| Grant number: | 15/23176-2 |
| Support type: | Scholarships in Brazil - Master |
| Effective date (Start): | May 01, 2016 |
| Effective date (End): | April 30, 2018 |
| Field of knowledge: | Health Sciences - Physical Education |
| Principal Investigator: | Bruno Gualano |
| Grantee: | Guilherme de Carvalho Yamaguchi |
| Home Institution: | Escola de Educação Física e Esporte (EEFE). Universidade de São Paulo (USP). São Paulo , SP, Brazil |
Abstract Beta-alanine supplementation increases intramuscular carnosine concentrations following several weeks of supplementation. A principal role of muscle carnosine is buffering capacity, thus, the increase of carnosine would enhance intramuscular buffering capacity, potentially delaying muscle fatigue and the decline of performance during high-intensity exercise limited by acidosis. Initial studies on the washout of carnosine following beta-alanine supplementation showed that concentrations return to baseline only after 6 to 20 weeks. However, there is a lack of studies in the literature to confirm washout kinetics using the gold standard method for quantification of muscle carnosine (liquid chromatography of a muscle biopsy sample). It is speculated that the rate of carnosine degradation is related to the content in muscle, so that the concentration of carnosine in muscle influence this rate of degradation (i.e. the higher the content, the quicker the degradation). Thus, a higher rate of decay may be expected during the early period of washout with a lower rate over time. In this study we aim to evaluate the washout kinetics of muscle carnosine following prolonged beta-alanine supplementation. Furthermore, we aim to evaluate the efficacy of beta-alanine in improving high intensity exercise performance. Thirty young, healthy, physically active and non-vegetarian men will be recruited to this randomized, double-blind, placebo controlled study. Participants will be randomly assigned to beta-alanine or placebo groups. The beta-alanine group (n = 20) will receive 6.4gday-1 provided in slow release tablets (NAI, USA) for 8 weeks; the placebo group (n = 10) will receive the same amount of dextrose for the same period. Vastus lateralis samples will be collected through muscle biopsies, which will be taken before and after 8 weeks of supplementation, as well as 1, 2, 4, 8, 12 and 16 weeks after the end of supplementation. Additionally, participants will perform a high-intensity cycling test (performed on a cycle ergometer at 110% of previously determined maximum power) before and after supplementation, as well as 4, 8, 12 and 16 weeks after the supplementation period. Food intake will be evaluated in the week before each muscle biopsy through dietary recall. Data will be analyzed using mixed model analysis with Tukey-Kramer adjustment for multiple comparisons and a single degree of freedom for specific contrast analysis. The significance level will be set at pd0.05. All analyses will be performed using SAS®. (AU) | |