Energy systems

Energy SystemsEnergy Systems

And physical activity…And physical activity…

EnergyEnergy

The body needs energy for basic The body needs energy for basic bodily functions and activity during bodily functions and activity during your whole life.your whole life.

This includes breathing, sleeping, This includes breathing, sleeping, digesting, sitting in a chair, sprinting digesting, sitting in a chair, sprinting for a bus, and everything else you do for a bus, and everything else you do day and night.day and night.

Adeonsine Triphosphate (ATP)Adeonsine Triphosphate (ATP)

A chemical compound.A chemical compound.

Is the energy source for all muscular Is the energy source for all muscular effort.effort.

Sources of ATP: Carbohydrate, fat Sources of ATP: Carbohydrate, fat and protein.and protein.

CarbohydrateCarbohydrate

When digested is broken down to When digested is broken down to glucose and stored as glycogen in glucose and stored as glycogen in the muscles and liver.the muscles and liver.

Glycogen can provide the energy for Glycogen can provide the energy for ATP production under both anaerobic ATP production under both anaerobic (no oxygen required) and aerobic (no oxygen required) and aerobic (oxygen required) conditions.(oxygen required) conditions.

FatFat

Major source of energy for long term Major source of energy for long term activity.activity.

Is used to meet sub-maximal energy Is used to meet sub-maximal energy demands.demands.

During rest conditions, fat produces During rest conditions, fat produces the majority of the required ATP.the majority of the required ATP.

ProteinProtein

Only minimally contributes to ATP Only minimally contributes to ATP production.production.

Is only used in severe circumstances Is only used in severe circumstances (such as a marathon or starvation) (such as a marathon or starvation) when the body has severely depleted when the body has severely depleted it’s supplies of carbohydrate and fat.it’s supplies of carbohydrate and fat.

Energy from ATPEnergy from ATPATP is stored in limited quantities in the muscle, ATP is stored in limited quantities in the muscle, so each muscle fibre must be able to create it’s so each muscle fibre must be able to create it’s own from the food fuels.own from the food fuels.ATP is an adenosine molecule with three ATP is an adenosine molecule with three phosphate molecules attached.phosphate molecules attached.For release of energy, one phosphate molecule For release of energy, one phosphate molecule breaks off, releasing energy and creating breaks off, releasing energy and creating adenosine diphospate (ADP).adenosine diphospate (ADP).As long as there are sufficient energy substrate As long as there are sufficient energy substrate this process can be reversed with the use of food this process can be reversed with the use of food fuels and ATP is rebuilt with the addition of fuels and ATP is rebuilt with the addition of another phosphate molecule. another phosphate molecule.

Three Energy SystemsThree Energy SystemsPhosphate, Anaerobic Glycolysis and Phosphate, Anaerobic Glycolysis and Aerobic EnergyAerobic Energy

All three pathways operate at one All three pathways operate at one time.time.

The contribution of each varies The contribution of each varies depending on the intensity of the depending on the intensity of the activity.activity.

Phosphate Energy SystemPhosphate Energy System

Provides the bulk of ATP during Provides the bulk of ATP during powerful or explosive efforts.powerful or explosive efforts.

May be a once off movement such as May be a once off movement such as jumping or ongoing such as a 100m jumping or ongoing such as a 100m sprint.sprint.

Lasts for about 10 seconds of Lasts for about 10 seconds of maximal effort.maximal effort.

Anaerobic Glycolysis SystemAnaerobic Glycolysis System

Also known as the Lactic Acid Also known as the Lactic Acid System.System.

Provides energy in high intensity, sub Provides energy in high intensity, sub maximal efforts.maximal efforts.

Muscle stores of glycogen are broken Muscle stores of glycogen are broken down to resynthesise ADP.down to resynthesise ADP.

Lasts from around 10 seconds until Lasts from around 10 seconds until 60 seconds of exercise.60 seconds of exercise.

Aerobic Energy SystemAerobic Energy SystemAlso known as aerobic glycolysis.Also known as aerobic glycolysis.Provides the bulk of energy for sub Provides the bulk of energy for sub maximal efforts and recovery.maximal efforts and recovery.Contributes to all activities from Contributes to all activities from about 1 minute onwards.about 1 minute onwards.Fat becomes a significant contributor Fat becomes a significant contributor to ATP production.to ATP production.Can operate for an unlimited work Can operate for an unlimited work period.period.

ATP production – different exertion ATP production – different exertion conditionsconditions

The length and intensity of physical The length and intensity of physical exertion determine which of the energy exertion determine which of the energy systems is dominant.systems is dominant.As activity time increases, the influence of As activity time increases, the influence of the aerobic system on ATP production also the aerobic system on ATP production also increases.increases.