Glycogen Kinetics of Wistar Rats: Different Exercise Intensities and Tissue Analyzed Influence

International Journal of Exercise Science 15(2): 289-299, 2022. The aim of this study is to verify the influence of the intensity on muscle and hepatic glycogen depletion and recovery kinetics of Wistar rats, submitted to three acute training sessions with equalized loads. 81 male Wistar rats performed an incremental test to determine maximal running speed (MRS) and divided into 4 groups: baseline group (Control; n = 9); low intensity training session (GZ1; n = 24; 48 minutes at 50% of MRS); moderate intensity group (GZ2; n = 24; 32 minutes at 75% of MRS) and high intensity group (GZ3; n = 24; 5x5 minutes and 20 seconds at 90% of MRS). Immediately after the sessions and after 6, 12 and 24 hours, 6 animals from each subgroup were euthanized for glycogen quantification in soleus and EDL muscles and liver. A Two-Way ANOVA and the Fisher\u27s Post-hoc test was used (p \u3c 0.05). Glycogen supercompensation occurred between 6 and 12 hours after exercise in muscle tissue and 24 after exercise in the liver. The muscle and hepatic glycogen depletion and recovery kinetics are not modulated by exercise intensity since the load was equalized, but effects were distinct in different tissues. Hepatic glycogenolysis and muscle glycogen synthesis processes seem to run in parallel

Avaliação de um teste progressivo de campo para a determinação da potência aeróbia em jogadores de goalball

BACKGROUND: Goalball is a paralympic sport developed especially for people with visual impairments. Although the game occurs through intermittent actions subsidized by anaerobic alactic metabolism, the predominance is aerobic. Thus, considering the importance of this parameter for the maintenance and recovery of efforts, its evaluation is essential for goalball training. OBJECTIVE: To analyze the reproducibility and validity of a specific graded exercise test to determine maximum aerobic capacity in goalball players. METHODS: A progressive test, Fit-Go, was developed and applied to 10 male players. The reproducibility and validity of the Fit-Go were tested, respectively, based on the test and retest and retest and verification phases. RESULTS: The Fit-Go test demonstrated reproducibility, assuming that: (i) the analysis of variance of oxygen consumption and heart rate showed no effects between the test and retest moments; (ii) similar variations were found in the rated perceived exertion. The Fit-Go proved valid for analyzing maximum heart rate and peak lactate concentration since these variables did not show differences for both validation situations (i.e., retest and verification effort). The effectiveness of Fit-Go in filling three or more exhaustion criteria confirmed the functionality of the test as a specific progressive intensity protocol for goalball players. CONCLUSION: Coaches and sports scientists should use Fit-Go as a maximum progressive protocol for goalball players.INTRODUÇÃO: O goalball é um esporte paralímpico desenvolvido especialmente para pessoas com deficiência visual. Embora a dinâmica do jogo ocorra por ações intermitentes subsidiadas pelo metabolismo anaeróbio alático, a exigência da modalidade é predominantemente aeróbia. Dessa forma, considerando a importância desse parâmetro para a manutenção e recuperação dos esforços, sua avaliação é fundamental para o treinamento do goalball. OBJETIVO: Avaliar um protocolo progressivo específico para a determinação da potência aeróbia máxima em jogadores de goalball. MÉTODOS: Um teste progressivo, denominado Fit-Go, foi desenvolvido e aplicado em 10 jogadores do sexo masculino. A reprodutibilidade e validade do Fit-Go foram testadas, respectivamente, com base nos momentos teste e reteste e, reteste e fase de verificação. RESULTADOS: O teste Fit-Go demonstrou reprodutibilidade ao assumir que: (i) as análises de variância do consumo de oxigênio e frequência cardíaca não apresentaram efeitos entre os momentos teste e reteste, e; (ii) variações similares foram encontradas na percepção subjetiva de esforço. O Fit-Go se mostrou válido para as análises da frequência cardíaca máxima e concentração pico de lactato, uma vez que essas variáveis não apresentaram diferenças para ambas as situações de validação (i.e. reteste e esforço de verificação). A efetividade do Fit-Go no cumprimento de três ou mais critérios de exaustão confirmaram a funcionalidade do teste como um protocolo específico de intensidade progressiva para jogadores de goalball. CONCLUSÃO: Treinadores(as) e cientistas do esporte podem utilizar o Fit-Go como protocolo progressivo máximo para jogadores(as) de goalball

