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

Glossary Words Glycogen Insulin Pancreas Enzymes Lactate inflection point (LIP) Steady state Excess post exercise oxygen consumption (EPOC) VCE Physical Education - Unit 3

Foods, fuels and energy systems

FUEL SOURCES There 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) VCE Physical Education - Unit 3

At rest Fuel sources at rest clearly show that fats are our preference over carbohydrates. VCE Physical Education - Unit 3

FOODS AS ENERGY SOURCES

PHOSPHATE CREATINE = chemical substrate 6-10 sec worth Stored in muscles Rapid energy for high/max intensity <1 ATP per PC molecule VCE Physical Education - Unit 3

CARBOHYDRATES Referred to as glucose in the blood, glycogen in the muscles Can be used both aerobically and anaerobically Stored in the muscles Few chemical reactions to break down Anaerobically = can produce 2-3 ATP Aerobically = can produce 38 ATP VCE Physical Education - Unit 3

Carbohydrate Contributions Intake of Carbohydrates depends on the intensity and duration of exercise. Normal contribution to diet is 55-60% CHO Carbohydrate loading (80% CHO intake) is used to endurance activities. Carbohydrate rich diet; Increases glycogen stores CHO preferred fuel over fats during exercise due to requiring less oxygen to release energy. VCE Physical Education - Unit 3

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 VCE Physical Education - Unit 3

ATP Copy Diagram VCE Physical Education - Unit 3 GETS BROKEN DOWN TO=

FATS Stored as triglycerides and break down into free fatty acids (FFA) Only aerobic 1 st fuel source at rest due to high oxygen available, and low energy demand Used when glycogen stores are depleted, approx hrs 1 fat molecule = 44 ATP produced VCE Physical Education - Unit 3

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. VCE Physical Education - Unit 3 FOOD FuelMaximum energy (ATP per molecule) Carbohydrates36 Fats441

Protein Contributions Role of protein (Amino acids) in the body; Growth and repair Speed up reactions in the body (Enzymes) Produces hormones and antibodies Protein and exercise 1. Only used in extreme circumstances 2. Normal diet contains enough protein (15%). VCE Physical Education - Unit 3

Glycemic Index (GI) Glycemic index; Rating of CHO effect on blood glucose Quick 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 food Avoid high GI food prior to exercise. High GI cause an insulin surge, effecting the performance of an athlete VCE Physical Education - Unit 3

Food Fuels in the Body and Recommended Dietary Intake Food FuelStored As Site(s)The proportions of essential nutrients contained in a balanced diet Example foods CarbohydratesHigh GI: Low GI: Fat Protein VCE Physical Education - Unit 3 COMPUTER ACTIVITY Answers on next slide

VCE Physical Education - Unit 3

PEAK PERFORMANCE ACTIVITY TTT Page 48 Chapter 3 Activity Manual All multiple choice VCE Physical Education - Unit 3

The Three Energy Systems The systems used to resynthesis of ATP depend on a number of factors including; Duration Intensity If oxygen is present Availability and restoration of chemical/food fuels Systems and their names 1. ATP-PC Energy System 2. 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. VCE Physical Education - Unit 3

All Systems Go Again Video Show video clip from “All Systems Go Again” and answer worksheet Show Inside our muscles Show Anaerobic Energy Systems VCE Physical Education - Unit 3

Foods, fuels and energy systems

The ATP-PC System Quickest system Breaks 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 VCE Physical Education - Unit 3

Foods, fuels and energy systems

Anaerobic Glycolysis System The anaerobic glycolysis system; Activated at the start of intense exercise Makes 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 system Provides twice as much energy for ATP resynthesis than the ATP-PC system. VCE Physical Education - Unit 3

How the system works; Stored glycogen in the muscle is converted to glucose A 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 VCE Physical Education - Unit 3

TEST YOUR UDERSTANDING Read page ‘Summary of the ‘Anaerobic glycolysis’ Answer the following question in your workbooks List 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 VCE Physical Education - Unit 3

Answer Answer: 200m sprint. 100m swim, 500m kayak and consecutive sprints in intermittent sports such as netball, football, basketball, squash, hockey and water polo VCE Physical Education - Unit 3

Foods, fuels and energy systems

The Aerobic System The aerobic system Slowest contributor to ATP resynthesis Produces much more energy than the anaerobic systems Becomes 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) VCE Physical Education - Unit 3

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. VCE Physical Education - Unit 3

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. Event Percentage of Aerobic Respiration Less than 1%100 m 10%200 m 20%400 m 50%800 m 60%1,500 m 83%5,000 m 95%10,000 m 100%Marathon

The relationship between energy systems and fitness components Copy figure 3.7 page 54 VCE Physical Education - Unit 3

Foods, fuels and energy systems

Energy Demands - Intensity Low intensity ATP requirements are met aerobically using the aerobic system. High Intensity Explosive 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. VCE Physical Education - Unit 3 Aerobic Anaerobic

Interplay Between Energy Systems All 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. VCE Physical Education - Unit 3

Interplay table Go back and fill-in the energy system column on the table with food fuel, duration, intensity and enegy system used. Answers next slide VCE Physical Education - Unit 3