare thephysical growth with references of students of Campinas-2014 and international reference of CDC-2012; and b) to compare therelationship between motor performance and biological maturation classification. Methodology: A cross-sectional descriptivestudy was carried out. The sample consisted of twenty three (23) young male athletes between 12 and 14 years of age. Thevariables of decimal age, height, body weight, trunk-cephalic stature were evaluated. The Body Mass Index (BMI), the BodyComposition in the four components (Fat, Muscular, Bone and Residual Mass) were calculated. Biological maturation wasdetermined by the Peak Growth Rate (PVC). Motor performance was determined by abdominal muscle resistance test,horizontal jump without impulse, medical ball throw (2Kg), 30 and 50 meter run and manual pressure force. Results: It wasdetermined that (PVC) of baseball players is reached at (13.9 years) (0.4SD). In relation to the physical growth, athletes who are(-1 year of PVC) are shorter than those of the references, as regards weight and (BMI) present values slightly above the 50thpercentile. While athletes who are (in the year of PVC) have a height and weight equal to or above the 75th percentile and (BMI)below the 75th percentile.

Defining a prognostic criterion of orthopaedic complications development in patients with an injury of anterior cruciate ligament of knee joint

IntroductionPrognostic indices of orthopaedic implications development were investigated among patients with anterior cruciate ligament (ACL) injuries on the basis of stabilography research during the functional period of rehabilitation.MethodsThe study included 52 randomly selected individuals with a complete ACL tear qualified for surgical reconstruction. The patients’ age was 18–59 (average: 37.8 ± 2.0) years. All participants underwent rehabilitation treatment in the Institute of Traumatology and Orthopaedics, National Academy of Medical Sciences of Ukraine, and had surgeries in the Institute’s clinics. The crural part of the graft was fixed with the assistance of either the RigidFix system or the Cross-Pin system, and the Biointrafix or Biosure Sync system was applied for the tibial part.Results and conclusionsOn the basis of the performed analysis of indices that characterize the functional condition of the injured limb of patients with an injury of ACL of knee joint at the functional stage of rehabilitation treatment, it is possible to identify a high and medium level of loading asymmetry in the lower extremities, decrease of electrobiological activity and muscle resistance ability during bending, stretching, adduction, and abduction, as the main prognostic criterion of orthopaedic complications development.

Increase in the constrictor effects of Rho-kinase in skeletal muscle and coronary arteries of rats with chronic hypothyroidism

Aim. The deficit of thyroid function is known to be accompanied by an increase in the overall peripheral vascular resistance. This work tested the hypothesis that long-term hypothyroidism leads to an increase in the vasoconstrictor effect of Rho-kinase in skeletal muscle and heart resistance arteries of adult rats.Materials and methods.Male Wistar rats consumed the antithyroid drug propylthiouracil (PTU) in drinking water (0.025%), starting at 10 weeks of age. The rats of the control group received PTU-free water. After 14 weeks, the contractile responses of the gastrocnemius muscle arteries (to the α1-adrenoceptor agonist methoxamine) and the septal coronary artery (to the thromboxane A2 receptor agonist U46619) were isometrically recorded. The contribution of the Rho-kinase to the arterial contractile responses was assessed using inhibitor Y27632 (3 μM).Results.The consumption of propylthiouracil was accompanied by a marked decrease of thyroid hormone concentrations and an increase in total cholesterol serum level as well as a decrease in body weight. Maximal contractile responses of studied arteries were also reduced in hypothyroid rats. However, basal tone and reactivity to the moderate concentrations of agonists in arteries of hypothyroid rats were increased compared to control animals. Y27632 significantly weakened the contractile responses of the arteries and negated the differences between the two groups of rats.Conclusion.Chronic hypothyroidism leads to an increase in the activity of the Rho-kinase signaling pathway in the arteries of the gastrocnemius muscle and heart, which results in the increase of the spontaneous tone of the arteries and their reactivity to agonists.