Physiological and molecular responses of three models of running training with equalized loads in Wistar rats

Poucos estudos verificaram as respostas fisiológicas e moleculares a partir da manipulação das variáveis volume e intensidade com equiparação das cargas dos treinamentos. O objetivo do presente estudo foi investigar as respostas fisiológicas e moleculares de ratos, submetidos a três modelos agudos e crônicos de treinamento de corrida, com diferentes relações entre volume e intensidade, mas com cargas equiparadas. Verificamos as respostas agudas (Estudo 1) de três sessões aguda de treinamento de corrida: GZ1 (n = 24; intensidade abaixo do limiar anaeróbio obtido em teste incremental; volume = 43min, intensidade = 70% Lan); GZ2 (n = 24; intensidade de Lan; volume = 31min, intensidade = 100% Lan) e GZ3 (n = 24; esforços supra-Lan; volume = 25min, intensidade = 120,4% Lan). Os animais neste experimento foram subdivididos em eutanasiados imediatamente (n = 6), 6 (n = 6), 12 (n = 6) e 24 (n = 6) horas após a sessão de exercício físico. Também verificamos as adaptações (Estudo 2) de programas de treinamento de 5 semanas com frequência semanal de 3 sessões baseados nas mesmas sessões (Z1, Z2 e Z3). Os resultados do Estudo 1 mostraram a supercompensão do glicogênio muscular entre 6 e 12 após o exercício e 24 após no fígado. O Estudo 2 mostrou que 5 semanas de treinamento de corrida em esteira baseados nas zonas 1, 2 e 3 de intensidade melhoraram o desempenho e aumentaram as concentrações de glicogênio no músculo sóleo. Nos dois experimentos não observamos alterações nas vias de sinalização a partir das análises das proteínas da via oxidadtiva. A partir dos resultados dos estudos 1 e 2 concluímos que a modulação da intensidade, no exercício de corrida em esteira, não altera a cinética das variáveis fisiológicas biomoleculares, no que diz respeito a respostas agudas e adaptações crônicas, desde as cargas estejam equiparadas.Few studies analyzed the physiological responses from the manipulation of the variables volume and intensity with equalization of loads. The aim of the present study was to investigate the physiological and molecular responses of rats, submitted to three acute and chronic running training models, with different relations between volume and intensity, but with similar loads. We verified the acute responses (Study 1) of three acute running training sessions: GZ1 (n = 24; intensity below the anaerobic threshold (AnT) obtained in incremental test; volume = 43min, intensity = 70% AnT); GZ2 (n = 24; AnT intensity; volume = 31min, intensity = 100% AnT) and GZ3 (n = 24; above AnT efforts; volume = 25min, intensity = 120.4% AnT). The animals in this experiment were subdivided into euthanized immediately (n = 6), 6 (n = 6), 12 (n = 6) and 24 (n = 6) hours after the physical exercise session. We also checked the adaptations (Study 2) of 5-week training programs with weekly frequency of three sessions based on the same sessions (Z1, Z2 and Z3). Results from Study 1 showed muscle glycogen supercompensation between 6 and 12 after exercise and 24 after in the liver. Study 2 showed that 5 weeks of treadmill running training based on intensity zones 1, 2, and 3 improved performance and increased glycogen concentrations in the soleus muscle. In both experiments we did not observe changes in the signaling pathways from the oxidative pathway proteins analysis. From the results of studies 1 and 2, we conclude that intensity modulation in treadmill running exercise does not change the kinetics of biomolecular physiological variables regarding acute responses and chronic adaptations, since the loads are equalized

Confiabilidade de um circuito multimodal incremental na determinação do limiar anaeróbio de idosos por meio da dosagem do lactato sanguíneo

