P Cr System Flashcards
ATP Hydrolysis
ATP + H20
↓
ADP + Pi + energy + H+
Limited ATP supply in body
80- 100 g in entire body
Energy sources to synthesize ATP
1) ATP PCr System
2) Adenylate kinase (myokinase)
3) Anaerobic glycolysis
4) Aerobic metabolism- GTP
ATP PCr System Power and Capacity
Power = less than 5-8 seconds
Capacity = 8-12 seconds
Peak muscular force and power = less than 1-2 seconds
Training Adaptations to increase ATP PCr System
1) Increase enzyme activity
- Myokinase (20%)
- ATPase (30%)
- creatine kinase (30-55%)
To increase POWER
2) Increase PCr (40%) (cannot increase ATP stores as much)
To increase Capacity
Creatine Loading
Ingesting Cr increases muscular stores of Cr
Consequently PCr
Effects of Cr Supplementation
1) Increases PCr availability to increase capacity
2) Less reliant on glycolytic system = less cellular acidosis
3) Pulls water into cell to increase protein synthesis
4) Increase PCr resynthesis
Creatine Loading and exercise performance
1) Increase a bout of strength / power
2) Increase ability to repeat performance
HOW TO creatine load
Load
Maintain
Stop
Short term Effects of Creatine Loading
1) Increase in muscle mass due to WATER retention
2) No muscle hypertrophy
3) Increase in Cr NOT PCr
4) Ability to repeat performance increases
Long term effects of Creatine supplementation
1) Increase in FFM
2) Increase area in all fiber types
3) Increase in strength
Physiological Changes due to LONG term creatine supplementation
1) No direct relationship between Cr and muscle hypertrophy
- may be due to activation of satellite cells or stretch induced protein synthesis
2) May be able to train at higher intensity
3) No change in aerobic endurance
Side Effects of Cr Supplementaion
1) Increase in body mass
2) GI pain
3) Stress on liver and kidneys
4) Supression of Natural Cr
5) cytotoxic cross linking of DNA