Diferenças de sexo na relação entre indicadores de força e resistência muscular de membros inferiores e a presença de incontinência urinária em nonagenários e centenários

Aims: To verify the possible relation between urinary incontinence and lower limbs strength and resistance indicators and the sex influence in this relation.Methods: Cross-sectional and analytical study with nonagenarians and centenarians from “Multiprofessional Attention to the oldest-old” project. Presence of incontinence, the ease to walking and climbing stairs, Timed up and Go test, sex, age, marital status and depression symptoms were the study variables. Descriptive and analytical analysis (chi-square tests, analysis of variance and univariate and sex-adjusted logistic regression) were performed accepting p<0.05.Results: We evaluated 238 oldest-old, 174 women. The ease of walking 400 meters and stand up from a chair and the time during the Timed Up and Go were significant indicators of muscle strength and resistance in the correlation between incontinence and muscle strength and resistance adjusted by sex (respectively, RC=0.832, p=0.011, RC=0.846, p=0.012 and RC=0.352, p=0.002). Sex was the most significantly related to incontinence (RC=0.349, p=0.001) and its presence in the complete model decreased the significance of other variables. Depressive symptoms increase the chance of presenting incontinence in men.Conclusions: Incontinence can be associated with strength and resistance in lower limbs, mainly in women. Strength and resistance exercises focus on lower limbs can be added to traditional and recognized prevention programs to incontinence.

The diabetic phenotype is preserved in myotubes established from type 2 diabetic subjects: a critical appraisal.

Cultured human myotubes offer a unique model to distinguish between primary and environmental factors in the aetiology of insulin resistance in human skeletal muscle. The objective of this review was to summarize our and other group studies on insulin resistance in human myotubes established from lean, obese and type 2 diabetes (T2D) subjects. Overall, studies of human myotubes established from lean, obese and T2D subjects clearly show that part of the diabetic phenotype observed invivo is preserved in diabetic myotubes. Diabetic myotubes express a primary coordinated impairment of lipid oxidation, oxidative phosphorylation (OXPHOS) and insulin-stimulated glucose metabolism. Currently, both the responsible molecular mechanisms as well as the extent to which these alterations depend on genetic and/or epigenetic alterations have yet to be identified. Based on the data, it is hypothesized that the impaired insulin-mediated glucose metabolism, impaired OXPHOS and reduced lipid oxidation observed in diabetic myotubes are caused by the reduced peroxisome proliferator-activated receptor gamma coactivator-1α (PGC1α) expression.

Effect of nonmeat, high-protein supplementation on quality of life and clinical outcomes in older residents of care homes: a systematic review and meta-analysis.

Care home residents are at risk of malnutrition owing to reduced food intake, anabolic resistance in aging muscle, and a high prevalence of medical morbidity and functional dependency. There has been limited consensus regarding the effectiveness of a high-protein diet on quality of life or clinical outcomes in care home residents. The aim of this review was to evaluate the effectiveness of nonmeat, high-protein supplementation on health-related quality of life (HRQOL) and relevant clinical and nutritional outcomes in older people in a care home setting. The following databases were searched (to February 2018) for randomized controlled trials: Embase, AMED, CINAHL, MEDLINE, the Cochrane Central Registry of Controlled Trials, OpenGrey, clinicaltrials.gov, the WHO International Clinical Trials Registry Platform, the ISRCTN registry, and the NIHR Clinical Research Network Portfolio. Trials were selected if they assessed a nonmeat, high-protein dietary intervention provided to care home residents who were aged 65 years or older. Data from included trials were extracted if they assessed care home residents aged 65 years or older and compared those residents who received protein supplementation with those who did not. Trial quality was assessed using the Cochrane risk-of-bias tool. Meta-analysis was undertaken when appropriate. Seventeen studies with 1246 participants fulfilled the inclusion criteria. All studies were of low or moderate quality. There was no evidence of improved HRQOL when the Short Form 36 (SF-36) was used to assess outcomes (standardized mean difference [SMD] = -0.10; 95%CI, -0.51 to 0.31; P = 0.62), although significant improvement was seen in the 1 trial that used the EQ-5D instrument (SMD = 2.58; 95%CI, 2.05-3.10; P < 0.00001). Nonmeat, high-protein oral supplements can improve markers of nutritional status in care home residents. However, there is insufficient high-quality evidence to determine the effect of such supplements on HRQOL in older adults in care homes. PROSPERO registration number: CRD42015029313.

