Key terms you must know:• Energy • ATP / PC System• Adenosine triphosphate (ATP) • Phosphocreatine (PC)• Adenosine diphosphate (ADP) • Lactic Acid System• ATP Splitting • Onset of Blood Lactate• Carbohydrate Accumulation (OBLA) - Glucose, Glycogen • Anaerobic Threshold (AT)• Fat (lipids) • Aerobic System - Triglycerides, FFA’s • Krebs Cycle• Protein • Electron Transport Chain• Anaerobic • Mitochondria• Aerobic • Energy Continuum• Glycolysis • Slow / Fast Twitch Muscle Fibres
Energy? Nerveconductio n•Can be defined as “the ability Building new body Hormonemanufa tissues (growth) ureto do work.”•Measured in kilojoules (kJ) orCalories (C). 1kJ = 24 Calories ENERGY• ATP – is the chemicalcompound that serves as the (catabolism ofimmediate source of energyfor most energy consuming ATP)reactions in the body,including: muscularcontraction, processing food,tissue growth & repair, Digesting & Repairing bodyproduction of hormones as well processing of food Muscular tissuesas nerve conduction. contraction
Energy for skeletal muscle contractions• Energy for the cross-bridges to pull. * Myosin and Actin filaments work together to create movement as cross- bridges are formed.
Sliding Filament Theory http://www.youtube.com/watch?v=gJ309LfHQ3M
What is ATP?• ATP is the energy source for all • When these high energy bonds muscular effort, whether for a break, a phosphate separates small subconscious movement from ATP and energy is released such as the blinking of an eye, or for muscular effort. planned repetitive effort in • This can be simplified as: weight training. ATP ADP + Pi + Energy• ATP =Adenosine + 3 Phosphates. • Also known as ‘ATP Splitting’ ‘Tri’ meaning three• The phosphates are linked to High energy adenosine via high energy bonds. bonds (12,000 Calories) A P P P A P P + Pi + Energy Adenosine + 3 Phosphates Adenosine + 2 Phosphates ATP ADP
Rebuilding ATP • A muscle fibre stores only a limited amount of ATP! • ‘ATP Splitting’ is reversible process, whereby ADP undergoes phosphorylation (rejoins with a phosphate) with the assistance of energy to resynthesize ATP:Fat CHO Protein Energy + Pi + A P P A P P P Adenosine + 2 Phosphates Adenosine + 3 Phosphates ADP ATP
Energy for rest and activityThe body can create energy (ATP) under two mainconditions:1. Rest conditions,• Where there is sufficient oxygen available for the body to continue to function at resting level.2. Active conditions,• Where physical exertion means there is insufficient oxygen available for the body to continue to function at a particular level without a marked increase in oxygen intake either during or after the effort. These conditions occur during anaerobic activity and aerobic activity.
ATP production during rest conditions• Rest is when the body is not under physical stress and when breathing and heart rates are low and stable.• The body has an abundant supply of oxygen, so preference is to produce ATP from the breakdown of fat (as no fatiguing by-products). - ⅔ ATP from breakdown of fats(but with greater O2) - ⅓ ATP from the breakdown of CHOs• Occurs in the Mitochondria – bean shaped ‘power house’ of the cell.• End products of this aerobic respiration are: CO2, H2O & Heat
ATP production during activity• ‘Activity’ in physical education is a wide ranging term that refers to any physical state more exertive than rest. The ATP produced during activity depends on a number of factors:1. The length of time (duration) of the exercise2. How hard an athlete works (intensity) in the exercise bout3. How well-developed his/her cardiorespiratory system is (aerobic fitness)4. The degree of recovery in between successive bouts of exercise.• REMEMBER: due to the time it takes to get necessary O2 into the lungs, absorption into the bloodsteam& transportation to working muscles, our bodies sometimes must make use of anaerobic systems.
Sources of ATP• ATP is an end product in your diet. All the food, processed drinks and water that you consume contain nutrients that your body requires for: - Healthy growth - Repair of body ‘wear and tear’ from everyday activities - Energy for all body functions.• The components of a healthy diet are: - Carbohydrates - Fat - Protein - Vitamins & Minerals - Water• ATP can be created from any carbohydrate, fat or protein.
