ATP-PCr system

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The Effects of Creatine
Supplementation on
Anaerobic Exercise
Performance
By: Nick Wall & Jeff Rothstein
Outline
• Physiological Introduction
• Effects of Creatine Supplementation
• Experiment results
– Performance
– Dosage
• Conclusion
Introduction
• Anaerobic exercise performance:
– Maintained for very short duration
– Muscular fatigue & exhaustion reached
– Energy requirement met by ATP
Introduction (cont.)
• ATP + ATPase (enzyme)  ADP + Pi +
energy
– ATP used for energy produces ADP
– PCr high energy molecule
• Used to regenerate ATP
– ATP and PCr limited in body
• Depleted quickly during anaerobic performance
• Limit affects duration
– PCr + ADP + H+  ATP + Cr
Introduction (cont.)
• 3 energy systems in the human body:
– ATP-PCr system
– Glycolytic system
– Oxidative system
ATP-PCr system
• Immediate fuel sources are ATP, PCr, and
ADP
• ADP is reformed into ATP by PCr or
another ADP molecule
• Creatine kinase breaks PCr into Pi and Cr
• Pi is paired with ADP forming new ATP
• Lasts 10-30 seconds
(Linderman, Redondo, Wilmore)
Glycolytic System
• Glucose found in blood and glycogen stored in
muscles or liver
– Converted to glucose-6-phosphate
• Anaerobic Glycolysis
– 12 enzymatic reactions
• Breakdown glycogen to lactic acid without oxygen
• Net gain - Glucose yields 2 ATP, Glycogen yields
3 ATP
• Lasts 20-120 seconds – high intensity exercise
Oxidative System
• 3 Processes to produce ATP:
– Aerobic glycolysis
– Krebs Cycle
– Electron Transport Chain
• Slow in producing ATP
• Tremendous energy-yielding capacity
• Used in endurance events
(Wilmore)
Creatine Supplementation
Effects on Body PCr
• PCr occurs naturally in the muscles of the body
• Creatine obtained through diet
(Chwalbinska-Moneta, Redondo)
PCr levels high?
– Increased levels of dietary creatine
• Increase levels of PCr in the muscles???
• Increase synthesis of ATP???
Creatine Supplementation
Effects on Body PCr
(cont.)
• Studies suggest creatine supplementation
– Increases levels of PCr in the muscles
(Burke, Hamilton, Mujika, Tarnopolsky)
– Increasing PCr in the body results in
• More ATP produced during high intensity exercise.
• Useful Force
– Increases in strength?
– Increases in speed?
• Creatine = ergogenic aid
(Hamilton, Ostojic, Redondo, Tarnopolsky)
Summary of Experiments
on Results
Forgot my creatine
this morning!
• Results vary proving creatine
as ergogenic aid
– Positive results for power
increase
– Delayed onset of fatigue
– Mixed results on increases of
speed
– Mixed results on decreased sprint
times
• Creatine proven effective
– Proper dosages
Low PCr = Low ATP = Less energy =
Slower start?
Summary (cont.)
• Tests performed
– Creatine increased power
– Creatine decreased fatigue
– Tests producing negative results
• Protocol durations too long
• Once exceeding immediate energy system
capabilities
– Non-oxidative system used primarily
» Doesn’t use PCr
Results
• Creatine supplementation
– Increase in PCr concentrations in muscles
– More PCr to re-synthesize ATP
– Dosage affects results
• 20g / day * 5-8 days
– Mixed results
• Appears high dosage for 5-8 days
– Enough time for muscles to increase PCr concentrations
• 7.7g / day * 21 days
– Significant increase in power
– Significant delay of fatigue
– Amount and time frame consumed main factor
Results
• Studies yielding no results
– Affected by dosage and/or duration
– Trained or not
– Most studies on athletes
• Different results compared to athlete vs. non-athlete
• Creatine might not affect the already trained individual
• Overall
– Supplementation needs to follow dosage and duration
– Protocol for testing must utilize immediate energy
system (>10-30 seconds)
Table of Results
Non-Performance Related
Findings
• Adverse Effects
– Protective effects
– Gastrointestinal disturbances
– Muscle cramps
– Liver and kidney dysfunction
– Well controlled studies almost nonexistent
(Poortmans)
Non-Performance Related
Findings
• Body Composition
– 28d period
• Used Phosphagen HP (creatine + glucose/taurine electrolyte
supplement)
• Body weight increased
• No differences in % of total body water
(Kreider)
– 42d period
• Body mass increased
– Not attributed to water retention
– Muscle growth
(Francaux)
Conclusion
• Muscle cells have 2 high energy
substrates
– ATP and PCr
– ATP fuels the working muscle
– Converted to ADP during use
– PCr converts ADP back to ATP
– Provides more immediate energy
• Immediate energy system
– First 10-30 seconds on maximal sprint
Conclusion (cont.)
