Lucas Guimarães Ferreira | Universidade Federal do Espirito Santo (original) (raw)

Papers by Lucas Guimarães Ferreira

Journal of the International Society of Sports Nutrition, 2018

Background: Post-activation potentiation (PAP) is the phenomenon by which muscular performance is... more Background: Post-activation potentiation (PAP) is the phenomenon by which muscular performance is enhanced in response to a conditioning stimulus. PAP has typically been evidenced via improved counter movement jump (CMJ) performance. This study examined the effects of PAP, with and without prior caffeine ingestion, on CMJ performance. Methods: Twelve male professional soccer players (23 ± 5 years) performed two trials of plyometric exercises and sled towing 60 min after placebo or caffeine ingestion (5 mg.kg − 1) in a randomized, counterbalanced and double-blinded design. CMJ performance was assessed at baseline and 1, 3 and 5 min after the conditioning stimulus (T1, T3 and T5, respectively). Results: Two way ANOVA main effects indicated a significant difference in jump height after the PAP protocol (F[3, 11] = 14.99, P < 0.001, partial η2 = 0.577). Analysis also indicated a significant difference in CMJ performance across conditions, with caffeine eliciting a greater response (F[1, 11] = 10.12, P = 0.009, partial η2 = 0.479). CMJ height was increased at T1, T3 and T5 in caffeine condition (5.07%, 5.75% and 5.40%, respectively; P < 0.01) compared to baseline. In the placebo condition, jump performance was increased at T3 (4.94%; P < 0.01) only. Jump height was higher in caffeine condition on T1, T3 and T5 (P < 0.05) but not on baseline (P > 0.05) compared to placebo. Conclusions: The results of this study suggest that acute plyometric and sled towing stimuli enhances jump performance and that this potentiation is augmented by caffeine ingestion in male soccer players.

JOURNAL OF PHYSICAL EDUCATION AND SPORT,, 2019

Purpose: The purpose of this study was to evaluate the effects of energy drink ingestion on the p... more Purpose: The purpose of this study was to evaluate the effects of energy drink ingestion on the performance of running performance in amateur runners with different levels of physical fitness. Material: Sixty healthy subjects were selected and randomized according to the level of physical fitness (Low: <29.9 ml.kg-1 .min-1 ; Moderate: 30-37.9 ml.kg-1 .min-1 ; and High: > 38 ml.kg-1 .min-1). Thereafter, they were further distributed in Placebo (27g glucose) and Energy Drink (27g glucose, 30g sodium, 1000mg taurine, 600mg glucuronolactone, 80mg caffeine, 50mg inositol, 16mg vitamin B3, 5mg vitamin B5, 1,3mg vitamin B2, 3 mg vitamin B6 and 2.4 mg vitamin B12), resulting in six groups according to physical fitness level such Placebo (P, Low: L, Moderate: M, High: H) and Energy Drink (ED, Low: L, Moderate: M, High: H). The drinks were administered 60 minutes prior to the cooper test. Results: Energy drink ingestion did not elicit performance improvement despite physical fitness level. However, the L group running distance was longer (P:3168 ± 167; ED: 3228 ± 218, meters) than M (P:1962 ± 75; ED: 2035 ± 105, meters) and L (P: 1422 ± 74; ED: 1440 ± 62, meters) (p<0.01). The same result was found following the use of the equation for calculating oxygen consumption (L group P: 20±1.4; BE: 23±1.4; ml.kg-1 .min-1 ; M group P: 35±1.0; BE: 34±0.9 ml.kg-1 .min-1 ; and H group P: 54±3.7; ED: 60±4.8 ml.kg-1 .min-1). Conclusion: Data from the present study demonstrated that the use of energy drinks does not enhance performance of amateur runners regardless of the level of physical fitness.

