Creatine is found naturally in the body. It is an essential component of one of the body’s three energy systems called the ATP-PC system. The ATP-PC system provides ATP at the beginning of all activity to initiate movement including muscle contraction during exercise. This system is able to provide a large quantity of ATP very quickly, but can only be maintained for a very short time. It is the main energy source for high intensity short duration activities like sprinting and weight lifting.
Creatine supplementation could benefit those with lower than average Total Cr stores who engage in activities of high intensity and short duration especially if it involves repeated bouts. Some sports in which Creatine supplementation can be beneficial are: body building, power lifting, football, basketball, baseball, soccer, hockey and some track and field events. However, the associated increase in body mass with Cr supplementation maybe counterproductive in some sporting events.
Through this energy system creatine allows ATP to be re-synthesized after it has been chemically split apart and converted to ADP to produce energy. The re-synthesized ATP is then available for continued energy production for muscle contraction.
Creatine is found in two forms in skeletal muscle, free creatine and phosphocreatine. Phosphocreatine is creatine that, as its name implies, has a phosphate molecule attached to it. At rest about 60% is bound to phosphate producing phosphocreatine(PCr). ATP (Adenosine tri phosphate) losses its phosphate and becomes ADP to produce energy. Phosphocreatine will donate its phosphate to ADP to re-synthesize ATP for continued energy production. The PCr that donated the phosphate is now free creatine. This process will continue as long as PCr is available.
About 95% of the total body stores of creatine are found in skeletal muscle
Creatine supplementation can increase performance by following way.
- Help performance by increasing resting PCr stores
- Increases the rate of PCr re-synthesis between bouts of exercise more PCr will be available to re-synthesis ATP.
- Increases Total Cr can increase the buffering ability within the cell.
- Increased PCr stores should assist in maintaining levels of ATP and
- Improve performance in short term high intensity exercise
- With Increased PCr concentration, high power outputs can be maintained longer which will in turn increase performance.
- Delay muscular fatigue
Many sports consist of repeated bouts of high intensity exercise with varying amounts of recovery time. In these type of activities most of the energy is derived from anaerobic pathways which makes quick recovery very important. The rate of PCr resynthesis will influence energy availability for the next bout of exercise. Phosphocreatine degradation is the major source of ATP utilization during repeated bouts of high intensity exercise. Therefore increased re-synthesis of PCr back to, or near resting levels could greatly increase performance in repeated exercise bouts.
Possible Health Benefits
Power is result of force of muscle contraction which is energy dependent. Creatine plays vital role in energy release thus helps to increase force of contraction so more power.
- Creatine is an example of a physiologically important nitrogenous compound synthesized from amino acids.
- Muscular contraction results in an accumulation of Cr because creatine plays an important role in the transfer of energy.
- Creatine depends on various dietary factors and body can conserve the dietary essential amino acids, arginine and methionine, during times of dietary insufficiency or stress.
- Growth hormone and thyroid hormone deficiency decrease AGAT (Enzyme that plays chief role in creatine synthesis) activity, thus decreases creatine synthesis.
- Limitations in Cr synthesis might exist during conditions of folic acid and/or vitamin B 12 deficiencies
- Testosterone stimulates AGAT expression and thus, Cr biosynthesis.
- The rate of Cr biosynthesis is on the order of 1-2 g/d.
- Research with food and supplement sources of Cr has shown that consuming 2 g of Cr in solution resulted in a peak plasma concentration of nearly 400 mmol/L at 30-60 min.
- Once absorbed into the bloodstream, Cr (from both endogenous and dietary sources) is either cleared by the kidneys or taken up at the tissue level, primarily skeletal muscle, to be used.
- Creatine uptake has been shown to be stimulated following sub maximal exercise bouts.
- This increase in Cr uptake following exercise has been demonstrated to only occur in skeletal muscles involved in the exercise.
- Enhances the performance
- Increase lean body mass, strength, and total work
- Increase anaerobic work capacity
- Helps in protein synthesis for greater muscles gain
- Remove lactic acid from muscles after intense workout.
- Improves cognition and brain function
- Increase bone density
- Enhances glycogen storage and carbohydrate loading