Respostas ventilatórias durante e após sessões de treino de força sob duas técnicas: restrição de fluxo sanguíneo e tradicional de alta intensidade
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2015-09-30
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O treino de força (TF), uma das áreas do conhecimento das ciências do deporto, tem sido foco de estudos em relação à efetividade de novos métodos de prescrição do exercício. Nesta linha, o TF com cargas baixas (<50% da 1-RM) conjugado com a técnica de restrição de fluxo sanguíneo (RFS) provou ser tão eficaz quanto ao tradicional de alta intensidade (AI) para os ganhos força e hipertrofia muscular. Igualmente, o uso desta metodologia, tem revelado um aumento do consumo de oxigênio (VO2) e do dispêndio energético. Contudo, com a utilização de exercícios de força as respostas ventilatórias e metabólicas carecem de conhecimento científico comprovado. Desta forma, o objetivo deste estudo é analisar as respostas ventilatórias durante e após sessões de treino de força sob duas técnicas: restrição de fluxo sanguíneo e tradicional de alta intensidade. Trata-se de uma pesquisa quase experimental, com delineamento cruzado (cross-over) randomizado. Para o efeito foram selecionados oito homens treinados (25.7 ± 3 anos; 78.56 ± 8.17 kg; 1.75 ± 0.08 m; 14.26 ± 1.75 %G) que realizaram quatro sessões de exercícios. Nas duas iniciais, foram medidas e remedidas a carga do teste de repetição máxima (1-RM) e estimadas a percentagem dessa carga a utilizar em todos os exercícios efetuados nas duas posteriores sessões. Nas duas sessões experimentais (SE) seguintes, e de forma randomizada, foram executados três séries de quatro exercícios de TF, (supino horizontal, agachamento, remada inclinada e levantamento terra, por esta ordem), com uma cadência de 52 bpm. Estas duas sessões diferem entre si na utilização da RFS e no número de repetições e carga utilizada, sendo, 15 repetições e 20% da carga de 1-RM com RFS (BI + RFS) e oito repetições e 80% de 1-RM para o tradicional de alta intensidade. Todas as quatro sessões foram separadas entre si por 72 horas. Foi mensurada a percepção subjetiva de esforço (PSE Omni-Res), e as medidas ventilatórias: taxa metabólica de repouso (TMR); consumo de oxigênio (VO2) absoluto e relativo; produção de gás carbônico (VCO2); frequência cardíaca (FC); e a ventilação (VE) durante e após (EPOC) as duas sessões de exercícios. A determinação da pressão de Restrição de Fluxo Sanguíneo foi estabelecida em 80% do valor de pressão sanguínea registrada no momento em que cessa a ausculta do pulso arterial na artéria braquial nos membros superiores e na artéria femoral nos membros inferiores, utilizando-se de torniquetes pneumáticos e doppler vascular portátil. As comparações entre os protocolos (BI + RFS x AI) foram realizadas por meio do modelo linear geral univariado, e para analisar efeito isolado de cada sessão a análise de medidas repetidas. Os resultados indicaram diferenças estatísticas (p < 0.01) entre o exercício tradicional de alta intensidade (80% 1-RM) e BI + RFS, com valores superiores, em todas as medidas ventilatórias, para a sessão de treino AI, com única exceção dos cincos minutos finais do EPOC. O VO2, mensurado durante o treino, foi 23% superior para o de AI (20.32 ml.kg-1.min-1) comparado ao BI +RFS (15.65 ± 1.14 ml.kg-1.min-1). Vale destacar que, os protocolos tiveram estimativa de tamanho de efeito similar quando analisados de forma isolada, considerado alto, tanto para o BI + RFS (ηp2 = 0.97) quanto para o AI (ηp2 = 0.98). A PSE apresentou curva de elevação ao longo das séries, para ambas as intervenções, com os maiores valores registrados para o treino de AI (8.35) em comparação (p = 0.001) ao BI + RFS (6.08). Com base na amostra, o presente estudo permitiu concluir que as respostas ventilatórias e de PSE são superiores no treino de AI, quando comparadas com o treino de BI+ RFS. Contudo, em relação ao dispêndio energético, medido pelo VO2, e tendo em conta o volume de treino proporcionado por ambas os métodos, essas diferenças atenuam-se.