Nutrients, 2019

Mixed martial arts (MMA) is a combat sport where competitors utilize strikes (punches, kicks, kne... more Mixed martial arts (MMA) is a combat sport where competitors utilize strikes (punches, kicks, knees, and elbows) and submission techniques to defeat opponents in a cage or ring. The aim of this study was to investigate the effect of acute caffeine ingestion on punching performance by professional MMA athletes. The study used a double-blind, counterbalanced, crossover design. Eleven professional MMA competitors (27.6 ± 4.3 years and 83.5 ± 7.8 kg of body weight) ingested a dose of caffeine (5 mg·kg −1) or placebo 60 min prior to three sets of punching. Each set consisted of 15 s, at which participants were asked to perform straight punches with maximum strength and frequency with his dominant arm. After each set, a 45 s recovery time was applied. Using a force transducer attached to a cushioned plate, the punch frequency, and mean and maximal punch force was measured. The readiness to invest in both physical (RTIPE) and mental (RTIME) effort was assessed prior to the protocol, and the rating of perceived exertion (RPE) was recorded after. Caffeine ingestion did not result in increased punching frequency, mean and maximum punch force, RTIPE, RTIME, and RPE when compared to the placebo condition. Based on these results, acute caffeine ingestion did not improve punching performance in professional MMA athletes.

BRAZILIAN JOURNAL OF MEDICAL AND BIOLOGICAL RESEARCH, 2019

Abstract The effect of a short-term creatine supplementation on hindlimb suspension (HS)-induced ... more Abstract The effect of a short-term creatine supplementation on hindlimb suspension (HS)-induced muscle atrophy was investigated. Creatine monohydrate (5 g/kg b.w. per day) or placebo, divided in 2 daily doses, was given by oral gavage for 5 days. Rats were maintained in HS with dietary supplementation concomitantly for 5 days. Body weight, soleus and EDL muscle masses, and cross-sectional areas (CSA) of the muscle fibers were measured. Signaling pathways associated with skeletal muscle mass regulation (FST, MSTN, FAK, IGF-1, MGF, Akt, mTOR, atrogin-1, and MuRF1 expressions, and Akt, S6, GSK3B, and 4EBP1 proteins) were evaluated in the muscles. Soleus muscle exhibited more atrophy than the EDL muscle due to HS. Creatine supplementation attenuated the decrease of wet weight and increased p-4EBP1 protein in the EDL muscle of HS rats. Also, creatine increased mTOR and atrogin-1 expressions in the same muscle and condition. In the absence of HS, creatine sup-plementation increased FAK and decreased MGF expressions in the EDL muscle. Creatine attenuated the increase in FST expression due to HS in the soleus muscle. MuRF1 expression increased in the soleus muscle due to creatine supplementation in HS animals whereas atrogin-1 expression increased still further in this group compared with untreated HS rats. In conclusion, short-term creatine supplementation changed protein metabolism signaling in soleus and EDL muscles. However, creatine supplementation only slightly attenuated the mass loss of both muscles and did not prevent the CSA reduction and muscle strength decrease induced by HS for 5 days.

Revista Brasileira de Fisiologia do Exercício, 2020

A pandemia de COVID-19 que se espalhou por todo o mundo em 2020 demandou ações coletivas para con... more A pandemia de COVID-19 que se espalhou por todo o mundo em 2020 demandou ações coletivas para controle da transmissão da doença. Dentre as medidas adotadas, o distanciamento social vem sendo amplamente adotado, visando a redução do con-tato e aglomeração de pessoas. Com a limitação ao acesso a locais de treinamento que dispõe de equipamentos e variedade de carga para o treinamento de força e potência, estratégias alternativas para realização no ambiente doméstico se fazem importante para manutenção do condicionamento físico e atenuação dos efeitos deletérios do destreinamento. Utilizando como base a literatura científica disponível, o presente artigo apresenta recomendações práticas para o treinamento de força no ambiente doméstico. Recomenda-se a utilização de exercícios que utilizam o peso do próprio corpo, itens domésticos e, quando disponíveis, halteres e bandas elásticas. Ao se uti-lizar baixas cargas (30-50% de 1 repetição máxima), a realização das séries até a falha concêntrica parece ser necessária para otimizar os ganhos de força e massa muscular. A prática de exercícios físicos deve ser realizada na maioria dos dias da semana (>5 dias/semana), combinada a atividades domésticas e de lazer que envolvam a mo-vimentação de todo o corpo. Para manutenção e/ou desenvolvimento da potência muscular, movimentos balísticos devem ser incluídos, com ou sem cargas externas. Palavras-chave: Treinamento de força, ABSTRACT The COVID-19 pandemic that scattered across the world in 2020 has required collective action to control the transmission of the disease. Among the measures, social distancing has been widely adopted, aiming to reduce contact and people gathering. With the limited access to training places that have equipment and a variety of loads for strength and power training, alternative strategies to be carried out in the domestic environment are important for maintaining physical conditioning and mitigating the deleterious effects of detraining. Based on the available scientific literature, this article presents practical recommendations for strength training in Detraining attenuation during the COVID-19 pandemic: practical considerations for home-based strength and power training