Carbohydrates (CHOs)• Primary source of ATP for muscle contraction during exercise.• Broken down into glucose for transportation in the blood.• Stored as glycogen in the muscles and liver (~ 90 mins)• Excess is converted to fat and stored in adipose tissue.• Glycogen can then be used to power ATP production in both the Lactic Acid and Aerobic Systems.• e.g. Grains, breads, pasta, fruit and vegetables.• Carbohydrate Loading – a nutritional strategy to maximise muscle glycogen stores prior to endurance competition. e.g. Few days before competition: - decrease volume & intensity of training - increase CHO intake in diet (~70%)
Fats (Lipids)• VERY energy dense (37 kJ/g) & produce large amounts of ATP.• BUT requires much more Oxygen, therefore must decrease work load.• Broken down to freefatty acids (FFAs), which circulate in the blood, and triglycerides, which are found in the muscles and liver.• Excess stored largely as adipose tissue.• Energy from the breakdown of fats is used mainly at rest and periods of low intensity sub-maximal exercise.• Secondary source of ATP for muscle contraction during exercise.• Under special conditions, however, an athlete may use fat earlier in the activity to ‘spare’ the CHO stores and therefore enable high-level effort closer to the end of competition. (Glycogen sparing)• e.g. dairy products, nuts, and oils.
Protein• Made up of amino acids (i.e. Leucine, Tryosine, Lysine) – building blocks of our bodies (contain N,H & C).• Stored in the muscles and adipose tissue.• Protein only minimally contributes to ATP production.• In extreme circumstances (such as starvation or ultra triathlon / marathon events) when the body has severely depleted its supplies of CHO and fat, proteins become a viable source of ATP.• e.g. meat, fish, eggs and dairy products. Q: Why is protein the least preferred fuel source for energy?
Fuels - SummaryFood Fuel Stored as SiteCarbohydrate • Glucose • Blood(Primary Source when •Glycogen • Muscle & liverexercising due to • Excess as fat • Adipose Tissueefficiency)Fat • Free Fatty Acids • Blood(Primary Source at rest 66- • Triglycerides • Muscle75%, Secondary Source • Fat • Adipose Tissuewhen exercising to CHO)Protein • Muscle amino acids • Skeletal Muscle(Last resort situations only) • Excess as fat • Adipose Tissue
Energy (ATP) Production• There are 2 pathways for energy production: (1) Aerobic Pathway - in the presence of Oxygen (2) Anaerobic Pathway - in the absence of Oxygen• There are 3 Energy Systems. 1. ATP-PC Energy System Anaerobic Pathways for 2. Lactic Acid System Energy Production 3. Aerobic Aerobic Energy System
ATP-PC System • This energy pathway provides ATP for once off powerful, explosive efforts e.g.• ATP-CP or Phosphagen System 100m sprint, tennis serve or a take off in•Pathway: Anaerobic•Fuel:PCr (chemical) and Muscle long jump.ATP stores.•Intensity: High to maximal•Time of most effectiveness:•By-products: None•Takes place in the muscle cellNOT Mitochondria.•ATP production: Small amountsinstantly; > 1 ATP per mol. of PCr• Recovery: Q: List 5 activities from 5 completely different sports that would use the Phosphagen system.
ATP Resynthesis (ATP-PC) http://www.youtube.com/watch?v=BR3dDO1Sz0E
ATP-PC Systemis closely linked to several fitness components:• Muscular strength• Muscular power Q: Which muscle fibre type would this system predominantly• Speed recruit? Q: Examples of Fitness Tests• Agility which assess this energy• Reaction Time system might be?
Lactic Acid System
Lactic Acid System • Energy released from the breakdown of• Anaerobic Glycolysis or Anaerobic glucose into Pyruvic Acid is the secondGlycolytic system•Pathway: Anaerobic means by which ADP + Pi reforms into•Fuel: Glycogen (stored CHO) ATP.•Intensity: Near maximal • From approx. 10-30 secs the ATP-PC•Time of most effectiveness: System energy contribution diminishesApprox. 30 secs – 2 mins to almost nothing, and anaerobic glycolysis becomes the predominant• By-product: Lactic Acid•Takes place in the cell cytoplasm energy system.NOT Mitochondria.•ATP production: Limited amounts 50m Swimrapidly, 2 ATP per molecule ofglycogen fuel.•Recovery: Lactic Acid removaldependant upon amount of energyused up & the method of recovery:Active 95% removal in 30mins Q: List 3 different sportingPassive 95% removal in examples which use the LA 60mins System.
