ABSTRACT
           Background and objectives: The present study was designed to determine the effect of blood flow restriction training (BFRT) on follistatin to myostatin ratio, body composition and anaerobic power of trained volleyball players.
           Methods: Eighteen trained volleyball players were randomly assigned into two study groups: resistance training with blood flow restriction (BFRT; n=9) and resistance training without blood flow restriction (WBFRT; n=9). The subjects performed trainings three sessions a week, for eight weeks. In each session, barbell squat, leg extension, leg curl and dumbbell lunges were performed in three sets of 15 repetitions, with rest intervals of 30 seconds. Serum follistatin and myostatin concentrations, body composition and anaerobic power were assessed before and after the study. Data were analyzed using the paired sample t-test, Wilcoxon test, independent sample t-test and Mann-Whitney U test. All statistical analyses were done in SPSS (version 22), and a P-value of less than 0.05 was considered statistically significant.
           Results: Follistatin levels increased significantly (P=0.001), while myostatin levels decreased significantly in both groups (P=0.001). Follistatin to myostatin ratio increased significantly in both groups (P=0.001). Although body fat percentage decreased in both groups, it did not differ significantly between the two groups (P=0.28). Moreover, anaerobic power increased significantly in both groups (P=0.001), but this increase was more profound in the BFRT group (P=0.001).
           Conclusion: Based on our findings, blood flow restriction can be applied as remarkable approach to boost body adaptation responses to resistance training.
           KEYWORDS: Resistance training, Myostatin, Follistatin, Blood flow restriction.