Purpose: To investigate the effects of Tribulus terrestris (TT) extracts on muscle mass, muscle damage, and anaerobic performances of trained male boxers and its mechanisms: roles of plasma androgen, insulin growth factor 1 (IGF-1), and IGF-1 binding protein-3 (IGFBP-3).
Methods: Fifteen male boxers were divided into exercise group (E, n = 7) and exercise plus TT group (E + TT, n = 8). The 2 groups both undertook 3-week high-intensity and 3-week high-volume trainings separated by a 4-week rest. TT extracts (1250 mg/day) were orally administered by boxers in E + TT group. TT extract compositions were detected by UHPLC-Q-TOF/MS. Before and at the end of the 2 trainings, muscle mass, anaerobic performance, and blood indicators were explored.
Results: Compared with E group, decreases of plasma CK (1591.5 ± 909.6 U/L vs. 2719.9 ± 832.5 U/L) and IGFBP-3 (3075.5 ± 1072.5 ng/mL vs. 3950.8 ± 479.3 ng/mL) as well as increases of mean power (MP, 459.4 ± 122.3 W vs. 434.6 ± 69.5 W) and MP/body weight (MP/BW, 7.5 ± 0.9 W/kg vs. 7.1 ± 1.1 W/kg) were detected in E + TT group after a high-intensity training. For high-volume training, reduction of IGFBP-3 (2946.4 ± 974.1 ng/mL vs. 3632.7 ± 470.1 ng/mL) and increases of MP (508.7 ± 103.2 W vs. 477.8 ± 49.9 W) and MP/BW (8.2 ± 0.3 W/kg vs. 7.5 ± 0.9 W/kg) were detected in E + TT group, compared with E group. Muscle mass, blood levels of testosterone, dihydrotestosterone (DHT), and IGF-1 were not signifiantly changed between the 2 groups.
Conclusion: Taking 1250 mg capsules containing TT extracts did not change muscle mass and plasma levels of testosterone, DHT, and IGF-1 but significantly alleviated muscle damage and promoted anaerobic performance of trained male boxers, which may be related to the decrease of plasma IGFBP-3 rather than androgen in plasma.
Keywords: IGF binding protein-3; Insulin growth factor 1 (IGF-1); Muscle damage; Performance; Testosterone; Tribulus terrestris.