The Effect of Resistance Training with Two Different Intensities Combined with Blood Flow Restriction and Detraining on Irisin, Follistatin, and IGF-1 in Male Students

Background& purpose: Blood Flow Restriction (BFR) resistance training is recognized as an innovative method that induces physiological and functional adaptations similar to traditional resistance training, while reducing the risk of injury. This study aimed to examine the effects of eight weeks of BFR training at two different intensities, followed by a detraining period, on levels of irisin, follistatin, IGF-1, body fat percentage, and muscular strength in male university students. Methods: Fifty-one male students were randomly and equally assigned to one of three groups: low-intensity BFR resistance training (20–30% of one-repetition maximum [1RM]), moderate-intensity BFR resistance training (40–55% 1RM), or a control group. The training groups exercised three times per week for eight weeks, followed by a four-week detraining period. Research variables—including circulating irisin, follistatin, IGF-1 levels, body fat percentage, and maximal muscular strength—were measured 48 hours before and after the training protocol, as well as immediately after the detraining period. Follistatin levels were assessed using enzyme immunoassay, while IGF-1 and irisin concentrations were measured using ELISA. Paired t-tests, ANOVA, and post hoc tests were used to analyze the data. Results: In the low-intensity BFR group (20–30% 1RM), significant increases were observed in follistatin, IGF-1, and muscular strength (P ≤ 0.05). In the moderate-intensity BFR group (40–55% 1RM), significant improvements were found in follistatin, IGF-1 (P ≤ 0.01), muscular strength, and a reduction in body fat percentage (P ≤ 0.05). However, no significant changes were observed in irisin levels (P ≥ 0.05), and the four-week detraining period had no statistically significant effects on any of the measured variables. Conclusion: These findings suggest that BFR resistance training—even at lower intensities—can effectively enhance anabolic responses and muscular strength. Furthermore, the hormonal adaptations and strength gains were relatively maintained following four weeks of detraining