[Effects of strength training on serum levels of irisin and myostatin hormones, and their association with lipid profiles in untrained women]

Introduction: It seems that, relatively studies have examined the effects of strength training on irisin and myostatin hormones and to date, the association between irisin and myostatin with blood lipids in response to strength training has been assessed. Therefore, the purpose of this study was to investigate the effect of strength training on serum level of irisin and myostatin hormones, and their association with lipid profile in untrained women

Materials and Methods: In a semi experimental study 16 active untrained women were randomly assigned into two, the training [n=10; body mass index: 23.45 +/- 2.83 kg/m2] and the control [n=6; age; body mass index: 23.28 +/- 2.62 kg/m2] groups. The strength training program consisted of 8 weeks, three sessions per week, each session 65 minutes. Serum levels of irisin, myostatin and lipid profile concentrations were measured before and 24 hours the after last training session. Data analyses were performed using SPSS version 22 and significance was assigned at P<0.05

Results: Results showed significant decrease in levels of cholesterol and myostatin in the training group [P<0.05] with a strong correlation between irisin and myostatin levels after 8 weeks of training [P<0.05]. However no correlation were seen between irisin and myostatin with lipid profile [p>0.05]

Conclusion: In conclusion the results of the study demonstrated that strength training can have favorable effects on myostatin and cholesterol serum levels in untrained women and that myostatin level is strongly correlated with irisin

[Effect of resistance training on bone mineral density and serum levels of myostatin in young men]

Muscle mass is known to be a significant predictor of bone mineral density [BMD], and myostatin is a negative regulator of muscle growth. The aim of present study was investigate the effects of resistance training on bone mineral density and serum myostatin in healthy young men. in this clinical trial thirty young men were assigned to resistance training [n=15] and control [n=15] groups. The training group participated in months of progressive whole-body resistance training. Total body fat, lean body mass, total body BMD, femoral neck BMD and L2-L4 spine BMD were determined by Dual-Energy X-ray Absorptiometry [DEXA] before and after 6 months of resistance training. Serum level myostatin measured by enzyme immunoassay. Resistance training caused significant increases in chest press [52.36 +/- 6.36 vs 62.20 +/- 8.96 kg], leg press [135.24 +/- 13.77 vs 146.91 +/- 17.66 kg], lean body mass [61.00 +/- 0.96 vs 62.58 +/- 2.08 kg] and femoral neck BMD [1.115 +/- 0.078 vs 1.131 +/- 0.088 g/cm[2]], whereas myostatin were decreased [102.91 +/- 10.18 vs 94.03 +/- 13.93 ng/ml] P<0.05]. Total body BMD and L2-L4 spine BMD did not change with 6 months resistance training. A 6 month resistance training program increases muscle mass, power and improves BMD of the femoral neck in young men, and myostatin inhibition may play an important role in increasing BMD which is induced by resistance training