Acute and chronic effects of traditional and high-speed resistance training on blood pressure in older adults: A crossover study and systematic review and meta-analysis.

PURPOSE: The present study included two related investigations that explored the acute and chronic effects of high-speed resistance training (HSRT) on blood pressure (BP) in older adults. METHODS: The first study involved a randomized crossover study that compared the acute effects of traditional resistance exercise (TRT) and high-speed resistance training (HSRT) on hemodynamic parameters in frail older adults. Sixteen institutionalized frail older adults were recruited. BP was recorded before, over 1 h, and 24 h after the end of the experimental session. Participants performed 4 resistance exercises involving 4-8 sets with 4-10 repetitions at moderate intensity. The second study was a systematic review and meta-analysis of experimental studies that investigated the acute and chronic effects of HSRT on BP in older adults. Crossover, quasi-experimental, and randomized controlled trials that examined the effects of HSRT on BP in people aged 60+ years as a primary or secondary outcome were included. Studies were retrieved from MEDLINE, SPORTDiscuss, CINAHL, SCOPUS and AgeLine databases from inception through December 31, 2021. The risk of bias was evaluated using the Newcastle - Ottawa Quality Assessment Scale (NOS). A pooled effect size was calculated based on standard mean differences (SMD). RESULTS: In study 1, we observed that both TRT and HSRT caused post-exercise hypotension (PEH). However, systolic BP (SBP) was significantly lowered for up to 60 min after TRT, while it was only reduced 30 and 50 min after HSRT. There was no difference in SBP between resistance exercise protocols. A reduction in mean arterial pressure was only observed after TRT. In study 2, 1114 articles were identified, and 8 were included in the meta-analysis. Pooled analyses indicated that HSRT did not cause significant PEH. However, a significant reduction in SBP was observed after HSRT programs in comparison to controls (SMD = 0.61, P = 0.009) and baseline values (SMD = 2.03, P = 0.04). CONCLUSION: In study one, we observed that both TRT and HSRT caused systolic PEH in comparison to baseline in frail older adults. However, specific patterns were observed according to each type of RT. Indeed, a longer PEH in comparison to baseline was observed after TRT, whereas HSRT had greater reductions in comparison to CS. In addition, TRT had exclusive reductions in MAP. These results were not supported by our meta-analysis, given that no significant effects of an acute session of HSRT on office and ambulatorial BP were observed. On the other hand, our findings suggest that HSRT might significantly reduce SBP in older adults.

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.

Resistance Exercise Intensity Does Not Influence Neurotrophic Factors Response in Equated Volume Schemes.

The aim of the present study was to evaluate the effects of 2 different intensities of resistance training (RT) bouts, performed with the equated total load lifted (TLL), on the acute responses of neurotrophic factors (NFs) (brain-derived neurotrophic factor [BDNF]; and nerve growth factor [NGF]), as well as on metabolic (lactate concentration) and hormonal (salivary cortisol concentration) responses. Thirty participants (males, 22.8 ± 2.3 years old, 177 ± 6.8 cm, 75.5 ± 7.9 kg, n = 15; and females, 22.2 ± 1.7 years, 163.7 ± 6.5 cm, 57 ± 7.6 kg, n = 15) performed 2 separate acute RT bouts with one week between trials. One bout consisted of 4 sets of 5 submaximal repetitions at 70% of 1RM and the other of 4 sets of 10 submaximal repetitions at 35% of 1RM for each exercise. Both RT bouts were conducted using the bench press and squat exercises. The TLL in each bout (determined by sets x repetitions x load [kg]) was equated. Serum BDNF, serum NGF, salivary cortisol, and blood lactate concentration were determined pre- and post-RT. No significant pre- to post-exercise increase in neurotrophic factors (p > 0.05; BDNF; effect size = 0.46 and NGF; effect size = 0.48) was observed for either of the RT bouts. A similar increase in blood lactate concentration was observed pre- to post-exercise for both RT bouts (p < 0.05). Cortisol increased similarly for both RT bouts, when compared to the resting day condition (p < 0.05). In conclusion, the results suggest that, despite differences in RT schemes, a similar acute neurotrophic, metabolic and hormonal response was observed when the TLL is equated.

