Comparison between critical speed and maximal lactate steady state in amateur distance runners

The purpose of this study was to compare maximal lactate steady state (MLSS) and the critical speed (CS) in distance runners. Six male athletes were submitted to the CS test, to linear regression of the distances (800, 1.500, 3.000 and 5.000m). The CS was determined by the angular coefficient of the linear regression (Distance x Time). The predicted workloads for the MLSS determination were: 103; 100 and 98% of the CS, randomized and in a continuous way in subsequent days. In MLSS test, the athletes run for 30 min, and it was collected blood samples (25μL) at 10th and 30th min, to determine the lactate concentration (YSI 1500 sport). It was determined MLSS the non lactate variation higher than 1.0 mmol/L between the 10th and 30th minute. The MLSS occurred for 5 athletes on the 100% intensity of CS (15.1 ± 1.5 Km/h) and for 1 athlete on the 95% (14.3 Km/h). At 100% of CS, the MLSS concentration was: rest lactate (RL)= 1.0 ± 0.3 mmol/L; 10thmin= 3.28 ± 0.64; 30th 3.92 ± 1.14. At 103% of CS, the MLSS concentration was: RL= 1.10 ± 0.41 mmol/L; 10thmin= 3.06 ± 1.44; 30th 4.12 ± 1.59. The MLSS occurred at 100% of MLSS. These results showed that the CS is a trustful test to predict the MLSS in distance runners with MLSS velocity at 15Km/h

Influence of the pedaling cadence in determining the critical power in the cycloergometer

The objective of this study was to determine the critical power (PCrit) using intensities of 230, 250, 270 and 300 Watts (W) under different speeds ranging from pedaling (60 and 80 rotations per minute - rpm). Two young adults, male, healthy and active, with an average age 22 years were selected. The test was conducted in cycle model Monark® ergomedic 894 E. The depth charges were chosen randomly, changing the relationship load and speed from the cadence. The exhaustion criterion was the voluntary withdrawal or failure to maintain the speed for 5 seconds. To determine the PCrit and anaerobic work capacity (CTA) the linear model of power 1/tempo x exhaustion was used. The results are expressed as mean ± standard deviation of the mean. The t Student test for independent samples for comparison PCrit CTA and the cadences of 60 and 80 rpm was used. During the tests the heart rate (bpm) every 15 seconds was recorded. The results of PCrit to 60 rpm (Pcrit60rpm) and PCrit at 80 rpm (Pcrit80rpm) were not statistically different (Pcrit60rpm=208.1±12.0 W and Pcrit80rpm=165.5±33.2 W). The average Pcrit60rpm was 25% higher than Pcrit80rpm. The absolute values of CTA were not different (CTA60rpm=10316.6±3766.7, CTA80rpm=15996.5±5247.4). The CTA80rpm was 55% higher compared to CTA60rpm. Thus, one can conclude that the cadence of pedaling at 60 rpm and 80 did not statistically influence the values of PCrit and CAT. However, the percentage of Pcrit80rpm was significantly below Pcrit60rpm