Revista Brasileira de Medicina do Esporte, 2020

Introduction: Resistance training (RT) has been related to increased protein synthesis, and in th... more Introduction: Resistance training (RT) has been related to increased protein synthesis, and in the myocar-dium it triggers morphological adaptations that result in improved cardiac contractility. In skeletal muscle, RT promotes an improvement in functional capacity and in sarcopenia caused by aging. However, the efficacy of this training method in the cardiac and skeletal systems has not yet been clarified. Objective: To investigate the effect of different vertical ladder RT protocols on cardiac and skeletal structure and morphology. Materials and Methods: Wistar rats (n = 28) were randomized into four groups: sedentary (C); RT protocol with 4 to 9 climbs, 3 sessions/week, 120 second interval and intensity of 50% to 100% of the maximum load (ML) with progressive addition of 30 g (RT1); RT protocol with 4 to 5 climbs, 3 sessions/week, 60 second interval and intensity of 50% to 100% of the ML, where a 30 g overload was added in the 5 th climb (RT2); RT protocol with 4 to 5 climbs, 5 sessions/week, 60 second interval and intensity of 50% to 100% of the ML; the animals that completed the 4 th climb underwent the 5 th climb with 100% ML plus 30 g (RT3). RT protocols were performed for 9 weeks with a duration of 30 to 45 minutes/day. The nutritional profile and cardiac/skeletal muscle morphology were evaluated along with the cross sectional area and collagen fraction. Results: RT did not promote adaptations in cardiac and musculoskeletal structure and morphology, nor was it able to reduce body weight and body fat deposits. However, RT brought about an increase in absolute and relative strength. Conclusion: Vertical ladder RT protocols, regardless of weekly frequency, lead to increased muscle strength without cardiac and skeletal structural adaptations. Level of evidence I, Therapeutic studies-Investigating treatment results.

Life Sciences, 2017

L-Arginine has emerged as an important supplement for athletes and non-athletes in order to impro... more L-Arginine has emerged as an important supplement for athletes and non-athletes in order to improve performance. Arginine has been extensively used as substrate for nitric oxide synthesis, leading to increased vasodilatation and hormonal secretion. However, the chronic consumption of arginine has been shown to impair insulin sensitivity. In the present study, we aimed to evaluate whether chronic arginine supplementation associated with exercise training would have a beneficial impact on insulin sensitivity. We, therefore, treated Wistar rats for 4 weeks with arginine, associated or not with exercise training (treadmill). We assessed the somatotropic activation, by evaluating growth hormone (GH) gene expression and protein content in the pituitary , as well is GH concentration in the serum. Additionally, we evaluate whole-body insulin sensitivity, by performing an insulin tolerance test. Skeletal muscle morpho-physiological parameters were also assessed. Insulin sensitivity was impaired in the arginine-treated rats. However, exercise training reversed the negative effects of arginine. Arginine and exercise training increased somatotropic axis function, muscle mass and body weight gain. The combination arginine and exercise training further decreased total fat mass. Our results confirm that chronic arginine supplementation leads to insulin resistance, which can be reversed in the association with exercise training. We provide further evidence that exercise training is an important tool to improve whole-body metabolism.

