Creatine phosphate (creatine-P) serves as an “energy buffer” in the muscle. (A buffer is a chemical that maintains a near-constant pH in a solution or liquid, even when acid or base is added.) Creatine-P helps maintain a constant concentration of ATP in the muscle during sudden explosions or exercises that would otherwise deplete the concentration of ATP in the cell. A sudden burst of exercise or a short period of exhausting movement can deplete cellular ATP before hormonal changes can activate glycogen phosphorylase or hormone-sensitive lipase. Plasma glucose is a readily available source of energy that can be used during sudden or strenuous exercise. However, a decrease in plasma blood glucose is not desirable, as the central nervous system needs glucose. Research on creatine phosphate training has relied primarily on creatine with supplements rather than natural creatine. The results are based on extremely fast rotations such as a sprint, where a competitor can take off and sprint at any time, you have to react quickly and jump forward. Creatine and creatine phosphate play an important role in regulating adenosine triphosphate cell reservation. Function is impaired in brain syndromes of creatine deficiency. This group of diseases includes a defect in the X-linked creatine transporter (XCrT) as well as deficiencies in two enzymes involved in de novo creatine synthesis, arginine glycine amidinotransferase (AGAT) and guanidine acetate methyltransferase (GAMT). Key clinical features include seizures, mental retardation, autism and speech delay. Although there is a significant amount of phenotypic overlap, these disorders differ in their presentation and pathogenesis.

Laboratory diagnosis of these disorders is based on the determination of creatine and guanidine acetate in plasma and urine. While determination of plasma-creatine and guanidine acetate levels is used to detect AGT and GAT deficiencies, measurement of the creatine to creatinine ratio in urine is a sensitive screening for XCrT deficiency. Treatment of cerebral creatine deficiency syndromes typically includes creatine supplementation and attempts to reduce interfering intermediates such as guanidine acetate. Understanding the function of creatine requires basic knowledge of biochemistry. In short, creatine is part of a process that uses ATP. While ATP is the chemical that triggers actual contraction — by activating fibrous proteins in muscles called myosin — very little is stored in muscles. During intense exercise, ATP is depleted within seconds and must be replenished into phosphocreatine. FIGURE 4.33. Biosynthesis of creatine from glycine. Arginine donates from the guanidinium group; SAM donates the methyl group.

Muscles use phosphocreatine in the first seconds of intense muscle contraction, such as powerlifting or sprinting. Unlike aerobic contractions, which use oxygen to produce energy, phosphocreatine triggers energy without oxygen. As such, it is considered anaerobic. All native cells of the central nervous system, including neurons and glia, express creatine kinase (CK), the enzyme that catalyzes the balance between phosphocreatine, ADP, creatine and ATP. A high-energy muscle has a lot of creatine phosphate, while a tired muscle has little creatine phosphate. When extra creatine phosphate is stored in your muscles, you have that extra backup energy to help you climb the top of the hill or cross the final sprint to the finish line. Schönfeld BJ. The mechanisms of muscle hypertrophy and their application to resistance training. 2010;24(10):2857-2872. doi:10.1519/JSC.0b013e3181e840f3 Phosphocreatine is able to donate its phosphate group to convert adenosine diphosphate (ADP) into adenosine triphosphate (ATP). This process is an important part of the bioenergetic systems of all vertebrates.

For example, while the human body produces only 250 g of ATP per day, it recycles all its body weight into ATP every day through creatine phosphate. Smith RN, Agharkar AS, Gonzales EB. An overview of creatine supplementation for age-related diseases: more than a supplement for athletes. F1000Res. 2014;3:222. doi:10.12688/f1000research.5218.1 Creatine supplements can help build muscle mass by providing your body with the building blocks of phosphocreatine. This accelerates the reconstitution of ATP and therefore the duration of high-intensity training. Biochemistry and cell biology are not things that most cyclists are passionate about, but a working knowledge of movement metabolism is very relevant when cycling. Training metabolism includes the energy pathways and systems used to convert food into energy during cycling. What is creatine phosphate? It is part of that system.

Antonio J, Ciccone v. The effects of creatine monohydrate supplementation before and after exercise on body composition and strength. J Int Soc Sports Nutr. 2013;10:36. All muscle cells contain ATP (not much) that they can use immediately – but only enough to last about 3 seconds. For this reason, all muscle cells contain and use creatine phosphate, which is broken down to produce more ATP quickly. Creatine phosphate can provide the energy needs of a muscle that works at a very high rate, but only for about 5 to 6 seconds. Other studies have up to ten seconds.

Although red meat is a natural source of creatine, it is not concentrated enough to increase phosphocreatine levels in muscles. To achieve significant increases, athletes turn to creatine supplements such as creatine monohydrate or creatine ethyl ester. While current dosage recommendations are loosely supported by research, many sports nutritionists recommend a daily loading dose of 0.3 grams of creatine per kilogram of body weight for 4 to 6 weeks.