1. Chapter 2 Fuel Sources & Exercise Metabolism

9. Table3.7 Major characteristics of the human energy systems
ATP-PCr
Lactic Acid
Oxygen
Main energy source
ATP, PCr
CHO
Fat
Intensity level
Highest
High
Lower
Lowest
Rate of ATP Production
Power
ATP Capacity
Low
Endurance Capacity
O2 Needed No
Yes
Track Event
100 m m
5,000 m
Ultra
Time
1-10 s s
>5 min
hours

10. Table 3.8 Percentage contribution of anaerobic and aerobic energy sources during different time periods of maximal work
Time
10 sec 1
min 2 4
10 min
30 min
50 min
130 min
Anaerobic
Aerobic 85 15 70 30 50 5 90 98 99

11. Energy Stores In the Average Man
Mass (lb)
Energy (kJ)
Energy (kcal)
Rx Time (Min)
Liver Glycogen
0.22
1,600
400 20
Muscle Glycogen
0.88
6,400 80
Blood Glucose
0.022
160 40 2
Fat 23
390,000
93,000
4,900
Protein
18.75
142,000
34,000
1,800

14. Some Possible Causes of Fatigue During Exercise
Increased formation of depressant neurotransmitters
Increased serotonin levels
Decreased levels of energy substrates
Phosphocreatine
Muscle glycogen
Blood-sugar level
Branched-chain amino acids

15. Fatigue Sites Cont’d Disturbed intracellular environment
Impaired calcium recycling
Disturbed acid-base balance
Increased H+ due to lactic acid
Decreased oxygen transport
Decreased blood volume due to dehydration
Increased core temperature
Decreased cooling due to dehydration
Disturbed electrolyte balance
Increased or decreased concentration due to sweat losses and H2O replacement