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, 2017

The aim of this study was to evaluate the acute effects of high-intensity eccentric exercise (HI-... more The aim of this study was to evaluate the acute effects of high-intensity eccentric exercise (HI-ECC) combined with blood flow restriction (BFR) on muscle damage markers, and perceptual and cardiovascular responses. Nine healthy men (26 AE 1 years, BMI 24 AE 1 kg m À ²) underwent unilateral elbow extension in two conditions: without (HI-ECC) and with BFR (HI-ECC+BFR). The HI-ECC protocol corresponded to three sets of 10 repetitions with 130% of maximal strength (1RM). The ratings of perceived exertion (RPE) and pain (RPP) were measured after each set. Muscle damage was evaluated by range of motion (ROM), upper arm circumference (CIR) and muscle soreness using a visual analogue scale at different moments (pre-exercise, immediately after, 24 and 48 h postexercise). Sys-tolic (SBP), diastolic (DBP), mean blood pressure (MBP) and heart rate (HR) were measured before exercise and after each set. RPP was higher in HI-ECC+BFR than in HI-ECC after each set. Range of motion decreased postexercise in both conditions; however, in HI-ECC+BFR group, it returned to pre-exercise condition earlier (post-24 h) than HI-ECC (post-48 h). CIR increased only in HI-ECC, while no difference was observed in HI-ECC+BFR condition. Regarding cardiovascular responses, MBP and SBP did not change at any moment. HR showed similar increases in both conditions during exercise while DBP decreased only in HI-ECC condition. Thus, BFR attenuated HI-ECC-induced muscle damage and there was no increase in cardiovascular responses.

International Journal of Sports Science, 2016

There is currently no consensus regarding the best periodization model to increase muscle strengt... more There is currently no consensus regarding the best periodization model to increase muscle strength and hypertrophy. However, most recently the undulating periodization (UP) has been believed to be better than traditional periodization (TP) model. The purpose of this study was to conduct a meta-analysis to investigate whether the UP is superior to TP to induce gains in strength and hypertrophy. Studies were searched in databases covering three idioms. Twenty-five studies met the inclusion criteria, allowing 72 and 6 effects sizes (ES) to strength performance and hypertrophy, respectively, covering 400 males and 192 females. Duration of training protocols ranged 6 to 16 weeks. Continuous data from maximum strength (1RM), isometric, power, and muscular endurance (RMs) tests were collected. Additionally, only gold-standard measures were included for hypertrophy assessment. Statistical analyses were performed using dedicated software for meta-analysis. Considering the pooled data, UP was significantly (P = 0.005) larger than TP model to 1RM test (ES= 0.22; 95% IC= 0.07, 0.38). However, there was no significant difference (P > 0.05) between UP vs. TP for power (ES=-0.04; 95% IC=-0.29, 0.22), RMs (ES = 0.20; 95% IC =-0.07, 0.48), isometric strength (ES =-0.13; 95% IC =-0.50, 0.24), and hypertrophy (ES = 0.32; 95% IC =-0.07, 0.71). UP model seems better than TP model to improve maximum strength performance, but not to power, muscular endurance, isometric strength, and muscle hypertrophy.

Journal of Physiological Sciences, 2017

Beta-hydroxy-beta-methylbutyrate (HMB), a leucine metabolite, enhances the gain of skeletal muscl... more Beta-hydroxy-beta-methylbutyrate (HMB), a leucine metabolite, enhances the gain of skeletal muscle mass by increasing protein synthesis or attenuating protein degradation or both. The aims of this study were to investigate the effect of HMB on molecular factors controlling skeletal muscle protein synthesis and degradation, as well as muscle contractile function, in fed and fasted conditions. Wistar rats were supplied daily with HMB (320 mg/kg body weight diluted in NaCl-0.9%) or vehicle only (control) by gavage for 28 days. After this period, some of the animals were subjected to a 24-h fasting, while others remained in the fed condition. The EDL muscle was then removed, weighed and used to evaluate the genes and proteins involved in protein synthesis (AKT/4E-BP1/S6) and degradation (Fbxo32 and Trim63). A subset of rats were used to measure in vivo muscle contractile function. HMB supplementation increased AKT phosphorylation during fasting (threefold). In the fed condition, no differences were detected in atrogenes expression between control and HMB supplemented group; however, HMB supplementation did attenuate the fasting-induced increase in their expression levels. Fasting animals receiving HMB showed improved sustained tetanic contraction times (one-fold) and an increased muscle to tibia length ratio (1.3-fold), without any cross-sectional area changes. These results suggest that HMB supplementation under fasting conditions increases AKT phosphorylation and attenuates the increased of atrogenes expression, followed by a functional improvement and gain of skeletal muscle weight, suggesting that HMB protects skeletal muscle against the deleterious effects of fasting.

