Hábitos alimentares de atletas brasileiros durante a pandemia do Coronavírus / Eating habits of Brazilian athletes during the Coronavirus pandemic

O objetivo do presente trabalho foi avaliar a alteração nos hábitos alimentares de atletas brasileiros durante a pandemia do Coronavírus. Por meio de questionário online estruturado, 249 atletas com pelo menos 10 anos de prática e/ou pelo menos uma convocação pela seleção brasileira de sua respectiva modalidade, tiveram suas respostas analisadas. Houve decréscimo da frequência de consumo de verduras e legumes considerando a categoria de consumo "5 ou mais dias por semana", sendo 137 atletas (55,0%) antes da pandemia e 113 atletas (45,4%) durante a pandemia do Coronavírus (p<0,05). A frequência de consumo de frutas também apresentou redução de consumo, passando de 150 atletas (60,2%) que consumiam frutas "5 ou mais dias por semana" antes para 130 atletas (52,2%) durante a pandemia do Coronavírus (p<0,05). Contudo, houve aumento do número de atletas que consumiam frituras (15,3% antes para 23,3%, durante), bem como pizza, lanches e sanduíches, em "2 a 4 dia por semana" (21,3% antes para 31,7%, durante) (p<0,05) durante a pandemia do Coronavírus. Houve mudança na responsabilidade dos atletas em preparar suas refeições durante a pandemia do Coronavírus, bem como redução na frequência de refeições realizadas diariamente. Apesar de haver aumento do consumo de alimentos prontos durante a pandemia do Coronavírus (p<0,05), os atletas não aumentaram o consumo de alimentos/refeições por aplicativos (p>0,05). Concluindo, os dados do estudo demonstram que atletas de elite brasileiros apresentaram modificação nos hábitos alimentares em consequência da pandemia do Coronavírus. Tal fato sugere atenção, posto que se mantidas por períodos prolongados ou intensificadas, as alterações observadas poderiam se caracterizar na piora do perfil alimentar dos atletas brasileiros.

The aim of the present study was to evaluate the change in the eating habits of Brazilian athletes during the Coronavirus pandemic. Through a structured online questionnaire, 249 athletes with at least 10 years of practice and/or at least one call by the Brazilian team of their respective modality had their answers analyzed. There was a decrease in the frequency of consumption of vegetables considering the consumption category "5 or more days a week", with 137 athletes (55.0%) before the pandemic and 113 athletes (45.4%) during the Coronavirus pandemic (p<0.05). The frequency of fruit consumption also showed a reduction, from 150 athletes (60.2%) who consumed fruit "5 or more days a week" before the pandemic to 130 athletes (52.2%) during the pandemic (p<0.05). However, there was an increase in the number of athletes who consumed fried foods (15.3% before to 23.3% during), as well as pizza, snacks, and sandwiches, "2 to 4 days a week" (21.3% before to 31.7% during) (p<0.05) during the Coronavirus pandemic. There was a change in the responsibility of athletes to prepare their meals during the Coronavirus pandemic, as well as a reduction in the frequency of meals taken daily. Although there was an increase in the consumption of ready-to-eat foods during the Coronavirus pandemic (p<0.05), athletes did not increase their consumption of food/meals through apps (p>0.05). In conclusion, the study data demonstrate that Brazilian elite athletes showed changes in eating habits as a result of the Coronavirus pandemic. This fact draws attention, since if maintained for prolonged or intensified periods, the observed changes could be characterized by the worsening of the dietary profile of Brazilian athletes.

O efeito da idade relativa nas delegações olímpicas brasileiras / The relative age effect on the olympic brazilian delegations

Estudos prévios sugerem que jovens atletas nascidos nos primeiros meses do ano podem ser beneficiados no processo de seleção e formação quando comparados a atletas de mesma idade nascidos nos últimos meses do ano. Esse fenômeno é descrito na literatura como o efeito da idade relativa (EIR). O objetivo do presente estudo foi analisar o EIR nas delegações brasileiras participantes dos Jogos Olímpicos de Atenas 2004, Pequim 2008 e Londres 2012. Para esta investigação, a amostra foi composta por 543 atletas olímpicos (masculino e feminino). O teste Qui-Quadrado (x 2 ) foi adotado para a comparação entre a distribuição esperada e a distribuição observada. O nível de significância adotado foi de p<0,05. Os resultados do presente estudo não indicam diferença significante para distribuição de nascimentos entre os quartis do ano para a amostra investigada (p>0,05). Considerando que a análise principal foi realizada com agrupamentos das modalidades, é possível especular que esse resultado pode ser atribuído a diversos fatores, como: i) menor demanda por uma vaga nas categorias de base em determinadas modalidades esportivas, ii) divisões por categorias competitivas que além da idade também levam em consideração outras variáveis, iii) adoção de diferentes abordagens de formação de jovens atletas.(AU)

Previous studies suggest that young athletes born in the first months of the year may have an advantage during selection and development process compared to athletes of the same age born in the last months of the year. This phenomenon is described in the literature as the relative age effect (RAE). The aim of this study was to analyze the occurrence of RAE in participants of Brazilian delegations of the Olympic Games Athens 2004, Beijing 2008 and London 2012. For this study, the sample consisted of 543 Olympic athletes (male and female). The chi-square (x 2 ) was adopted to compare the expected distribution and the observed distribution. The significance level was set at p <0.05. The results of this study do not indicate significant difference in the birth distribution among quarters of the year for the population investigated (p> 0.05). Considering that the main analysis was conducted by pooled data, it is reasonable to speculate this outcome might be due to multiple factors such: i) lower demand for a place in the early categories in some sports, ii) rating for competitive categories beyond age also take into account other variables such as weight and height iii) the adoption of different long-term youth training approaches.(AU)

Identification of muscle fatigue by tracking facial expressions.

