The Effect of Eight Weeks of Polarized Training on GH/IGF-1 Axis Hormones Response in Active Young Male

Background & objectives: Insulin-like growth factor -1 (IGF-1) has a variety of roles, but the abundance of scientific evidence indicates that it is a metabolic biomarker associated with physical fitness and health. The present study investigates the effect of eight weeks of polarized exercise training on serum GH / IGF-1- indices in active young men. Methods: In this double-blind experimental study, 20 young males were allocated randomly into polarized training group (N=10) and a control group (N=10). The polarized training group performed 80-70% of the main workout volume (30 minutes) with light to moderate with 50-60% reserve heart rate (RHR) intensity and the remaining 20-30% at 85-95% RHR intensity; in a way that they ran two periods consisting 3 repetitions of 15-30 seconds, with 30-60 seconds of active rest after each repetition and 3 minutes of active rest after each period. Blood samples were taken from all subjects in three stages, including: pre-test stages, 24 hours before the start of the post-test, and after 12 hours overnight fasting. Post-test samples were collected, one sample immediately after the first session and the another  48 hours after the end of the last exercise session. Results: The results of the present study showed that bipolar training significantly increased growth hormone and free IGF-I levels after one training session, and after eight-week bipolar training program. However, total IGF-1 levels decreased significantly after one exercise session and after eight-week bipolar exercise program. Also, no significant change was observed in IGFBP-3 and IGFBP-5 levels after one training session and eight-week training program. Acid-labile subunit levels did not change significantly after one training session, but decreased significantly after eight weeks of bipolar training. Conclusion: Based on the results of the present study, it seems that the use of bipolar exercises, training may be a good way to improve the hormonal function and assess the level of health and physical fitness of active young men.