The Effects of Two Kinds of Resistance Training and Detraining on Serum Levels of Myostatin, Cortisol, Testosterone and Muscle Strength of Non-Athlete Men

The aim of this study was to determine the effect of two kinds of resistance training and one period of detraining on serum levels of myostatin, cortisol, testosterone and muscle strength of non-athlete men. For this purpose, 34 non-athlete men (age 33.35+2.8 yr) were divided into three groups: experimental A (4 sessions of training per week), experimental B (3 sessions of training per week) and control. The resistance training (24 sessions) was performed based on Cramer et al. (2004) including 3 sets of 8-10 repetitions with 60-70% 1RM in big muscles. Blood sampling, strength test and body composition measurement were performed before the first session, after the last session and after one period of detraining. The data were analyzed by Mix ANOVA and Tukey post hoc test. The results showed that resistance training increased muscle strength, fat free body mass and testosterone while it decreased cortisol and myostatin in both groups. This increase and decrease were higher in experimental A group than experimental B group (P˂0.05). Also, a period of detraining increased serum levels of myostatin and cortisol in experimental B group (P˂0.05). Finally, the findings showed that training frequency led to higher increase and maintenance of those changes resulted from resistance training.