The effect of resistance training with slow and fast speeds on some anabolic and catabolic hormones in healthy young women

Background and objective: Resistance training is a potential stimulus to increase muscle protein synthesis and the time under tension of muscle is one of the variables of strength training that contributes to its adaptation. The aim of this study was to investigate the effect of resistance training with slow and fast speeds on some anabolic and catabolic hormones in healthy young women. Methods: This quasi- experimental study was conducted on 20 female students (mean age 21.65±2.03 years). The subjects were randomly and equally assigned to two groups with a time under tension of 1s-1s (fast contraction speed (FCS)) and 3s-3s (slow contraction speed (SCS)). The training load was the same in both groups and resistance training was done in a circular manner for six weeks, three days a week in eight stations. Blood samples were taken from the subjects to study the research variables before the training period and 48h after the last session of the training. Results: There was no significant difference between the serum levels of GH(P = 0.82), IGF-1(P = 0.13) and cortisol(P = 0.59) in both groups, but the levels of myostatin in the fast group increased and in the slow group decreased, and the difference between the two groups was significant (P = 0.04). Also, in the strength test, the slow group experienced further increased strength. (P = 0.02) Conclusion: Although no significant changes in the levels of IGF-1, myostatin, and cortisol is observed in intragroup comparison at six weeks, resistance training with slow contraction speed can lead to further increases in the growth hormone levels and strength.