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

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.

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.

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.

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.