Creatine Supplementation

Dietary supplementation of creatine serves to increase muscle creatine and PCr by what percentage?

20-40% This is because in a normal diet that contains 1-2 g/day of creatine, muscle creatine stores are about 60-80% saturated (so, 20-40% left unsaturated)

Once muscle creatine stores are fully saturated, what dosage is needed to maintain them?

3-5 g/day, although some studies indicate that larger athletes may need to ingest as much as 5-10 g/day in order to maintain creatine stores

Where is creatine stored?

95% in skeletal muscle, 5% in brain and testes (the upper limit of creatine storage appears to be about 160 mmol/kg of dry muscle mass in most individuals)

What form is creatine stored in?

About 2/3 of intramuscular creatine is phosphocreatine (PCr) with the remaining being free creatine.

Where is creatine obtained from?

About half of the daily need for creatine is obtained from the diet, primarily in red meat and seafood.

Effect of creatine loading on performance

After creatine loading, performance of high intensity and/or repetitive exercise is generally increased by 10-20% depending on the magnitude of increase in muscle PCr

What is an alternative supplementation protocol for creatine and what is its disadvantage

Alternative supplementation protocol: ingest 3 g/day of creatine monohydrate for 28 days Disadvantage: this method would only result in a gradual increase in muscle creatine content compared to the more rapid loading method and may therefore have less effect on exercise performance and/or training adaptations until creatine stores are fully saturated

Benefits of creatine supplementation in men vs women

Benefits have been reported in men and women, although the majority of studies have been conducted on men and some studies suggest that women may not see as much gain in strength and/or muscle mass during training in response to creatine supplementation

Creatine's effect on recovery

Creatine supplementation can help athletes recover from intense training.

Examples of sport events that may be enhanced bycreatine supplementation

Creatine supplementation has primarily been recommended as an ergogenic aid for power/strength athletes to help them optimize training adaptations or athletes who need to sprint intermittently and recover during competition (e.g., American football, soccer, basketball, tennis, etc.)

International Society of SportsNutrition (ISSN)'s stance on creatine supplementation

ISSN has previously concluded that creatine monohydrate is the most effective nutritional supplement currently available to athletes in terms of increasing high-intensity exercise capacity and lean body mass during training

Benefits of creatine supplementation (general list)

Increased single and repetitive sprint performance Increased work performed during sets of maximal effort muscle contractions Increased muscle mass & strength adaptations during training Enhanced glycogen synthesis Increased anaerobic threshold Possible enhancement of aerobic capacity via greater shuttlingof ATP from mitochondria Increased work capacity Enhanced recovery Greater training tolerance

What is the most effective way to increase muscle creatine stores?

Ingest 5g of creatine monohydrate (or approximately 0.3 g/kg body weight) four times daily for 5-7 days

How can you promote greater creatine retention?

Ingest creatine with carbohydrate or carbohydrate and protein

Creatine dosing strategies

Larger athletes engaged in intense training may need to consume 5-10 g/day of creatine to maintain optimal or capacity whole body creatine stores Clinical populations may need to consume 10-30 g/day throughout their lifespan to offset creatine synthesis deficiencies and/or provide therapeutic benefit in various disease states

Additional clinical applications of creatine supplementation other than exercise performance and injury prevention

Neurodegenerative diseases (e.g., muscular dystrophy, Parkinson's, Huntington's disease), diabetes, osteoarthritis, fibromyalgia, aging, brain and heart ischemia, adolescent depression, and pregnancy

Is creatine banned by any sport organization?

Nope. Creatine is found in high amounts in the food supply and therefore its use is not banned by any sport organization although some organizations prohibit provision of some types of dietary supplements to athletes by their teams

Describe the CK/PCr energy shuttle

The CK/PCr energy shuttle connects sites ofATP production (glycolysis and mitochondrial oxidative phosphorylation) with sites of ATP utilization (ATPases) in order to fuel energy metabolism. It is an important regulator of metabolism which may explain the health benefits of creatine supplementation

How does creatine increase ATP availability?

The free energy released from the hydrolysis of PCr into Cr + Pi can be used as a buffer to resynthesize ATP (since ATP is degraded into ADP and Pi to provide free energy for metabolic activity during exercise) This helps maintain ATP availability particularly during maximal effort anaerobic sprint-type exercise

Summarize supplementation protocol of creatine

The most effective way to increase muscle creatine stores is to ingest 5 g of creatine mono-hydrate (or approximately 0.3 g/kg body weight) four times daily for 5-7 days Once muscle creatine stores are fully saturated, creatine stores can generally be maintained by ingesting 3-5 g/day, although some studies indicate that larger athletes may need to ingest as much as 5-10 g/day in order to maintain creatine stores

Which group have been reported to have lower intramuscular creatine stores? (hint: think of main dietary source of creatine)

Vegetarians Vegetarians have lower intramuscular creatine stores compared to others (90-110 mmol/kg of dry muscle vs 160 mmol/kg of dry muscle in non-vegetarians) --> vegetarians observe greater gains in muscle creatine from creatine supplementation

Overall effect of creatine supplementation in athletes

Creatine supplementation increases intramuscular creatine concentrations --> can improve exercise performance, and/or improve training adaptations. Creatine supplementation may also enhance post-exercise recovery, injury prevention, thermoregulation, rehabilitation, and concussion and/or spinal cord neuroprotection.

What is creatine?

Creatine, a member of the guanidine phosphagen family, is a naturally occurring non-protein amino acid compound