Certificate IV in Fitness | Exercise Science Principles: Energy systems charts Page 1 of 2

The table below elaborates on the one above by adding specific details about each system such as:

intensity, duration, recovery, fuel source, limitations and waste.

Energy System Intensity of Exercise

Duration Recovery Time Fuel Source Limitations and Waste

Phosphocreatine (ATP-CP)

Very high 1-10 seconds 30 seconds to 2 minutes Creatine phosphate Small supply, no waste

Lactic acid Moderate to high

Up to 3 minutes 20 minutes to 2 hours Carbohydrate in the form of glycogen or glucose

Lactic acid

Aerobic

Low to moderate

3 minutes plus (can be endless with adequate fuel)

Time it takes to replace fuel stores

Carbohydrate, fat, protein Water and carbon dioxide

Certificate IV in Fitness | Exercise Science Principles: Energy systems charts Page 2 of 2

0-3sec

ATP

ATP + Creatine (10 Steps)

Pyruvate + ATP

ADP + CP Muscle and Blood

Glucose and Glycogen

Carbohydrate

Fat (Triglycerides)

Energy Systems

Anaerobic System Aerobic System

3-10sec 10-45sec 45sec-2min 2-3min 3min +

ATP

(muscle

stores)

Phosphagen System

(ATP-CP)

Glycolysis

Anaerobic (Fast) Glycolysis (without Oxygen) Aerobic (Slow) Glycolysis (with oxygen)

Oxidative

Phosphorylation

ATP

Protein (Amino Acids)

Glucose and

Glycogen

Blood Lactate

(Lactic Acid)

Krebs Cycle

in Mitochondrion

(Citric Acid Cycle)

(8 Steps)

Cori Cycle

(Liver)

ATP