Efeitos crônicos do treinamento de força com restrição de fluxo sanguíneo sobre o desempenho físico de pessoas com DPOC

Abstract

The strength training (ST) is an efficient type of exercise for enhancing muscular strength and hypertrophy. In order to obtain the maximum benefits of ST, is recommended the use of loads greater than 65% of one repetition-maximum (1RM), however there are populations that do not support high loads. The ST with blood flow restriction (BFR) appears as an alternative to the high loads ST, because it uses loads smaller than 30% of 1RM associated with BFR to promote strength and hypertrophy gains similar to conventional ST. Individuals with chronic obstructive pulmonary disease (COPD) may be beneficed by this type of exercise since they present peripheral muscular dysfunction, that causes a decrease on physical performance, however they do not support the high loads of the conventional training. The aim of this study was to analyze the chronic effects of strength training with blood flow restriction on the physical performance of people with COPD. It was a randomized clinical trial, controlled, parallel, and double-blinded, in which 17 individuals (64.56±7.32 years) diagnosed with moderate or severe COPD were divided into three groups as follows: LLBFR – ST at 30% of 1RM with 50% of BFR; ML – ST at 60% of 1RM; and C – control. The intervention lasted for 6 weeks with two weekly exercise sessions in which the LLBFR and ML groups performed the knee extension and elbow flexion exercises. The following statistical tests were used for data analysis: Shapiro-Wilk to verify the normality of the data and ANOVA twoway with Bonferroni post-hoc to check the possible differences on the variables of interest. All analysis were performed on the SPSS 22.0 with significance value of p<0,05. The dyspnoea level assessed by the Borg modified and Dyspnoea-12 scales and the performance on the 6 minute walking test improved on the LLBFR and ML groups (p<0,05). Regarding maximum strength, the LLBFR and ML groups increased the 1RM values for the knee extension and elbow flexion (p<0,001) and for the elbow extension, the strength gain was only observed on the LLBFR group (p<0,001). In conclusion, the ST with BFR is efficient to improve the physical performance of people with COPD and superior to the ST with ML on the variables: dyspnoea, functional performance and strength.