Download 4. Energy continuum

Section A: Exercise and Sport
Physiology
4. Energy continuum
Syllabus
• The predominant energy system used related
to:
– The type of exercise
– The interchanging between thresholds during an
activity
• The effect of the level of fitness, availability of
oxygen and food fuels, and enzyme control on
energy system used
Training Effects
• ATP-PC System
• Anaerobic training OVERLOADS the system
• Increases the stores of ATP and PC
• Delays the threshold between ATP-PC and
Lactic Acid system
Training Effects
• Lactic Acid System
•
•
•
•
Anaerobic training OVERLOADS the system
Increased tolerance to Lactic Acid
Increases store of glycogen
Prolongs lactic acid threshold
Training Effects
• Aerobic System
•
•
•
•
•
Aerobic training
Raised storage of glycogen
Increased enzyme mobilisation
Earlier use of FFAs
Prolongs aerobic threshold
• Helps delay muscle fatigue by:
– Increasing intensity of work before lactic acid too high
– Faster removal of lactic acid in recovery
A threshold is the point at which one energy system is taken over
by another as the predominant system for ATP resynthesis
Factors Affecting the Energy Systems
Used
• Intensity of exercise
• Duration of exercise
• Onset of Blood Lactate Accumulation (OBLA)
• Oxygen availability
• Fitness level
• Enzyme activation level
OBLA
• Higher intensity exercise
• Lactic acid accumulates above resting levels
• 4mmol/L
• Reach this figure the production of LA exceeds the
speed of removal
• If intensity of exercise maintained
– Lowering blood pH
– Inhibit enzyme activity
– Muscle fatigue / pain
Oxygen availability
• If sufficient supply of oxygen present – aerobic
• If oxygen supply falls then aerobic threshold
met and LA system breaks down glucose
anaerobically
• High int/Short dur = glucose broken down
• Low int/ Long dur = FFAs and glucose broken
down
Enzyme Activation Level
ACTIVATING FACTOR
ENZYME
ENERGY SYSTEM
Increase in ADP
Creatine Kinase
PC
Decrease in PC
PFK
LA system
Increase in adrenalin
Decrease in insulin
PFK
Aerobic
Fitness Level
• All to do with altering THRESHOLD
• Aerobically fit
–
–
–
–
Use FFA earlier and conserve Glycogen
OBLA delayed
Untrained reach this point at 50% of VO2 max
Trained reach this point at 85% of VO2 max
• Anaerobically fit
– Increase threshold of both ATP-PC / LA systems
– Increase fuel store and tolerance