Resistance training (RT) is performed at distinct levels of intensity from the beginning to the end of exercise sets, increasing the sensation of effort as the exercise progress to more vigorous levels, commonly leading to changes on the facial expression of RT practitioners. The objective of this study is to evaluate changes in facial expressions using the Facial Action Coding System(FACS) and the activation of facial muscles by surface electromyography(sEMG) at two different levels of effort during resistance exercise and to investigate the correlation between facial expression and exercise intensity and fatigue. Eleven healthy male participants [23±6years; 1.77±6 m; 78±10kg] performed a set of arm curl exercise at 50% and 85% 1RM until muscle fatigue. The Surface electromyography (sEMG activity was recorded simultaneously in areas of the epicranius muscle (EM) and zygomatic major muscle (ZM). Facial expression was recorded and blindly scored by five experienced examiners. Scores (0-5) were based on the level of activity of the ZM (lip corner puller-Action Unit 12-FACS) during exercise. Facial expression and sEMG data were obtained during the exercise at the first repetition and at muscle failure. The root mean square (RMS) of the sEMG amplitude of the EM was significantly increased between the first and last repetition (50%1RM:p = 0.002,d = 1.75; and 85%1RM:p = 0.002,d = 1.54). The RMS values for the ZM were significantly increased between the first and last repetition (50%1RM:p<0.001,d = 2.67; 85%1RM:p<0.001,d = 0.50). The RMS values for the ZM were also increased in 85%1RM compared to values obtained from 50%1RM (p = 0.001,d = 1.12) at the first repetition. AU12 scores and RMS values were not statistically different between 85%1RM and 50%1RM at the last repetition. Furthermore, there was a strong correlation (r = 0.61;p = 0.045) between AU12 scores and the sEMG peak for the ZM. In conclusion, changes in facial expression may be directly correlated with different resistance exercise intensities and fatigue.

Resistance training downregulates macrophages infiltration in the kidney of 5/6 nephrectomized rats.

INTRODUCTION: Chronic kidney disease (CKD) is considered a significant world health problem with elevated mortality rates. Patients with CKD are restricted to mild physical activity, present chronic inflammatory state and loss of muscle strength. Currently, the influence of resistance exercise (RE) on the progression of renal disease has not being fully elucidated. PURPOSE: To evaluate the effects of RE on the progression of CKD in a remnant kidney model (5/6Nx) in rats. METHODS: Eight-week-old Wistar rats were submitted to 5/6 nephrectomy and were divided into four groups: Sham sedentary (Sham SD); Sham RE (Sham RE); 5/6Nx SD and 5/6Nx RE. The animals were trained for 8 weeks in a vertical climbing ladder for 3 days per week, on non-consecutive days. RESULTS: As expected, 5/6Nx SD group presented a markedly loss of renal function, increased plasma inflammatory cytokines and increased oxidative stress with a reduced activity of nitric oxide. The higher macrophage infiltration and fibrosis confirmed these conditions. RE attenuated systolic blood pressure and renal function decrease and also improved serum lipid parameters in 5/6 Nx animals. It was evident the increase of muscle strength and mass in the trained groups while the sedentary group showed reduced muscle weight and strength compared to Sham SD. CONCLUSIONS: RE implemented following 5/6Nx retard the progression of chronic kidney injury while simultaneously allowed the maintenance of skeletal muscle strength.

Resistance training attenuates inflammation and the progression of renal fibrosis in chronic renal disease.

Patients with chronic kidney disease (CKD) have progressive renal fibrosis, inflammation, and reduced muscle mass and strength. Resistance training (RT) has been suggested to mitigate the loss of muscle mass, of strength and the inflammation in CKD, but the mechanisms are unknown. The aim of this study was to evaluate the influence of RT on renal fibrosis, renal cytokine expression, creatine kinase levels, and muscle mass and strength in CKD rats. A CKD model was obtained by 5/6 nephrectomy (Nx). Fifteen 8-week-old male rats were divided into 3 groups: Sham (control), Nx SED (CKD sedentary) and Nx RT (CKD trained). The RT consisted of ladder climbing at 70% of the animal's maximal carrying capacity for 10 weeks. Muscle strength, creatine kinase levels, renal fibrosis and mRNA interleukin (IL)-4, IL-6 and IL-10 were analyzed after the RT protocol. There was significant improvement in the muscle strength and creatine kinase levels in the Nx RT group. Moreover, renal fibrosis and inflammation were attenuated, with increased IL-4 and IL-10 expression and reduced IL-6 expression in the Nx RT group compared with that in the Nx SED group. No difference in muscle mass was observed among the groups. In conclusion, RT was effective in reducing fibrosis and inflammation, in addition to increasing muscle strength and creatine kinase levels, in rats with CKD, independent of muscle mass.

Resistance Training in Spontaneously Hypertensive Rats with Severe Hypertension / Treinamento de Força em Ratos Espontaneamente Hipertensos com Hipertensão Arterial Grave

Abstract Background: Resistance training (RT) has been recommended as a non-pharmacological treatment for moderate hypertension. In spite of the important role of exercise intensity on training prescription, there is still no data regarding the effects of RT intensity on severe hypertension (SH). Objective: This study examined the effects of two RT protocols (vertical ladder climbing), performed at different overloads of maximal weight carried (MWC), on blood pressure (BP) and muscle strength of spontaneously hypertensive rats (SHR) with SH. Methods: Fifteen male SHR ENT#091;206 ± 10 mmHg of systolic BP (SBP)ENT#093; and five Wistar Kyoto rats (WKY; 119 ± 10 mmHg of SBP) were divided into 4 groups: sedentary (SED-WKY) and SHR (SED-SHR); RT1-SHR training relative to body weight (~40% of MWC); and RT2-SHR training relative to MWC test (~70% of MWC). Systolic BP and heart rate (HR) were measured weekly using the tail-cuff method. The progression of muscle strength was determined once every fifteen days. The RT consisted of 3 weekly sessions on non-consecutive days for 12-weeks. Results: Both RT protocols prevented the increase in SBP (delta - 5 and -7 mmHg, respectively; p > 0.05), whereas SBP of the SED-SHR group increased by 19 mmHg (p < 0.05). There was a decrease in HR only for the RT1 group (p < 0.05). There was a higher increase in strength in the RT2 (140%; p < 0.05) group as compared with RT1 (11%; p > 0.05). Conclusions: Our data indicated that both RT protocols were effective in preventing chronic elevation of SBP in SH. Additionally, a higher RT overload induced a greater increase in muscle strength.

