Optimizing liver and muscle glycogen storage is a goal of many athletes wishing to maximize performance, particularly those involved in disciplines requiring prolonged sub-maximal exertion (65–75 % VO2peak) or repeated bursts of high intensity exercise. Anyone that has ever tried to train intensely on a low carbohydrate diet will notice a decrease in exercise performance when carbohydrates are kept low. A recent study published in Medicine in Sports and Science and Exercise determined that glycogen replenishment is essential for post-exercise recovery and next day performance. In the study, subjects were assigned to low and high carbohydrate groups after a glycogen-depleting exercise session. At the end of the study, every participant in a high-carbohydrate group had better performance than low carbohydrate group. Muscle glycogen concentrations were higher at the end of recovery in high carbohydrate versus low carbohydrate group. Increasing carbohydrate intake during short-term recovery accelerates glycogen repletion in previously exercised muscle and thus improves the capacity for repeated exercise. The availability of skeletal muscle glycogen is, therefore, an important factor in the restoration of endurance capacity because fatigue during repeated exercise is associated with a critically low absolute muscle glycogen concentration. So the replenishment of glycogen is essential for recuperation the next day for exercise performance. The key is getting more glycogen in muscle.
Studio portrait of shirtless male fitness athlete perfectly shaped and muscle toned wearing red shorts and exercising with blue kettlebells.
Subsequently, creatine supplementation has become a common practice in both recreational and professional athletes. As most research on creatine has focused on the ergogenic capacity of creatine loading, far less attention has been attributed to the potential of creatine to affect muscle glucose metabolism. As an increase in muscle glycogen synthesis should probably be accompanied by an increase in muscle glucose uptake, it has been speculated that creatine supplementation might up-regulate GLUT-4 expression (GLUT4 is the insulin-regulated glucose transporter found primarily in adipose tissues and striated muscle (skeletal and cardiac.) in muscle tissue. Creatine has been found to increase muscle strength and muscle mass, but new research suggests that creatine may increase glycogen replacement better. Creatine plays a significant role in rapid energy provision during muscle contraction involving the regeneration of ATP.
Previous research demonstrated that dietary Creatine supplementation can increase post-exercise muscle glycogen storage during a conventional ‘Carbohydrate-loading’ regimen in healthy, young, male volunteers. Researchers had 14 healthy, male volunteers cycled to exhaustion at 70 % VO2peak. Muscle biopsies were obtained at rest immediately post-exercise and after 1, 3 and six days of recovery, during which Creatine supplementation or placebo supplements (20 g day−1) were ingested along with a prescribed high carbohydrate diet ( >80 % of total calories coming from carbohydrates).
At the end of the study, the researchers found that dietary creatine supplementation markedly enhanced post-exercise muscle glycogen storage above placebo during a conventional ‘carbohydrate-loading’ regime and that this augmentation of glycogen storage occurred almost exclusively within the first 24 hours of supplementation. The magnitude of glycogen re-synthesis during the first 24 hours of supplementation was ~82 % greater in the Creatine group compared to a carbohydrate only group).
Key Points: For years, everyone has traditionally thought of creatine as a strength supplement, but based on this new research, creatine can increases glycogen replenishment along with high carbs which can be useful for just about any athletes who wants to increase performance.
Roberts, PA, Fox, J, Peirce, N, Jones, SW, Casey, A, Greenhaff, PL. Creatine ingestion augments dietary carbohydrate supercompensation during the intitial 24h of recovery following prolonged exhaustive exercise in humans. Amino Acids. Published online 3 May 2016.
Op ‘t Eijnde, B., Urso, B., Richter, E. A., Greenhaff, P. L.
and Hespel, P. (2001) Effect of oral creatine supplementation on human muscle GLUT4 protein content after immobilization. Diabetes 50,18–2.