Several lines of research suggest that creatine could playa role in augmenting skeletal muscle fiber hypertrophy. Gyrate atrophy patients who consumed 1.5 g creatine per day for 1 year showed significant increases in type II muscle fiber diameter. Creatine supplementation has also been shown to facilitate muscle rehabilitation following disuse atrophy. In fact, our laboratory recently published data showing that muscle fiber hypertrophy was enhanced in men who consumed 25 g of creatine per day for 7 days followed by a daily 5-gram dose for the remainder of a 12-week resistance training program. In addition, creatine-supplemented subjects showed significantly greater improvements in maximal strength, fat-free mass, and creatine accumulation compared with placebo subjects. The percentage increases in cross­sectional area for all fiber types in creatine subjects ranged from 29-35%, more than twice the increase observed in placebo subjects (6-15%). Greater muscle fiber hypertrophy implies enhanced myofibrillar protein synthesis and/or reduced degradation. Creatine may play a direct role in myosin and actin synthesis in vitro, which may be mediated via cell swelling. A more likely scenario to explain the augmented skeletal muscle fiber cross-sectional areas observed with creatine supplementation is that the intensity of individual resistance training sessions is enhanced (Le., heavier loads can be lihed), leading to a greater stimulus for muscle fiber hypertrophy.

The direct or indirect nature of this anabolic effect of creatine has not been elucidated, however, most researchers agree that endocrine mechanisms are most likely not involved. Furthermore, there is still uncertainty regarding the optimal amount of creatine required to maximize the ergogenic potential of creatine. An ideal dose may be dependent on individual differences in diet composition, fiber type distribution, sex, age, and initial total muscle creatine concentrations. Creatine requirements may be altered depending on the specific training regimen and exercise configurations. The ability to exercise more intensely with creatine supplementation and thus augment training adaptations has wide application for a large number of athletes who participate in resistance training as a part of their overall training program.