Resumo Fundamentos: O treinamento de força (TF) tem sido recomendado como tratamento não farmacológico para hipertensão arterial moderada. Apesar do papel importante que a intensidade do exercício desempenha sobre a prescrição do treinamento, ainda não há nenhum dado avaliando os efeitos da intensidade do TF sobre a hipertensão arterial grave (HAG). Objetivo: Este estudo analisou os efeitos de dois protocolos do TF(subida em escada vertical), realizados com diferentes sobrecargas do peso máximo carregado (PMC), sobre a pressão arterial (PA) e a força muscular de ratos espontaneamente hipertensos (SHR) com HAG. Métodos: Quinze SHR machos (206 ± 10 mmHg de PA sistólica (PAS)) e cinco ratos Wistar Kyoto (WKY; 119 ± 10 mmHg de PAS) foram divididos em 4grupos:sedentários: (SED-WKY) e SHR (SED-SHR); treinados: TF1-SHR conforme o peso corporal (~40% do PMC); e TF2-SHR conforme o teste de PMC (~70% do PMC). Foram coletadas medidas de PAS e a frequência cardíaca (FC) semanalmente usando o método de pressão arterial caudal. A progressão da força muscular foi determinada a cada 15 dias. O TF consistiu de 3 sessões semanais em dias não consecutivos durante 12 semanas. Resultados: Os dois protocolos de TF preveniram o aumento da PAS(respectivamente, delta - 5 e -7 mmHg; p > 0, 05), enquanto que a PAS do grupo SED-SHR aumentou em 19 mmHg (p < 0, 05). Houve queda na FC apenas para o grupo TF1 (p < 0, 05). Foi observado um aumento mas significativo de força no grupo do protocolo TF2 (140%; p < 0, 05) em comparação com o TF1 (11%; p>0, 05). Conclusões: Nossos dados indicam que ambos os protocolos de TF foram efetivos na prevenção da elevação crônica da PAS na HAG. Além disso, sobrecargas maiores de TF induziram a um maior aumento de força muscular.

Resistance Training in Spontaneously Hypertensive Rats with Severe Hypertension.

BACKGROUND: Resistance training (RT) has been recommended as a non-pharmacological treatment for moderate hypertension. In spite of the important role of exercise intensity on training prescription, there is still no data regarding the effects of RT intensity on severe hypertension (SH). OBJECTIVE: This study examined the effects of two RT protocols (vertical ladder climbing), performed at different overloads of maximal weight carried (MWC), on blood pressure (BP) and muscle strength of spontaneously hypertensive rats (SHR) with SH. METHODS: Fifteen male SHR ENT#091;206 ± 10 mmHg of systolic BP (SBP)ENT#093; and five Wistar Kyoto rats (WKY; 119 ± 10 mmHg of SBP) were divided into 4 groups: sedentary (SED-WKY) and SHR (SED-SHR); RT1-SHR training relative to body weight (~40% of MWC); and RT2-SHR training relative to MWC test (~70% of MWC). Systolic BP and heart rate (HR) were measured weekly using the tail-cuff method. The progression of muscle strength was determined once every fifteen days. The RT consisted of 3 weekly sessions on non-consecutive days for 12-weeks. RESULTS: Both RT protocols prevented the increase in SBP (delta - 5 and -7 mmHg, respectively; p > 0.05), whereas SBP of the SED-SHR group increased by 19 mmHg (p < 0.05). There was a decrease in HR only for the RT1 group (p < 0.05). There was a higher increase in strength in the RT2 (140%; p < 0.05) group as compared with RT1 (11%; p > 0.05). CONCLUSIONS: Our data indicated that both RT protocols were effective in preventing chronic elevation of SBP in SH. Additionally, a higher RT overload induced a greater increase in muscle strength.

Exercise during pregnancy protects adult mouse offspring from diet-induced obesity.

BACKGROUND: Physical exercise induces positive alterations in gene expression involved in the metabolism of obesity. Maternal exercise provokes adaptations soon after birth in the offspring. Here, we investigated whether adult mouse offspring of swim-trained mothers is protected against the development of the deleterious effects of high fat diet (HFD). METHODS: Our study comprises two parts. First, female C57BL/6 mice were divided into one sedentary and one swim-trained group (before and during pregnancy, n = 18). In the second part, adult offspring (n = 12) of trained and sedentary mothers was challenged to HFD for 16 weeks. Notably, most of the analysis was done in male offspring. RESULTS: Our results demonstrate that maternal exercise has several beneficial effects on the mouse offspring and protects them from the deleterious effects of HFD in the adult. Specifically, swimming during pregnancy leads to lower birth weight in offspring through 2 months of age. When subjected to HFD for 4 month in the adulthood, our study presents novel data on the male offspring's metabolism of trained mothers. The offspring gained less weight, which was accompanied by less body fat, and they used more calories during daytime compared with offspring of sedentary mothers. Furthermore, we observed increased adiponectin expression in skeletal muscle, which was accompanied by decreased leptin levels and increased insulin sensitivity. Decreased interleukin-6 expression and increased peptide PYY levels were observed in sera of adult offspring of mothers that swam during pregnancy. CONCLUSIONS: Our results point to the conclusion that maternal exercise is beneficial to protect the offspring from developing obesity, which could be important for succeeding generations as well.

