The effect of eight weeks high intensity intermittent training (HIIT) on the expression of miRNA-1 and miRNA-21 in sedentary adolescent boys

The microRNA (miRNA) is a new class of biomarkers that are involved in many biological processes and gene expression. The present study examined the effect of eight weeks of high intensity intermittent training (HIIT) on the levels of miRNA-1 and miRNA-21 in adolescent boys. In this experimental study, 22 adolescent boys in a randomly were allocated in two equal groups: HIIT group and control group. Training programs were conducted 3-4 times per week for 8 weeks. The HIIT program consisted of 6-8 running sprints (30-60 seconds) with a 3.5-4 min recovery. Mentioned indicators assessments were performed 18-24 hours pre and post intervention. The miRNA-1 was significantly higher after 8 week HIIT than they were pre-exercise training (pre-HIIT vs. post-HIIT) (P<0.05). However, miRNA-21 was significantly lower after the training period (P<0.05) ‏. The miRNA-1 and miRNA-21 can be used as an indicator to assess the adaptations associated with exercise training.