KEY KNOWLEDGEKEY SKILLS  The characteristics of the two anaerobic (without oxygen) and aerobic (with oxygen) energy pathways.  The energy pathways used for different movement types and intensities and the dominant muscle fibre type linked to each pathway  Identify the effects intensity and duration have on the anaerobic and aerobic energy pathways and use of predominant energy source.  Participate in, analyse and report on class data linked to the anaerobic and aerobic pathways and associated exercise responses.

Food Fuels Carbohydrates, fats and proteins are the only food fuels that produce energy Phosphocreatine (PC) is a chemical fuel source Carbohydrates are our preferred exercise fuel either as blood glucose or muscle glycogen (2/3 rds ) & liver glycogen (1/3 rd ). They are: Easy to access Quick to breakdown (either with or without oxygen) Plentiful (Stored in large amounts)

Fats are involved in: protecting body organs maintaining body temperature hormone production energy storage and supply Triglycerides are broken down to free fatty acids (FFA’s) which are broken down aerobically to provide energy Fats are mainly used at rest require more oxygen to produce energy produce more ATP than carbohydrates produce energy slowly Proteins are mainly consumed for growth and repair of body cells & tissues. All enzymes are made up of proteins Proteins are mainly used as a “last resort” fuel have a very high “oxygen cost” produce energy slowest of all food fuels

Intensity of Exercise vs. Preferred Food Fuels Robert Malpeli - Balwyn High School 2010

Overview: Energy can be defined as the capacity to perform work. Energy cannot be created or destroyed, it is transformed from one form to another. It is the transformation of chemical energy in the human body to mechanical energy that enables human movement. The energy to allow this movement to occur comes from food. However, the energy released during the breakdown of food - carbohydrates, fats, protein - is not directly used to perform work, it is used to resynthesize ATP. ATP is stored in the muscle cells. The energy released during the breakdown of ATP is the only source of energy that can be used directly by the muscle cell to perform work (physical activity). Because muscle cells only store a very small amount of ATP (enough for 1-2 seconds of maximal activity) and it is only through the breakdown of ATP that energy is released for work; the body must have ways of putting the ATP molecule back together again.

The Energy Systems 1.ATP-PC 2.Anaerobic glycolysis 3. Aerobic There are three systems where chemical energy is made available for the rebuilding of ATP Anaerobic Systems (Without oxygen) Aerobic Systems (With oxygen)

What is their purpose? All three suppliers of energy for ATP rebuilding operate from the same principle - energy liberated from the breakdown of food and phosphagens is used to put the ATP molecule back together again - to resynthesize it..

Anaerobic Vs Aerobic Two of the three systems, the ATP-PC system and Anaerobic Glycolysis system are termed anaerobic. Anaerobic means 'without oxygen'. Anaerobic metabolism refers to the rebuilding of ATP through chemical reactions that do not require oxygen. The other system, Aerobic System is aerobic which means “with oxygen” and needs oxygen to metabolise fuels.

Aerobic vs. Anaerobic glycolysis

ATP-PC SYSTEM

ATP-PC System The ATP-PC System The first energy system in terms of order of predominance and power (the rate at which energy is released) is the ATP-PC system. This works on the interaction between ATP and a fuel called phosphocreatine (or creatine phosphate) which is stored in the muscles. Creatine phosphate is termed a 'chemical fuel' and can be synthesis by our body. ATP (adenosine triphosphate) is stored in the muscles – we have 50g worth, enough for 1-2 seconds of intense physical activity (larger muscles slightly more). When ATP is used for muscular contraction it is split. The breakage of the outermost bond causes a phosphate to be released so that ADP (adenosine diphosphate) and Pi (Inorganic phosphate) remains. The bond breakage releases energy. Both ADP and Pi can be recycled to make ATP again, however a bond of some sort must break to release energy and recombine the two again.