Kinin B2 receptor does not exert renoprotective effects on mice with glycerol-induced rhabdomyolysis.

AIM: To investigate a potential protective role of the kinin B2 receptor in a glycerol-induced rhabdomyolysis mouse model. METHODS: We separated 28 C57Bl/6 male mice into 4 groups: untreated WT animals, untreated B2 knockout mice, glycerol-treated WT and glycerol-treated B2 knockout mice. Glycerol-treated animals received one intramuscular injections of glycerol solution (50% v/v, 7 mL/kg). After 48 h, urine and blood samples were collected to measure creatinine and urea levels. Additionally, kidney samples were extracted for histological evaluation, and the mRNA expression levels of kinin B1 and B2 receptors and inflammatory mediators were measured by real-time polymerase chain reaction. RESULTS: Serum creatinine and urea levels showed differences between untreated wild-type and glycerol-treated wild-type mice (0.66 ± 0.04 vs 2.61 ± 0.53 mg/dL, P < 0.01; and 33.51 ± 2.08 vs 330.2 ± 77.7 mg/dL, P < 0.005), and between untreated B2 knockout mice and glycerol-treated knockout mice (0.56 ± 0.03 vs 2.23 ± 0.87 mg/dL, P < 0.05; and 42.49 ± 3.2 vs 327.2 ± 58.4 mg/dL, P < 0.01), but there was no difference between the glycerol-treated wild-type and glycerol-treated knockout mice. Glycerol was able to induce a striking increase in kinin B2 receptor expression (> 30 times, 31.34 ± 8.9) in kidney. Animals injected with glycerol had a higher degree of tubular injury than untreated animals. Wild-type and knockout mice treated with glycerol intramuscularly present kidney injury, with impairment in renal function. However, B2 knockout mice treated with glycerol did not show a different phenotype regarding kidney injury markers, when compared to the wild-type glycerol-treated group. CONCLUSION: We conclude that the kinin B2 receptor does not have a protective role in renal injury.

Moderate exercise increases the metabolism and immune function of lymphocytes in rats.

Exercise modulates both glucose and glutamine metabolism which influences lymphocyte function. We investigated the influence of chronic moderate exercise on glucose and glutamine metabolism in lymphocytes, the associated influence on proliferation, and cytokine and immunoglobulin production. Male Wistar rats (8 weeks old) were placed in an exercise training group (N = 15, 1 h day(-1) at 60 % VO2max, 5 days week(-1)) for 8 weeks of exercise, or a sedentary control group. Twenty-four hours following the final training session, lymphocytes were separated, and the incorporation of [U-14C]-glucose, [U-14C]-glutamine, and [2-14C]-thymidine from the supernatant was measured. The activity of glucose-6-phosphate dehydrogenase, hexokinase, and glutaminase was measured. Lymphocytes were stimulated with ConA and LPS and incubated with the Mycobacterium bovis bacille Calmette-Guerin (BCG) vaccine and plasma IgG and IgE were measured. Glutamine metabolism increased in both T and B lymphocytes in the trained group. In the trained group, proliferative capacity increased T lymphocytes under ConA stimulation, and increased B lymphocytes with LPS. There was a significant increase in IL-2 production and decrease in IL-4 in the trained group compared with sedentary controls. IL-2R and TNFR increased in trained rats while IL-4R decreased and were more pronounced in T lymphocytes compared with B lymphocytes. In both lymphocyte subsets, exercise training significantly increased the expression of CD54+ and CD30+ cell markers. Exercise training increased plasma IgG compared with the sedentary group. In conclusion, moderate exercise training improves immune function and metabolism in T and B lymphocytes, reflecting an increased ability to respond to immune challenges.

Bradykinin inhibits hepatic gluconeogenesis in obese mice.

The kallikrein-kinin system (KKS) has been previously linked to glucose homeostasis. In isolated muscle or fat cells, acute bradykinin (BK) stimulation was shown to improve insulin action and increase glucose uptake by promoting glucose transporter 4 translocation to plasma membrane. However, the role for BK in the pathophysiology of obesity and type 2 diabetes remains largely unknown. To address this, we generated genetically obese mice (ob/ob) lacking the BK B2 receptor (obB2KO). Despite similar body weight or fat accumulation, obB2KO mice showed increased fasting glycemia (162.3 ± 28.2 mg/dl vs 85.3 ± 13.3 mg/dl), hyperinsulinemia (7.71 ± 1.75 ng/ml vs 4.09 ± 0.51 ng/ml) and impaired glucose tolerance when compared with ob/ob control mice (obWT), indicating insulin resistance and impaired glucose homeostasis. This was corroborated by increased glucose production in response to a pyruvate challenge. Increased gluconeogenesis was accompanied by increased hepatic mRNA expression of forkhead box protein O1 (FoxO1, four-fold), peroxisome proliferator-activated receptor gamma co-activator 1-alpha (seven-fold), phosphoenolpyruvate carboxykinase (PEPCK, three-fold) and glucose-6-phosphatase (eight-fold). FoxO1 nuclear exclusion was also impaired, as the obB2KO mice showed increased levels of this transcription factor in the nucleus fraction of liver homogenates during random feeding. Intraportal injection of BK in lean mice was able to decrease the hepatic mRNA expression of FoxO1 and PEPCK. In conclusion, BK modulates glucose homeostasis by affecting hepatic glucose production in obWT. These results point to a protective role of the KKS in the pathophysiology of type 2 diabetes mellitus.