The effects of acute exercise on serum biomarkers in diabetics rats

INTRODUÇÃO: As respostas ao exercício agudo dos biomarcadores, como a fosfatase alcalina (FA) e a creatina quinase (CK) séricas têm sido pouco investigadas em ratos diabéticos. OBJETIVOS: Verificar os efeitos do exercício físico aeróbio agudo sobre as concentrações de CK e FA, bem como, avaliar o estado hídrico em ratos diabéticos experimentais. MATERIAIS E MÉTODOS: Foram utilizados ratos Wistar machos, adultos jovens, distribuídos em dois grupos: diabéticos (DA) e controles (CA). O diabetes foi induzido por meio da administração de aloxana monoidratado Sigma(r) (32 mg/kg de peso corporal). Duas semanas após confirmação do diabetes, ambos os grupos foram submetidos a uma sessão aguda de natação por 30 min, com carga aeróbia (4,5 % do peso corporal). Foram avaliados: glicose, hematócrito, CK, FA, albumina e a cinética de lactato durante o exercício por meio de coletas 25 µL de sangue da cauda dos animais, nos minutos 0, 10, 20 e 30 de exercício. RESULTADOS: ANOVA de dois fatores para medidas repetidas e o teste post hoc de Tukey apontaram diminuição significativa dos valores de glicemia após o exercício para o grupo DA, aumento significativo de CK pós-exercício para o grupo DA, aumento significativo de hematócrito para ambos os grupos após exercício e manutenção da FA após exercício para o grupo DA. CONCLUSÃO: O exercício agudo aeróbio foi eficiente no controle dos níveis glicêmicos de ratos diabéticos. Entretanto, deve ser aplicado com cautela, pois induziu altos valores de CK, sugerindo possíveis lesões teciduais2013235INTRODUCTION: The responses to acute exercise on biomarkers, such as alkaline phosphatase (ALP) and creatine kinase (CK) serum levels have been little investigated in diabetic rats. OBJECTIVES: To investigate the effects of acute aerobic exercise on the concentrations of CK and ALP as well as evaluating the hydration status in diabetic rats. MATERIALS AND METHODS: Were used male Wistar rats, young adults, divided into two groups: diabetic (DA) and controls (CA). The diabetes was induced in the rats by administration of alloxan monohydrate Sigma(r) (32 mg/kg body weight). Two weeks after confirmation of diabetes, both groups were subjected to an acute swim session for 30 min, with aerobic load (4.5% body weight). Glucose, hematocrit, CK, ALP, albumin and lactate kinetics during exercise were evaluated by collecting 25µL of blood from the tail of the animals in minutes 0, 10, 20 and 30 of exercise. RESULTS: Two-way ANOVA for repeated measures and post hoc Tukey test showed significant decrease of glycemia after exercise for the DA group, significant increase in CK after exercise for the DA group, significant increase in hematocrit for both groups after exercise and maintenance of ALP after exercise for the DA group. CONCLUSION: The acute aerobic exercise was effective in controlling glucose levels in diabetic rats. However, it should be applied with caution, because it induced high CK values, suggesting possible tissue damagesem informaçã

Padronização e validação de uma equação para determinação do volume corporal em ratos winstar saudáveis e sedentários com idade entre 60 e 240 dias

A determinação da composição corporal pode ser utilizada para evidenciar diversos fatores entre eles a dieta, o uso de drogas, a incidência de patologias, diferenças genética, nível de treinamento, gênero e idade. No modelo de natação para ratos a composição corporal pode ter um papel determinante na intensidade de exercício, uma vez que os animais utilizados podem apresentar diferentes densidades corporais. Nesse sentido, o objetivo do presente projeto baseia-se na possibilidade de desenvolver uma equação para estimar o volume corporal de ratos sedentários a partir da relação linear entre peso e volume corporais (r=1,00) encontrada em estudos anteriores. Dessa forma, tornando prático e viável o uso da densidade corporal para precisa determinação da intensidade de exercício em estudos que utilizam a natação como ergômetro de exercício animal. Para isso serão utilizados 105 Rattus norvegicus albinus da linhagem Wistar, os quais serão avaliados em um estudo longitudinal que consiste em avaliações a cada 30 dias, a partir dos 60 até 240 dias de idade, para a determinação do volume corporal através de pesagens hidrostáticas, do índice de lee e análise da composição química da carcaça. Com isso, espera-se poder derivar uma equação para estimar o volume corporal dentro de toda a faixa de idade utilizada ou, no caso não seja encontrada uma relação linear entre peso e volume corporais entre ratos de diferentes idades, o desenvolvimento de várias equações para estimar o volume corporal em faixas etárias. Além disso, a composição química da carcaça dos mais será determinada na tentativa de validar o método de pesagem hidrostática e buscar eventuais correlações entre os parâmetro corporais (volume corporal, peso corporal, índice de lee e densidade) e os componentes de gordura, massa magra, água e proteína dos animai

Spontaneous activity of rats measured by gravimetry and relationships with aerobic capacity and gene expression of MCTs 1 and 4 : effects of age and chronic exercise

