Creatine Supplementation

1
Creatine Supplementation
2
What is Creatine?

• Naturally occurring constituent found in food
• Also synthesized in the kidneys, liver, and
  pancreas from amino acids arginine, glycine, and
  methionine.

3
Where is Creatine Found?

• Creatine is a naturally occurring amino acid
  found in the body (primarily muscle tissue)
• The daily requirement of creatine is about 2-3
  grams/day
• About half of the daily needs are obtained from
  the diet (primarily meat and fish)
• The remaining daily need for creatine is
  synthesized from the amino acids glycine,
  arginine, and methionine primarily in the liver

4
(No Transcript)
5
Creatine Stores

• Normal creatine content in muscle tissue is
  120-140 mmol/kg dm (60 as PCr, 40 as Cr)
• Dietary availability of creatine may result in
  higher or lower stores
• Creatine supplementation can increase creatine
  stores to as much as 160 mmol/kg dm

6
Forms of Creatine Supplements

• Creatine Monohydrate Most Common
• Creatine Phosphate
• Creatine Citrate
• Creatine blended w/CHO, Proteins, AA, Caffeine
• Powders
• Tablets
• Gel
• Liquid

7
Supplement Strategies

• Load 20 g/day (4 equal doses 5g) - 5-7 days
• Increase TCr stores approx. 20 (Grande)
• Maintain 3-5 g/day (0.03 g/kg)
• Others recommend 2-3g/day over longer load period
  (1mo.)- just as effective

8
Factors Affecting Cr Loading Success

• Cr w/ CHO (glucose) Insulin Effect
• Studies shown 60 greater increase in TCr stores
  over Cr only
• Ingestion following exercise is best
• Greatest increase occur in those with lowest
  initial levels
• There are responders and non-responders (20-30)
• Best response is in Type II muscle.
• No differences between genders

9
Documented Side Effects

• Potential side effects are minor
• Gastrointestinal (GI) distress
• No renal or liver dysfunction
• No cramping in controlled studies
• Increased Body Mass (water retention in muscle
  cell due to osmotic changes)
• Urinary Volume decrease during loading

10
Creatine Enhancing Performance
11
Function of Creatine

• The body only has limited stores of ATP ADP
• When a Cr supplement is ingested, enters the
  intestines, a majority of Cr is absorbed into the
  bloodstream.
• Cr from bloodstream is taken up by skeletal and
  cardiac muscle through insulin-mediated active
  transport

12
Function of Creatine (cont.)

• After absorption, a portion of Cr combines with
  phosphate to form PCr
• This storage of Cr and PCr allows rapid
  resynthesis of ATP to meet energy demands via the
  creatine kinase (CK) reaction
• Theoretically, Cr supplementation will increase
  Cr and PCr stores, providing more PCr to be
  utilized in CK reactions

13
History of Cr Supplementation

• Soviets and Eastern block countries began using
  Cr as potential performance (1960s 70s)
• First real studies of Cr supplementation for
  performance enhancement began in 1990s in US and
  GB
• GB Olympic Champions Linford Christie (100m) and
  Sally Gunnell (400 hurdles) - 1992 Barcelona games

14
Mechanisms of Performance Enhancement

• Increased PCr concentrations in muscle should aid
  in rapid resynthesis of ATP via the Cr kinase
  reaction
• Increases PCr diffusion between mitochondria and
  myosin heads.
• Reduce muscle acidity by consuming H in process
  of ADP-ATP
• Muscle can accumulate more lactic acid before
  reaching limiting muscle pH Increase duration
  of high intensity exercise

15
Mechanisms of Performance Enhancement

• Causes osmotic changes in muscle cell which
  increases water content of cell
• Stimulus for protein synthesis
• Decreases rate of protein degradation
• Facilitates calcium uptake by the sarcoplasmic
  reticulum which shortens relaxation time.

16
Does IT Work?

• High intensity, short duration activities lasting
  lt 2 min especially repeated with short rest
  periods
• Sprints, jumps, weight lifting, sprinting, etc.

17
Does It Work? (cont.)

• No effect in continuous aerobic activities
• Effective in both genders
• Effective in young and old.
• Effectiveness is greatest in novice athletes.