Blood flow restriction during the resting periods of high-intensity resistance training does not alter performance but decreases MIR-1 and MIR-133A levels in human skeletal muscle

Blood flow restriction(BFR)during exercise bouts has been used to induce hypertrophy of skeletal muscle,even with low loads.However,the effects of BFR during the rest periods between sets are not known.We have tested the hypothesis that BFR during rest periods between sets of high-intensity resistance training would enhance performance.Twenty-two young adult male university students were recruited for the current study,with n=11 assigned to BFR and n=11 to a control group.The results revealed that four weeks training at 70%of 1 RM,five sets and 10 repetitions,three times a week with and without BFR,resulted in similar progress in maximal strength and in the number of maximal repetitions.The miR-1 and miR-133a decreased significantly in the vastus lateralis muscle of BFR group compared to the group without BFR,while no significant differences in the levels of miR133b,miR206,miR486,and miR499 were found between groups.In conclusion,it seems that BFR restrictions during rest periods of high-intensity resistance training,do not provide benefit for enhanced performance after a four-week training program.However,BFR-induced downregulation of miR-1 and miR-133a might cause different adaptive responses of skeletal muscle to high intensity resistance training.