Acute Effect of Knee Eccentric Contraction with Blood Flow Restriction on Corrected QT Interval During Repetition and Recovery in Healthy Men

The purpose of this study was to investigate the acute effect of eccentric knee contractions with BFR on the corrected QT interval (QTc) during repetition and recovery in healthy men to determine a cardiac safe resistance exercise for people who cannot exercise with high intensity because of diseases or disability.Eight healthy men (age ۲۷.۸±۲.۸ years) were randomly divided into two groups through the crossover method. One group performed the method of muscle contraction with blood flow restriction with an intensity of ۳۰% of MVC (maximum voluntary contraction), and the other group completed the same program without the BFR program under ۷۰% of MVC. Training sessions were performed under ۳۰% of MVC with BFR with ۳۰, ۱۵, ۱۵, and ۱۵ repetitions, assigning ۶۰-second recovery intervals for each repetition. The lead II of electrocardiogram was recorded by electrocardiograph belt. QT, QTc, and RR intervals were measured at each repetition and recovery. The t-test was used to assess the differences of all variables between training protocol with and without BFR.A significant difference was observed between training with and without BFR in QT interval in the first recovery, RR interval in the third ۱۵ repetitions, and QTc interval in the first ۱۵ repetitions (P=۰.۰۰۶, P=۰.۰۳, and P=۰.۰۰۶, respectively).The cardiac response to BFR training was nearly similar to that without BFR. In low-intensity BFR training, the cardiovascular system responded faster but remained stable throughout exercise. In high-intensity non-BFR training, the cardiovascular system responded with delay and raised by increasing training duration.

کلیدواژه ها:

Resistance exercise ، Electrocardiogram ، BFR