ATP-PC System

ATP-PC SYSTEM SUMMARY : FOOD FUEL: None, PC is not a food fuel. FUEL INPUT: Creatine Phosphate (PC/CP) Energy Output (Yield): 1 ATP molecule from each PC molecule Energy system dominance: 0-10 seconds Peak power output: 3-5 seconds Fatigue factors: Depletion of PC stores->cannot maintain the same power output. Accumulation of inorganic phosphates and ADP

Anaerobic Glycolysis

Glycolysis: Food-> CHO-> Glucose->stored as Glycogen in liver and muscles->glucose= small amount of ATP The process does not need oxygen This energy is released more slowly than the ATP-PC system. The lack of Oxygen results in fatigue causing by-products: lactic acid and hydrogen ions This system is limited due to the accumulation of these by-products. *Lactic acid can be re-used as a fuel source or converted back into glycogen in the liver.

Anaerobic Glycolysis summary PLACE OF REACTION: Anaerobic glycolysis occurs in the cytosol. FOOD FUEL: Carbohydrates FUEL INPUT: Glucose/Glycogen ENERGY OUTPUT (Yield): 2 ATP molecule from each glucose molecule ENERGY SYSTEM DOMINANCE: seconds PEAK POWER OUTPUT: seconds Fatigue factors: Hydrogen ion (H+) accumulation interferes with the breakdown of glucose. Lactate concentration correlates with fatigue but does not directly cause fatigue.

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Aerobic System

The aerobic system is the most efficient but slowest of all the energy systems due to its complex nature of its chemical reactions. The aerobic system requires oxygen for its two stages. It contributes significant amounts of energy during high-intensity/maximal activities lasting one to two minutes. The aerobic system is also activated at the start of intense exercise, and peak power from this system is usually reached between one and two minutes and will continue to be the major ATP contributor as the lactic acid system decreases its contribution.

Aerobic System Summary PLACE OF REACTION : Glycolysis occurs in the cytosol in the mitochondria. FOOD FUEL: Carbohydrates (preference), fats and in negligibly protein. FUEL INPUT: Glucose/Glycogen, FFA (Free fatty acids) ENERGY OUTPUT (Yield): ATP molecule from each glucose molecule, 100+ from each triglyceride ENERGY SYSTEM DOMINANCE: 30 seconds + PEAK POWER OUTPUT: 1-2 minutes. FATIGUE FACTORS: Increased body temperature= decrease in water= decrease in Blood volume s and therefore cardiac output also decreases, resulting in less oxygen going to the muscles. Depletion of glycogen stores. When hypoglycaemia (low blood glucose) sets in, the body is forced to utilise more fat and this requires more oxygen.

Aerobic System Sme780

Systems and Fitness Components

Notice the different fuels used depending on duration and intensity Robert Malpeli - Balwyn High School 2010

INTERPLAY All three energy systems are initiated at the start of exercise and none function independently of one another. This is called energy system interplay - the main supplier of energy changes but all energy systems have some contribution to energy output

All 3 systems work together to supply energy / ATP

Rate (frequency) of ATP production and the yield for each system Energy SystemFuel used Rate of ATP (car speed analogy) Total amount of ATP (yield) Duration ATP-PCPhosphocreatineFastest (110km/h) sec Anaerobic glycolysisGlucoseFast (80km/h) sec Aerobic glycolysisGlucoseModerate (60km/h) sec Aerobic LipolysisFatty acidsSlowest (40km/h)147Dominates during sub-maximal exercise

Your task… A coaching position has been advertised for the State [insert your chosen team sport here] team at the AIS and part of the interview process is to demonstrate your understanding of the energy systems involved in _____. 1.What energy system(s) would be predominant for the athletes in your future team? 2.In small groups, design a training session that demonstrates your understanding of the principle of specificity (what you do in training should be appropriate to the desired outcome). You will need to address all the energy systems used in hockey and how you would like to train each system. 3.Present your groups ideas to the rest of the class, providing a demonstration of the session plan and discuss reasons why team sport athletes need to include a variety of training intensities and durations. Refer to energy systems and the rate//yield of ATP in your presentation.