Orientador: Claudio Alexandre GobattoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências AplicadasResumo: A locomoção representa um comportamento extremamente importante e primordial para a vida animal. Diante disso, torna-se notório que o restrito confinamento imposto aos animais de laboratório pode causar negativas implicações fisiológicas, uma vez que diversos comportamentos locomotores naturais são suprimidos. Baseado nessa problemática, desejamos verificar se animais alojados em gaiolas convencionais possuem piores indicadores de desempenho ao exercício, quando comparados a animais expostos a condições aumentadas de espaço físico. Além disso, buscamos analisar se a característica do espaço físico das gaiolas representa um fator mais relevante que a própria aplicação do exercício, haja vista que protocolos de treinamento físico em modelos animais não conseguem promover melhoras expressivas da capacidade aeróbia ao longo da idade. Em outra temática, a locomoção também se apresenta intimamente relacionada a aspectos genéticos, uma vez que marcantes diferenças individuais são distinguidas quando rodas de atividades são disponibilizadas para animais de laboratório. Entendendo que o aspecto genético é de suma importância nesse contexto, nós supomos que animais mais ativos na gaiola, exibiriam maiores vantagens metabólicas e genéticas para a prática de exercício quando comparados a animais mais inativos. Diante disso, buscamos explorar se as atividades espontâneas e voluntárias dos animais já refletem propensões para melhores desempenhos físicos. Embora pareçam similares, tais atividades são consideradas distintas pela literatura, e carecem de serem relacionadas com a capacidade aeróbia, e com respostas moleculares envolvidas com a performance. Tendo em vista todos os temas abordados, o objetivo geral do presente projeto baseia-se em verificar a influência do espaço físico da gaiola, bem como sua interação com as duas principais intervenções experimentais científicas (treinamento físico ou livre acesso à roda de atividade) sobre respostas fisiológicas e moleculares relacionadas com o metabolismo aeróbio e anaeróbio, composição corporal e estresse em ratos ao longo da idade (60, 90 e 150 dias). Além disso, verificar as relações entre a atividade espontânea e voluntária com parâmetros fisiológicos envolvidos com a performance no exercícioAbstract: Locomotion is extremely important and essential for animal life behavior. Thus, it becomes clear that the restricted confinement and therefore the suppression of many locomotors behaviors imposed to laboratory animals can cause negative physiological implications. Based on these problems, we verified if animals housed in conventional cages have worse exercise performance indicators when compared to animals exposed in increased housing space. Furthermore, we analyzed if the physical space of the cages is a more important factor than implementation of the exercise, given that physical training protocols in animal models fail to promote improvements in aerobic capacity over the age. On another topic, locomotion is closely related to genetic factors. We assumed that animals more active in the cage, exhibit higher metabolic and genetic advantages for the practice of exercise when compared to inactive animals. Therefore, we investigated whether the spontaneous and voluntary activities of animals already reflect propensities for better physical performance. Although they look similar, these activities are considered distinct in the literature. There is scarce information about the relationship of such with aerobic capacity and molecular responses involved with the performance. The overall goal of this project is based on checking the influence of the housing space of the cage as well as its interaction with the two main scientific experimental interventions (physical training or free access to activity wheel) on physiological and molecular responses related aerobic and anaerobic metabolism, body composition and stress in rats along age. In addition, to check the relationship between spontaneous and voluntary activity with physiological parameters involved with the exercise performanceMestradoBiodinâmica do Movimento Humano e EsporteMestre em Ciências da Nutrição e do Esporte e Metabolism

Metabolic profile and spontaneous physical activity modulation under short-term food restriction in young rats.

Abstract AIMS The aim of this study was to investigate the effects of short-term food restriction (6-weeks) on metabolic profile and spontaneous physical activity (SPA) of young male Wistar rats. METHODS Thirty rats had their baseline SPA measured at 21 days-old and were separated into two groups at 28 days-old: Control (CG) and 50% of food restriction (FR). The food restriction protocol lasted six weeks, being the SPA measured weekly by a gravimetric apparatus. At the end of the experiment, biochemical analyses were performed in serum and tissue samples with statistical significance set at 5%. RESULTS FR showed less SPA than CG, as occurred for body mass, water intake, adipose tissue and liver, heart and soleus glycogen, serum glucose, total protein, triglycerides and total cholesterol (P<0.05). CONCLUSION Data set demonstrates that low substrate stores signaled to decrease spontaneous physical activity to save energy

Housing conditions modulate spontaneous physical activity, feeding behavior, aerobic running capacity and adiposity in C57BL/6J mice