• Short term use
– <6 days does not affect performance
• Dosage
– <20g during short term use results in no
change
– Most important factor
• >20g/day for more than 5 days provided results
• Low dose for long term provides results
Questions?
References
•
Burke, Darren G., Shawn Silver, Laurence E. Holt, Truis Smith-Palmer, Christopher J. Culligan, and Philip D.
Chilibeck. The Effect of Continuous Low Dose Creatine Supplementation on Force, Power, and Total Work.
International Journal of Sport Nutrition and Exercise Metabolism 2000; 10: 235-244
•
Burke, Louise M., David B. Pyne, and Richard D. Telford. Effect of Oral Creatine Supplementation on SingleEffort Sprint Performance in Elite Swimmers. International Journal of Sport Nutrition 1996; 6: 222-233
•
Chwalbinska-Moneta, Jolanta. Effect of Creatine Supplementation on Aerobic Performance and Anaerobic
Capacity in Elite Rowers in the Course of Endurance Training. International Journal of Sports Nutrition and
Exercise Metabolism 2003; 13: 173-183a
•
Delecluse, C, R. Diels, M. Goris. Effect of Creatine Supplementation on Intermittent Sprint Running
Performance in Highly Trained Athletes. Journal of Strength and Conditioning Research 2003; 17: 446-454
•
Francaux, Marc, J.R. Poortmans. Effect of Training and Creatine Supplement on Muscle Strength and Body
Mass. European Journal of Applied Physiology and Occupational Physiology 1999; 80: 165-168
•
Hamilton, Karyn L., Michael C. Meyers, William A. Skelly, and Robert J. Marley. Oral Creatine
Supplementation and Upper Extremity Anaerobic Response in Females. International Journal of Sport and
Exercise Metabolism 2000; 10: 277-289
•
Juhn, Mark S. Oral Creatine Supple-mentation: Separating Fact From Hype. The Physician and
Sportsmedicine 1999; 27: 47-61
•
Kreider, R.B, M. Ferreira, M. Wilson. Effects of Creatine Supplementation on Body Composition, Strength,
and Sprint Performance. Occupational Health and Industrial Medicine 1998; 38: 203
•
Hoffman, J.R, J.R. Stout, M.J. Falvo, J. Kang, N.A. Ratamess. Effect of Low-Dose, Short-Duration Creatine
Supplementation on Anaerobic Exercise Performance. Journal of Strength and Conditioning Research 2005;
19: 260-264
References (cont.)
•
Linderman, Jon K. and Kristin L. Gosselink. The Effects of Sodium Bicarbonate Ingestion of Exercise
Performance. Sports Medicine 1994; 18(2): 75-80
•
Maughan, Ronald J. Creatine Supple-mentation and Exercise Performance. International Journal of Sport
Nutrition 1995; 5: 94-101
•
Mujika, I., S. Padilla, J. Ibanez, M. Izquierdo, and E. Gorostiaga. Creatine supplementation and sprint
performance in soccer players. Medicine and Science in Sports and Exercise 2000; by American College of
Sports Medicine
•
Ostojic, Sergej M. Creatine Supple-mentation in Young Soccer Players. International Journal of Sport Nutrition
and Exercise Metabolism 2004; 14: 95-103
•
Poortmans, J.R, M. Francaux. Adverse Effects of Creatine Supplementation: Fact or Fiction? Sports Medicine
2000; 30: 155-170
•
Redondo, Diego R., Elizabeth A. Dowling, Bryan L. Graham, Anthony L. Almada, and Melvin H. Williams. The
Effect of Oral Creatine Monohydrate Supplementation on Running Velocity. International Journal of Sport Nutrition
1996; 6: 213-221
•
Tarnopolsky, Mark A. and Dan P. MacLennan. Creatine Monohydrate Supple-mentation Enhances High-Intensity
Exercise Performance in Males and Females. International Journal of Sport Nutrition and Exercise Metabolism
2000; 10: 452-463
•
Toler, Stephen M. Creatine Is an Ergogen for Anaerobic Exercise. Nutrition Reviews 1997; 55: 21-23
•
Wilmore, Jack H and David L. Costill. Physiology of Sport and Exercise. 2004: 122-130
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