Module 13: Energy systems

The Body in Action

1. Energy introduction
2. Adenosine triphosphate (ATP)
3. Energy systems
   1. Phosphocreatine system
   2. Lactic acid system (anaerobic glycolysis)
   3. Aerobic system
4. Energy systems activity
5. Energy continuum
6. Energy continuum activity

Energy continuum

All three energy systems are operational at any one time. The interaction of these can be seen in the graph below:

[D]

The duration and intensity of the activity will determine which the predominant system is. For example, a 1500metre race represents a mixture of energy systems used when the athlete kicks at the start and finish of a race the phosphocreatine system will be used. During the race there will be a mixture of the lactic acid and aerobic system depending on the time taken to run the distance.

For some activities it is easy to decide which energy systems are involved to produce energy, for example, a marathon probably uses 95-100% of the energy from the aerobic system.

A basketball game is usually accepted as roughly 80% anaerobic, but this depends on several factors, such as:

- The fitness of the player

- The standard of the game

- The tactics being employed

- The commitment of the players.

It is important to identify the role of each energy system in relation to the sport/position the athlete takes part in. This can calculate the total energy requirement for that activity. Knowledge of how the intensity and duration of exercise affects the source of energy, along with how each system is regulated is therefore very important.