Cytosolic lipid excess-induced mitochondrial dysfunction is the cause or effect of high fat diet-induced skeletal muscle insulin resistance: a molecular insight.

Mitochondria play a central role in the energy homeostasis in eukaryotic cells by generating ATP via oxidative metabolism of nutrients. Excess lipid accumulation and impairments in mitochondrial function have been considered as putative mechanisms for the pathogenesis of skeletal muscle insulin resistance. Accumulation of lipids in tissues occurs due to either excessive fatty acid uptake, decreased fatty acid utilization or both. Consequently, elevated levels cytosolic lipid metabolites, triglycerides, diacylglycerol and ceramides have been demonstrated to adversely affect glucose homeostasis. Several recent studies indicate that reduced insulin-stimulated ATP synthesis and reduced expression of mitochondrial enzymes and PPAR-γ coactivator, in high fat feeding (lipid overload) are associated with insulin resistance. Despite the fact, few notable studies suggest mitochondrial dysfunction is prevalent in type 2 diabetes mellitus; it is still not clear whether the defects in mitochondrial function are the cause of insulin resistance or the consequential effects of insulin resistance itself. Thus, there is a growing interest in understanding the intricacies of mitochondrial function and its association with cytosolic lipid excess. This review therefore critically examines the molecular cascades linking cytosolic lipid excess and mitochondrial dysfunction in the pathogenesis of high fat diet-induced insulin resistance in skeletal muscle. The sequential processes following the excess intake of high fat diet in skeletal muscle includes, accumulation of cytosolic fatty acids, increased production of reactive oxygen species, mutations and ageing, and decreased mitochondrial biogenesis. The consequent mitochondrial dysfunction is then leading to decreased β-oxidation, respiratory functions and glycolysis and increased glucolipotoxicity. These events collectively induce the insulin resistance in skeletal muscle.

Ectopic fat, insulin resistance and metabolic disease in non-obese Asians: investigating metabolic gradation.

Although metabolic abnormalities commonly occur in non-obese Asians, their pathogenesis is not fully understood. Proton magnetic resonance spectroscopy has been used to analyze intracellular lipids in humans, and results suggest that ectopic fat accumulation in muscle and liver may induce insulin resistance in each tissue independently of obesity. Thus, measurement of ectopic fat currently plays an important role in the study of insulin resistance in non-obese Asians. In addition, studies using 2-step hyperinsulinemic euglycemic clamp with a glucose tracer may clarify how tissue-specific insulin resistance in muscle, liver, and adipose tissue contributes to the development of metabolic disease in non-obese Japanese. Although numerous studies have elucidated the pathophysiology of insulin resistance in obese subjects, research on "metabolic gradation," defined as the gradual transition from an insulin-sensitive to an insulin-resistant state, is less common, especially in terms of early metabolic changes. This review addresses a simple question: when and how is insulin resistance induced in non-obese East Asians? Several studies revealed that impaired insulin clearance and hyperinsulinemia not only compensated for insulin resistance, but also secondarily facilitated insulin resistance and weight gain. In this regard, we recently found that impaired insulin clearance and hyperinsulinemia could occur in apparently healthy subjects without significant insulin resistance, suggesting that this change may be an initial trigger that drives subsequent insulin resistance and weight gain. Further research is required to clarify the pathogenesis of metabolic gradation in non-obese Asians.

Combined exercise and calorie restriction therapies restore contractile and mitochondrial functions in skeletal muscle of obese-insulin resistant rats.