Effect of food restriction and intense physical training on estrous cyclicity and plasma leptin concentrations in rats.

Intense physical training and dietary energy restriction have been associated with consequences such as nutritional amenorrhea. We investigated the effects of intense physical training, food restriction or the combination of both strategies on estrous cyclicity in female rats, and the relationship between leptin ad these effects. Twenty-seven female Wistar rats were distributed into four groups: SF: sedentary, fed ad libitum; SR: sedentary subjected to 50% food restriction (based on the food intake of their fed counterparts); TF: trained (physical training on a motor treadmill with a gradual increase in speed and time), fed ad libitum; TR: trained with 50% food restriction. We analysed estrous cyclicity, plasma leptin and estradiol as well as chemical composition of the carcass, body weight variation, and weight of ovaries and perirenal adipose tissue. Data demonstrate that physical training alone was not responsible for significant modifications in either carcass chemical composition or reproductive function. Food restriction reduced leptin levels in all animals and interrupted the estrous cyclicity in some animals, but only the combination of food restriction and physical training was capable of interrupting the estrous cyclicity in all animals. Leptin was not directly related to estrous cyclicity. From our findings, it may be concluded that there is an additive or synergistic effect of energy intake restriction and energy expenditure by intense physical training on estrous cyclicity. Leptin appears to be one among others factors related to estrous cycle, but it probably acts indirectly.

Effects of different levels of protein intake and physical training on growth and nutritional status of young rats.

This study aimed to investigate the effects of physical training, and different levels of protein intake in the diet, on the growth and nutritional status of growing rats. Newly-weaned Wistar rats (n=48) were distributed into six experimental groups; three of them were subjected to physical swim training (1 h per day, 5 d per week, for 4 wk, after 2 wk of familiarization) and the other three were considered as controls (non-trained). Each pair of groups, trained and non-trained, received diets with a different level of protein in their composition: 14%, 21% or 28%. The animals were euthanized at the end of the training period and the following analyses were performed: proteoglycan synthesis as a biomarker of bone and cartilage growth, IGF-I (insulin-like growth factor-I) assay as a biomarker of growth and nutritional status, total RNA and protein concentration and protein synthesis measured in vivo using a large-dose phenylalanine method. As a main finding, increased dietary protein, combined with physical training, was able to improve neither tissue protein synthesis nor muscle growth. In addition, cartilage and bone growth seem to be deteriorated by the lower and the higher levels of protein intake. Our data allow us to conclude that protein enhancement in the diet, combined with physical exercise, does not stimulate tissue protein synthesis or muscle mass growth. Furthermore, physical training, combined with low protein intake, was not favorable to bone development in growing animals.

Suplementação proteica não aumenta a concentração plasmática de óxido nítrico em homens saudáveis / Protein supplementation does not increase nitric oxide plasmatic concentration in healthy men

Suplementos nutricionais, supostamente, capazes de potencializar a produção endógena de óxido nítrico (NO) têm experimentado crescente popularidade entre os indivíduos fisicamente ativos. Diante da carência de informações sobre o assunto, o objetivo do presente estudo foi avaliar o efeito de um suplemento comercial à base de proteínas e aminoácidos sobre a produção endógena de NO. MÉTODOS: A amostra foi constituída de 12 homens sedentários, mas sem fatores de risco para doenças cardiovasculares. O protocolo de suplementação foi conduzido conforme o arranjo experimental duplo-cego cruzado. Os participantes receberam, aleatoriamente, placebo (PLA) ou suplemento proteico (SP), em dois momentos diferentes, separados por uma semana. Com o intuito de determinar a concentração plasmática de NO, amostras de sangue foram coletadas antes (24h e imediatamente antes) e depois (30 e 60 minutos) do consumo da substância PLA ou do SP. RESULTADOS: Não foi observada alteração na concentração plasmática de NO após a ingestão do SP em comparação com o PLA (pós- suplementação 30min - PLA: 19,3 ± 4,7µmol.L- 1 vs. SP: 18,9 ± 4,4µmol.L-1 e pós-suplementação 60min - PLA: 21,3 ± 6,5µmol.L-1 vs. SP: 20,3 ± 4,9µmol.L-1). Também não foi verificada alteração da pressão arterial. CONCLUSÃO: O suplemento nutricional à base de proteínas e aminoácidos, testado no presente estudo, não potencializou a produção endógena de NO.

Nutritional supplements, theoretically able to increase endogenous nitric oxide (NO) production have experienced great popularity among physically active individuals. AIM: scientific evidence available regarding this issue is scarce. Therefore, the purpose of this study was to evaluate the effect of a dietary supplement commercialized as a nitric oxide booster. MATERIALS AND METHODS: twelve sedentary men with no risk factors for cardiovascular diseases were supplemented with placebo or protein in two different occasions. The present study was conducted in a cross double-blind design. In order to assess plasmatic NO concentration, blood samples were obtained before (24hs and immediately before) and after (30 and 60 minutes) consumption of placebo (PLA) or protein supplement (SP). RESULTS: there was no difference in plasmatic nitric oxide concentration between both trails (Post-supplementation 30 min - PLA: 19.3±4.7 µmol.L-1 vs. SP: 18.9±4.4 µmol.L-1 and Post-supplementation 60 min - PLA: 21.3±6.5 µmol.L-1 vs. SP: 20.3±4.9 µmol.L-1). In addition, no difference was detected for arterial blood pressure. CONCLUSION: the dietary supplement analyzed in the present study failed to increase nitric oxide endogenous production.

Acute effect of a ballistic and a static stretching exercise bout on flexibility and maximal strength.