There is evidence of reduced adiposity in rodents living in a large cages (LC) as compared to animals housed in small cages (SC). Because spontaneous physical activity (SPA) provides an important portion of the total daily energy expenditure, an increase of SPA in rodents kept in LC could explain their reduced body fat accumulation. The relationship between SPA and components of physical fitness (i.e. aerobic and anaerobic fitness and body leanness) has not been previously determined. We examined the effects of eight weeks of LC exposure on SPA, body composition, feeding behavior, as well as aerobic and anaerobic running capacity in adult C57BL/6J mice. Male mice were housed in cages of two different sizes for 8 weeks: a small (SC, n = 10) and large (LC n = 10) cages with 1320 cm(2) and 4800 cm(2) floor space, respectively. SPA was measured gravimetrically, and food and water intake were recorded daily. Mice had critical velocity (CV) and anaerobic running capacity (ARC) evaluated at the beginning, middle course (4th week) and at the end of study (8th week). Despite non-significant differences in each week LC-mice were more active than SC-mice by considering all SPA values obtained in the entire period of 8 weeks. The difference in SPA over the whole day was mainly due to light phase activity, but also due to activity at dark period (from 6 pm to 9 pm and from 5 am to 6 am). LC-mice also exhibited higher food and water intake over the entire 8-wk period. LC-mice had lower content of fat mass (% of the eviscerated carcass) than SC-mice (SC: 8.4 +/- 0.4 vs LC: 6.3 +/- 0.3, p < 0.05). LC-mice also exhibited reduced epididymal fat pads (% of body mass) compared to SC-mice (SC: 1.3 +/- 0.1 vs LC: 0.9 +/- 0.1, p < 0.05) and retroperitoneal fat pads (SC: 0.4 +/- 0.05 vs LC: 0.2 +/- 0.02, p < 0.05). The LC-group showed significantly higher critical velocity than SC-group at the fourth week (SC: 14.9 +/- 0.6 m.min(-1) vs LC: 18.0 +/- 0.3 m.min(-1), p < 0.05) and eighth week (SC: 17.1 +/- 0.5 m.min(-1) vs LC: 18.8 +/- 0.6 m.min(-1), p < 0.05). Our findings demonstrate that eight weeks of LC housing increases SPA of C57BL/6J mice, and this may lead to reduced fat accumulation as well as higher aerobic fitness. Importantly, our study implies that SC limits SPA, possibly generating experimental artifacts in long-term rodent studies115CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP307395/2013-8; 302827/2015-3não tem2015/00272-6; 2015/01362-9; 2017/10201-

Effects of preferred music on physiological responses, perceived exertion, and anaerobic threshold determination in an incremental running test on both sexes.

This study aimed to investigate and compare the effects of preferred music on anaerobic threshold determination in an incremental running test, as well the physiological responses and perceived exertion at this intensity, in physically active men and women. Additionally, by using area under the curve (AUC) analysis of the parameters of interest during the graded test, we studied the effects of music at two physiological moments-before and after anaerobic threshold intensity (iAT)-in men and women. Twenty (men = 10; women = 10) healthy and active participants completed four visits to the laboratory. The first and second sessions were used for sample characterization. In the third and fourth sessions, participants performed an incremental running test (started at 7 km.h-1 with increments of 1 km.h-1 at each 3-minute stage) under preferred music and non-music conditions. Blood lactate ([Lac]), heart rate (HR), and perceived exertion were measured by two scales (RPEBorg and the estimation of time limit ‒ ETL) during all tests, and the total time of effort (TT) was considered as performance. Individual curves of the "intensity vs blood lactate" analyzed by the bissegmentation method provide the iAT and the AUC of [Lac], HR, RPEBorg, and ETL before and after the iAT attainment were calculated. The iAT for men (non-music: 11.5±0.9km.h-1 vs music: 11.6±1.1km.h-1) and women (non-music: 9.8±0.7km.h-1 vs music: 9.7±0.7km.h-1) was not affected by music, and for both sexes, there was no difference between non-music and music conditions in all variables obtained at iAT. The AUC of all variables were not affected by music before the iAT attainment. However, [Lac], HR, and RPEBorg presented higher values of AUC after iAT for the female group with preferred music. This may be due to the fact that 70% of women have increased TT under music conditions. Overall, preferred music did not affect the iAT determination in an incremental running test. However, some physiological responses and perceived exertion after iAT of female subjects seems to be influenced by preferred music

