VCE PE

Exam Preparation 2

Food To Energy

VCE Physical Education - Unit 3

Food Fuels for Energy1. Carbohydrates (CHO) –

Preferred source of fuel during exercise (Glycogen)

2. Fat – Concentrated fuel used during rest and prolonged sub-maximal exercise.

3. Protein – Used for growth and repair (Negligible use during exercise)

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VCE Physical Education - Unit 3

Vitamins and Minerals

Vitamins assist: Point 3• Red Blood Cell Production• Tissue Repair• Protein SynthesisMinerals:Iron: Absorbed in the blood and assists in the

production of haemoglobinCalcium: Major component of bones and teeth. Plays

a part of muscle contraction and nerve transmission

Sports Nutrition

Pre Event Meal (point 10-11)• 1-4 hours prior to event• Low GI foods (sustain energy)• Low Fat and Protein: Ease digestion and avoid

stomach upset.Post Event MealRestore Muscle glycogen as quickly as possible. High GI

foods (1g per 1kg of body weight within 30min of event). Can take 24hours to fully restore glycogen following event.

Test Yourself

• Answer Multiple Choice Questions 1-9• 1 C, 2 A, 3 D, 4 C, 5 A, 6 B, 7 A, 8 D, 9 C

Energy Systems

ATP-PC SystemCharacteristic ATP-PC energy System

Also known as PC System, CP system, phosphagen system, alactic system

Fuel Source Phospho Creatine (PC) or Creatine Phosphate: same thing

Intensity of Activity High 95+ % max Heart rate

Duration of system being dominant in activity

Short (1-5 sec)

Peak power 2-4 Sec

ATP amount produced Small : 0.7 ATP each PC molecule

Speed ATP produced Explosive: relies on simple chemical reactions

By-products Inorganic Phosphates (Pi) ADP and AMP

Lactic Acid SystemCharacteristic Lactic Acid System

Also known as Anaerobic glycolysis, Lactacid system

Fuel Source Glycogen

Intensity of Activity High: 85+% of max HR

Duration of system being dominant in activity

Intermediate duration 5-60 sec

Peak power 5-15 sec

ATP amount produced Small 2-3 ATP each glucose molecule

Speed ATP produced Fast: Longer chemical reactions than ATP system

By-products Lactic Acid, H+ ions, ADP

Aerobic SystemCharacteristic Aerobic System

Also known as Oxygen System, aerobic glycolysis

Fuel Source Rest: FFA’s and CHOSub max activities: CHO, Fats when CHO diminished, Protein: Extreme condition

Intensity of Activity RestSub Max activity: under 80% HR max

Duration of system being dominant in activity

Long duration: 75 + sec

Peak power 1-1.5 min

ATP amount produced Lots (endless)CHO (38 ATP per glucose molecule)Fats (441 ATP per triglyceride molecule

Speed ATP produced Medium: Complex chemical reactions. Fats slower to resynthesise ATP than fats

By-products CO2, H2O Heat

VCE Physical Education - Unit 3

Common Mistake• The three energy systems

do not turn on and off like a traffic light.

• They are always interactive– the relative contribution of each system varies depending on factors such as intensity, type of activity and duration. X

VCE Physical Education - Unit 3

Interplay Between Energy Systems

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.

VCE Physical Education - Unit 3

Anaerobic v Aerobic Contributions

Key Points

• Accumulation of Hydrogen Ions: Hydrogen Ions are a By-Product of the Lactic Acid System (anaerobic glcolysis). H+ cause the muscle pH to drop (become more acidic). This inhibits the glycolytic enzymes and makes contractions difficult.

Maximal Oxygen Uptake

• The maximum amount of oxygen per minute that can be transported to, taken up and used by the body for energy production. Measured as mL/kg x min

Male Female

Active young men 50.8 Active young women 45.4

AFL players 53.9 National Hockey 50.1

National Volleyball 56.4 National Volleyball 46.8

National Middle Dist 67 National Middle Dist 62.1

Long Dist 73.5

Test Yourself

• Answer Short Answer QuestionAnswera/ ATP-PC Systemb/ 50%c/ You can work at a percentage greater than

100% VO2 Max by working anaerobically.d/ The test Percentage is different because it is

not at maximal intensity, unlike a 400m race.

Complete Multiple choice Questions

• Question 1-9Answers 1 B, 2 D, 3A, 4 C, 5 C, 6 B, 7 A, 8A, 9C

Fatigue and Recovery

• Fatigue occurs when the body is unable to function at it’s optimum level. Energy levels are depleted.

Causes of Fatigue Anaerobic Exercise Aerobic Exercise

Fuel Depletion, ATP-PC, Creatine Phosphate

Fuel Depletion: Glycogen

Metabolic By-Product AccumulationHydrogen Ions, Inorganic Phosphate and ADP

Increase Body Temp

Dehydration

Effects of Fatigue

• Increased Body Temp: Blood is directed away from the working muscles for cooling. Results in reduced blood and oxygen to the working muscle.

• Dehydration: Can result in impaired performance (Blood flow away from working muscles). Blood plasma volumes decrease. To maintain Q, HR must increase.

RECOVERY

• Active Recovery (cool down): Low intensity exercise to continue movement of blood from working muscles (avoid blood pooling).

• Passive Recovery: Best to replenish PC stores as more o2 available to replenish.

• Lactic Acid Breakdown: 50% removal in 30min (halved with active recovery) 95% removal in 30min with an active recovery

Test Yourself

• Answer Multiple Choice 1-8• Answers 1 D, 2 A, 3A, 4C, 5C, 6D, 7A, 8B

Short Answer Ques 9

a/ The athlete is restoring Muscle glycogenb/ This should be eaten in the first 30 minute

following a race.c/ To promote muscle repair and growthd/ Best fuel source is High GI Carbs as the

provide a fuel source that can be used immediately.