What is creatine phosphate?
Creatine phosphate is a power source for working muscle. Creatine is a substance found mostly in skeletal muscle cells, but it is also found in heart muscle cells and brain. Creatine is made in the body and we also get it in the diet by eating meats and other animal foods. We can also consume creatine in the form of dietary supplements, like creatine monohydrate.
When ATP is abundant in these cells, such as while muscle is not active (at rest), phosphate is transferred to creatine. This forms creatine phosphate, which is a rapid ATP-regenerating resource. When ATP is used to power muscle contractions, the phosphate of creatine phosphate can be transferred to ADP to quickly regenerate ATP. This involves only one chemical reaction and can happen very rapidly. However, these beneficial actions are short-lived as the level of creatine phosphate in muscle is limited.
How does creatine phosphate power skeletal muscle efforts during exercise?
This regeneration of ATP from creatine phosphate is especially important for rapid, high energy demanding activities such as sprinting and weight training. However, this system is extremely limited and will last only a few seconds. Yet this function helps muscle cells bridge the gap between the rapid depletion of ATP at the onset of exercise and the point when a muscle cell’s other ATP-generating operations are sufficiently ramped up. Subsequently, when muscle returns to a resting state, such as in between sets or sprints, creatine phosphate is regenerated to prepare for the next high intensity exercise effort.
Does rest in between sets allow for creatine phosphate regeneration?
When you engage in resistance training you are making great demands on your muscles. Therefore, the worked muscle should be given adequate time to rest and recover after a set of repetitions (reps). Depending on the intensity of the set, muscle will need about one to three minutes to rest between sets to recover. During a set the limited stores of ATP and creatine phosphate are rapidly depleted. Giving muscle a break between sets allows for regeneration of ATP and creatine phosphate.
As muscle contracts it temporarily pinches blood vessels and hinders blood flow within that muscle. This not only decreases nutrient and oxygen delivery to working muscle fibers but also decreases the removal of waste such as lactate and carbon dioxide. The period of rest between sets allows for the blood to bring more nutrients and oxygen and remove waste and at the same time also.
Can creatine supplementation enhance muscle and strength development?
Creatine is naturally made by the human body and has become one of the most studied sport supplements. Muscle and certain other tissue, use ATP is used to transfer energy and a phosphate group to creatine, forming creatine phosphate. Creatine phosphate serves a readily available means of regenerating ATP when it is in high demand. For muscle, this would be during the early stage of an exercise. Meanwhile, for the brain and heart, creatine phosphate can help maintain ATP levels during brief periods of poor oxygen supply. The brain and heart rely on aerobic ATP production, so periods of decreased oxygen availability are extremely critical. ATP can be regenerated from creatine phosphate in a single chemical reaction, which does not require oxygen.
How is Creatine made in the body?
Creatine is made in the body using three amino acids (methionine, glycine, and arginine) and two organs (liver and kidneys). Creatine is also found in animal foods, primarily the muscle part of animals. Therefore, meat eaters tend to consume approximately one to two grams of creatine in their diets. The practice of supplementing creatine became extremely popular in the 1990s as several research studies showed that muscle creatine levels could be increased with supple¬mentation. This change was often associated with increases in total body mass, lean body mass, strength, and power. Creatine is mostly supplemented as creatine monohydrate, but other forms have been marketed over the years including creatine ethyl ester, fumarate, nitrate, malate, etc. However, no form of creatine has been shown to be more effective than the monohydrate form.
How much creatine is needed for exercise performance benefit?
Much of the early research with creatine and exercise performance used a “loading phase” followed by a “maintenance phase”. In the loading phase, about 5 grams is consumed four times daily for five to seven days. This equates to about 0.3 grams per kilogram body weight and serves to increase muscle creatine phosphate levels by 20 to 40 percent. At this level, the muscle is said to be “saturated”. After the loading phase, an individual can transition to a maintenance phase of three to five grams daily.
The loading phase can be challenging for some people. The good news is that supplementation of three to five grams of creatine daily will saturate muscle with creatine as well, however it takes a few weeks longer to achieve muscle saturation. This the practical supplementation regimen applied by most people. It approximates about 0.06g/kg creatine (as creatine monohydrate) daily.
For most people who are simply trying to build muscle and maintain it, a couple extra weeks will not matter in the long term. However, loading may be more of interest for athletes preparing to enter camp or a competitive season. Furthermore, you can think of creatine supplementation as an investment nutrient and incremental muscle creatine levels are built over time. You can supplement more on some days than others and influence the speed to saturation or maintenance of saturation. Meanwhile, if creating supplementation stops, it will take about four to six weeks to return to the levels before you started.
Is creatine supplementation safe?
Creatine supplementation has been studied extensively and believed to be generally safe, especially at commonly consumed levels. Moreover, higher levels of creatine (e.g., 30 grams/day) for years has been noted in some medical applications without problems in otherwise healthy individuals. Moreover, people who supplement with creatine are among the most loyal to on-going supplementation. After roughly three decades of commercial availability and positioning among the top supplements, no significant concerns have been validated.
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