The present invention provides a composition comprising HMB and ATP. Methods of administering HMB and ATP to an animal are also described. HMB and ATP are administered to increase power and strength. The combination of HMB and ATP together has a synergistic effect, which results in a surprising and unexpected level of improvement in power and strength. HMB and ATP are also administered to increase lean body mass and muscle hypertrophy and to prevent typical declines in performance that are characteristic of overreaching.
