Effects of branched - chain amino acids and ornithine α - Ketoglutarate administration on perceived exertion and on endurance performance |
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Abstract |
B rain 5-hydroxytryptamine(5-HT) has been suggested to be involved in central fatigue during endurance exercise. Changes in the ratio of plasma free tryptophan(Trp) to branched- chain amino acids(BCAA) are associated with altered brain 5-HT synthesis. It has been hypothesized that BCAA supplementation can reduce uptake of tryptophan during prolonged exercise. Howerever, some researchers have been shown that supplementation with BCAA does not appear to be any significant advantage to the human and the rats to improve endurance performance. The purpose of this study was to examine the effect of branched-chain amino acids(BCAA) plus ornithine α-ketoglutarate(OKG) compared to BCAA supplementation on plasma concentration of some amino acids and on perceived exertion, endurance performance. Five trained college cyclists(VO_2max=49.18±7.27㎖㎏^-min)cycled to all-out at a power output corresponding to VO_2 at anaerobic threshold(approximately 66% VO_2max) on three occasions separated by one week. Subjects drank 200㎖ of among a water placebo, or solution containing BCAA(77㎖㎏^-body wt^-.) or BCAA plus OKG(each 77㎖㎏^-body wt^-.) beginning at 50min. before exercise and 150㎖ at 15min., 30min. during exercise. BCAA composition was 35%, 25% and 40% for leucine, isoleucine and valine. OKG composition was 64%, 36% for ornithine and α-ketoglutarate. During the exercise at 40mim. and 60min, the subjects` ratings of perceived exertion when they were given BCAA plus OKG were significantly lower(p<0.05) than when they were given BCAA or placebo. Exercise time to all-out was significantly longer(p<0.05) in subjects receiving BCAA plus OKG(89.16±5.21min) as compared to placebo(74.80±3.9min)and BCAA(72.77±4.1min). The concentration of BCAA of BCAA plus OKG trial were significantly higher(p<0.05) than that of placebo trial, but not different with BCAA trial at rest 2(50min after ingested solution containing each agents) and during exercise. The plasma ratios of free Trp to BCAA concentration of BCAA plus OKG trial were significantly lower(p<0.05) than that of placebo trial, but not different with BCAA trial at rest 2 and during exercise. The concentration of glutamate of BCAA plus OKG trial were significantly higher(p<0.05) than those of placebo trial and BCAA trial during exercise. The concentration of glutamie of BCAA plus OKG trial were only significantly higher (p<0.05) than those of placebo trial and BCAA trial at all-out time. The concentration of ornithine of BCAA plus OKG trial were significantly higher(p<0.05) than those of placebo trial and BCAA trial at rest 2 and during exercise. The differences of heart rate were not found, but that of BCAA plus OKG trial had a trend of decrease as compared to two trials. These data suggest that the simultaneous administration of BCAA and OKG could be inhibited the genesis of central fatigue and improve endurance performance. |
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