1. Energy Transfer During Exercise
The Energy Systems

3. Energy Sources From Food: For Exercise: CHO = 4 kcal Fat = 9 kcal
Pro = 4 kcal
For Exercise:
ATP > ADP + P

4. Methods of Supplying ATP For Energy
Stored ATP
CP or ATP-CP
Anaerobic metabolism/glycolysis/lactic acid system
Aerobic metabolism

6. ATP-PC System Intramuscular phosphagens Short anaerobic
Uses stored ATP
Strength/power movements
Replenishes

7. Lactic Acid System Glycolytic Long anaerobic Burns glucose
Accumulates lactate at high intensities
Muscular endurance activities

8. Blood Lactate Threshold
Exercise intensity at the point of lactate buildup.
Predicts aerobic exercise performance.
Untrained ~ 55% of VO2 max.
Trained ~ 75% of VO2 max.

10. Aerobic System Oxidative Burns fatty acids Long-term energy
Better butter burner
Cardiorespiratory endurance activities

12. Energy Systems ATP-PC Glycolysis Beta Oxidation
Stored ATP allows for 3-5 sec. of activity
Breakdown of glucose – end result is pyruvate
Breakdown of triglyceride – yields ATP
ATP-PC used up in sec. of activity
Converted to lactic acid if anaerobic envir.
> Fat oxidation = better butter burner

13. The Energy-Time Continuum
As the work time increases, the percentage of energy contributed by the aerobic system increases.

17. Oxygen Uptake During Aerobic Exercise
Increases sharply at onset
Levels off within a few minutes if pace is constant (steady state)
Oxygen demand met by supply

19. Maximal Oxygen Uptake (VO2 max)
The region where oxygen uptake plateaus and does not increase despite an additional increase in exercise intensity.

21. Maximal Oxygen Uptake
Affected by body size: larger size means larger VO2 max.
Absolute oxygen uptake (ml.min.)
Relative oxygen uptake (ml.kg.min.)
Relative to body mass

22. Oxygen Deficit
Difference between oxygen consumed during exercise and amount that would have been consumed had a steady rate, aerobic metabolism occurred at onset of exercise.

23. Oxygen Deficit: Trained vs. Untrained
Trained reach steady rate quicker
Higher total oxygen consumption
Less reliance on anaerobic glycolysis
Lower deficit in trained individuals due to:
Earlier aerobic ATP production
Less lactate formation

25. Excess Post-Exercise Oxygen Consumption (EPOC)
Formerly called oxygen debt
Excess oxygen above the resting level in recovery
Most lactate does not synthesize into glycogen as originally thought
Heart, liver, kidneys, and skeletal muscle use lactate as energy substrate during recovery

26. Active Recovery for Heavy Exercise
Facilitates lactate removal because of:
increased perfusion of blood through the liver and heart
increased blood flow in muscles because muscle tissue oxidizes lactate during Krebs Cycle