title: β-Hydroxy-β-methylbutyrate free acid reduces markers of exercise-induced muscle damage and improves recovery in resistance-trained men.
abstract: The purpose of the present study was to determine the effects of short-term supplementation with the free acid form of b-hydroxyb-methylbutyrate (HMB-FA) on indices of muscle damage, protein breakdown, recovery and hormone status following a high-volume resistance training session in trained athletes. A total of twenty resistance-trained males were recruited to participate in a high-volume resistance training session centred on full squats, bench presses and dead lifts. Subjects were randomly assigned to receive either 3 g/d of HMB-FA or a placebo. Immediately before the exercise session and 48 h post-exercise, serum creatine kinase (CK), urinary 3-methylhistadine (3-MH), testosterone, cortisol and perceived recovery status (PRS) scale measurements were taken. The results showed that CK increased to a greater extent in the placebo (329%) than in the HMB-FA group (104%) (P¼0·004, d ¼ 1·6). There was also a significant change for PRS, which decreased to a greater extent in the placebo (9·1 (SEM 0·4) to 4·6 (SEM 0·5)) than in the HMB-FA group (9·1 (SEM 0·3) to 6·3 (SEM 0·3)) (P¼0·005, d ¼ 20·48). Muscle protein breakdown, measured by 3-MH analysis, numerically decreased with HMB-FA supplementation and approached significance (P¼0·08, d ¼ 0·12). There were no acute changes in plasma total or free testosterone, cortisol or C-reactive protein. In conclusion, these results suggest that an HMB-FA supplement given to trained athletes before exercise can blunt increases in muscle damage and prevent declines in perceived readiness to train following a high-volume, muscle-damaging resistance-training session.
authors.affiliation: Department of Health Sciences and Human Performance, University of Tampa, Tampa, FL 33606, USA. jmwilson@ut.edu
authors.forename: Jacob M
authors.initials: JM
authors.lastname: Wilson
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Lowery
authors.forename: Jordan M
authors.initials: JM
authors.lastname: Joy
authors.forename: Joe A
authors.initials: JA
authors.lastname: Walters
authors.forename: Shawn M
authors.initials: SM
authors.lastname: Baier
authors.forename: John C
authors.initials: JC
authors.lastname: Fuller
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Stout
authors.forename: Layne E
authors.initials: LE
authors.lastname: Norton
authors.forename: Eric M
authors.initials: EM
authors.lastname: Sikorski
authors.forename: Stephanie M C
authors.initials: SM
authors.lastname: Wilson
authors.forename: Nevine M
authors.initials: NM
authors.lastname: Duncan
authors.forename: Nelo E
authors.initials: NE
authors.lastname: Zanchi
authors.forename: John
authors.initials: J
authors.lastname: Rathmacher
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D003402:Creatine Kinase / Q000097:blood; D019587:Dietary Supplements; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D009124:Muscle Proteins / Q000652:urine*; D009135:Muscular Diseases / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism; D010465:Perception; D055070:Resistance Training; D012146:Rest; D014631:Valerates / Q000494:pharmacology / Q000627:therapeutic use*; D014891:Weight Lifting / Q000502:physiology*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D009124:Muscle Proteins; D014631:Valerates; C004961:beta-hydroxyisovaleric acid; D003402:Creatine Kinase