Creatine is one of the most thoroughly researched ergogenic aids today, with evidence strongly supporting its ability to increase muscle growth (alongside resistance training), increase strength in athletes, and improve power-based sports performance.
WHAT IS CREATINE?
Creatine (fig. 1) is a small, endogenously produced (made naturally in our bodies) peptide — a structure composed of amino acids. Specifically, creatine is composed of L-arginine, glycine, and methionine and is primarily made in the liver and to a lesser extent in the kidneys and pancreas. It’s widely taken by strength athletes due to the performance improvements associated with its use.
Generally speaking, the recommended clinical dosage of creatine is 0.03 g/kg/day (i.e. 2.25g per day for a 75kg individual), however, some prefer to take 5g/day because of the low price of creatine monohydrate and the possibility of experiencing increased benefits with the increased dose. Higher doses (up to 10 g/day) may be beneficial for people with a high amount of muscle mass and high activity levels or for those who do not respond to the lower 5 g/day dose.
Figure 1: Creatine
WHAT DOES IT DO? Creatine stores high-energy phosphate groups in the form of phosphocreatine (fig. 2) in our cells. Phosphocreatine (PCr) serves as a rapidly mobilizable store of high-energy phosphates in skeletal muscle, myocardium, and the brain to recycle adenosine triphosphate (ATP), the currency of cellular energy in our bodies.
Figure 2: Phosphocreatine
When we perform aerobic exercise we can rely on our aerobic system to produce energy, however, when we lift weights and perform high-intensity work, the aerobic system doesn’t produce energy quickly enough to keep up with demands. We need continued ATP production at a fast enough rate to perform optimally under anaerobic conditions. Our bodies rely on anaerobic glycolysis to provide ATP, but it’s not the fastest process and so our bodies rely on the ATP system as the fastest method of energy generation. Unfortunately, ATP stores deplete quickly with high-intensity exercise and so that is why many athletes supplement with creatine.
The mobilized phosphates are donated to ADP (adenosine diphosphate) (fig. 3), regenerating it to ATP (adenosine triphosphate) (fig. 4), the primary energy carrier in our cells. This is the body’s fastest energy production system and so is vital for us when performing high-intensity anaerobic exercise like powerlifting. Although the system is quick, it is more economical for our muscles to store ADP as it is less reactive than ATP. Therefore, there is a demand for a large store of phosphocreatine to provide phosphorous molecules to ADP to produce ATP on demand as and when high-intensity exercise is performed.
Figure 3: Adenosine Diphosphate (ADP)
Figure 4: Adenosine Triphosphate (ATP)
SO WHY SUPPLEMENT WITH IT?
Supplementing with creatine allows us to ensure that there is increased availability of creatine for producing phosphocreatine and so a larger backup of stored phosphorous molecules available to produce ATP from ADP during intense anaerobic exercise.
By increasing the overall pool of cellular phosphocreatine, creatine supplementation can accelerate the recycling of ADP into ATP. Since ATP stores are rapidly depleted during intense muscular effort, one of the major benefits of creatine supplementation is its ability to regenerate ATP stores faster, which can promote increased strength and power output. Over 95% of creatine is stored in muscle and has a maximum concentration level of 30uM. Creatine storage capacity is limited, though it increases as muscle mass increases.
Logic tells us that if we can have larger energy stores for lifting, we will be able to perform more reps and use heavier weights than we would without that improved availability of creatine for energy production.
TAKE AWAY POINTS: 1. Creatine monohydrate is one of the most scientifically studied substances and has been shown to significantly increase power output, muscle growth, and performance in strength athletes. 2. Creatine plays a vital role in energy production in our cells when we perform high intensity exercise i.e. powerlifting. 3. By supplementing with creatine we make sure that creatine availability is not a limiting factor in anaerobic energy production. 4. Generally speaking, 5g/day is the recommended dose, however, clinical studies have suggested that 0.03g/kg bw/day is an appropriate dose.