Sarcopenia: current theories and the potential beneficial effect of creatine application strategies.

Sarcopenia, defined as the age-related loss of muscle mass, subsequently has a negative effect on strength, metabolic rate and functionality leading to a reduced quality of life. With the projected increase in life expectancy, the incidence of muscle loss may rise and further drain the health care system, with greater need for hospitalization, treatment, and rehabilitation. Without effective strategies to counteract aging muscle loss, a global health care crisis may be inevitable. Resistance training is well established to increase aging muscle mass and strength. However, muscle and strength loss is still evident in older adults who have maintained resistance training for most of their life, suggesting that other factors such as nutrition may affect aging muscle biology. Supplementing with creatine, a high-energy compound found in red meat and seafood, during resistance training has a beneficial effect on aging muscle. Emerging evidence now suggests that the timing and dosage of creatine supplementation may be important factors for aging muscle accretion. Unfortunately, the long-term effects of different creatine application strategies on aging muscle are relatively unknown.