Strength training (ST), one of the areas of knowledge of sports science, has been the focus of studies regarding the effectiveness of new exercise prescription methods. In this line, strength training with low loads (<50% of 1-RM) together with the blood flow restriction technique (BFR) proved to be as effective as the traditional high intensity (HI) for gains strength and muscle hypertrophy. Also, the use of this methodology has revealed an increase in oxygen consumption (VO2) and energy expenditure. With the use of ST exercises, this ventilatory and metabolic response, lack of proven scientific knowledge. The objective of this study is to analyze the ventilatory responses during and after strength training sessions under two techniques: traditional high intensity and restricted blood flow. This is a quasi-experimental study with randomized crossover design. For this purpose were selected eight trained men (25.7 ± 3 years; 78.56 ± 8.17 kg; 1.75 ± 0.08 m; 14.26 ± 1.75 %BF) that undertook four four exercise sessions, In the two experimental sessions (SE) following were performed 3 sets of four ST exercises (bench press, squat, barbell bent-over row and deadlift, in that order), with a rhythm of 52 bpm. These differ in the use BFR and number of repetitions and intensity, been 15 repetition and 20% of 1-RM with BFR (LI + BFR) and 8 repetitions and 80% of 1-RM for HI. All four sessions were separated by 72 hours. Was measured the perceived exertion (Omni-Res), and ventilatory measures: resting metabolic rate (RMR); oxygen consumption (VO2) absolute and relative; carbon dioxide production (VCO2); heart rate (HR); and ventilation (VE) during and after (EPOC) the two exercise sessions. Determination of Blood Flow Restriction pressure was set at 80% of the recorded blood pressure value at the time of termination of the arterial pulse auscultation, the brachial artery in the upper limbs and tibial artery in the lower limbs, using pneumatic tourniquets and a portable vascular doppler. Comparisons between protocols (LI + BFR x HI) were performed using univariate general linear model, and for analyze isolated effect of each session the analysis of repeated measures. The results showed statistically significant differences (p <0.01) between the traditional high-intensity exercise (80% 1-RM) and BI + RFS, with higher values in all ventilatory measures for AI training session, with the exception only of five final minutes of the EPOC. The VO2, measured during training, was 23% higher than for the HI (20.32 ml.kg-1.min-1) compared to LI + BFR (15.65 ± 1.14 ml.kg-1.min-1). Note that the protocol had an effect similar size when analyzed separately, considering both the high BI + RFS (ηp2 = 0.97) and AI (ηp2 = 0.98). The PSE presented elevation curve along the series, for both interventions, with higher values observed for the AI training (8.35) compared (p = 0.001) with BI + RFS (6.08). Based on the sample, this study concluded that the ventilatory responses and RPE are higher in HI training, compared with the training LI + BFR. However, with respect to energy expenditure as measured by VO2, and taking into account the volume of training provided by both methods, these differences are attenuated.
Strength training (ST), one of the areas of knowledge of sports science, has been the focus of studies regarding the effectiveness of new exercise prescription methods. In this line, strength training with low loads (<50% of 1-RM) together with the blood flow restriction technique (BFR) proved to be as effective as the traditional high intensity (HI) for gains strength and muscle hypertrophy. Also, the use of this methodology has revealed an increase in oxygen consumption (VO2) and energy expenditure. With the use of ST exercises, this ventilatory and metabolic response, lack of proven scientific knowledge. The objective of this study is to analyze the ventilatory responses during and after strength training sessions under two techniques: traditional high intensity and restricted blood flow. This is a quasi-experimental study with randomized crossover design. For this purpose were selected eight trained men (25.7 ± 3 years; 78.56 ± 8.17 kg; 1.75 ± 0.08 m; 14.26 ± 1.75 %BF) that undertook four four exercise sessions, In the two experimental sessions (SE) following were performed 3 sets of four ST exercises (bench press, squat, barbell bent-over row and deadlift, in that order), with a rhythm of 52 bpm. These differ in the use BFR and number of repetitions and intensity, been 15 repetition and 20% of 1-RM with BFR (LI + BFR) and 8 repetitions and 80% of 1-RM for HI. All four sessions were separated by 72 hours. Was measured the perceived exertion (Omni-Res), and ventilatory measures: resting metabolic rate (RMR); oxygen consumption (VO2) absolute and relative; carbon dioxide production (VCO2); heart rate (HR); and ventilation (VE) during and after (EPOC) the two exercise sessions. Determination of Blood Flow Restriction pressure was set at 80% of the recorded blood pressure value at the time of termination of the arterial pulse auscultation, the brachial artery in the upper limbs and tibial artery in the lower limbs, using pneumatic tourniquets and a portable vascular doppler. Comparisons between protocols (LI + BFR x HI) were performed using univariate general linear model, and for analyze isolated effect of each session the analysis of repeated measures. The results showed statistically significant differences (p <0.01) between the traditional high-intensity exercise (80% 1-RM) and BI + RFS, with higher values in all ventilatory measures for AI training session, with the exception only of five final minutes of the EPOC. The VO2, measured during training, was 23% higher than for the HI (20.32 ml.kg-1.min-1) compared to LI + BFR (15.65 ± 1.14 ml.kg-1.min-1). Note that the protocol had an effect similar size when analyzed separately, considering both the high BI + RFS (ηp2 = 0.97) and AI (ηp2 = 0.98). The PSE presented elevation curve along the series, for both interventions, with higher values observed for the AI training (8.35) compared (p = 0.001) with BI + RFS (6.08). Based on the sample, this study concluded that the ventilatory responses and RPE are higher in HI training, compared with the training LI + BFR. However, with respect to energy expenditure as measured by VO2, and taking into account the volume of training provided by both methods, these differences are attenuated.
Descrição
Tese de Doutoramento em Ciências do Desporto
Palavras-chave
Força muscular , Consumo de oxigénio