Efeito agudo de diferentes treinamentos intermitentes de alta intensidade : respostas cardiorrespiratórias e neuromusculares na corrida

The aim of the study was to examine the effect of different ratios of effort and recovery (E:R) high-intensity intermittent training (HIIT) with fixed intensity in cardiorespiratory and neuromuscular performance in amateur athlete runners. To this end, 11 men, amateur street runners (25.45 ± 1.25 years; body mass 64.91 ± 2.48, height 1.74 ± 0.03 and 7.09 ± fat percentage 0.62 ) executed in four different days the following tests: incremental test to determine maximum oxygen consumption (VO2max), maximum heart rate (HRmáx) and peak speed (Vpeak); and three highintensity intermittent protocols at 110% of Vpeak (forty seconds of effort with forty seconds of recovery [40:40], thirty seconds of effort with thirty seconds of recovery [30:30] and forty seconds of effort with twenty seconds of recovery [40:20]) on different days, with analysis before, after 5 and 10 minutes of maximum voluntary isometric contraction (MVIC), obtaining also the rate of peak force development (RPFD) with simultaneous recording of electromyographic activity of the vastus lateralis, rectus femoris and vastus medialis root mean square values (RMS) and average and median frequency. In addition, during the execution of the protocols, analysis for the protocols of cardiorespiratory variables, maintenance time equal or close to 90% of VO2max (TM90%VO2max); and lactate concentrations before, immediately after, 5 and 10 minutes after each different protocol proposed were quantified. For comparisons between groups in different variables, we used the analysis of variance (ANOVA) with repeated measures with post-hoc Tukey's test when found interaction between some variable. Throughout the process, we adopted a significance level of 5%. The results pointed to time in exercise and exhaustion different statistically (p < 0.05) for the 30:30 and 40:40 protocol for 40:20 and between 30:30 and 40:40. Lactate concentrations were different at the time after 10 minutes between 40:20 and 30:30 protocol with higher values for the first. The TM90%VO2máx was not different between different TIAI, just when it was taken into account the total exercise time and time to exhaustion, 40:20 showed higher percentages for the other two. The force ratios, the MVCI showed reductions between the post moments 5 and 10 minutes to the different HIIT, without difference statistic between them RPFD was not different between the times for the 40:20 (p > 0.05) and showed a significant difference to the 30:30 in the post 10 minutes time and after five minutes to 40:40. The RMS was different for the different muscle of the vastus lateralis, rectus femoris and vastus medialis, between times, but not between protocols. In addition, there was a slight increase of the average frequency and median in increase in the moments after for all protocols, but no difference between HIIT. Based on the study results we can conclude that different ratios of effort and recovery respond similarly in neuromuscular and cardiorespiratory indexes, but with different behavior of the end of the year time for different reasons.Fundação de Amparo a Pesquisa do Estado de Minas GeraisDissertação (Mestrado)O objetivo do estudo foi examinar o efeito de diferentes razões entre esforço e recuperação (E:R) em treinamentos intermitentes de alta intensidade (TIAI), com intensidade fixa, no desempenho cardiorrespiratório e neuromuscular em corredores amadores. Para esse fim, 11 homens, corredores de rua amadores (25,45 ± 1,25 anos; massa corporal 64,91 ± 2,48; estatura 1,74 ± 0,03 e percentual de gordura 8,09 ± 0,62) realizaram em quatro dias diferentes os seguintes testes: teste incremental para determinação do consumo máximo de oxigênio (VO2máx), frequência cardíaca máxima (FCmáx) e velocidade pico (Vpico); e três protocolos intermitentes de alta intensidade a 110% da Vpico (quarenta segundos de esforço com quarenta segundos de recuperação [40:40], trinta segundos de esforço com trinta segundos de recuperação [30:30] e quarenta segundos de esforço com vinte segundos de recuperação [40:20]) em dias diferentes, com análise antes, após 5 e 10 minutos da contração isométrica voluntária máxima (CIVM), com obtenção também da taxa de desenvolvimento de força pico (TDFp) com registro simultâneo da atividade eletromiográfica dos músculos vasto lateral, reto femoral e vasto medial, obtendo valores de root mean square (RMS) e da frequência média e mediana. Ademais, durante os protocolos, variáveis cardiorrespiratórias do tempo de manutenção igual ou próximo a 90% do VO2máx (TM90%VO2máx); e concentrações de lactato antes, imediatamente após, pós 5 e 10 minutos de cada diferente protocolo proposto foram quantificados. Foram registrados também, o tempo total de exercício e o tempo de exaustão para cada TIAI. Para comparações entre os grupos nas diferentes variáveis, foi empregado o teste de variância (ANOVA) com medidas repetidas com teste de post-hoc de Turkey quando encontrada interação entre alguma variável. Em todo o processamento, foi adotado nível de significância de 5%. Os resultados apontaram para tempo em exercício e de exaustão diferente estatisticamente (p < 0,05) para o protocolo 30:30 e 40:40 para o 40:20, e entre o 30:30 e 40:40. As concentrações de lactato foram diferentes no momento pós 10 minutos entre o protocolo 40:20 e o 30:30 com valores maiores para o primeiro. O TM90%VO2máx não foi diferente entre os diferentes TIAI, apenas quando foi levado em consideração o tempo total de exercício e o tempo de exaustão; o 40:20 apresentou valores percentuais maiores para os outros dois. Nos índices de força, a CIVM apresentou reduções entre os momentos pós 5 e 10 minutos para os diferentes TIAI sem diferença significativa relatada entre os mesmos. A TDFp não foi diferente entre os momentos para o 40:20 (p > 0,05) e apresentou diferença significativa para o 30:30 no momento pós 10 minutos e no após 5 minutos para o 40:40. O RMS foi diferente para os diferentes músculos do vasto lateral e medial e reto femoral, entre os momentos, mas não entre os protocolos. Ademais, houve um leve aumento da frequência média e mediana, nos momentos pós para todos os protocolos, porém sem diferença entre os TIAI. Com base nos resultados do presente estudo podemos concluir que diferentes razões entre esforço e recuperação respondem de forma semelhante nos índices neuromusculares e cardiorrespiratórios, porém com distinto comportamento do tempo final do exercício para razões diferentes

