WHAT DO WE NEED TO BE ABLE TO MOVE? CHAPTER 3 PAGE 45-60

Transcription

1 WHAT DO WE NEED TO BE ABLE TO MOVE? CHAPTER 3 PAGE 45-60

2 LEARNING GOALS To be able to explain the characteristics of aerobic and anaerobic pathways and their contribution to movement and dominant fibre type associated with each pathway SUCCESS CRITERIA I can identify and explain the dominant energy pathway utilised in a variety of aerobic or anaerobic activities I can collect, analyse and report on data related to responses to exercise and anaerobic and aerobic pathways

3 MOVEMENT REQUIRES ENERGY! Nutrients in food are converted into the body s energy currency which is called ATP. This allows a muscle to contract. The energy released from the breakdown of foods cannot be transferred directly to our cells, so it has to be stored. ATP can only be stored in limited amounts, whether you re a couch potato or an Olympic athlete.

4 MUSCULAR WORK How we move determines our energy requirements and associated processes:

5 ENERGY DEMAND Two factors determine the energy (ATP) demand of an event: Exercise intensity determines rate of ATP resynthesis needed Exercise duration determines yield of ATP resynthesis needed

6 WHAT? 1 WHEN? 4 Energy Systems WHY? 2 HOW? 3

7 WHAT? Energy systems break the bonds of different body fuels via a series of complex reactions to extract chemical energy. This energy is used to resynthesise ATP for muscle contraction. A car engine uses one type of fuel (petrol), skeletal muscle has the advantage of obtaining energy from breaking down as many as four different fuel sources: Creatine Phosphate (CP) or Phosphocreatine (PC) Carbohydrates (CHO) Lipid (fat) Protein These are mainly found in our diets and are stored in our bodies including our muscles, liver, adipose tissue and blood.

8 WHAT? The energy systems work together to meet the ATP requirements. We have three energy systems or pathways that work together to supply the body with ATP, our universal energy currency. Anaerobic or O 2 independent ATP-PC system Anaerobic glycolysis system Aerobic or O 2 dependant Aerobic system

9 ATP-PC SYSTEM (F1 POWER) This system provides the fastest rate of ATP resynthesis as it uses the fuel creatine phosphate (CP) or phosphocreatine (PC) already stored in the muscle. This system has the fastest rate of ATP resynthesis, therefore is used as the predominant energy system by athletes competing in short duration, high-intensity power events. This is the most powerful system, but has a limited capacity to generate ATP as it fatigues rapidly. This can only be used as the predominant energy system for up to 6 10 seconds. The first 2 3 seconds of maximal effort work will rely on the breakdown of existing ATP stores in the muscle. You may also hear this system being referred to as the alactacid system or the phosphagen system.

10 ANAEROBIC GLYCOLYSIS SYSTEM (V8 SUPERCAR) This system involves more complex chemical reactions that breakdown the fuel known as muscle glycogen to release energy via the process of anaerobic glycolysis. This results in the formation of the byproduct lactic acid. This system can resynthesise ATP at a fast rate allowing for the continuation of high-intensity effort. This system is normally used in activities that last between 10 and 75 seconds. Anaerobic glycolysis literally means the breakdown of sugar independent of oxygen. ATP is resynthesised from the breakdown of carbohydrates mainly in the form of muscle glycogen (some can come from blood glucose) As oxygen is not present, glycogen is not completely broken down and pyruvic acid is formed which then ferments to produce lactate.

11 AEROBIC SYSTEM (SMARTCAR) This system is the most complex and involves the greatest number of chemical reactions. It has three distinct stages and is able to use either carbohydrate (CHO) or lipids (fat) fuels stored inside and outside of the working muscles. The by-products formed as a result of using this system include CO 2, H 2 O and heat. The three stages are known as: 1. Glycolysis 2. Kreb s Cycle 3. Electron Transport System (ETS) This system has a considerably slower rate of ATP resynthesis due to a reduction in intensity, but has an unlimited capacity for resynthesis and is therefore the predominant energy system used at rest and during events lasting over 75 seconds.

