The present invention is directed to compositions having an effective amount of Adenosine Triphosphate ("ATP") sufficient to effect intracellular and extracellular concentrations of ATP in a mammal to improve anaerobic exercise capacity by increasing muscle size and/or strength and methods for using the same. Preferably, a gastric acid secretion inhibitory coating is applied to the effective amount of ATP in a manner that protects the ATP from degradation by gastric juices. ATP compositions of the present invention may be administered in nutraceutical or functional food dosage forms, including oral and non-oral delivery forms. In addition, the effective amount of ATP maybe combined with amino acids, botanicals, functional foods, herbals, nucleotides, nutraceuticals, nutrients, pharmaceuticals, proteins, and/or vitamins in an effort to enhance the targeted activity of the composition.