JOURNAL OF HUMAN SPORT & EXERCISE, 2017

The main purpose was to investigate whether the perception of effort during the two first repetit... more The main purpose was to investigate whether the perception of effort during the two first repetitions of strength exercises could be an adequate strategy for estimating the strength-training zone. The sample comprised 11 women (18 to 35 years-old). In the first week, the volunteers performed a 1-RM test in seven exercises on strength machines, and the load was calculated to reach 50%, 70% and 90% of the 1-RM. Over the next three weeks, the volunteers were required to perform randomly the exercises at these three intensities. After the two first repetitions, the volunteers were questioned about how many repetitions they believed they could achieve until failure (self-estimated). Additionally, volunteers were asked to indicate their exertion according Borg scale. After volunteers performed every exercise until concentric failure to complete the repetition maximum test (RMs test). The data were analyzed using linear regression, Pearson correlation and paired t-test. The results showed that the self-estimated number of repetitions underestimated 44% and 30% of the mean values of repetition maximum obtained directly at intensities of 50% and 70% (p < 0.05), respectively. Although repetition maximum were correlated with Borg scale (r =-0.23 to-0.41; p < 0.05) and self-estimated number of repetitions (r = 0.25 to 0.41; p < 0.05), the standard errors of estimate obtained by linear regression were very high (40% to 49%), which prevented any estimation equations. In conclusion, the perception of effort during the two first repetitions is not a satisfactory strategy for estimating the strength-training zone. (2017). The perception of effort is not a valid tool for establishing the strength-training zone.

This study examined the effect of short duration, moderate and high-intensity exercise on a Go/No... more This study examined the effect of short duration, moderate and high-intensity exercise on a Go/NoGo task. Fifteen, habitually active (9 females and 6 males aged 28 ± 5 years) agreed to participate in the study and cognitive performance was measured in three sessions lasting 10 min each, performed at three different exercise intensities: rest, moderate and high. Results indicated significant exercise intensity main effects for reaction time (RT) (p = 0.01), the omission error rate (p = 0.027) and the decision error rate (p = 0.011), with significantly longer RTs during high intensity exercise compared to moderate intensity exercise (p = 0.039) and rest (p = 0.023). Mean ± SE of RT (ms) was 395.8 ± 9.1, 396.3 ± 9.1 and 433.5 ± 16.1 for rest, moderate and high intensity exercise, respectively. This pattern was replicated for the error rate with a significantly higher omission error and decision error rate during high intensity exercise compared to moderate intensity exercise (p = 0.003) and rest (p = 0.001). Mean ± SE of omission errors (%) was 0.88 ± 0.23, 0.8 ± 0.23 and 1.8 ± 0.46% for rest, moderate and high intensity exercise, respectively. Likewise, mean ± SE of decision errors (%) was 0.73 ± 0.24, 0.73 ± 0.21 and 1.8 ± 0.31 for rest, moderate and high intensity exercise, respectively. The present study's results suggest that 10 min workout at high intensity impairs RT performances in habitually active adults compared to rest or moderate intensity exercise.

Several studies have indicated a positive influence of leucine supplementation and aerobic traini... more Several studies have indicated a positive influence of leucine supplementation and aerobic training on the aging skeletal muscle signaling pathways that control muscle protein balance and muscle remodeling. However, the effect of a combined intervention requires further clarification. Thirteen month old CD-1 ® mice were subjected to moderate aerobic exercise (45 min swimming per day with 3% body weight workload) and fed a chow diet with 5% leucine or 3.4% alanine for 8 weeks. Serum and plasma were prepared for glucose, urea nitrogen, insulin and amino acid profile analysis. The white gastrocnemius muscles were used for determination of muscle size and signaling proteins involved in protein synthesis and degradation. The results show that both 8 weeks of leucine supplementation and aerobic training elevated the activity of mTOR (mammalian target of rapamycin) and its downstream target p70S6K and 4E-BP1, inhibited the ubiquitin-proteasome system, and increased fiber cross-sectional area (CSA) in white gastrocnemius muscle. Moreover, leucine supplementation in combination with exercise demonstrated more significant effects, such as greater CSA, protein content and altered phosphorylation (suggestive of increased activity) of protein synthesis signaling proteins, in addition to lower expression of proteins involved in protein degradation compared to leucine or exercise alone. The current study shows moderate aerobic training combined with 5% leucine supplementation has the potential to increase muscle size in fast-twitch skeletal muscle during aging, potentially through increased protein synthesis and decreased protein breakdown.

