The effect of four weeks resistance training along with blood flow restriction on the cross-sectional area of non-restricted muscles in active men

Resistance training with blood flow restriction stimulates the response and release of anabolic hormones and increases hypertrophy in restricted muscles, however, the effect of this training method on adjacent non-restricted muscles has not been studied well. The aim of this study was to evaluate the effect of 4 weeks of resistance training along with blood flow restriction on anatomical cross-sectional area (CSA) of adjacent non-restricted muscles in active young men.

Sixteen young men aged 25-30 years old were randomly divided into two groups (n=8) high-intensity resistance training (HIRT) and low-intensity resistance training with blood flow restriction (L-BFR). Both groups performed bench press and squat exercises three sessions per week during four weeks. In HIRT group, three sets of 10 repetitions (75%1RM), and in the L-BFR, four sets of 30, 15, 15 and 15 repetitions (30%1RM) was performed during every exercise. For L-BFR group, the restriction pressure was considered as 50% resting atrial occlusion pressure (AOP) at the beginning of the exercises and this pressure gradually was increased to 80% AOP during four weeks. At the beginning and 72 hours after the last training session, the CSA of triceps brachii, pectoralis major, quadriceps and gluteus maximus were calculated by MRI. Data were analyzed by paired sample t-test and analysis of covariance (ANCOVA) test at the significance level of p<0.05.

Four weeks of training lead to significant increase in the cross-sectional area of triceps brachii, quadriceps, pectoralis major and gluteus maximus in the HIRT (4%, 7.5%, 10%, 10% respectively) and L-BFR (11%, 12%, 18%, 22% respectively) groups.

It seems that the anabolic effects caused by blood flow restriction exercises are not limited locally and can be transferred to the adjacent muscles involved in the exercise that are not directly affected by the blood flow restriction.