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)

Physiological demands of archery: effect of experience level / Demandas fisiológicas do tiro com arco: efeito do nível de experiência

Abstract The understanding of fatigue development during Archery competition would guide sports scientists, coaches and athletes on how to optimize the training routines of athletes from different competitive levels. This study investigated the effect of expertise level on physiological responses, during simulated archery competition (double-round 70m, 12 series, 6 arrows for an elite Brazilian Archer (EA) and a Novice Archer (NA). Ratings of perceived exertion, blood lactate and glucose, handgrip strength and electromyography were registered at the beginning, after each set from the 2nd to the 12tharrow and, 30-min after the competition simulation. The EA showed a greater handgrip strength for both arms, a constant lower mean RMS value (Baseline 0.279V and 12th set 0.221V, -20.7%), and a stable MF value throughout the competition (Baseline 146Hz to 12th set 140Hz). The NA showed a smaller handgrip strength, an increase in RMS after the 6th set towards the end of the competition (Baseline 0.387V, 6th 0.576V, and 12th set 0.720V, +46.2%) and a minor decrease in MF from the 6th to the end of 12th set (2nd set 122Hz, 4th set 127Hz, 6th set 112Hz and 12th set 117Hz, - 4.1%). In summary, all the fatigue-related markers showed a mild response to the Archery competition simulation, although a greater magnitude was observed in the NA, compared to the EA. This study reported the physiologic demands of an Archery simulated competition, in an official format, allowing coaches and sport scientists to draw more confident decisions on competition strategy and training design.

Resumo O entendimento da fadiga durante a competição de Tiro com Arco pode auxiliar na otimização da rotina de treinamento de atletas em diferentes níveis competitivos. Este estudo investigou o efeito do nível de experiência do atleta sobre as respostas fisiológicas, durante competição simulada de Tiro com Arco para um atleta de elite (EA) e um arqueiro iniciante (NA). Esforço percebido, concentração de lactato e glicose sanguínea, força de preensão manual e eletromiografia foram registrados no início, após cada série e, 30-min após a simulação. O EA apresentou maior força de preensão manual para ambos braços, valor de média RMS constantemente mais baixo (Baseline 0,279V e 12ª série 0,221V, -20,7%), e valor de MF estável no decorrer da competição (Baseline 146Hz a 12a série 140Hz). O NA demonstrou menor força de preensão manual, aumento na RMS após a 6a série até o final da competição (Baseline 0,387V, 6a 0,576V, and 12a série 0,720V, +46,2%) e pequena diminuição na MF da 6ª até o final da 12ª série (2a série 122Hz, 4a série 127Hz, 6a série 112Hz e 12a série 117Hz, - 4,1%). Assim, todos os marcadores relacionados a fadiga apresentaram resposta discreta na simulação de competição de Tiro com Arco, com maior magnitude no NA, em comparação com EA. Este estudo apresentou as demandas fisiológicas da competição simulada de Tiro com Arco, no formato oficial, permitindo que treinadores e cientistas do esporte possam tomar decisões com maior confiança sobre estratégias de competição e treinamento.

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.

Efeito de diferentes durações do alongamento no desempenho de saltos unipodais / The effect of different stretching times on single-leg jump performance / Efecto de diferentes duraciones del alongamiento en el desempeño de saltos unipodales

INTRODUÇÃO: A prática de exercícios de alongamento é muito comum como parte do aquecimento em diversas modalidades esportivas, porém, esta prática pode ser negativa para aqueles que desejam o aprimoramento da força e potência muscular, consequentemente, o rendimento dos saltos pode ficar reduzido após exercícios de alongamento, que depende do tempo de duração e intensidade do mesmo. OBJETIVO: Avaliar a influência do tempo de permanência no exercício alongamento sobre o desempenho do drop jump unilateralmente (unipodal). MÉTODOS: A amostra foi composta por 16 adultos jovens hígidos, com larga experiência em saltos. O protocolo de teste consistiu em realizar três drop jumps unipodais máximos a partir de uma plataforma de 15 cm sobre um tapete de salto (Hidrofit(r)), antes e após duas durações (i.e. uma série 3 min. de um lado, e 6 min. para outro, a escolha foi de forma aleatória) de alongamento dos músculos tríceps sural, utilizando uma intensidade entre 70-90% da percepção subjetiva de desconforto. A análise de variância ANOVA (2x2) foi utilizada para verificar diferenças para a altura de salto, tempo de contato e flexibilidade, utilizando um nível de significância de 5%. RESULTADOS: Apresentaram diferenças significativas entre condições pré e pós-alongamento para as durações de 3 e 6 minutos (P=0,002 e P=0,001, respectivamente), com a diminuição na altura máxima do salto. O tempo de contato foi maior apenas para a duração de 6 minutos (P=0,039). CONCLUSÃO: A realização de exercícios de alongamento do músculo tríceps sural por 3 ou 6 minutos de duração resulta na queda do desempenho do drop jump unipodal, diminuição da altura do salto vertical ...