RESUMO Introdução: Pesquisas demonstram que a obesidade pode ter início na infância. Além disso, ... more RESUMO Introdução: Pesquisas demonstram que a obesidade pode ter início na infância. Além disso, o excesso de peso presente em 50% na infância é fator preditor da obesidade na vida adulta. As consequências são preo-cupantes pela associação com diversas comorbidades, entre elas, a hipertensão arterial. Estudos mostram que crianças obesas apresentam risco superior de hipertensão arterial em relação às não obesas. Objetivo: Identificar a prevalência de hipertensão arterial e sua relação com o sobrepeso e obesidade em crianças e adolescentes estudantes da rede pública do município de Vitória, ES, Brasil. Foram estudados 477 alunos, com idade entre 7 e 17 anos, sendo 42,56% e 57,44% dos gêneros masculino e feminino, respectivamente, selecionados por meio de amostragem estratificada por conglomerados. Métodos: Na análise do perfil antropométrico foram utilizados: percentual de gordura por meio de medida de dobras cutâneas e índice de massa corporal (IMC). Além disso, foi realizada aferição da pressão arterial para classificação da hipertensão arterial. Resultados: Os resultados mos-tram nos estudantes de Vitória, ES, com sobrepeso, valores pressóricos elevados (limítrofes e hipertensos 1 e 2), representando nos gêneros masculino e feminino 21,1% (PAS: 112 ± 10,4 mmHg e PAD: 65,6 ± 8,91 mmHg) e 19,2% (PAS: 108 ± 12,1 mmHg e PAD: 65,6 ± 8,90 mmHg), respectivamente. No entanto, nos estudantes obesos, a prevalência foi maior, abrangendo 26,3% (PAS: 113 ± 11,3 mmHg e PAD: 67,8 ± 10,1 mmHg) no gêneros mas-culino e 25% (PAS: 108 ± 14,4 mmHg e PAD: 68,3 ± 10,2 mmHg) no feminino. Conclusão: Os achados relatados neste estudo mostram altos índices de crianças e adolescentes acometidos tanto por excesso de peso quanto pela hipertensão arterial. Estes resultados sugerem a implementação de medidas preventivas e de tratamento dos fatores de risco cardiovascular em crianças e adolescentes do município de Vitória, ES. ABSTRACT Introduction: Researches show that obesity can start in childhood. Furthermore, the excess of body weight, present at 50% in childhood, is a predictor of obesity in adulthood. Consequences are alarming due to the association with several comorbidities, among them, hypertension. Studies show that obese children are at higher risk for hyperten-sion compared to non-obese population. Objective: To identify the prevalence of hypertension and its relation to overweight and obesity in children and adolescents from public schools of the municipality of Vitória, ES, Brazil. We studied 477 students, aged between 7 and 17 years, 42.56% male and 57.44% female, who were randomly selected by stratified cluster sample. Methods: In the analysis of anthropometric profile the following were used: percentage of body fat by measuring skinfold thickness and body mass index (BMI). Moreover, measurement of blood pressure was performed to classify the arterial hypertension. Results: The results show in overweight students of Vitória, ES, high blood pressure values (pre-hypertension and stages 1 and 2 hypertension), representing 21.1% in males (SBP: 112 ± 10.4 mmHg and DBP: 65.6. ± 8.91 mmHg) and 19.2% in females (SBP: 108 ± 12.1 mmHg and DBP: 65.6 ± 8.90 mmHg), respectively. However, in obese students, the prevalence was higher, comprising 26.3% in males (SBP: 113 ± 11.3 mmHg and DBP: 67.8 ± 10.1 mmHg) and 25% in females (SBP: 108 ± 14.4 mmHg and DBP: 68.3 ± 10.2 mmHg). Conclusion: The findings reported in this study show high rates of children and adolescents affected by both overweight and hypertension. These results suggest the implementation of preventive measures and treatment of cardiovascular risk factors in children and adolescents from the municipality of Vitória, ES.

