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Athletes use a variety of nutritional ergogenic aids to enhance performance. Most nutritional aids can be categorized as a potential energy source, an anabolic enhancer, a cellular component, or a recovery aid. Studies have consistently shown that carbohydrates consumed immediately before or after exercise enhance performance by increasing glycogen stores and delaying fatigue. Protein and amino acid supplementation may serve an anabolic role by optimizing body composition crucial in strength-related sports. Dietary antioxidants, such as vitamins C and E and carotenes, may prevent oxidative stress that occurs with intense exercise. Performance during high-intensity exercise, such as sprinting, may be improved with short-term creatine loading, and high-effort exercise lasting 1-7 min may be improved through bicarbonate loading immediately prior to activity. Caffeine dosing before exercise delays fatigue and may enhance performance of high-intensity exercise.

The desire to win leads physically active individuals to look for anything to improve performance. Many ergogenic aids are available; however, claims made about many of these products are not appropriate. To evaluate such products, one must consider the physiological sense of the claims, the supportive evidence provided, the research articles quoted, and the legal and health implications of use.

The use of ergogenic aids is common in sport, even among preadolescent athletes (8,15,25). The aim of this study was to investigate the relationship between preadolescents’ use of nutritional ergogenic aids (creatine and amino acids) and gender, age, athletic participation, and sport-relevant psychological factors (i.e., sport success motivation, task and ego orientation, self-efficacy). Two thousand four hundred fifty 11- to 13-year-old children participated in this study. Results suggest that substance use increases with age, especially among male preadolescents; that gender differences are particularly marked among older preadolescents; and that a high commitment to sport training represents a risk factor of ergogenic supplementation only when it is linked to certain psychological dispositions, such as a high ego orientation and a low task orientation.

Most hormonal agents used for nonmedical purposes in athletes have legitimate medical uses. This review introduces each compound by its pharmacology, clinical pharmacology, and legitimate medical use and reviews information on its abuse. Human growth hormone is presently available in virtually unlimited quantities due to its production by recombinant DNA technology. Its use in athletes is considered for its muscle-building, fat-depleting properties. Erythropoietin is a kidney hormone that increases red cell mass. It is used for renal dialysis patients to avoid blood transfusions. Its use in athletes is to raise red blood cell mass in an attempt to augment maximal oxygen capacity and the ability to do endurance work. Human chorionic gonadotropin has the biological activity of luteinizing hormone to increase testosterone synthesis and to maintain (partially) testicular volume when exogenous androgens are taken. Clenbuterol is a beta₂ adrenergic agonist with muscle-building properties that are seemingly specific to striated muscle; clenbuterol may cause reduction in body fat.

Three nutritional products that have very different mechanisms of action are antioxidant vitamins, carnitine, and choline. Antioxidant vitamins do not appear to have a direct effect on physical performance in well-fed people but have been touted for their ability to detoxify potentially damaging free radicals produced during exercise. Carnitine purportedly enhances lipid oxidation, increases VO₂max, and decreases plasma lactate accumulation during exercise. However, studies of carnitine do not generally support its use for ergogenic purposes. Choline supplements have been advocated as a means of preventing the decline in acetylcholine production purported to occur during exercise; this decline may reduce the transmission of contraction-generating impulses across the skeletal muscle, an effect that could impair one’s ability to perform muscular work. However, there are no definitive studies in humans that justify choline supplementation. Much of the scientific data regarding the aforementioned nutrients are equivocal and contradictory. Their potential efficacy for improving physical performance remains largely theoretical.