A combined exercise training and calorie-restriction program is the mainstream treatment of obesity. However, the effect of the dual-action program on mitochondrial function in skeletal muscles has not yet been clarified. The aim of this study was to determine if the combined program, rather than a single program, restored both lost muscle activity and mitochondrial function in obesity. The study included 30 female Wistar rats. Six rats fed a normal diet for 27 wk were used as the control group. The remaining 24 rats were fed a high-fat diet (HFD) for 27 wk. At week 20, the HFD rats were divided into the following four groups: sedentary lifestyle, endurance exercise five times per week, 60% of calorie restriction (CR) per day, and combined exercise training and CR. All conditions were maintained for 7 wk. We found that HFD-fed rats without therapy developed obese insulin resistance (IR) and impaired function of skeletal muscles. Skeletal muscles of the HFD-fed rats without therapy also exhibited early fatigability; impaired mitochondrial function, as indicated by increased reactive oxygen species production, membrane depolarization, and swelling; reduced mitochondrial dynamics as indicated by increased phosphorylation of DRP1 and decreased MFN2 expression; diminished mitochondrial biogenesis, as shown by decreased PGC1α and CPT1 expression; and increased apoptosis. Both exercise and CR in HFD-fed rats equally attenuated the impairment of muscle functions. However, combined therapies in HFD-fed rats restored functions of skeletal muscles. These findings reinforce the synergistic beneficial effects of combined exercise and CR on skeletal muscles of HFD-fed rats.

Effect of the Elevation Training Mask on the Functional Outcomes of the Respiratory Muscles

The results of this study confirm that the Elevation Training Mask 2.0 (ETM) increases the physiological characteristics and functional reserve capacity of the respiratory muscles. This is manifested in an increase in the maximal strength of muscle contraction, significantly greater maximal voluntary ventilation, an increase in the endurance and resistance of inspiratory and expiratory muscles to the development of fatigue when performing heavy exercise. An adequate indicator of the functional status of inspiratory muscles for the assessment of their functional potential is the tension–time index, ТТ0.1.

Ameliorative Effect of Watermelon rind ingestion on the Pancreas of Diabetic Female Albino Rat (Histological, immunohistochemical and morphometric study).

Introduction: Type II diabetes is a multifactorial metabolic disorder that affects more than 348 million people worldwide. The pathway of type II diabetes is characterized both by insulin resistance in muscle, fat, and liver in addition to a relative failure of pancreatic cells. CitrullusLanatus (Watermelon) is one of the few foods naturally rich in amino acids citrulline and lycopene which decrease serum glucose concentration in diabetic rats.Aim of the study: To study the structural changes in diabetic pancreas and the possible role of watermelon rind ingestion in ameliorating the pancreatic changes in experimentally-induced type II diabetes mellitus in rats.Materials and methods: Eighteen female adult albino rats weighing 170g-200g were randomly divided into three equal groups. Diabetes was induced in all the rats except GI by intraperitoneal injection of 120 mg/kg.b.wnicotinamide, followed by streptozotocin (STZ) at a dose of 60mg/kg.b.w. 15 minutes later, to induce type 2 diabetes. Rats were divided into three groups: namely GI control, GII diabetic, GIII diabetic watermelon rind juice treated. The mean values of body weight and the blood glucose levels were assessed. Histological study of the different experimental groups was done using H&E, Mallory trichrome, Orcein, and immunohistochemical stain for detection of eNOS positive endothelial cells. Data obtained by morphometric and statistical studies were discussed in relation to the microscopic findings. Results: Diabetes caused harmful effects on the structure of the pancreas. In addition, watermelon rind improved the histological findings if compared with the diabetic untreated group. Also, watermelon rind treatment showed strong immunohistochemical expression for eNOS. Conclusion: Watermelon rind ingestion in Streptozotocin-induced diabetic female albino rat resulted in ameliorating the structural changes in the pancreas.

Th1 cytokines TNF-α and IFN-γ promote corticosteroid resistance in developing human airway smooth muscle.