The non-steroidal anti-inflammatory drug Diacerein has been shown to reduce markers of inflammati... more The non-steroidal anti-inflammatory drug Diacerein has been shown to reduce markers of inflammation in animal models of type 2 diabetes mellitus; however, the effects of Diacerein on endoplasmic reticulum stress mediated inflammation are unknown. The aim of the current study was to investigate the potential protective role of Diacerein against palmitate-induced induction of ER stress and markers of apoptosis in pancreatic INS-1E beta cells. Three plates of INS-1E cells were treated with palmitate, palmitate and Diacerein, or maintained as control. Palmitate resulted in the induction of the protein tubulin alpha 1 and eukaryotic elongation factor Eef1 and inhibited the protein expression of mitochondrial malic enzyme and protein isoform 1 of ribonucleus protein (HNRPD). Palmitate was shown to decrease expression of eukaryotic initiation factor eIF2 (Control 100% vs Palmitate 51%; P = .05), responsible for global translation of mRNA; however there were no differences between conditions. Western blot analysis demonstrated that Diacerein did not restore key proteins
in apoptotic pathway including CHOP/GADD 34 and CHOP/GADD 153. Thus, our experiments suggest that while palmitate treatment reduced global protein synthesis inducing ER stress, Diacerein treatment does not appear to play a protective role in INS1-E under conditions of ER stress induced cellular damage

The aim of this study was to evaluate the effect of overload-induced hypertro-phy on extensor dig... more The aim of this study was to evaluate the effect of overload-induced hypertro-phy on extensor digitorum longus (EDL) and soleus muscles of streptozoto-cin-induced diabetic rats. The overload-induced hypertrophy and absolute tetanic and twitch forces increases in EDL and soleus muscles were not different between diabetic and control rats. Phospho-Akt and rpS6 contents were increased in EDL muscle after 7 days of overload and returned to the pre-overload values after 30 days. In the soleus muscle, the contents of total and phospho-Akt and total rpS6 were increased in both groups after 7 days. The contents of total Akt in controls and total rpS6 and phospho-Akt in the diabetic rats remained increased after 30 days. mRNA expression after 7 days of overload in the EDL muscle of control and diabetic animals showed an increase in MGF and follistatin and a decrease in myostatin and Axin2. The expression of FAK was increased and of MuRF-1 and atrogin-1 decreased only in the control group, whereas Ankrd2 expression was enhanced only in diabetic rats. In the soleus muscle caused similar changes in both groups: increase in FAK and MGF and decrease in Wnt7a, MuRF-1, atrogin-1, and myostatin. Differences between groups were observed only in the increased expression of follistatin in diabetic animals and decreased Ankrd2 expression in the control group. So, insulin deficiency does not impair the overload-induced hypertrophic response in soleus and EDL muscles. However, different mechanisms seem to be involved in the comparable hypertrophic responses of skeletal muscle in control and diabetic animals.

AIM: The aim of the present study was to evaluate the effect of oral caffeine ingestion during r... more AIM:

The aim of the present study was to evaluate the effect of oral caffeine ingestion during repeated sets of resistance.
METHODS:

Fourteen moderately resistance-trained men (20.9±0.36 years and 77.62±2.07 kg of body weight) ingested a dose of caffeine (5 mg.kg-1) or placebo prior to 3 sets of bench press and 3 sets of leg press exercises, respectively. The study used a double-blind, counterbalanced, crossover design. Repetitions completed and total weight lifted were recorded in each set. Readiness to invest in both physical (RTIPE) and mental (RTIME) effort were assessed prior each set, and rating of perceived exertion (RPE) was recorded after each set. Rest and peak heart rates were determined via telemetry.
RESULTS:

Caffeine ingestion result in increased number of repetitions to failure in bench press (F[1,13]=6.16, P=0.027) and leg press (F[1,13]=9.33, P=0.009) compared to placebo. The sum of repetitions performed in the 3 sets was 11.60% higher in bench press (26.86±1.74; caffeine: 30.00±1.87; P=0.027) and 19.10% in leg press (placebo: 40.0±4.22; caffeine: 47.64±4.69; P=0.009). Also, RTIME was increased in the caffeine condition both in bench press (F[1,13]=7.02, P=0.02) and in leg press (F[1,13]=5.41, P=0.03). There were no differences in RPE, RTIPE and HR (P>0.05) across conditions.
CONCLUSION:

Acute caffeine ingestion can improve performance in repeated sets to failure and increase RTIME in resistance-trained men.