INTRODUCTION: Stretching is very common as part of the warm-up in several sports modalities. However this practice can be negative to strength improvement and muscular power. Consequently, jump performance can be reduced after stretching exercises, depending on its duration and intensity. OBJECTIVE: To evaluate the acute effects of different long-term stretching times on single-leg drop jump performance. METHODS: The sample was composed of 16 healthy jump experienced young adult athletes. The experimental protocol consisted of performing three maximum unipodal drop jumps from a 15 cm high platform, and landing on a contact mat (Hidrofit(r)), before and after two stretching times of the triceps surae muscles (i.e. a series of 3 minutes on one side and 6 minutes on the other, with the sides being randomly chosen), using an intensity of 70-90% of their subjective perception of discomfort. An ANOVA (2x2) analysis was used to verify differences for the jump height, contact time and flexibility, using a significance level of 5%. RESULTS: The results showed significant differences between pre and post-stretching times of 3 and 6 minutes (P=0.002 and P=0.001, respectively). Contact time was higher only for the stretching time of 6 minutes (P=0.039). CONCLUSION: We conclude that stretching exercises of the triceps surae muscle, for 3 or 6 minutes, resulted in a decreased performance in the single-leg drop jump, a decrease in the vertical jump height (for 3 and 6 minutes) and contact time (for 6 minutes only), reinforcing the need for more debates in this area regarding stretching before power activities. .

INTRODUCCIÓN: La práctica de ejercicios de alongamiento es muy común como parte del calentamiento en diversas modalidades deportivas. No obstante, esta práctica puede ser negativa para aquellos que desean la mejora de la fuerza y potencia muscular. Consiguientemente, el rendimiento de los saltos puede ser reducido después de ejercicios de alongamiento, que depende del tiempo de duración e intensidad del mismo. OBJETIVO: Evaluar la influencia del tiempo de permanencia en el ejercicio de alongamiento sobre el desempeño del drop jump unilateralmente (unipodal). MÉTODOS: La muestra fue composta por 16 adultos jóvenes sanos, con amplia experiencia en saltos. El protocolo de test consistió en realizar tres drop jumps unipodales máximos a partir de una plataforma de 15 cm sobre una alfombra de salto (Hidrofit(r)), antes y después de dos duraciones (i.e. una serie de 3 min. de un lado, y 6 min. para otro, la elección fue de forma aleatoria) de alongamiento de los músculos tríceps sural, utilizando una intensidad entre 70-90% de la percepción subjetiva de incomodidad. El análisis de variación ANOVA (2x2) fue utilizado para verificar diferencias para la altura de salto, tiempo de contacto y flexibilidad, utilizando un nivel de significancia de 5%. RESULTADOS: Presentaron diferencias significativas entre condiciones pre y post-alongamiento para las duraciones de 3 y 6 minutos (P=0,002 y P=0,001, respectivamente), con la disminución en la altura máxima del salto. El tiempo de contacto fue mayor sólo para la duración de 6 minutos (P=0,039). CONCLUSIÓN: La realización de ejercicios de alongamiento del músculo tríceps sural por 3 ó 6 minutos de duración resulta en la caída del desempeño del drop jump unipodal, disminución de la altura del salto vertical (para 3 y 6 min. de duración) ...

Effects of dietary restriction or swimming on lymphocytes and macrophages functionality from old rats.

Although aging compromises the functionality of macrophages (MΦ) and lymphocytes (LY), and dietary restriction (DR) and exercise partially counterbalance immunosenescence, it is unknown what effects of both strategies have on the functionality of these immune cells. Rats were randomly distributed into adult control (AD), older group (OLD), older submitted to 50% of DR (DR) and older submitted to swimming (EX) (n = 10 in each group). The function of immune cells (proliferative index, phagocytic capacity and H2O2 production), the weight and protein content of lymphoid organs (thymus and spleen), plasma glutamine concentration, interleukins (IL-1, IL-2, IL-6) and, immunoglobulins (IgA and IgG) were analysed. There was an increase of 74% in body weight in aged animals as compared with the AD group, while body weight reduced 19% in the DR as compared with the OLD group. Swimming training stimulated MΦ phagocytosis, while the EX group presented a decrease of the proliferative capacity of LY from the mesenteric lymph nodes (44% and 62%, respectively), when stimulated with ConA and LPS as compared with the old rats. These data demonstrated that DR and exercise affects differentially MΦ and LY function.