Different stretching techniques have been used during warm-up routines. However, these routines may decrease force production. The purpose of this study was to compare the acute effect of a ballistic and a static stretching protocol on lower-limb maximal strength. Fourteen physically active women (169.3 +/- 8.2 cm; 64.9 +/- 5.9 kg; 23.1 +/- 3.6 years) performed three experimental sessions: a control session (estimation of 45 degrees leg press one-repetition maximum [1RM]), a ballistic session (20 minutes of ballistic stretch and 45 degrees leg press 1RM), and a static session (20 minutes of static stretch and 45 degrees leg press 1RM). Maximal strength decreased after static stretching (213.2 +/- 36.1 to 184.6 +/- 28.9 kg), but it was unaffected by ballistic stretching (208.4 +/- 34.8 kg). In addition, static stretching exercises produce a greater acute improvement in flexibility compared with ballistic stretching exercises. Consequently, static stretching may not be recommended before athletic events or physical activities that require high levels of force. On the other hand, ballistic stretching could be more appropriate because it seems less likely to decrease maximal strength.

Treino de corrida não interfere no desempenho de força de membros superiores / Endurance exercise bout does not interfere in strength performance of upper limbs

OBJETIVO: O presente estudo avaliou o efeito do exercício de endurance (corrida) sobre o subseqüente desempenho de força de músculos dos membros superiores e do tronco. METODOLOGIA: A amostra foi composta por 13 universitárias, saudáveis e fisicamente ativas. A primeira fase do experimento consistiu na realização de um teste de corrida, simulando uma sessão de treino, com duração de 45 minutos a 70 por cento da FC MAX. Imediatamente após a corrida, foram aplicados testes de força (dinamometria - preensão palmar, teste de 1-RM e teste de repetições máximas a 70 por cento-1RM no supino). A glicemia foi mensurada no início do experimento e imediatamente antes dos testes de força. RESULTADOS: Não foi observada diferença significativa no desempenho dos testes de força após o treino de corrida (dinamometria, 1-RM e REPMAX - sem a prévia execução do treino de corrida - 29,9 ± 3,8 kgf; 34,4 ± 3,1 kg; 1ºset: 12,5 ± 3,3 reps e 2ºset: 11,7 ± 2,7 reps vs. com a prévia execução do treino de corrida - 29,2 ± 3,1 kgf; 33,9 ± 2,5 kg; 1ºset: 13,2 ± 2,1 reps e 2ºset: 12,2 ± 2,8 reps). Com relação à glicemia, não foi detectada alteração significativa durante o experimento. CONCLUSÃO: A execução do treino de corrida não afetou o subseqüente desempenho de força dos membros superiores e do tronco. Esse dado sugere que a interferência, freqüentemente, observada no exercício concorrente, é dependente do grupo muscular treinado. Possivelmente, o efeito adverso induzido pelo treino concorrente, realizado, exclusivamente, com membros inferiores, é decorrente da fadiga residual instalada nos músculos recrutados na atividade anterior. É importante ressaltar que a atividade de endurance não promoveu alteração na concentração plasmática de glicose. A manutenção da glicemia associada à ausência de interferência sobre o desempenho dos testes de força reforça, mais ainda, a hipótese de que o efeito adverso do treinamento concorrente é, provavelmente, causado por alterações...

AIM: the present study evaluated the effect of endurance exercise (running) on the subsequent strength performance of muscles of upper limbs and trunk. METHODOLOGY: Thirteen healthy female, university students, physically active were selected to compose the sample. The first phase of the experiment the subjects were submitted to an endurance exercise bout (treadmill), simulating a training session, with duration of 45 minutes at 70 percent of the HRmax. Immediately after the endurance exercise bout, the subjects performed strength tests (Dynamometry test - handgrip, 1RM test and maximal repetitions test at 70 percent-1RM in the bench press). Glycemia was measured in the beginning of the experiment and immediately before the strength tests. RESULTS: No significant difference was observed in the strength tests performance after the endurance exercise bout (Dynamometry, 1-RM and REPMAX - with no previous endurance exercise - 29.9 ± 3.8 kgf; 34.4 ± 3.1 kg; 1st set 12.5 ± 3.3 reps and 2nd set 11.7 ± 2.7 reps vs. with previous endurance exercise - 29.2 ± 3.1 kgf; 33.9 ± 2.5 kg; 1st set 13.2 ± 2.1 reps and 2nd set 12.2 ± 2.8 reps). Regarding glycemia, no significant alteration was observed during the experiment. CONCLUSION: the endurance exercise bout did not affect the subsequent strength performance of the upper limbs and trunk. This data suggests that the common interference observed in the concurrent training is dependent on which muscular group has been recruited. Possibly, the adverse effect induced by the concurrent training, exclusively performed with lower extremities, is due to the residual fatigue installed in the muscles recruited in the previous activity. It is important to highlight that endurance exercise did not promote alteration in the glucose plasma concentration. The glycemia maintenance associated with the lack of interference on the performance of the strength tests reinforces even more the hypothesis that the adverse effect...

Consumo de aminoácidos de cadeia ramificada não afeta o desempenho de endurance / Branched-chain amino acids ingestion does not affect endurance performance

A suplementação com aminoácidos de cadeia ramificada (BCAA) é uma das manipulações dietéticas mais populares entre atletas engajados em atividades de endurance. Entretanto, o papel ergogênico destes aminoácidos ainda não está totalmente estabelecido. Portanto, o objetivo do presente trabalho foi avaliar o efeito do consumo de BCAA sobre o exercício de endurance realizado até a exaustão. A fim de provocar redução do estoque de glicogênio muscular e, por conseguinte, maximizar a utilização dos BCAA, os sujeitos (n=17) foram submetidos a uma sessão prévia de exercício (corrida realizada a 75 por cento do VO2max por 40 min seguida por 2 tiros a 90 por cento do VO2max por 10 min cada um). Subseqüentemente, após o consumo aleatório de BCAA (77 mg.kg-1) ou placebo, seguindo modelo duplo cego cruzado, os participantes executaram um teste para determinação da capacidade de endurance (corrida a 90 por cento do Limiar anaeróbio) até a exaustão. Ambos os experimentos, BCAA e placebo, foram separados por uma semana. Com relação ao tempo até a exaustão e a distância percorrida, nenhuma diferença foi detectada entre as condições experimentais. (Placebo: 50,1±8,9 vs BCAA: 52,4±4,5 min, respectivamente) (Placebo: 8,8±1,3 vs BCAA: 9,1±0,6 km, respectivamente). Além disto, também não foi evidenciada diferença na concentração plasmática de glicose, de lactato e de amônia entre ambas condições experimentais. Em conclusão, a suplementação de BCAA não afetou o desempenho de endurance em um teste de corrida até a exaustão.

