F-12L FREE COMMUNICATION/POSTER ERGOGENIC AIDS
Supplementation with β-hydroxy-β-methylbutyrate (HMB) has been shown to reduce muscle proteolysis and increase both muscle mass and strength following resistance training; in addition, there is evidence that HMB reduces muscle damage following high-intensity exercise.
The purpose of this study was to examine the effects of HMB supplementation on indices of exercise-induced muscle damage following a single bout of eccentric exercise.
Eight male subjects, body mass and height (mean±SD) 81.9±18.4 kg and 178.3±5.8 cm, respectively, performed a single bout of eccentric exercise designed to induce muscle damage on two separate occasions. Exercise was performed on the dominant or non-dominant arm in a randomised crossover design, and comprised 3 sets of 10 eccentric repetitions of single arm biceps curls, at 70% of a pre-determined one repetition maximum (1RM). Subjects were also randomly assigned to an HMB treatment (Maximuscle HMB 1000, Maximuscle Ltd., Watford, U.K.) which comprised a daily dose of 3 g HMB and 0.3 g alpha-ketoisocaproic acid; and a placebo treatment (corn flour) for 14 days in the crossover design. 1RM, delayed onset muscle soreness (DOMS), limb girth, plasma creatine kinase activity (CK) and range of motion (ROM) were determined pre-exercise, and at 1 h, 24 h, 48 h and 72 h post-exercise.
Significant time effects were observed for 1RM, DOMS, limb girth and ROM (p<0.05). A significant treatment effect was found for CK, which was lower in the HMB treatment (p<0.05) and a significant interaction effect (p<0.05) was found for DOMS which was reduced at 24 h post-exercise in the HMB treatment.
The results indicate that HMB supplementation is effective in the management and reduction of muscle damage and soreness following a single bout of eccentric exercise.