Influência do exercício de força com diferentes volumes de tempo sob restrição do fluxo sanguíneo: efeitos sobre o dano muscular, respostas perceptuais e metabólicas em sujeitos saudáveis

Abstract

Low-load strength training with blood flow restriction (LL-BFR) promotes increase in strength and muscle hypertrophy even with reduced loads (20-50% 1RM). Although the dose-responses related to training volume, load exercise and pressure used in the cuffs have already been described in the literature, there is still a gap related to the effects of manipulation while the limb remains under BFR causes on neuromuscular, biochemical, perceptual and metabolic variables. The purpose was to investigate the acute responses of resistance exercise combined with different volumes of time under blood flow restriction on indirect markers of muscle damage, perceptual and metabolic responses in healthy individuals. Twelve physically active young males performed leg press exercise at 45° leg press (30+15+15+15 repetitions – 20% 1RM) in three conditions. In condition 1 (PC), exercise was performed without BFR, in condition 2 (P5), BFR was applied only during exercise (limb under BFR= 5 minutes) and in condition 3 (P10), BFR was started 5 minutes before exercise and remained until completing all sets (limb under BFR= 10 minutes); Countermovement vertical jump performance (CMJ), creatine kinase (CK) and muscle soreness (VAS-soreness) were collected as indirect markers of muscle damage at moments before, immediately after (only CMJ and VAS-soreness) and 24 hours post exercise. Subjective perceptual of discomfort (rate of discomfort) and session rate of perceived exertion (S-RPE) were assessed at the end of each exercise recovery interval and a 30 minutes post exercise, respectively. Lactate concentrations (LAC) were measured at moments before, immediately after and 5 minutes post exercise. Results shown no statistically significant difference for indirect markers of muscle damage at any moments and protocols (PC, P5 and P10), whereas rate of discomfort, S-RPE and LAC were significantly higher (p≤ 0.05) at P5 and P10 when compared to PC. The results showed that staying longer time under BFR did not increase indirect markers of muscle damage, however the addition of BFR promoted greater discomfort and perceived exertion regardless of time under restriction.