The effect of blood flow restricted resistance training on serum hormone levels in relation to muscle size and strength in young men

Resistance training is one of the most essential components of exercise programs. The aim of the study was to investigate the effect of blood flow restricted resistance (BFR) training on serum levels of growth hormone (GH) and insulin like growth factor 1 (IGF-1). A total of 30 healthy young men (aged 19-24 yrs) were volunteered for this study. Subjects were randomly assigned into three groups: a low intensity blood flow restricted resistance exercise (BFR) group (20% of 1-RM, 3 sets 15 reps), a traditional high intensity resistance exercise without blood flow restriction (HI) group (3 sets of 10 repetitions at 80% of 1-RM) and a control group. Both BFR and HI groups trained 3 days per week for 3 weeks for knee extension and squat exercises. Fasting growth hormone (GH) and IGF-1 levels were measured in the morning pre-and post- exercise sessions. Data were analyzed with one-way ANOVA in the level of p< 0.05. GH and IGF-1 significantly increased in post exercise in BFR group compared to baseline (P<0.05). GH significantly increased in post exercise in HI group compared to baseline (P<0.05). After 3 weeks, serum GH and IGF-1 levels increased significantly in BFR group compared to HI and control groups (P<0.05). In conclusion, short term BFR exercise stimulated increases in anabolic hormones in young men.