Corticosteroids (CSs) are commonly used to manage wheezing and asthma in pediatric populations. Although corticosteroids are effective in alleviating airway diseases, some children with more moderate-severe asthma phenotypes show CS resistance and exhibit significant airflow obstruction, persistent inflammation, and more frequent exacerbations. Previous studies have demonstrated that Th1 cytokines, such as TNF-α and IFN-γ, promote CS resistance in adult human airway smooth muscle (ASM). In the present study, using a human fetal ASM cell model, we tested the hypothesis that TNF-α/IFN-γ induces CS resistance. In contrast to TNF-α or IFN-γ alone, the combination of TNF-α/IFN-γ blunted the ability of fluticasone propionate (FP) to reduce expression of the chemokines CCL5 and CXCL10 despite expression of key anti-inflammatory glucocorticoid receptor target genes being largely unaffected by TNF-α/IFN-γ. Expression of the NF-κB subunit p65 and phosphorylation of Stat1 were elevated in cells treated with TNF-α/IFN-γ, an effect that remained in the presence of FP. siRNA knockdown studies demonstrated the effects of TNF-α/IFN-γ on increased p65 are mediated by Stat1, a transcription factor activated by IFN-γ. Expression of TNFAIP3, a negative regulator of NF-κB activity, was not altered by TNF-α/IFN-γ. However, the effects of TNF-α/IFN-γ were partially reduced by overexpression of TNFAIP3 but did not influence p65 expression. Together, these data suggest that IFN-γ augments the effects of TNF-α on chemokines by enhancing expression of key inflammatory pathways in the presence of CS. Interactions between TNF-α- and IFN-γ-mediated pathways may promote inflammation in asthmatic children resistant to CSs.

Efficacy of hypopressive abdominal gymnastics in rehabilitating the pelvic floor of women: A systematic review

BackgroundHypopressive abdominal gymnastics has been proposed as a new paradigm in rehabilitating the pelvic floor. Its claims contraindicate the recommendation for pelvic floor muscle training during the postpartum period. ObjectiveTo determine whether hypopressive abdominal gymnastics is more effective than pelvic floor muscle training or other alternative conservative treatments for rehabilitating the pelvic floor. MethodsWe consulted the databases of the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Cochrane Library, Latin American and Caribbean Health Sciences Literature (LILACS), Physiotherapy Evidence Database (PEDro), PubMed, Scopus, Trip Database and Web of Science. We selected systematic reviews, clinical trials and analytical studies that assessed the efficacy of hypopressive abdominal gymnastics in women. The measured outcomes were the strengthening of the pelvic floor muscles, the incidence of urine incontinence or prolapse and symptom remission.We included 4 clinical trials, whose quality was measured with the PEDro scale. ResultsHypopressive gymnastics is less effective than pelvic floor muscle training for activating pelvic floor muscles, achieving closure of the levator hiatus of the anus and increasing pelvic floor muscle thickness, strength and resistance. Practical implicationThe evidence reviewed does not support the recommendation for hypopressive abdominal gymnastics for strengthening the pelvic floor either during the postpartum period or outside that period. Pelvic floor muscle training remains the first-line treatment for pelvic floor dysfunction. ConclusionThere is a lack of quality clinical trials that have evaluated the efficacy of hypopressive abdominal gymnastics.

PO-167 Effects of Hydrogen-rich Water on Rat Skeletal Muscles' Oxidative Damage and Autophagy Induced by Repeated Exhaustive Exercise

Objective This study was carried out to detect the effects of hydrogen-water intervention on oxidative stress and cell autophagy in skeletal muscle of rats with repeated exhaustion. &#x0D; Methods 30 male SD rats in the age of 3 months, weighing 180-210g, were randomly divided into control group (C), repeated exhaustion group (EX), and the repeated exhaustion with hydrogen intervention group (EH), 10 rats in each group. The EX and EH groups were subjected to a four-weeks of repeated-exhaustive exercise. The initial speed of the exercise was 15 m/min, and increasedby 5 m/min every 5 min, the final speed is 35m/min until exhaustion, 5 d/wk, with a total of 4 wk. In EH group, hydro-water was given to rats 30 mins before exercise. The ultrastructural changes of skeletal muscle were observed by using a transmission electron microscopy. Activity of SDH and CK in serum and SOD activity, MDA content and T-AOC level in skeletal muscle tissue were detected. Western blotting was used to detect the proteins expression of autophagy related proteins in skeletal muscle, mTOR, p-mTOR, LC3B-2 and P53. &#x0D; Results Compared with the EX group, in the EH group, the ultrastructural damage and mitochondrial swelling were significantly reduced, and the time of exhaustion was significantly prolonged (p&lt;0.05), Serum SDH activity increased significantly (p&lt;0.05), CK activity decreased significantly (p&lt;0.05), and skeletal muscle tissue SOD activity and total antioxidant capacity significantly increased (p&lt;0.05), MDA content decreased significantly (p&lt;0.01), mTOR and p-mTOR protein expression was significantly increased(p&lt;0.05), the LC3B-2 and P53 protein expression was significantly lower (p&lt;0.05).&#x0D; Conclusions Hydrogen water intervention could significantly improve repeatedly exhaustion exercise result in rat skeletal muscle injury, oxidative stress and cell ultrastructure damage excessive autophagy, improving oxidation resistance of the skeletal muscle and exercise endurance.