Efeitos do exercicio agudo sobre biomarcadores sericos de ratos diabeticos

INTRODUÇÃO:As respostas ao exercício agudo dos biomarcadores, como a fosfatase alcalina (FA) e a creatina quinase (CK) séricas têm sido pouco investigadas em ratos diabéticos.OBJETIVOS:Verificar os efeitos do exercício físico aeróbio agudo sobre as concentrações de CK e FA, bem como, avaliar o estado hídrico em ratos diabéticos experimentais.MATERIAIS E MÉTODOSForam utilizados ratos Wistar machos, adultos jovens, distribuídos em dois grupos: diabéticos (DA) e controles (CA). O diabetes foi induzido por meio da administração de aloxana monoidratado Sigma(r) (32 mg/kg de peso corporal). Duas semanas após confirmação do diabetes, ambos os grupos foram submetidos a uma sessão aguda de natação por 30 min, com carga aeróbia (4,5 % do peso corporal). Foram avaliados: glicose, hematócrito, CK, FA, albumina e a cinética de lactato durante o exercício por meio de coletas 25 µL de sangue da cauda dos animais, nos minutos 0, 10, 20 e 30 de exercício.RESULTADOS:ANOVA de dois fatores para medidas repetidas e o teste post hoc de Tukey apontaram diminuição significativa dos valores de glicemia após o exercício para o grupo DA, aumento significativo de CK pós-exercício para o grupo DA, aumento significativo de hematócrito para ambos os grupos após exercício e manutenção da FA após exercício para o grupo DA.CONCLUSÃO:O exercício agudo aeróbio foi eficiente no controle dos níveis glicêmicos de ratos diabéticos. Entretanto, deve ser aplicado com cautela, pois induziu altos valores de CK, sugerindo possíveis lesões teciduais.INTRODUCCIÓN:Las respuestas al ejercicio agudo de los biomarcadores, como la fosfatasa alcalina (FA) y la creatina quinasa (CK) séricas han sido poco investigadas en ratones diabéticos.OBJETIVOS:Verificar los efectos del ejercicio físico aeróbico agudo sobre las concentraciones de CK y FA, bien como evaluar el estado hídrico en ratones diabéticos experimentales.MATERIALES Y MÉTODOS:Fueron utilizados ratones Wistar machos, adultos jóvenes, distribuidos en dos grupos: diabéticos (DA) y controles (CA). La diabetes fue inducida por medio de la administración de aloxana monohidratado Sigma(r) (32 mg/kg de peso corporal). Dos semanas después de la confirmación de la diabetes, ambos grupos fueron sometidos a una sesión aguda de natación por 30 minutos, con carga aeróbica (4,5% del peso corporal). Fueron evaluados: Glucosa, hematocrito, CK, FA, albumina y La cinética de lactato durante el ejercicio por medio de colectas de 25 µL de sangre de la cola de los animales, en los minutos 0, 10, 20 y 30 de ejercicio.RESULTADOS:ANOVA de dos factores para medidas repetidas y el test post hoc de Tukey apuntaron disminución significativa de los valores de glicemia después del ejercicio para el grupo DA, aumento significativo de CK después del ejercicio para el grupo DA, aumento significativo de hematocrito para ambos grupos después del ejercicio y mantenimiento de la FA después del ejercicio para el grupo DA.CONCLUSIÓN:El ejercicio agudo aeróbico fue eficiente en el control de los niveles glicémicos de ratones diabéticos. Entretanto, debe ser aplicado con cautela, pues indujo altos valores de CK, sugiriendo posibles lesiones tisulares.INTRODUCTION:The responses to acute exercise on biomarkers, such as alkaline phosphatase (ALP) and creatine kinase (CK) serum levels have been little investigated in diabetic rats.OBJECTIVES:To investigate the effects of acute aerobic exercise on the concentrations of CK and ALP as well as evaluating the hydration status in diabetic rats.MATERIALS AND METHODS:Were used male Wistar rats, young adults, divided into two groups: diabetic (DA) and controls (CA). The diabetes was induced in the rats by administration of alloxan monohydrate Sigma(r) (32 mg/kg body weight). Two weeks after confirmation of diabetes, both groups were subjected to an acute swim session for 30 min, with aerobic load (4.5% body weight). Glucose, hematocrit, CK, ALP, albumin and lactate kinetics during exercise were evaluated by collecting 25µL of blood from the tail of the animals in minutes 0, 10, 20 and 30 of exercise.RESULTS:Two-way ANOVA for repeated measures and post hoc Tukey test showed significant decrease of glycemia after exercise for the DA group, significant increase in CK after exercise for the DA group, significant increase in hematocrit for both groups after exercise and maintenance of ALP after exercise for the DA group.CONCLUSION:The acute aerobic exercise was effective in controlling glucose levels in diabetic rats. However, it should be applied with caution, because it induced high CK values, suggesting possible tissue damage