12 WHAT? 1 WHEN? 4 Energy Systems WHY? 2 HOW? 3

13 WHY? We require ATP for muscle contraction and movement everyday. ATP is the body s universal energy currency used by all systems: cardiac, respiratory, muscular. Actual ATP store (70kg) 50g Required ATP for 1 day 190kg

14 WHAT? 1 WHEN? 4 Energy Systems WHY? 2 HOW? 3

15 HOW? Energy systems resynthesise ATP using energy released from fuels stored in the body. Food Fuels Chemical fuels (substrates) Energy system Lipids (Fat) Carbohydrate (CHO) Creatine (Cr) Protein (AA) Free Fatty Acids FFA (blood) Triglycerides (adipose tissue, muscle) Glucose (blood) Glycogen (muscle, liver) Phosphocreatine PC or CP (muscle) Amino acids AA (blood, muscle) Substrate: is a fuel stored in the body in a chemical form that is broken to release energy for ATP. Aerobic Aerobic Anaerobic Glycolysis ATP-PC Aerobic

16 WHAT? 1 WHEN? 4 Energy Systems WHY? 2 HOW? 3

17 WHEN? Energy System Predominant fuel(s) Predominant Power (rate) Capacity (yield) By-products Fatigue mechanism Event ATP-PC Anaerobic Glycolysis Aerobic Phosphocreatine (PC) Muscle glycogen Glucose Muscle glycogen/glucose 6 10 sec Fastest Smallest None Fuel depletion (PC) 100m sprint, field events, weightlifting 30 to 60 sec Fast Small H+, lactate Accumulation of by-products (H+) 1-2 mins to 3 hours Medium Large CO 2, H 2 O, heat Accumulation of by-products (H+) 400m sprint, 100m freestyle 1500m freestyle, 800m run Muscle triglyceride Free Fatty Acids 4 hours + Slow Largest Fuel depletion (MG) Thermoregulation Ironman (triathalon) Aerobic glycolysis Aerobic lipolysis

18 ENERGY SYSTEM INTERPLAY The energy systems do not work in isolation. The way they work together is referred to as interplay. The energy system said to be contributing the most to ATP resynthesis is referred to as the predominant energy system. Energy systems are not switched on or off, but instead increase and decrease their contributions. At the start of any event, all 3 systems will contribute with ATP.

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21 RELATIVE CONTRIBUTIONS TO MEET THE REQUIREMENTS OF HIGH- INTENSITY EFFORTS.

22 Match the bars in the graph with the following events. a) 400-metre sprint b) 200-metre run c) 3-kilometre run d) 100-metre sprint

23 Refer to the graph. a) Identify which graph best represents a 3- kilometre run. Justify your answer. b) Identify the times at which the anaerobic systems would have been predominant. c) Explain the contribution of the anaerobic energy systems in the activity.

24 EXAM QUESTIONS Question 1 Christine Ohuruogu ran a time of seconds to win the gold medal in the 400-metre event at the 2008 Beijing Olympics. Identify the predominant fuel her body used for this event. Question 2 Identify the three by-products of the aerobic energy system. Question 3 Carbohydrates, fats and proteins are the three main food groups. Identify the chemicals that these three food groups are stored as in the muscles. 1 mark 1 mark 1 mark

25 Question 4 The table below shows the percentage of energy contribution for various activities Sport or event A B C D E F G H I Percentage anaerobic energy contribution Percentage aerobic energy contribution a) Which of the following would best match the letters A, E and H from the table in relation to the percentage contribution of anaerobic and aerobic energy systems for that particular sport or event? Steve Hooker's pole vault world record attempt John Van Wisse's winning 48-kilometre swim around New York's Manhattan Island An AFL centre player's first quarter of football An Australian soccer striker attempting a shot on goal Olympic standard shot-put event Elite male 400-metre running event School cross-country run Secondary school swimming team 50-metre freestyle swimming race For each of the events selected, justify your choice. 3 marks 3 marks

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27 ENERGY SYSTEMS AND MUSCLE FIBRE TYPE Muscle Fibre Characteristics Fuel Source used ATP generation Slow Twitch Fast Twitch (IIa) Fast Twitch (IIb) High resistance to fatigue Large capacity to resynthesise ATP Red Resynthesise ATP at a fast rate Fast oxidative fibres Red Contract rapidly Large force White Muscle glycogen Blood glucose FFA Triglycerides (Mixture of both) Phosphocreatine Muscle glycogen Aerobic Aerobic Anaerobic Anaerobic Event type Endurance Many team sports e.g. hockey, netball Short Explosive Powerful

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29 KEY TERMS ATP Energy systems Interplay Resynthesis ADP Pi High-energy phosphate Phosphocreatine (PC) Carbohydrate (CHO) Lipid (Fat) Protein Adipose Tissue Anaerobic Aerobic Predominant Glycogen Triglycerides Amino Acids Power Capacity Glycolysis Oxygen-independent Aerobic glycolysis Aerobic lipolysis Free Fatty Acids (FFA)