Erythropoietin (EPO) has been well characterized as a renal glycoprotein hormone regulating red b... more Erythropoietin (EPO) has been well characterized as a renal glycoprotein hormone regulating red blood cell production by inhibiting apoptosis of erythrocyte progenitors in hematopoietic tissues. EPO exerts regulatory effects in cardiac and skeletal muscles. Duchenne muscular dystrophy is a lethal degenerative disorder of skeletal and cardiac muscle. In this study, we tested the possible therapeutic beneficial effect of recombinant EPO (rhEPO) in dystrophic muscles in mdx mice. Total strength was measured using a force transducer coupled to a computer. Gene expression for myostatin, transforming growth factor-β1 (TGF-β1), and tumor necrosis factor-α (TNF-α) was determined by quantitative real time polymerase chain reaction. Myostatin expression was significantly decreased in quadriceps from mdx mice treated with rhEPO (rhEPO = 0.60 ± 0.11, control = 1.07 ± 0.11). On the other hand, rhEPO had no significant effect on the expression of TGF-β1 (rhEPO = 0.95 ± 0.14, control = 1.05 ± 0.16) and TNF-α (rhEPO = 0.73 ± 0.20, control = 1.01 ± 0.09). These results may help to clarify some of the direct actions of EPO on skeletal muscle.

Caffeine is a widely used nutritional supplement which has been shown to enhance both physical an... more Caffeine is a widely used nutritional supplement which has been shown to enhance both physical and cognitive performance in younger adults. However, few studies have assessed the effect of caffeine ingestion on performance, particularly functional performance in older adults. The present study aims to assess the effect of acute caffeine ingestion on functional performance, manual dexterity and readiness to invest effort in older adults.
METHODS:

19 apparently healthy, volunteers (10 females and 9 males aged 61-79; 66 ± 2 years) performed tests of functional fitness and manual dexterity post ingestion of caffeine (3mg*kg-1) or placebo in a randomised order. Pre and 60 minutes post ingestion, participants also completed measures of readiness to invest physical (RTIPE) and mental (RTIME) effort.
RESULTS:

A series of repeated measures ANOVAS indicated enhanced performance in the following functional fitness tests; arm curls (P = .04), 8 foot up and go (P = .007), six minute walk (P = .016). Manual dexterity was also improved in the presence of caffeine (P = .001). RTIME increased (P = .015) pre to post ingestion in the caffeine condition but not in the placebo condition. There were no significant main effects or interactions for RTIPE or gender in any analysis (all P > .05).
CONCLUSIONS:

The results of this study suggest that acute caffeine ingestion positively enhances functional performance, manual dexterity and readiness to invest effort in apparently healthy older adults.

Objectives: The purpose of this study was to investigate the effects of intensity on rating of pe... more Objectives: The purpose of this study was to investigate the effects of intensity on rating of perceived exertion (RPE) during multiple sets to volitional failure in bench press exercise.
Design and Methods: Thirteen moderately resistance trained men performed 2 experimental sessions in random order: 3 sets to failure in bench press with 1 minute rest at an intensity of 50% and 70% of 1 repetition maximum (1RM). RPE was measured using the OMNI scale after each set. Readiness to Invest in Physical (RTIPE) and Mental (RTIME) Effort were assessed before each set.
Results: Repetitions to failure (46.46 ± 9.43 vs 26.62 ± 8.19; P<0.001) and total weight lifted (2044.31 ± 414.5 vs 1650.15 ± 507.83 kg; P<0.001) were greater at 50% when compared to the 70% 1RM condition. There were no differences in RPE, RTIPE, RTIME and heart rate across conditions.
Conclusions: These results indicate that when repetitions are done to volitional failure, monitoring RPE is not a useful technique in regulating intensity during resistance training.