Energy systems and their role in sport and exercise Physiology of Fitness Energy systems and their role in sport and exercise

Learning Outcomes List the 3 main energy systems and their cellular fuel Describe the 3 energy systems giving sports related examples Explain why some sports require more of one energy system than another Measure and record the body’s responses to different types of exercise Explain the recorded measurements Produce a short magazine article describing the three main energy systems using examples.  

Actin & Myosin What are the contractile proteins in muscle? http://www.youtube.com/watch?v=gJ309LfHQ3M http://www.physics3110.org/images/240_actin.gif The key terms to remember from that clip are: ATP ADP + Creatine Phosphate Myosin Actin When ATP is released onto myosin the chemical bond breaks releasing a lot of energy causing actin and myosin filaments to contract ie muscle contraction Contractile proteins

The release of energy from ATP What is ATP? ATP is a protein (Adenosine) with 3 phosphates attached to it When chemical bonds are broken, energy is released and ATP becomes ADP (Adenosine diphosphate Di=2) The energy from this breaking is used to make muscles contract The release of energy from ATP

Energy Systems What are the 3 main energy systems that convert chemical fuel from food into energy? Creatine Phosphate System Lactic Acid System Aerobic Energy System What is this? The mitochondrion, shown here, is a tiny cellular structure that turns chemical fuel into cellular energy ie ATP.

Creatine Phosphate System

Creatine Phosphate System CP System (immediate energy) Here ATP is made without the presence of oxygen. When exercise intensity is high, or energy needs are instantaneous, creatine phosphate stored in your muscle is broken down to provide energy to make ATP. Explosive work can be achieved, but only for short periods of time at maximum intensity, as the supply of creatine phosphate is very limited, up to 10 seconds. Activity List as many sports activities as possible that use mainly the CP system.

Creatine Phosphate System Primary energy source: Duration of activity: Sporting events: Advantages: Limiting factors: Stored ATP, CP 7-12 s Weight lifting, high jump, long jump, 100m run, 25m swim Produce very large amount of energy in a short amount of time Initial concentration of high energy phosphates (ATP, PC)

Creatine Phosphate System

Training The CP System a) Interval training: eg 1min low intensity 1min high intensity & repeat - 20% increase in CP (creatine phosphate) stores - no change in ATP stores - increase in ATPase function (ATP -> ADP+P) - increase in CPK (creatine phosphokinase) function (CPK breaks down CP molecule and allows ATP resynthesis) b) Sprint training: - increase in CP stores up to 40% - 100% increase in resting ATP stores

Lactic Acid Energy System

Lactic Acid Energy System high intensity exercise up to 2 minutes. ATP is made by the partial breakdown of glucose and glycogen. This is caused by anaerobic glycolysis It’s an anaerobic process (no O2) Where does the body store glycogen? Muscles Liver What is the by-product of anaerobic glycolysis? Lactic acid http://www.youtube.com/watch?v=JLaVIPlPm6g&feature=related

Lactic Acid Energy System Primary energy source: Duration of activity: Sporting events: Advantages: Limiting factors: Stored glycogen, blood glucose 12 s – 3 min Lactic acid build up, H+ ions build up (decrease of pH) 800m run, 200m swim, downhill ski racing, 1500 speed skating Ability to produce energy under conditions of inadequate oxygen

Lactic Acid Energy System

Lactic Acid Energy System Anaerobic Threshold The exercise intensity at which lactic acid begins to accumulate within the blood The point during exercise where the person begins to feel discomfort and burning sensations in their muscles Lactic acid is used to store pyruvate and hydrogen ions until they can be processed by the aerobic system

Lactic Acid Energy System The primary source of substrates is carbohydrate Carbohydrates: primary dietary source of glucose primary energy fuels for brain, muscles, heart, liver

Aerobic Energy System Primary energy source: Duration of activity: Sporting events: Advantages: Limiting factors: Glycogen, glucose, fats, proteins > 3 min Lung function, max.blood flow, oxygen availability, excess. energy demands Walking, jogging, swimming, walking up stairs Large output of energy over a long period of time, removal of lactic acid

Aerobic Energy System

Aerobic Energy System

Aerobic Energy System The most important energy system in the human body Blood lactate levels remain relatively low (3-6mmol/L bl) Primary source of energy (70-95%) for exercise lasting longer than 10 minutes provided that: a) working muscles have sufficient mitochondria to meet energy requirements b) sufficient oxygen is supplied to the mitochondria c) enzymes or intermediate products do not limit the Kreb’s cycle Primary source of energy for the exercise that is performed at an intensity lower than that of the anaerobic oxidative system

Aerobic Energy System Long term energy, system for light exercise and every day movements. Uses O2 The production of energy in the aerobic system does not start instantly.... Why? In groups discuss this and write down your agreed answer Answer: It takes a few minutes for the heart to deliver oxygenated blood to the working muscles. Long, continuous moderate exercise produces energy using this system.

Types of Sport that use each system Remember, energy at any given time is derived from all 3 energy systems. However the emphasis changes depending on: the intensity of the activity the efficiency of your aerobic fitness

Energy Systems Summary Creatine Phosphate energy system ... for very short high intensity exercise ADP + Phosphocreatine ATP + creatine requires no O2 but only enough stored for about 10secs e.g. power lifting... Lactic Acid Energy System: short-term energy system Glucose 2 ATP + 2 lactic acid + heat Glycogen 3 ATP + 2 lactic acid + heat requires no O2 but produces energy for high intensity exercise for up to 60 – 90 secs e.g. 400m race..

Energy Systems Summary 3. Aerobic Energy System: long-term energy system Glucose +O2 38 ATP + CO2 + water + heat Fatty acids + O2 129 ATP + CO2 + water + heat

Activity Produce a magazine article that describes and explains the body’s energy systems to a football coach. What are the differences between the 3 energy systems? List one advantage and one disadvantage of each of the 3 energy systems. Give an example of three activities or sports that use each of (a) the creatine phosphate system, (b) the lactic acid system, and (c) the aerobic system as their primary source of energy (one sport for each energy system). What is the most important source of fuel in the body for all types of energy production - a substance also known as the energy currency of the body?