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Backyard Revolution

by Ssregina Regina (2019-04-29)

Harris RC1, Ponte J1, Hill CA1, Sale C1, Backyard Revolution Review Jones GA1, Kim HJ2), Wise JA3 Effect of 14 and 28 days ß-Alanine (Carnosyn(TM)) supplementation on isometric endurance of the knee extensors. 1University of Chichester, Chichester, UK; 2Korea National Sport University, Seoul, Korea; 3Natural Alternatives International, San Marcos, USCarnosine (Carn) occurs in high concentrations in muscle and is highly effective in buffering H+. Carn is synthesized in situ from ß-alanine (ß-Ala) and histidine. Synthesis appears to be limited by the availability of ß-Ala from ex-muscle synthesis and meat ingestion. We have reported ~60 and ~80% increases in muscle Carn with 4 and 10wk supplementation with ß-Ala. Evidence from our laboratory indicates that uptake of _-ala into muscle is further enhanced by co-administration with simple sugars. AIM To investigate, by means of two independently run, double blind studies, the effect of supplementing (6.4 g/d) ß-Ala for 28d and 14d [the last co-supplemented with carbohydrate (CHO)], upon isometric endurance of the knee extensors at 45-50%MVC. 45-50%MVC coincides with the peak in intramuscular lactate accumulation and pH decrease. METHODS Study a): [principal investigator JP] comprised 14 male subjects aged 22.9±(SD) 5.9 yrs and mass 80.2±10.5kg, randomly assigned to receive either [800 mg] x 8/d x 28d of ß-Ala (Carnosyn(TM), NAI, San Marcos, Ca) (n=8) or a matching placebo capsules containing maltodextrin (n=6). Study b): [principal investigator RCH] comprised 20 male subjects aged 25.3±7.5yrs and mass 78.0±10.2kg assigned to receive either [1600mg] x 4/d x 14d of ß-Ala (n=8) or a matching placebo (n=12). Each test and control treatment was ingested with 45-65g CHO comprising mostly glucose. In both studies isometric exercise endurance of the knee extensors, and impulse (kN/s) generated, were measured pre and post supplementation. RESULTS Study a): MVC's of test and control subjects (mean±SE) were 754±54 and 720±91N, respectively. Exercise endurance times, pre and post supplementation, were treatment: 75.5±6.8 and 83.7±7.8s, and control: 74.6±6.5 and 72.6±7.8s. The 8.2±3.3s gain (+11.1%) in the treatment group was significant (P than with supplementation alone.