Chapter 5 Aerobic and anaerobic pathways- an introduction to energy systems VCE Physical Education - Unit 3

Chapter 5Aerobic and anaerobic pathways- an introduction to energy systems

VCE Physical Education - Unit 3

Glossary Words

Glycogen InsulinPancreasEnzymesLactate inflection point (LIP)Steady stateExcess post exercise oxygen consumption (EPOC)


Foods, fuels and energy systems

FUEL SOURCESThere are three fuel sources:ATP: Already stored in the muscles

Phosphate Creatine (PC/CP)Carbohydrates=Glucose (stored in our muscles

and liver)Fats=Free fatty acids(FFAs) (Adipose tissue)Protein (in extreme circumstances)=Amino

acids (muscles)


At restFuel sources at rest clearly show that fats are

our preference over carbohydrates.


FOODS AS ENERGY SOURCES

PHOSPHATE CREATINE = chemical substrate

6-10 sec worthStored in musclesRapid energy for high/max intensity<1 ATP per PC molecule


CARBOHYDRATESReferred to as glucose in the blood, glycogen

in the musclesCan be used both aerobically and

anaerobicallyStored in the musclesFew chemical reactions to break downAnaerobically = can produce 2-3 ATPAerobically = can produce 38 ATP


Carbohydrate ContributionsIntake of Carbohydrates depends on the intensity and duration of exercise.Normal contribution to diet is 55-60% CHOCarbohydrate loading (80% CHO intake) is used to endurance activities.

Carbohydrate rich diet;Increases glycogen storesCHO preferred fuel over fats during exercise due to requiring less oxygen to release energy.


Adenosine Triphosphate (ATP) Our mechanical energy required for muscular contractions, require the chemical breakdown of the ATP molecule (Forms ADP).Our ATP stores are very limited, therefore it must continually be rebuilt through a fuel source.Fuel stores assist in rejoining the split molecule So the breakdown of ATP releases energy for muscular contraction


ATPCopy Diagram


GETS BROKEN DOWN TO=

FATSStored as triglycerides and break down into

free fatty acids (FFA)Only aerobic1st fuel source at rest due to high oxygen

available, and low energy demandUsed when glycogen stores are depleted,

approx. 1.5-2hrs1 fat molecule = 44 ATP produced


Why is CHO preferred?Lower oxygen used to breakdown fuel.

Therefore more oxygen available for energy production

Fats use more oxygen to breakdown triglycerides into (Free fatty acids)FFA = lower oxygen to muscles to create ATP.


FOOD Fuel Maximum energy (ATP per molecule)

Carbohydrates 36Fats 441

Protein ContributionsRole of protein (Amino

acids) in the body; Growth and repair Speed up reactions in

the body (Enzymes) Produces hormones

and antibodies

Protein and exercise1. Only used in extreme

circumstances2. Normal diet contains

enough protein (15%).


Glycemic Index (GI)Glycemic index;Rating of CHO effect on blood glucoseQuick breakdown with immediate effect on blood glucose levels are labelled high GI Slow breakdown are labelled low GI

Before exercise you should eat;Food that maintains blood glucose levels ie.low GI foodAvoid high GI food prior to exercise.High GI cause an insulin surge, effecting the performance of an athlete


http://www.glycemicindex.com/


Food Fuels in the Body and Recommended Dietary IntakeFood Fuel Store

d AsSite(s) The proportions

of essential nutrients contained in a balanced diet

Example foods

Carbohydrates

High GI:Low GI:

Fat

Protein


COMPUTER ACTIVITYAnswers on next slide


PEAK PERFORMANCE ACTIVITYTTT Page 48Chapter 3 Activity ManualAll multiple choice


The Three Energy SystemsThe systems used to resynthesis of ATP depend on a number of factors including;DurationIntensityIf oxygen is presentAvailability and restoration of chemical/food fuels

Systems and their names1. ATP-PC Energy

System2. Anaerobic Glycolysis-

must be called Anaerobic Glycolysis in year 12 (Lactic Acid (LA))

3. Aerobic Energy System

The three energy systems do not function independently or one at a time, but work together via the process of interplay to supply energy and rebuild ATP.


All Systems Go Again VideoShow video clip from “All Systems Go Again”

and answer worksheetShow Inside our muscles Show Anaerobic Energy Systems

http://www.youtube.com/watch?v=5G8cVpXpsL8





The ATP-PC System Quickest systemBreaks down phosphocreatine (PC) to form ATP anaerobically.However, PC stores require time to replenish.Dominant system for the first 10 seconds of maximum intensity exercise (95% max HR)Used in fast, powerful movements.

How does the system work?PC releases a free phosphate

PC = P + C ADP + P = ATP



Anaerobic Glycolysis SystemThe anaerobic glycolysis system;Activated at the start of intense exerciseMakes ATP quickly. It is the dominant provider of ATP from 5-60 seconds during an event. It reaches peak power between 5-15 seconds in maximal activities.More complex reactions than the ATP-PC systemProvides twice as much energy for ATP resynthesis than the ATP-PC system.


How the system works;Stored glycogen in the muscle is converted to glucoseA series of chemical reactions occurs & glucose is converted to pyruvic acid.When insufficient O2 is available, pyruvic acid converts to lactic acid. It is an increase in H+ ions which causes fatigue


TEST YOUR UDERSTANDINGRead page 51-52 ‘Summary of the ‘Anaerobic

glycolysis’ Answer the following question in your

workbooksList 4 sports that are predominantly powered by

anaerobic glycolysis? Make sure you include the value of the sport for example 200m sprint.

Answer on next slide


AnswerAnswer: 200m sprint. 100m swim, 500m kayak and

consecutive sprints in intermittent sports such as netball, football, basketball, squash, hockey and water polo



The Aerobic SystemThe aerobic systemSlowest contributor to ATP resynthesisProduces much more energy than the anaerobic systemsBecomes major contributor once anaerobic glycolysis decreases.Major contributor in prolonged exercise eg. Endurance events.Aerobic system does contribute in maximal intensity exercise (Eg. Between 55-65% in 800m)


How the system works;1. CHOs and Tryglycerides (FFA + glycerol)

broken down to release energy. This produces pyruvic acid.

2. When oxygen is present, Pyruvic acid is further broken down in the Kreb’s cycle producing by-products of carbon dioxide, heat and water.



Energy and Types of Physical Activities

Each physical activity or sport you undertake requires a different energy system…

Track Events and their use of Aerobic Respiration

Basketball players use both systems

Some use mainly aerobic respiration. Others use mainly anaerobic respiration. Most use a combination of the two.

EventPercentage of

Aerobic Respiration

Less than 1%100 m10%200 m20%400 m50%800 m60%1,500 m83%5,000 m95%10,000 m

100%Marathon

The relationship between energy systems and fitness

componentsCopy figure 3.7 page 54



Energy Demands - Intensity

Low intensityATP requirements are met aerobically using the aerobic system.High IntensityExplosive movements require instant supply of ATP which can’t be met aerobically, therefore the ATP-PC and anaerobic glycolysis systems need to be used anaerobically.


Aerobic

Anaerobic

Interplay Between Energy SystemsAll energy systems start at the same point, but each system will peak at different times.All activities use some energy from all three systems.The energy systems overlap – they never work independently.It it’s the relative contribution of each system that varies.


Interplay tableGo back and fill-in the energy system column

on the table with food fuel, duration, intensity and enegy system used.

Answers next slide



Documents

Chapter 5 Aerobic and anaerobic pathways- an introduction to energy systems VCE Physical Education - Unit 3