RIVALUS Sports Nutrition Blog

Creatine is a nitrogen-containing compound naturally produced in the body and/or consumed in the diet from red meat and seafood and derived from reactions involving the amino acids glycine, arginine, and methionine. Skeletal muscle creatine content is dependent on muscle fiber composition. Type II muscle fibers have high levels of free creatine (Cr) and phosphocreatine (PCr) which is needed to resynthesize adenosine diphosphate (ADP) and maintain adenosine triphosphate (ATP) during muscle contraction (i.e. PCr + ADP ATP + Cr). Intramuscular creatine stores range from 120-160 mmol/kg dry muscle with approximately 60% being PCr. Creatine supplementation increases intramuscular total creatine (i.e. Cr and PCr) and the increase in PCr may possibly allow one to train with a greater volume of resistance-exercise leading to muscle accretion. In addition to its primary role as a component of high-energy phosphate metabolism, creatine supplementation may increase muscle hypertrophy possibly through an increase in satellite cell activity, cellular hydration status, hormonal proliferation, myogenic transcription factors such as MRF-4 and myogenin or by reducing protein catabolism.

Muscle hypertrophy following resistance-exercise requires net protein synthesis of myofibrillar proteins and therefore, maximal stimulation of muscle protein synthesis is required for the development of muscle mass. It is well established that resistance-exercise results in increased protein catabolism and protein synthesis. Although the machinery for stimulating muscle protein synthesis is increased after resistance-exercise, it appears that this response may not be increased until some time after the resistance-exercise session. Recent evidence suggests that creatine ingestion, in close proximity to resistance-exercise sessions, may be more beneficial than ingesting creatine at other times of the day. For example, muscle hypertrophy was promoted specifically in muscle groups exercised immediately before and immediately after creatine supplementation in young adults. Consuming creatine immediately before and after resistance-exercise sessions for 10 weeks resulted in greater muscle hypertrophy and strength in healthy older males compared to placebo. Based on these preliminary findings across studies, it appears that the acute strategic ingestion of creatine supplementation before and after resistance-exercise sessions may lead to greater muscle hypertrophy and strength, possibly because of increased blood flow and delivery of creatine to skeletal muscle and perhaps through co-transport of creatine into muscle when the sarcolemmal sodium-potassium pump is active during exercise.

[Dr. Darren Candow, PhD, is an Assistant Professor in the Faculty of Kinesiology and Health Studies at the University of Regina. He serves on the editorial board of a number of prestigious academic journals and he runs a busy research laboratory with multiple graduate student researchers and technicians. Dr. Candow is a leading authority on nutraceutical intervention during exercise training on muscle and bone metabolism and has won numerous awards, published numerous peer-reviewed papers, and performed many invited lecture all over the world.]