Global Biogeochemical Cycles 1990, 4:5–12.CrossRef 42. Gomez-Cabrera MC, Domenech E, Romagnoli M, et al.: Oral administration of vitamin c decreases
muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance. Am J Clin Nutri 2008, 87:142–149. Competing interests The authors declare that they have no competing interests. Authors’ contributions CWH, WHC, YST, CYC, CYH and CHK designed the selleck chemicals llc experiments. CWH and YST performed the experiments. CWH performed the statistical analyses. CWH, JLI, and CHK wrote the manuscript. All authors read and approved the final manuscript.”
“Introduction Supplementing the diet with the amino acid leucine in combination with resistance training may increase lean body mass (LBM), strength and decrease body fat [1–3]. Moreover, leucine appears to decrease skeletal muscle soreness following eccentric exercise , and prevent declines in both circulating testosterone and skeletal muscle power following
an overreaching cycle . Leucine has been thought to augment adaptations to strength training by acting as the primary signal to activate protein synthesis (e.g. regulation of translation initiation) . Additionally, for over three decades this amino acid has been known to exert antiproteolytic effects . However, the effects of leucine on muscle proteolysis are maximized at 10–20 times (5–10 mM·L−1) the Autophagy inhibitor price concentration Selleckchem OICR-9429 required to maximally stimulate muscle protein synthesis . Thus, it is probable that these effects are partly mediated by the conversion of leucine to a specific metabolite . One strong candidate is the leucine-derived metabolite, beta-hydroxy-beta-methylbutyrate (HMB) [7, 8]. In 1996, Nissen et al. Oxymatrine  first demonstrated that supplementation with HMB lowered muscle proteolysis following resistance training, and augmented gains in LBM and strength in a dose-dependent manner. Since that time HMB has been
studied in a variety of anaerobic and aerobic training conditions (). While numerous studies have supported the efficacy of HMB supplementation for enhancing recovery [10, 11], LBM [10, 12], strength , power , and aerobic performance , there have been conflicting results (Tables 1 and 2). For this reason, the primary purpose of this Position Stand is to critically analyze the existing literature on HMB supplementation and provide careful recommendations on how to optimize its effects on body composition, strength, power, and aerobic performance across varying levels of age, sex, and training status. The second purpose of this Position Stand is to critically discuss the current and proposed mechanisms of action of HMB.