Comparison of growth hormone and insulin-like growth factor-1 responses to high intensity and low intensity resistance training with and without blood flow restriction in adolescent male athletes

Background: Resistance training is the most effective way to increase muscle mass. The hormonal axis of GH-IGF-1 is considered important for the health of the musculoskeletal system in both childhood and adulthood .The purpose of this study was to compare two types to resistance training with and without blood flow restriction on GH-IGF-1 axis after the exercise.

Methods: In this study, 36 adolescent gymnast boys aged 10 to 14 years participated in a quasi-experimental research design. The subjects (mean weight 37.11 ± 8.11 kg, height 145.16 ± 11.58 cm, body mass index 17.40 ± 1.77 kg m) were randomly divided into three groups; control (n=12), high intensity resistance training (n=12), and low intensity resistance training with blood flow restriction (n=12). Training protocol contained three motions included leg extension, elbow flexion and bench press. Blood samples were taken before and half an hour after training.

Results: The results of inter-group showed that a GH variable after acute exercise in resistance exercise with blood flow restriction group (p=0.195), traditional resistance training groups (p=0.182), and control (p=0.317) was not significant; But IGF-1 variable increased significantly in blood flow restriction group (P=0/004). There was no significant difference between groups in levels of GH and IGF-1 (p>0.05).

Conclusion: One session low intensity resistance training with blood flow restriction compared to high intensity resistance training, has a similar effect on increasing serum IGF-1 in children athletes. Such as high intensity resistance exercise seems appropriate to provide hypertrophy and increased in the muscle mass.