Autotaxin-LPA signaling contributes to obesity-induced insulin resistance in muscle and impairs mitochondrial metabolism

Autotaxin (ATX) is an adipokine that generates the bioactive lipid, lysophosphatidic acid (LPA). ATX-LPA signaling has been implicated in diet-induced obesity and systemic insulin resistance. However, it remains unclear whether the ATX-LPA pathway influences insulin function and energy metabolism in target tissues, particularly skeletal muscle, the major site of insulin-stimulated glucose disposal. The objective of this study was to test whether the ATX-LPA pathway impacts tissue insulin signaling and mitochondrial metabolism in skeletal muscle during obesity. Male mice with heterozygous ATX deficiency (ATX+/-) were protected from obesity, systemic insulin resistance, and cardiomyocyte dysfunction following high-fat high-sucrose (HFHS) feeding. HFHS-fed ATX+/- mice also had improved insulin-stimulated AKT phosphorylation in white adipose tissue, liver, heart, and skeletal muscle. Preserved insulin-stimulated glucose transport in muscle from HFHS-fed ATX+/- mice was associated with improved mitochondrial pyruvate oxidation in the absence of changes in fat oxidation and ectopic lipid accumulation. Similarly, incubation with LPA decreased insulin-stimulated AKT phosphorylation and mitochondrial energy metabolism in C2C12 myotubes at baseline and following palmitate-induced insulin resistance. Taken together, our results suggest that the ATX-LPA pathway contributes to obesity-induced insulin resistance in metabolically relevant tissues. Our data also suggest that LPA directly impairs skeletal muscle insulin signaling and mitochondrial function.

Altered Lipid Metabolism Impairs Skeletal Muscle Force in Young Rats Submitted to a Short-Term High-Fat Diet.

Obesity and ensuing disorders are increasingly prevalent in young populations. Prolonged exposure to high-fat diets (HFD) and excessive lipid accumulation were recently suggested to impair skeletal muscle functions in rodents. We aimed to determine the effects of a short-term HFD on skeletal muscle function in young rats. Young male Wistar rats (100–125 g) were fed HFD or a regular chow diet (RCD) for 14 days. Specific force, resistance to fatigue and recovery were tested in extensor digitorum longus (EDL; glycolytic) and soleus (SOL; oxidative) muscles using an ex vivo muscle contractility system. Muscle fiber typing and insulin signaling were analyzed while intramyocellular lipid droplets (LD) were characterized. Expression of key markers of lipid metabolism was also measured. Weight gain was similar for both groups. Specific force was decreased in SOL, but not in EDL of HFD rats. Muscle resistance to fatigue and force recovery were not altered in response to the diets. Similarly, muscle fiber type distribution and insulin signaling were not influenced by HFD. On the other hand, percent area and average size of intramyocellular LDs were significantly increased in the SOL of HFD rats. These effects were consistent with the increased expression of several mediators of lipid metabolism in the SOL muscle. A short-term HFD impairs specific force and alters lipid metabolism in SOL, but not EDL muscles of young rats. This indicates the importance of clarifying the early mechanisms through which lipid metabolism affects skeletal muscle functions in response to obesogenic diets in young populations.

Impact of vulvovaginal atrophy on pelvic floor muscle strength in healthy continent women.

