Chapter 5 Foods, fuels and energy systems VCE Physical Education - Unit 3 Text Sources 1.Nelson Physical Education VCE Units 3&4: 5 th Edition – Malpeli, Horton, Davey and Telford Live It Up 2: 2 nd Edition – Smyth, Brown, Judge, McCallum and Pritchard 2006.

Complete the following Peak Performance Ch 5 All Multiple Choice Questions Peak Performance Ch 5 Warm up Question 2a&b READ the following PowerPoint slides and answer the questions as you progress through each energy system. If PowerPoint is completed and all questions are answered complete your result ratings from you SAC results from your last Practical Lab. VCE Physical Education - Unit 3

Read the following slides on ATP and at answer the questions on Slide 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. Nutrients assist in re-joining the split molecule So the breakdown of ATP releases energy for muscular contraction 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 2. Anaerobic Glycolysis (Lactic Acid (LA)) 3. Aerobic 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

Foods, fuels and energy systems

The ATP-PC System pg 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

Body has a larger storage of PC (6-10sec worth) compared to ATP (2-3 sec worth) PC stores can be replenished through aerobic recovery/passive recovery. Passive recovery for maximum ATP resynthesis, also increase removal of H+ Once PC stores are depleted, the body must use glycogen through the anaerobic pathway. Anaerobically trained athletes can resynthesise ATP faster As resynthesis decreases, intensity must decrease 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

Anaerobic Glycolysis also contributes to making ATP when intensity increases (over 85% of max. HR) during long, sub-maximal activities. This allows for an increase in total energy output, increasing speed & intensity in predominantly aerobic activities. Anaerobic Glycolysis also contributes during repeated short efforts with insufficient recovery time for PC replenishment. 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. The lactic acid then forms hydrogen ions, resulting in the production of salt and lactate. This results in acidosis which is an increase in the acidity of the muscle & a decrease in muscle pH. It is an increase in H+ ions which causes fatigue VCE Physical Education - Unit 3

Glucose is transported to the muscles of the body via the blood. How Anaerobic Respiration Happens Glucose passes into the muscles cells and is used to produce energy for muscular contractions. Anaerobic respiration produces lactic acid as a waste product. Facts about Anaerobic Respiration  During anaerobic respiration, your muscles are not supplied with enough oxygen.  The lactic acid builds up due to the shortage of oxygen.  The increase in H+ ions due to lactic acid production will soon make your muscles feel tired and painful, so exercising anaerobically can only be carried out for short periods of time. 123

Complete Read page 127 ‘Summary of the Lactic acid (LA) energy system’ 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. VCE Physical Education - Unit 3

Complete ANAEROBIC METABOLIMS / PATHWAY ATP-PCANAEROBIC GLYCOLYSIS Fuel Source Fuel Location Dominant ATP Rate ATP Amount/Yield 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) See table 5.4 p.129 VCE Physical Education - Unit 3

How the system works; 1. CHOs and Triglycerides (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

Facts about Aerobic Respiration How Aerobic Respiration Happens… Glucose and oxygen are carried by the haemoglobin in the red blood cells. Glucose and oxygen pass into all the muscle cells of the body and is used to help produce energy for muscular contractions. Aerobic respiration produces carbon dioxide, heat & water as waste products.  During aerobic respiration, the heart and lungs supply the muscles with plenty of oxygen.  The carbon dioxide is breathed out via the lungs, while the water is lost as sweat, urine or in the air we breathe out as water vapour.  As long as the muscles are supplied with enough oxygen, exercising aerobically can be carried out for a long period of time. 123

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

Complete the following questions By comparing anaerobic and aerobic energy what is occurring at approximately 1 minute of maximal- intensity exercise? When are the two systems at the mark? (answer should be in seconds) VCE Physical Education - Unit 3

Complete the following Read ‘ Summary of the aerobic energy system’ page Complete ‘Think things through’ page 131 Nelson text VCE Physical Education - Unit 3