ABSTRACT
Several nutritional supplements have been proposed to have ergogenic effects relating to endurance performance and weight loss. The ability to perform sustained, high-intensity aerobic activity is important for competition in several sports and events including running, cycling, swimming and team sports such as soccer. This chapter aims to introduce some emerging ergogenic aids that have been proposed to enhance endurance activity and/or weight loss. Quercetin is one of the natural polyphenolic flavonoids that have been investigated for its potential benefits on health and performance. Several studies have examined the effects of quercetin supplementation on endurance performance, exercise capacity and maximal oxygen consumption in humans. Carnitine has become an increasingly popular supplement for weight loss and endurance performance due to its purported potential to enhance muscle fatty acid oxidation, decrease muscle glycogen depletion rates and improved muscle fatigue resistance. The theoretical basis for carnitine supplementation is to increase the concentration of endogenous carnitine, thereby increasing lipid metabolism and decreasing adiposity.
