week2 theory powerpoint: energy systems

7/28/2019 Week2 Theory PowerPoint: Energy Systems

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Energy is created by three main nutrients beingbroken down within the body. These nutrients arereferred to as energy nutrients.

Fats, Carbohydrates and Proteins.

The body collects these nutrients directly througheating plants that photosynthesise and indirectlythrough the animals that eat the plants.

Food travels through to our stomach when consumed,and through our intestines where it is digested.

The body digests food and stores nutrientsthroughout the body.


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The primary energy source for the body. Found in foods such as pasta, bread, fruits and

cereals. When eaten, carbohydrates are broken down into

glucose and transported via the blood to the muscles

for energy release. If this energy is not used immediately, it is stored as

Glycogen in the skeletal muscle. Once stored in themuscle, it can only be used by that specific musclegroup.

If muscle groups are full with glycogen, it istransported back to the liver and stored.

Excess glycogen is stored as triglycerides (fat) inadipose tissue.


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Fats are found in foods such as fatty meats, fastfoods, butter and nuts.

This is the secondary source in the body after

carbohydrates. After consumption, fats are digested into free

fatty acids for transport around the body via thebloodstream. They are stored in the body astriglycerides in skeletal muscle and adiposetissue.

Need oxygen to be broken down.


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Found in food sources such as meat, fish,eggs and milk.

Primarily used for growth and repair of thebody.

Proteins are only used in extremecircumstances for example starvation, whenall the carbohydrate and fat stores aredepleted.


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Energy stores are not used immediately tocreate energy, but are used to rebuild ATP.

ATP is an energy rich molecule which consistsof 1 Adenosine molecule and 3 Phosphatemolecules.

When a phosphate molecule releases fromATP, energy is created. Leaving Adenosine

Diphosphate. Energy from food sources is utilised, ADP+P

can be resynthesised to create ATP.


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A-P-P-P

AdenosineTriphosphate

A-P-P (+P)

AdenosineDiphosphate +

Phosphate

Food Energy

CarbohydratesFats

Proteins

Energy released

Muscular contractionDigestion

Nerve Transmission


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Carbohydrates and Fats are the main fuelsources used to supply energy demands butwhich is more dominant is dependant on the

exercise duration and intensity. Fats can only be broken down to resynthesise

ATP in a process which requires oxygen calledaerobic lipolysis.

Carbohydrates are broken down aerobically in aprocess called aerobic glycolysis or withoutoxygen in a process called anaerobic glycolysis.


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As intensity increases, the body will rely oncarbohydrates for a fuel source.

This is because carbohydrates require

considerably less work to be broken down andare therefore dominant during high intensityexercise.

As duration increases, the body will rely on fatsfor a fuel source.

This is because fats require oxygen to be brokendown. Therefore fats tend to be more dominantduring low intensity, long duration exercises.


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The bodys preferred fuel source is glycogen. However once the bodys glycogen stores are

depleted, athletes must rely upon fats as a fuelsource. As fats require oxygen to be broken down, this

creates harder work for the athlete. Athletes at this stage will notice their performancelevel drop significantly, they will lose concentrationand appear disorientated this is called Hitting thewall.

In any event lasting longer than 90 minutes, theexhaustion of glycogen is a limiting factor forathletes.

Glycogen stores can be manipulated through trainingand diet.


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There are three energy systems within thehuman body

ATP-CP system or Creatine Phosphatesystem Lactic acid system or Anaerobic system

(without oxygen) Oxygen system or Aerobic system (with

oxygen).


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First energy systemused.

The body has limitedstores and the use isrestricted. This system

will last 0-10seconds ofcontractions duringexercise.

Maximal or sprintexercise.

Once depleted thissystem can be restored50% after 30 secondsof rest. 100% restoredin 3 minutes.

A-P-P-P


A-P-P(+P)


Phosphate

C-PCreatinePhosphate

ENERGY + C + P


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Glycogen is broken down into

pyruvic acid which produces

enough energy to resynthesise

2 ATP molecules.

Without enough oxygenpyruvic acid creates a by-

product called lactic acid which

causes muscle failure as it

accumulates.

This is called anaerobicglycolysis.

Provides short term energy

and is dominant in activities

lasting 20-90 seconds of

maximal intensity.

A-P-P-P


A-P-P(+P)


Phosphate

Glycogen

ENERGY

PyruvicAcid

LacticAcid

NOOXYGEN


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A-P-P-PAdenosine

Triphosphate

A-P-P (+P)


Phosphate

Glycogen

ENERGY

Pyruvic AcidLactic Acid

NOOXYGEN

2 ATP

ENERGY

Glycogen

Pyruvic Acid

OXYGE

N

Krebs

Cycle

36 ATP


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Starts similar to the lactic acid system only whensufficient oxygen is delivered the pyruvic acid isfurther broken down into CO2 and H2O andresynthesises 36 ATP molecules.

Dominant in sub-maximal activities lasting morethan 2-3minutes

It takes a person 3-5 minutes to reach theirsteady state the state in which their oxygen

demands are met by sufficient oxygenconsumption. No by-products but exercise lasting more than 1-

2hours will result in depletion of glycogen storeswhich may take 24-48hours to replenish.


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The maximum volume of oxygen consumed bythe body for energy production the momentwhere oxygen intake peaks despite increase ofenergy expenditure.

Express in relative VO2 Max in millilitres perkilogram of body weight because of the size ofthe athlete.

Important indicator for a persons capacity to

resynthesise ATP. VO2 Max can only be achieved through the

dominant use of anaerobic glycolysis.


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The maximum intensity of a persons steady statewhich can be sustained without the accumulation oflactic acid is called the anaerobic threshold.

Anaerobic threshold is also know as OBLA (onset ofblood lactic acid). This determines the maximum exercise intensity they

can maintain for an extended period of time withoutfeeling the fatigued effects of lactic acidaccumulation.

The period where they body is desperately trying tocatch up to the oxygen demands of the body is calledoxygen deficit.


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Once the exercise activity is finish, recoverybegins immediately.

Oxygen consumption will remain high afterexercise to allow the body to return to pre-exercise levels oxygen debt.

EPOC is a result of replenishing of ATP-CPstores, removal of lactic acid, increased activity

of the heart and respiratory muscles, restorationof myoglobin and haemoglobin oxygen supplies,release of hormones during exercise and theincrease of core temperature.


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EPOC Alactacid component restoration of ATP-CPand replenishment of O2 for myoglobin andsurrounding tissues. Approx. 2-3 minutes in total.

EPOC Lactacid component the removal of lactic acidand slight glycogen replenishment. The removal of

lactic acid may take up to 90 minutes for full recovery. Both processes occur immediately and simultaneously

after exercise. Continuous activity post-exercise at approx. 50-65%

VO2 Max will: speed up the removal of lactic acid,

prevent blood pooling, allow skeletal muscles tooxididse some of the lactic acid for more energy andkeeps blood circulating through the liver to covertlactic acid back to glycogen. This is called and warmdown.

week2 theory powerpoint: energy systems

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