The document discusses three energy systems: phosphocreatine, lactic acid, and aerobic. Phosphocreatine provides immediate energy from ATP without oxygen. The lactic acid system is used for high intensity exercise over a longer period through glycogen breakdown without oxygen. The aerobic system produces the most energy over long periods through oxygen-dependent pathways.

1. Energy Systems
• Phosphocreatine
• Lactic Acid System
• Aerobic energy System

2. Phosphocreatine
• We need energy for: muscular contractions
and movement, circulation, transmissions of
nerve impulses, digestion of foods and
repairing and replacing of tissues.
• The first law of thermodynamics, energy
cannot be created or destroyed.
• Phosphocreatine is an immediate energy
source.
• ATP made = 1

3. Lactic Acid System
• Used for high intensity exercise and for a
longer period of time.
• Uses glycogen stored in liver and muscles
• Made without oxygen
• Used towards the beginning of an exercise
• When intensity is higher than aerobic
• ATP made = 2 or 3

4. Aerobic Energy System
• Made over long period of time for lower
intensity of exercise
• Uses oxygen unlike the lactic acid system
• Used for exercises over a minute
• ATP made = 38 or 129