Branched-chain amino acids (BCAA) supplementation is one of the most popular dietary manipulations used by endurance athletes. However, the ergogenic role of these amino acids in endurance exercise is not well established yet. Therefore, the aim of this study was to evaluate the effect of BCAA supplementation upon endurance exercise performed until exhaustion. In order to induce glycogen supply reduction, and thus maximize BCAA utilization, the subjects (n=17) were submitted to a prior exercise trial (one bout of running at 75 percent of VO2max for 40 min followed by two bouts at 90 percent of VO2max for 10 min each). Subsequently, the participants performed an endurance test (running at 90 percent of the anaerobic threshold) until exhaustion after the ingestion of 77 mg.kg-1 of BCAA or placebo, in a double blind crossover design. Both trials, BCAA and placebo, were a week apart. No differences were observed between placebo and BCAA experimental conditions regarding time to exhaustion (50.1±8.9 vs 52.4±4.5 min, respectively) and total distance performed (8.8±1.3 vs 9.1±0.6 km, respectively) in endurance capacity test. Furthermore, no difference was observed in glucose, lactate or ammonia plasma concentration between both experimental conditions. In conclusion, BCAA supplementation did not affect endurance exercise performance.

Effect of a high-intensity exercise training on the metabolism and function of macrophages and lymphocytes of walker 256 tumor bearing rats.

Epidemiologic studies suggest that moderately intense training promotes augmented immune function, whereas strenuous exercise can cause immunosupression. Because the combat of cancer requires high immune function, high-intensity exercise could negatively affect the host organism; however, despite the epidemiologic data, there is a lack of experimental evidence to show that high-intensity training is harmful to the immune system. Therefore, we tested the influence of high-intensity treadmill training (10 weeks, 5 days/week, 30 mins/day, 85% VO(2)max) on immune system function and tumor development in Walker 256 tumor-bearing Wistar rats. The metabolism of glucose and glutamine in lymphocytes and macrophages was assessed, in addition to some functional parameters such as hydrogen peroxide production, phagocytosis, and lymphocyte proliferative responses. The metabolism of Walker 256 cells was also investigated. Results demonstrated that high-intensity training increased the life span of tumor-bearing rats, promoted a reduction in tumor mass, and prevented indicators of cachexia. Several changes, such as a reduction in body weight and food intake and activation of glutamine metabolism in macrophages and lymphocytes induced by the presence of Walker 256 tumor, were prevented by high intensity training. The reduction in tumor growth was associated with an impairment of tumor cell glucose and glutamine metabolism. These data suggest that high-intensity exercise training may be a viable strategy against tumors.

Suplementação de creatina potencializa o desempenho de sprints consecutivos em jogadores de basquetebol / Creatine supplementation maximizes repeated-sprint capacity of basketball players

Objetivos: o presente estudo teve como objetivo verificar o efeito da suplementação de creatina sobre o tempo de execução de 6 sprints consecutivos em jogadores de basquetebol. Materiais e métodos: a amostra foi constituída de 16 atletas de basquetebol do sexo masculino, com idade média de 18 ± 0,5 anos, da categoria juvenil. Os atletas foram divididos aleatoriamente, por posição, em Grupo Placebo (n=8) e Grupo Creatina (n=8). O protocolo desuplementação foi conduzido segundo o modelo duplo-cego. Na fase de sobrecarga foram administrados25 gramas de creatina (ou placebo) por dia durante 5 dias. Posteriormente, foram oferecidos 5 gramas por dia, nos 5 dias subseqüentes. Para aferir a capacidade de realização desprints repetidos foi realizado um teste, no qual deveriam ser percorridos 30 metros no menor tempo possível. O teste foi constituído de 6 sprints consecutivos, com pausas de 120 segundos. Resultados: foi observado aumento significativo da massa corporal após a suplementação decreatina (p<0,05). Também foi verificada alteração significativa no tempo de execução dos sprints repetidos no Grupo Creatina. O quarto, quinto e o sexto sprints tiveram seu tempo de execução reduzido em 8,5%, 10% e 9%, respectivamente (pré vs. pós-suplementação - p<0,05). Conclusão: A suplementação de creatina potencializou o desempenho em sprints consecutivos de 30 metros em atletas de basquetebol.

Aim: The aim of the present study was to verify the effect of creatine supplementation upon repeated-sprint capacity of basketball players. Materials and Methods: Sixteen young basketball players (18 ± 0.5 yrs) were randomically divided in Creatine (n=8) and Placebo (n=8) groups. The supplementation protocol was conducted as double-blind design.It was administrated 25g.day-1 of creatine (or placebo) in the loading phase for 5 days and 5g.day-1 in the subsequent 5 days. In order to access repeated-sprint capacity, the athletes were submitted to 30 m sprint test which should be realized as fast as possible. Six consecutives sprints were realized with 120 seconds of recovery. Results: It was observed a weight gain in Creatine-supplemented group (p<0.05). It was noted a decrease in the time of consecutives sprints performed by Creatine-supplemented group. The time of the 4th, 5th and 6th sprints were reduced by 8.5%, 10% and 9%, respectively, in post-supplementation as compared to pre-supplementation condition (p<0.05). Conclusion: Creatine supplementation maximized repeated-sprint capacity (6x30m) of basketball players.