To assess the correlation between hormonal status and pelvic floor muscle strength. A total of 140 continent women were prospectively evaluated, and divided into four groups according to age: group1 (n=34) aged 30-40years; group2 (n=38) aged 41-50years; group3 (n=35) aged 51-60; and group4 (n=33) aged >60years. The following parameters were evaluated: demographic data using clinical questionnaire; hypermobility of the bladder neck using swab test; vaginal trophism by gynecological examination; hormonal status of the vagina by cytology; and pelvic floor muscle strength using a perineometer and electromyography. There were no statistical differences between pelvic floor muscle strength, demographic characteristics, vaginal trophism and hypermobility of the bladder neck between groups (P>0.05). There was a larger number of women with vaginal atrophy among those aged >60years. Vaginal trophism assessed by pelvic examination was highly consistent with the findings of colpocytology (kappa test=0.888). Electromyography showed that women with hypermobility had lower muscle resistance (endurance) when compared with those without hypermobility. Although vaginal atrophy is more intense in women aged >60years, no difference can be found in the pelvic floor muscle strength during the physiological aging process in continent women. As a consequence, trophism is not the only factor related to pelvic floor muscle strength, and it should not preclude the selection of patients who are referred to prophylaxis.

Effect of Inspiratory Muscle Training on Performance of Handball Athletes.

Inspiratory muscle training (IMT) is a strategy that has been used to improve performance in different sports modalities. This study investigated the effects of an IMT program on respiratory muscle strength and resistance as well as aerobic physical performance (PP) of handball athletes. Nineteen 20 ± 3 year-old male athletes were allocated into an experimental (EG, n = 10) or a placebo group (PG, n = 9). Their respiratory muscle strength was evaluated by measuring the maximum inspiratory and expiratory pressures (MIP and MEP), muscular respiratory resistance by maximum voluntary ventilation (MVV) and aerobic PP by the cardiopulmonary exercise test. The study was designed to evaluate the effects of a 12-week IMT program with five sessions a week. A significant difference was observed in the pre and post IMT values of the MIP (170 ± 34 to 262 ± 33 cmH2O) and MEP (177 ± 36 to 218 ± 37 cmH2O) in the EG, and MIP (173 ± 45 to 213 ± 21 cmH2O) in the PG, with a large effect size for the MIP, when the groups were compared. MVV showed a significant increase (162 ± 24 to 173 ± 30 L) in the EG, with a small effect size. There was a significant difference in maximum oxygen uptake (54 ± 8 to 60 ± 7 ml/kg/min) in aerobic PP. Oxygen uptake at the respiratory compensation point (RCP) (46 ± 6 to 50 ± 5 ml/kg/min), with a moderate effect size for both variables, was observed in the EG after IMT. We concluded that IMT provided a significant increase in respiratory muscle strength and resistance, contributing to increased aerobic PP in the EG, which suggests that IMT could be incorporated in handball players’ training.

Characterization of ohmic heating and sous-vide treatment of scallops: Analysis of electrical conductivity and the effect of thermal protein denaturation on quality attribute changes

Abstract A 20 kHz ohmic heating (OH) and two sous-vide (SV) treatments of scallop muscles were characterized, and their effects on thermal protein denaturation (TPD) and quality attribute changes were evaluated. TPD was analyzed by differential scanning calorimetry and estimated by kinetic analysis for several thermal schedules with a dynamic method. The OH process was evaluated by analyzing the electrical conductivities (ECs) between the frequencies of 50 Hz and 20 kHz, temperatures from −20 °C to 65 °C, and effects of parallel and series current directions. The increase of frequency and temperature caused a drop in the resistance of scallop muscles and an increase in the heating rate. Thereby, the process time decreased. OH obtained a lower quality attribute change in scallops in comparison with SV, owing to higher water retention within the muscle. OH significantly reduced the time of exposure to high temperatures, which in turn reduced the degree of actin denaturation. Industrial relevance The application of OH as an alternative to the sous-vide (SV) technique for scallop muscles has been explored assuming that OH could benefit the processed samples by providing better temperature uniformity and a reduction in the processing time, which avoids unnecessary damage to quality attributes. In this study, these assumptions were confirmed with a higher retention of quality attributes in scallops, where OH > novel SV > traditional SV. These results have the potential to promote the utilization of OH systems in central kitchens, gourmet restaurants, and catering instead of SV treatments based not only on the improved quality of the processed foods but also by a considerable reduction in the processing time and probably energy consumed. However, for the application of any of the two treatments, first they should be validated for product safety. The employed TPD approach, can also be used for the analysis of other thermal treatments, allowing the evaluation of the changes in quality attributes within the temperature range of protein denaturation.