Document Type : Research Paper I Open Access I Released under CC BY-NC 4.0 license


1 PhD. Candidate, Department of Sport Physiology, Faculty of Educational Sciences, Mohaghegh Ardabili University, Ardabil, Iran.

2 Associate Professor, Department of Sport Physiology, Faculty of Educational Sciences, Mohaghegh Ardabili University, Ardabil, Iran.

3 Assistance Professor, Department of Sport Physiology, Faculty of Educational Sciences, Mohaghegh Ardabili University, Ardabil, Iran.

4 Professor, Department of Sport Physiology, Faculty of Educational Sciences, Mohaghegh Ardabili University, Ardabil, Iran.

5 Assistant Prof., Dept. Sport Physiology, Faculty of Educational Sciences and Psychology, University of Mohaghegh Ardabili, Ardabil, Iran


The present study investigates the effect of 8 weeks of continuous and high intensity interval training on serum GH/IGF-1 indices and performance of active young men. In this quasi-experimental study, 20 young men (18-25 years old) were selected and randomly assigned into two homogenous groups of continuous training (n=10) and HIIT (n=10) and participated in an eight-weeks training course. The main activity of the continuous training group consisted of 30-50 minutes of continuous running with an intensity of 50-70% of heart rate reserve (HRR). HIIT group training were three sets of four repetitions and 15-30 seconds of running with an intensity of 85-95% HRR in each repetition. Blood samplings were taken from all subjects in three stages of pre-test, immediately after the first session and 48 hours after the last training session. Investigations showed that after a session of continuous training or HIIT, the amount of total IGF-1 decreased significantly in both groups (P = 0.0001), while the serum concentration of GH significantly increased in both group (P=0.04). Moreover, after 8 weeks, none of the training methods caused a change in total IGF-1 concentration (P=0.78); But GH concentration increased in both groups (P=0.001). Also, free IGF-1 concentration increased significantly after 1 session and 8 weeks of training in both groups (P=0.001). On the other hand, ALS has decreased significantly in the third stage test in both groups (P=0.001) and IGFBP3 values ​​did not change in any of the two groups (P=0.64). Also, the increase in VO2max was significant in both groups (P=0.001), but this increase was greater in the HIIT group (P=0.032, F=5.49, 1.17). It seems that the use of both continuous and interval training methods can create positive adaptations toward improving participants’ cardiovascular endurance and health, but considering factors such as increasing free IGF-1 and VO2max, HIIT training is a more appropriate method.


Main Subjects

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