Energy Systems

Aerobic System

Two Energy Systems

1. Aerobic– An energy system which is used in

prolonged continuous activity in the presence of oxygen and does not produce lactic acid.

2. Anaerobic– Energy systems that do not rely on the

immediate use of oxygen. There are two types of anaerobic energy systems.

3 Metabolic PathwaysAnaerobic Alactic (ATP-CP) or (ATP-PC)

Anaerobic Lactic (glycolysis)

Aerobic (cellular respiration)• A slow twitch muscle energy system which

is used in prolonged continuous activity in the presence of oxygen and does not produce lactic acid.

The Aerobic System: Long-Term Energy

• Exercise performed at a ______________level relies almost exclusively on the aerobic system for energy production and requires the athlete to use ____________ as its source of energy.o Most daily activities use energy provided by the

aerobic energy systemo The _________________________is the most important

energy system in the body.

• While this pathway cannot generate the speed of the anaerobic, it does provide a great deal more _____________________________________.

• Formula:

Key Nutrients• Remember your Fats, Proteins and Carbs

because they are crucial for the fuel for the aerobic system

The Aerobic System (Cellular Respiration)

• The aerobic system energy requires the metabolism of

Glucose(Glycogen)

FatsProteins

Oxygen

Combine to produce

ADP + P ATPADP + P ATP

Using energy produces

ENERGYENERGY

CO2 Water

Cellular Respiration

• Involves 3 separate pathways– Glycolysis– Kreb’s Cycle– Electron Transport Chain

Sub-Pathways – Cellular Respiration

Glycolysis – • first stage • Same as anaerobic lactic system (see previous

lesson)

Where Glycolysis changes with the Aerobic Systems:

• in the presence of oxygen, ________________is converted to ________________ (co-enzyme) – (rather than ___________________– No lactic acid produced with aerobic at this time

• acetyl CoA then enters a more complicated pathway known as the ____________________

Kreb’s Cycle- • Central pathway for the metabolism

of ____ and ____________ • series of __ reactions, __ ATP

molecules are produced at this stage, along with new compounds

• capable of storing ____________________

• high energy electrons are sent to a process within the _________________,

known as, the ______________________________

Electron Transport Chain-• During the final stage of aerobic

respiration, ______________________are produced,

• Electrons pass down the chain, highly reactive molecules (free radicals) are by-products – these molecules may be a contributor

to long-term muscle fatigue

ATP Produced

Energy System ATPGlycolysisKreb’s CycleElectron Transport ChainTotal

Aerobic Power: VO2maxOxygen uptake• The power of the aerobic system is

generally evaluated by measuring the maximum volume of oxygen that can be consumed in a given amount of time. – This can be measured by determining the

amount of oxygen exhaled as compared to the amount inhaled.

• As the intensity of work increases the capacity of aerobic system reaches a maximum. – You can only breath in and out so much

• The greatest rate at which oxygen (volume) can be taken in and used during exercise is referred to ____________________________or (___________)

Aerobic Power VO2Max

Each person has his or her own maximal rate of oxygen consumption (VO2 max).

•

• A normal VO2 max for most high school athletes would fall somewhere between

• The VO2 max values of trained athletes will reach

The more active we are the higher the VO2 max will be in that

range.

The Effect of Training on the Aerobic System

A person’s ability to perform an activity is limited by their maximal rate of oxygen consumption (VO2 Max). The most efficient method for improving the aerobic energy system is endurance training/exercise.

Long, slow distance training or exercise at the low end of your _________________tends to use slow twitch (ST) fibres. ST fibres are slower to fatigue and are well suited for endurance activities.

The Effect of Training on the Aerobic System

Endurance exercise consists of

Generally, the higher the intensity, the greater the oxygen consumption. When exercising the target heart rate (THR) should be raised to 70% of max.

Finding your Target Heart Rate

The Effect of Training on the Aerobic System Con’t

Examples include: running, swimming or biking for 40 minutes or more at a heart rate of 130-140 bpm

Note: A highly trained or elite athlete should be able to sustain a heart rate of 85% of their VO2 max. This type of training does not raise your anaerobic threshold.

Endurance training has four major effects on the aerobic system:

Characteristics of the Aerobic System

The oxygen system is highly efficient. When oxygen is used in muscle cells:– it prevents the build-up of _______________– an individual can work out longer before

_______________________________________– it is able to remove lactic acid from

muscles allowing the muscle to continue to contract allowing exercise to continue

– it promotes _________________of ATP for energy when work output is low.

Characteristics of the Aerobic System

As the duration of activity increases, the contribution of the aerobic system to the total energy requirement increases.

Due to this, there are two limitations to the aerobic system:

Using The Systems Together

While running at a comfortable pace you use both systems, butthe anaerobic: aerobic ratio is low enough that the lactategenerated is easily removed, and doesn't build up.

As the pace is increased, eventually a point is reached where the production of lactate, by the anaerobic system, is greater than its removal (anaerobic threshold).

Note: Depending upon the distance, and effort,the body can use different proportions ofboth of these systems. For example, the 800mrace is too long to be a sprint, but tooshort to be a distance race. Therefore, it isrun at the cross-over between the aerobicand anaerobic systems.

The best method to train all of the systems together is __________________. Interval work consists of repeating a series of short, high intensity, runs alternating with rest (recovery) periods.

Whichever method is used, the athlete must continually push themselves into a lactate burdened state which makes their body adapt. Regardless of the race distance you are training for, 5k or marathon, interval work will help you run faster.

Training The Systems TogetherTraining The Systems Together

Summary - The Energy Systems

• Energy for muscular activity depends on

a supply of ATP that can be broken down

into ADP and phosphate

• All of the body’s biochemical processes

and the three energy systems require ATP

• Trained individuals are able to use ATP

and remove lactic acid more efficiently

than untrained individuals

Roles of the Three EnergySystems in Competitive Sport

Anaerobic PathwaysAnaerobic Pathways Aerobic PathwaysAerobic Pathways

Primary Primary Energy Energy SourceSource

Energy Energy SystemSystem

FuelFuel

DurationDuration

Sport Sport EventEvent

                                                                                                                                                

                                                                                                                                                                                                                                                                                                                                            

ATP - CP System

Glycolytic System

Aerobic System

When the systems are used

Feel the burn!