7 Responses Energy Systems

Stored adenosine triphosphate (ATP)

Blood glucose

Glycogen

Fatty acids

To provide energy for long-duration activities

To supply immediate energy for short, explosive movements

To break down fatty acids for energy

To transport oxygen to muscles

Aerobic system

Lactate system

ATP-PC system

Fatty acid oxidation

Fatty acids

Blood glucose and muscle glycogen

Phosphocreatine

Oxygen

ATP-PC breakdown

Anaerobic glycolysis

Krebs cycle and electron transport chain

Phosphocreatine resynthesis

ATP-PC system

Lactate system

Creatine phosphate system

Aerobic system

2 ATP

4 ATP

38 ATP

1 ATP

The exclusive use of one energy system at a time

The sequential use of energy systems depending on exercise intensity and duration

The breakdown of only fats for energy

The use of only stored ATP

Onset of Blood Lactate Accumulation

Oxygen Balance Level Assessment

Output of Basal Lactic Acid

Overload of Blood Lactate Activity

2 mmol/L

4 mmol/L

6 mmol/L

8 mmol/L