O estudo teve por objetivo medir a confiabilidade de um circuito multimodal incremental na determinação do limiar anaeróbio (LAN) de idosos por meio da dosagem do lactato sanguíneo (LS). A amostra foi composta por 20 idosos com idade igual a 66,8 anos, não sedentários, do sexo feminino (75%). O circuito foi composto por quatro exercícios, em um protocolo de três fases, com intervalos de 72 horas entre as fases. A primeira fase consistiu na aprendizagem dos exercícios e marcação do metrônomo e teve duração de duas semanas. As fases 2 e 3 foram constituídas por teste e reteste, constituídos de quatro exercícios: meio agachamento com flexão e extensão de cotovelo; caminhada; sentar e levantar da cadeira; subir e descer do step. Ao final de cada estágio foram realizadas as coletas de LS e obtidos os valores para a Percepção Subjetiva de Esforço. Determinou-se o limiar anaeróbio 2 (LAN 2) com utilização do modelo Bi-segmentado e do modelo matemático Distância Máxima. Para a análise de confiabilidade intraobservador e de concordância, foram utilizados o Coeficiente de Correlação Intraclasse (CCI) e o teste de concordância Bland-Altman. Para análise da igualdade de médias no teste e no reteste foram utilizados os testes One-way ANOVA e os testes de Wilcoxon ou Friedman. Os resultados indicaram confiabilidade e concordância entre as medidas teste-reteste para as variáveis estudadas, sugerindo a adequação do circuito multimodal incremental na determinação do limiar anaeróbio de idosos por meio da dosagem do lactato sanguíneo.The study aimed to measure the reliability of an incremental multimodal circuit in determining the anaerobic threshold (AT) in the elderly through the measurement of blood lactate (BL). The sample consisted of 20 elderly people aged 66.8 years, non-sedentary, female (75%). The circuit was composed by four exercises, in a three-phase protocol, with 72-hour intervals between phases. The first phase consisted of learning the exercises and marking the metronome and lasted for two weeks. Phases 2 and 3 consisted of test and retest with four exercises: half squat with flexion and elbow extension; walking; sit and get up from the chair; up and down the step. At the end of each phase, BL collections were performed and the values for the Subjective Effort Perception were obtained. The anaerobic threshold 2 (AT 2) was determined using the Bi-segmented model and the Maximum Distance mathematical model. For the analysis of intraobserver reliability and concordance, the Intraclass Correlation Coefficient (ICC) and the Bland-Altman concordance test were used. One-way ANOVA and Wilcoxon or Friedman tests were used to analyze the equality of means in the test and in the retest. The results indicated reliability and agreement between the test-retest measures for the studied variables, suggesting the adequacy of the incremental multimodal circuit in determining the anaerobic threshold in the elderly through the measurement of blood lactate

Effectiveness, implementation, and monitoring variables of intermittent hypoxic bicycle training in patients recovered from COVID-19: The AEROBICOVID study.

Hypoxic exposure is safely associated with exercise for many pathological conditions, providing additional effects on health outcomes. COVID-19 is a new disease, so the physiological repercussions caused by exercise in affected patients and the safety of exposure to hypoxia in these conditions are still unknown. Due to the effects of the disease on the respiratory system and following the sequence of AEROBICOVID research work, this study aimed to evaluate the effectiveness, tolerance and acute safety of 24 bicycle training sessions performed under intermittent hypoxic conditions through analysis of peripheral oxyhemoglobin saturation (SpO2), heart rate (HR), rate of perceived exertion (RPE), blood lactate concentration ([La-]) and symptoms of acute mountain sickness in patients recovered from COVID-19. Participants were allocated to three training groups: the normoxia group (GN) remained in normoxia (inspired fraction of O2 (FiO2) of ∼20.9%, a city with 526 m altitude) for the entire session; the recovery hypoxia group (GHR) was exposed to hypoxia (FiO2 ∼13.5%, corresponding to 3,000 m altitude) all the time except during the effort; the hypoxia group (GH) trained in hypoxia (FiO2 ∼13.5%) throughout the session. The altitude simulation effectively reduced SpO2 mean with significant differences between groups GN, GHR, and GH, being 96.9(1.6), 95.1(3.1), and 87.7(6.5), respectively. Additionally, the proposed exercise and hypoxic stimulus was well-tolerated, since 93% of participants showed no or moderate acute mountain sickness symptoms; maintained nearly 80% of sets at target heart rate; and most frequently reporting session intensity as an RPE of "3" (moderate). The internal load calculation, analyzed through training impulse (TRIMP), calculated using HR [TRIMPHR = HR * training volume (min)] and RPE [TRIMPRPE = RPE * training volume (min)], showed no significant difference between groups. The current strategy effectively promoted the altitude simulation and monitoring variables, being well-tolerated and safely acute exposure, as the low Lake Louise scores and the stable HR, SpO2, and RPE values showed during the sessions