Effects of acute circuit resistance exercise on plasma myogenin and myostatin levels

 
Purpose: Myogenin is a important member of MRFs families that plays a role in muscular hypertrophy. The purpose of this study was to investigate effects of acute circuit resistance exercise on plasma myogenin and myostatin levels. Methodology: twelve subjects with mean ± SD; age 22.1±2.1 yrs, height 176.2±6.5 cm and weight 69.0-8.2 kg had been examined. After familiarization sessions and determining of maximal strength (1-RM), all subjects completed circuit resistance exercise trails at an intensity corresponding to 55% of 1-RM. The resistance exercise protocols consist 3 sets of 15 repetition and 2mins rest between circuits. With one week interval all subject participated in control session. After 8-10h fasting four blood samples were obtained before exercise, immediately after exercise, 1h recovery and next day in exercise session and same time in control session from anticubital vein, and analyzed for myogenin and myostatin. To determine the effect of resistance exercise on factors repeated measure ANOVA(2×4) had been used. Results: Data analysis revealed that myogenin levels were significantly higher in exercise session than control (P<0٫05). There were statistically significant interaction between time and exercise in myogenin (P<0٫05) and its levels after resistance exercise were significantly greater than other times. There were statistically significant interaction between time and exercise in myostatin and its levels after 24 hours were significantly lower than immediately and 1 hour after exercise (P<0٫05). Conclusion: The results of this study show that circuit resistance exercise is strong stimulus for the transient increase in plasma myogenin and decrease myostatin levels. Thus, this kind of exercise can be a stimulus for muscular hypertrophy. In regard to importance of myogenin and myostatin in the growth of muscle tissue, its suggested that future research evaluated effects of circuit resistance exercise or training on myogenin and myostatin gene expression.