Isometric handgrip does not elicit cardiovascular overload or post-exercise hypotension in hypertensive older women.

BACKGROUND: Arterial hypertension is a serious health problem affecting mainly the elderly population. Recent studies have considered both aerobic and resistance exercises as a non-pharmacological aid for arterial hypertension treatment. However, the cardiovascular responses of the elderly to isometric resistance exercise (eg, isometric handgrip [IHG]) have not yet been documented. OBJECTIVE: The purpose of this study was to investigate cardiovascular responses to different intensities of isometric exercise, as well as the occurrence of post-isometric exercise hypotension in hypertensive elderly people under antihypertensive medication treatment. PATIENTS AND METHODS: Twelve women volunteered to participate in the study after a maximal voluntary contraction test (MVC) and standardization of the intervention workload consisting of two sessions of IHG exercise performed in four sets of five contractions of a 10-second duration. Sessions were performed both at 30% of the MVC and 50% of the MVC, using a unilateral IHG protocol. Both intensities were compared with a control session without exercise. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) at rest (R), during peak exercise (PE), and after 5, 10, 15, 30, 45, and 60 minutes of post-exercise recovery were evaluated. RESULTS: No significant changes were observed after isometric exercise corresponding to 30% MVC for either SBP (R: 121 ± 10; PE: 127 ± 14; 5 min: 125 ± 13; 10 min: 123 ± 12; 15 min: 122 ± 11; 30 min: 124 ± 11; 45 min: 124 ± 10; 60 min: 121 ± 10 mmHg) or DBP (R: 74 ± 9; PE: 76 ± 6; 5 min: 74 ± 5; 10 min: 72 ± 8; 15 min: 72 ± 5; 30 min: 72 ± 8; 45 min: 73 ± 6; 60 min: 75 ± 7 mmHg). Similarly, the 50% MVC did not promote post-isometric exercise hypotension for either SBP (R: 120 ± 7; PE: 125 ± 11; 5 min: 120 ± 9; 10 min: 122 ± 9; 15 min: 121 ± 11; 30 min: 121 ± 9; 45 min: 121 ± 9; 60 min: 120 ± 7 mmHg) or DBP (R: 72 ± 8; PE: 78 ± 7; 5 min: 72 ± 7; 10 min: 72 ± 8; 15 min: 71 ± 7; 30 min: 72 ± 8; 45 min: 75 ± 10; 60 min: 75 ± 7 mmHg). CONCLUSION: Our data reveal that cardiovascular overload or post-exercise hypotension did not occur in elderly women with controlled hypertension when they undertook an IHG session. Thus this type of resistance exercise, with mild to moderate intensity, with short time of contraction appears to be safe for this population.

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.

Hormonal responses to different resistance exercise schemes of similar total volume.

This study assessed the effect of different resistance exercise scheme (RES) designs of similar total of load lifted on the responses of testosterone, cortisol, and creatine kinase (CK). Twenty-seven healthy males performed 1 of 4 bench press workouts described by the 1 repetition maximum (1RM) load: 4 sets of maximum repetitions at 50%-1RM (50%-1RM RES), 5 sets of maximum repetitions at 75%-1RM (75%-1RM RES), 10 sets of maximum repetitions at 90%-1RM (90%-1RM RES), or 8 sets of maximum repetitions at 110%-1RM (110%-1RM RES). Each RES was equated by the total volume of load lifted (repetitions x sets x load). Blood samples, collected pre-exercise (Pre) and post-exercise (Post) at 1 and 24 hours (24 h), were analyzed for total and free testosterone, total cortisol, and CK. In general, testosterone and cortisol showed little change within or between the different RES (p > 0.05), possibly because of the relatively low volume lifted and/or the small muscle mass activated by the bench press exercise. Cortisol was elevated after the 75%-1RM RES at the Post sample, with this response also exceeding the other RES (p < 0.05). The 24 h CK response was also elevated after the 75%-1RM RES (p < 0.05), thereby suggesting greater training strain for the same volume of load. These results confirm previous recommendations regarding the prescription of resistance exercise and the importance of total volume as a stimulus for activating the endocrine system and achieving long-term adaptation.