It's widely known that different people react differently to creatine supplementation. Creatine helps improve muscle mass and strength in some individuals but not in others.
Recent studies reveal that creatine's varying effects aren't just coincidental. In Canada, researchers at the University of Alberta, found that people who have a high percentage of type 2 muscle fibers, such as bodybuilders, respond better to creatine loading than those with a low percentage, such as long-distance runners.
Type 2, or fast-twitch, muscle fibers, are responsible for physical activities that involve strength, speed and velocity. People who have a high percentage of type 2 muscle fibers generally do better in sports that involve anaerobic exercise such as heavy resistance training.
Creatine availability profoundly affects the performance of fast-twitch muscle fibers. Phosphocreatine, the active form of cellular creatine, can generate ATP much faster than any other energy-releasing pathways can work, including glycolysis or oxidative phosphorylation. Evidently, cellular creatine plays a critical role in providing the instant energy required for fast and strong muscle actions.
Under normal conditions the body recycles its own creatine in a metabolic pathway known as the creatine/phosphocreatine shuttle system. When under extremely high demand for immediate energy, however, such as during heavy resistance exercise, the body is unable to operate that pathway fast enough. Desperate for more energy, the muscle is forced to accelerate glycolysis, which is the breakdown of glucose. If the situation continues, lactic acid, a by-product of carb metabolism, will accumulate in the muscle tissues, leading to immediate muscle fatigue.
Fast-twitch muscle fibers function and grow differently from slow-twitch muscle fibers. Type 2 fibers are stronger and grow larger than type 1 fibers; however, type 1 fibers are more efficient at performing endurance exercise.
Because they depend on creatine and carb fuel, type 2 muscle fibers are programmed to use glycogen and creatine more efficiently than slow-twitch ones, which can resist fatigue without any dependence on creatine or carbs.
Endurance athletes and beginning bodybuilders who wish to benefit from creatine supplementation should first perform a few weeks of heavy resistance training or any exercise that involves high intensity, such as wrestling, boxing or sprinting. After six to eight weeks of intense training the body adapts, thereby increasing its capacity for using creatine.
Keep in mind that creatine works in synergy with carbs. While carbs enhance creatine assimilation (via insulin activity), creatine spares glycogen reserves in the muscle. What that means in practical terms is that taking creatine with carbs will more likely help boost performance more than creatine alone.
Editor's note: Ori Hofmekler is the author of the books The Warrior Diet and Maximum Muscle & Minimum Fat, published by Dragon Door Publications (www.dragondoor.com). For more information or for a consultation, contact him at ori @warriordiet.com, www.warriordiet.com or by phone at (866) WAR-DIET.