AMINO-ACID SUPPLEMENTATION AND EXERCISE PERFORMANCE - ANALYSIS OF THEPROPOSED ERGOGENIC VALUE

Increasing the relative amount of protein in the diet of athletes has been suggested to optimise anabolic processes and improve both physiol ogical responses to training and performance. While energy balance stu dies generally support the concept that athletes may require additiona l protein in their diets in comparison with the Recommended Dietary Al lowances (RDA), most sport nutritionists contend that as long as athle tes maintain energy balance and ingest 15% of their total caloric inta ke in the form of protein, additional supplementation of protein is no t necessary. Recently, amino acids have become a popular nutritional s upplement marketed to athletes. In strength athletes, amino acid suppl ementation has been proposed to increase the availability of essential amino acids, enhance anabolic processes promoting tissue accretion, a nd accelerate the rate of recovery during training. In endurance athle tes, amino acid supplementation has been proposed to improve physiolog ical and psychological responses during endurance exercise and trainin g. There appears to be little scientific evidence to support the hypot hesis that amino acid supplementation may enhance the physiological re sponses to strength training when athletes consume dietary protein wit hin the recommended guidelines. Results of the effects of amino acid s upplementation on the physiological and psychological responses to end urance exercise are preliminary. However, the findings suggest that am ino acid supplementation with carbohydrate before, during and after ex ercise may alter the ratio of free tryptophan to branch-chained amino acids. Further research is required before definitive conclusions can be drawn regarding the proposed ergogenic value of amino acid suppleme ntation.