Aerobic System • This system includes the complete breakdown of glucose/fats/protein,• Oxygen system or Aerobic using the processes ofGlycolysis. glycolysis/lipolysis + Krebs Cycle + ETC.•Pathway: Aerobic (requires O2)•Fuel(s): Carbohydrate (glucose), • Remember: When the body is at rest orFats and then Protein. during low intensity sub-maximal•Intensity: Sub-maximal exercise, the demand for ATP is low and•Time of most effectiveness: it is produced aerobically+ 5 minutes • The energy from ATP resynthesis comes•By products: H2O, CO2 + heat primarily from 2 fuel sources:•Takes place in the Mitochondria - Fats (66-75%)•ATP production: unlimitedamounts slowly. - CHO (25-33%)CHO (Glucose) 38 ATPFats 460 ATP•Recovery: Depends on intermittent Q: List 3 other sports whichor continuous recovery (high CHO rely on the O2 System.intake is beneficial)
Krebs Cycle • In Aerobic Glycolysis, the Pyruvic acid breaks down in the presence of O2 (instead of producing Lactic Acid) • Sir Hans Krebs • Also known as the Citric Acid Cycle • Occurs in the Mitochondria (matrix) • Produces CO2. (C atoms) • 2 ATP made / 2 ATP pre Krebs Cycle Electron Transport Chain • After the Krebs Cycle, the other major stage is the ETC. • Produces H2O and Heat (H and O mix) • 34 ATP made.Aerobic Glycolysis = 38 ATP made
Aerobic Glycolysis Q: Which muscle fibre type would this system recruit?
Comparison between SystemsCharacteristic ATP-PC Lactic Acid AerobicFuel/s ATP stores and Glycogen CHO, Fats THEN Phosphocreatine ProteinATP production per Less than 1 Approx. 2 Glucose = 38molecule of energy Fats = 460sourceSpeed / rate of ATP Small amounts Limited amounts Unlimited amountsproduction instantly rapidly slowlyIntensity Maximal effort Near maximal (85- Sub-maximal 95%) (<85%)Duration 0-10 secs 30 secs–2 mins 5 minutes+Oxygen requirements Nil Nil O2 requiredBy products Nil Lactic acid H2O, CO2 and Heat
Characteristic ATP-PC Lactic Acid AerobicFatigue Fast fatigue Fast fatigue Slow fatigueMuscleFibre Type Fast twitch (white) Mainly fast twitch Slow twitch (red) (white)Speed of Muscle Very rapid Rapid SlowcontractionFitness components Muscular strength, Local Muscular Cardio-respiratory react. time, power, endurance endurance agility, speed.Sporting Examples Golf Swing 400m Sprint Marathon Tennis Serve 200m Sprint Triathlon 100m Sprint 50m Swim Cross-Country Javelin Throw Gymnastics Floor skiing Baseball Swing Routine 800m Swim Volleyball Spike Repeated ‘break 1500m Swim Football kick efforts’ in football, 2000m Rowing netball, b’ball etc.Fitness Tests Vertical jump Maximal push-up 20m beep test B’ball chest pass test (30secs) 12 min run/walk Grip strength Maximal sit up test 20-40m Sprints (60secs)
The Energy Continuum• The Energy Continuum illustrates theongoing and continual interplaybetween all 3 energy pathways and thefact that one system rarely acts inisolation.• All 3 systems CAN operate at the sametime providing different energycontributions depending on the intensityand duration of the activity. Energy System % Energy Contribution ATP-PC System 56 - - - - - - Lactic Acid System 44 60 50 35 15 3 - Aerobic System - 40 50 65 85 97 100 6s 30s 60s 2 min 5 min 30 min 60 min Time
Activities1. Draw an accurate representation of the Energy Continuum diagram. Explain in detail, using 3 sporting examples to support your answer.2. Make a list of the all the positives and negatives associated with the use of each Energy System.3. Explain in detail the differences between Anaerobic and Aerobic Glycolysis – be sure to include the Krebs Cycle and Electron Transport Chain in your answer.4. Write an equation to highlight the concept ‘ATP Splitting’. Explain. How is ATP resynthesized?5. Discuss the recovery of all three Energy Systems.6. Read the article ‘Makings of a Winner’ and attached readings on Energy Systems.