Analysis of co-contraction of the trunk muscles in the side bridge stabilization exercise with different unstable surfaces

The muscle co-contraction is a phenomenon characterized by the simultaneous contraction of two or more muscles around a joint. The objective of this study was to compare the antagonist co-contraction of the local and global trunk muscles during side bridge exercise, in four situations: (a) stable; (b) instability in the upper limbs with bosu; (c) instability in the upper limbs with disc and (d) double instability. The sample consisted of 20 male volunteers and data collection was performed with simple differential surface electrodes. The electromyographic activity was collected from the Rectus Abdominis (RA), Internal Oblique Abdominis (IO), Multifidus (MF) and Erector Spinae (ES). Were utilized specific routines developed in the Matlab program (Mathworks Natick, USA) to calculate the percentage of antagonist co-contraction between local (IO/MF) and global muscles (RA/ES). The collected data were submitted to parametric statistical analysis (repeated measures ANOVA) or non-parametric (Friedman). The results demonstrated that no significant differences were observed in the pattern of global and local co-contraction in the different side bridge exercises with and without unstable surface. It is concluded that the use of unstable surface in the side bridge stabilization exercise does not increase the level of co-contraction of the trunk flexor and extensor muscles compared to normal stability. However, future studies should use a longer time of isometric contraction in trunk stabilization exercises to optimize the understanding of the effects of different unstable equipment on global and local levels of co-contraction of the trunk muscles

Pode o consumo máximo de oxigênio e a frequência cardíaca máxima medidos em teste laboratorial serem preditos por equações em corredores amadores?

ABSTRACT Can the maximal oxygen uptake and maximum heart rate measured in laboratory test be predicted by equations in amateur runners?The maximum oxygen consumption (VO2max) and maximum heart rate (HRmax) are used constantly to describe the ability of the cardiovascular system and to estimate the load exercise tolerance. However there is no consensus in the literature regarding the reliable formula to determine them. The aim of the study was to determine whether the VO2max and HRmax can be predicted by formulas in young runners. Thirteen men (25.62 ± 8.87 years) performed an incremental test to exhaustion with analysis of VO2max and HRmax. These variables were compared between prediction formulas of VO2max (A = 15 x (HRmax / resting heart rate; B = 3.542 + (-0.014 x age) + (0.015 x body weight) + (-0.011 x resting heart rate); C = (0.2 x Vpeak-P) + (0.9 x Vpeak-P x slope) + 3.5; D = (0.2 x Vpeak-60) + (0.9 x Vpeak-60 x slope) + 3.5)) and HRmax (1 = 220 - age; 2 = 207 - 0.7 x age; 3 = 201 - 0.6 x age; 4 = 205-0685 x age; 5 = 210 - 0.65 x age). ANOVA was used adopting a significance level of 5%. The results showed for formulas A and B VO2max not differs from the actual found (p> 0.05) and the formula 3, differently from the actual HRmax (p 0.05) e para a fórmula 3, diferente da FCmáx real (p < 0.05). Assim, foi possível concluir que as fórmulas A e B e 1, 2, 4 e 5 podem ser utilizadas para predizer o VO2máx e a FCmáx em jovens corredores.

Physical exercise, IGF-1 and cognition A systematic review of experimental studies in the elderly

ABSTRACT One of hypothetical mechanisms related to cognition is exercise-induced IGF-1. Objective: The aim of this study was to analyze the effects of exercise on IGF-1 levels and cognition in the elderly. Methods: The article searches were conducted on Pubmed, Web of Science, PsycINFO and Scielo databases and reviewed according to PRISMA guidelines. The inclusion criteria were: [1] original articles published up to 2017; [2] samples including elderly; [3] protocols including physical exercise; [4] longitudinal studies having exercise as main outcome; [5] assessment of IGF-1; [6] cognition assessment. Results: Seven studies were included in this review. Three of the studies showed an exercise-induced increase in IGF-1; three found stable IGF-1 levels and one found a reduction in IGF-1; with and without improvement in cognition. Conclusion: Disparities in the type of physical exercise, protocols and samples under different conditions hinder the establishment of a consensus on IGF-1, cognition and physical exercise