Efeito de diferentes protocolos de treinamento de força sobre parâmetros morfofuncionais, hormonais e imunológicos / Effects of different resistance training protocols over the morphofunctional, hormonal and immunological parameters

O objetivo do estudo foi examinar a influência de dois diferentes protocolos de treinamento de força sobre parâmetros antropométricos (peso, IMC, massa gorda), funcionais (teste de 1-RM e teste de repetições máximas) e relacionados ao sistema endócrino (concentração de testosterona e de cortisol) e ao sistema imunológico (concentração de glutamina e de IgG). Participaram do estudo 12 homens treinados (27,4 ± 4,8 anos). Esses indivíduos foram aleatoriamente divididos em dois grupos, que posteriormente foram submetidos a dois protocolos de treinamento distintos: Múltiplas séries (MS) e Tri-set (TS). Amostras de sangue foram coletadas antes e depois de uma sessão de exercício de força, no início e no final do período de oito semanas de treinamento. Não foram observadas alterações nos parâmetros morfo-funcionais (com exceção do teste de repetições máximas para o agachamento). Com relação aos parâmetros endócrinos, foi observado que o TS provocou aumento significativo do cortisol, imediatamente após a sessão de treino, tanto no início como no final das oito semanas (p < 0,05). Ao observar o comportamento da relação testosterona para cortisol (T:C), pode-se notar um marcante aumento no grupo submetido ao protocolo MS após oito semanas de treinamento (p < 0,05). Com relação aos parâmetros imunológicos, não foi observada alteração na concentração de imunoglobulina G. A concentração de glutamina sofreu decréscimo após oito semanas em ambos os grupos. Esse decréscimo foi mais acentuado no grupo TS (p < 0,05). Os resultados obtidos sugerem que o método TS impôs maior estresse ao organismo. Além disso, os dados também indicam que o protocolo MS promove um ambiente mais propício ao anabolismo, após oito semanas de treinamento. Entretanto, ambos os métodos falharam em promover alterações significativas nos parâmetros morfofuncionais.

The purpose of this study was to assess the influence of two different resistance training protocols on the anthropometric (weight, BMI, fat mass), functional parameters (1-MR test, and maximal repetition test) and the parameters related to the endocrine system (testosterone and cortisol concentrations), as well as to the immunological system (glutamine and IgC concentrations). The study was composed by twelve trained men (27.4 ± 4.8 years), who were randomly divided in two groups that later were submitted to two different training protocols: the Multiple Series (MS), and Tri-set (TS). Blood samplings were collected before and after an resistance training session in the beginning and the end of the 8 weeks training period. It was observed no alterations in the morphofunctional parameters (except as to the maximal repetition test for the squat). As to the endocrine parameters, it was observed that the TS caused a significant increase in the cortisol immediately after the training session both in the beginning and in the end of the eight weeks (p < 0.05) period. Upon the observation of the testosterone vs. cortisol ratio (T:C) behavior, it can be observed a noticeable increase in the group submitted to the MS protocol after the 8 weeks training period (p < 0.05). As to the immunological parameters, it was observed no alterations in the concentration of the immunoglobulin G. The concentration of the glutamine suffered a decrease after 8 weeks in both groups. That decrease had a higher accentuation in the TS group (p < 0.05). Results attained suggest that the TS method imposed a higher stress to the body. Furthermore, these data also indicate that the MS protocol promotes a more propitious environment to the anabolism after the 8 weeks training period. However, both methods did not succeed in promoting significant changes in the morphofunctional parameters.

El objetivo del estudio fué examinar la influencia de 2 protocolos diferentes de entrenamiento de fuerza sobre parámetros antropométricos (peso, IMC, masa grasa), funcionales (prueba de 1-RM y prueba de repeticiones máximas) y los parámetros relacionados al sistema endocrino (concentraciones de testosterona y de cortisol) y al sistema inmunológico (la concentración del glutamina y de IgG). Participaron en el estudio 12 hombres entrenados (27,4 ± 4,8 años). Estos individuos fueron aleatoriamente divididos en 2 grupos que después se sometieron a 2 protocolos de entrenamiento en dos series diferentes, Múltiple (MS) y Tri-juego (TS). Las muestras de sangre eran reunidos antes y después de una sesión de ejercicio de fuerza, al principio y en el fin del período de 8 semanas de entrenar. No se observaron alteraciones en los parámetros morfo-funcionales (salvo la prueba de repeticiones máximas para el agachamiento). Con respecto a los parámetros endócrinos, se observó que TS provocó un aumento significante del cortisol, inmediatamente después de la sesión de entrenamiento, al principio y en el fin de las 8 semanas (p < 0,05). Al observar la conducta de la testosterona en relación con el cortisol (T:C), puede notarse un aumento excelente en el grupo sometido al MS protocolar después de 8 semanas de entrenar (p < 0,05). Con respecto a los parámetros inmunológicos, no se observó alteración en la concentración de la imunoglobulina G; la concentración del glutamina sufrió una disminución después de 8 semanas en ambos grupos. Esta disminución se acentuó más en el TS de grupo (p < 0,05). Los resultados obtenidos sugieren que el método TS impuso una tensión más grande al organismo. Además, los datos también indican que el MS protocolar promueve una atmósfera más favorable al anabolismo, después de 8 semanas de entrenar. Sin embargo, ambos métodos fallaron promoviendo las alteraciones significantes en los parámetros morfo-funcionales.