* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Energy Systems
Survey
Document related concepts
Electron transport chain wikipedia , lookup
Fatty acid metabolism wikipedia , lookup
Photosynthetic reaction centre wikipedia , lookup
Light-dependent reactions wikipedia , lookup
Lactate dehydrogenase wikipedia , lookup
Microbial metabolism wikipedia , lookup
Citric acid cycle wikipedia , lookup
Biochemistry wikipedia , lookup
Oxidative phosphorylation wikipedia , lookup
Basal metabolic rate wikipedia , lookup
Adenosine triphosphate wikipedia , lookup
Evolution of metal ions in biological systems wikipedia , lookup
Transcript
Energy Metabolism Energy Energy Transfer in the Body Refer to text for more detail. Metabolism Biologic Work in Humans Mechanical the capacity or ability to perform work. Energy is required for muscle contraction and other biological work such as digestion, nerve conduction, secretion of glands, etc. the sum total of all chemical reactions occurring in the body. Adenosine Triphosphate (ATP) Work Transport Work Chemical Work Nitrogen Phosphorous Carbon Oxygen The most common immediate energy currency of the cell (the all purpose nucleotide) Metabolic Production of ATP Energy Aerobic Processes processes which require the presence of oxygen delivered by the blood Adenosine Triphosphate Nitrogen Phosphorous +Pi Adenosine Diphosphate Carbon Oxygen 1 ATP-CP (Phosphagen) System All-out power for approximately 10 seconds Biologic Work ATP !## #" ADP + Pi + ATPase CP !## #" C + Pi + Creatine Energy Energy Kinase Principle of Coupled Reactions Anaerobic Glycolysis The Glycolytic System Glucose Net production of 2 or 3 ATP molecules 10 chemical reactions 2 Pyruvate Lactate Glucose Glucose can be made available in the muscle cells for breakdown to lactate principally by two methods: Lactate glucose molecules may pass from the blood through the muscle cell membrane into the cell interior (net 2 ATP), or the glucose can be split from glycogen stores in the muscle cell itself (net 3 ATP). Glycogen is stored in liver and muscle tissue. Anaerobic Glycolysis Anaerobic glycolysis can produce ATP rapidly to help meet ATP requirements during severe exercise when oxygen demand is greater than oxygen supply High rates of ATP production by glycolysis cannot be sustained for very long (40-60 sec.) Low muscle pH is associated with hydrogen ion concentration and lactate formation High acidity is believed to contributes to the acute muscular discomfort experienced during intense exercise. Predominates in all-out efforts 30-90 seconds 50-200 meters 2 Aerobic Processes Aerobic Carbohydrate Breakdown Pyruvic Acid Acetyl Coenzyme A Krebs Cycle Wall of Mitochondria Anaerobic Conditions No O2 available Pyruvate not worry about specific yields of ATP. on whether glycogen or glucose is used and depending on which shuttle system is used to transport NADH molecules to the mitochondria you can get yields of 36 to 40 ATP. The main thing is to see the approximate increase in ATP yield between anaerobic breakdown (2 or 3 ATP) versus aerobic breakdown (36-40 ATP) Depending Glucose Glycolysis (2 ATP) Aerobic Conditions ATP Yield Do Lactate Glycolysis (2 ATP) Pyruvate Electron Transport Chain O2 available Krebs cycle Electron TC 36 ATP +CO2 +H2O Total ≈ 38 ATP Predominates in the majority of daily activities and lower intensity, long-duration sports. An all-out effort of 2 minutes is approximately 50% aerobic and 50% anaerobic Aerobic Breakdown of a Glycogen Molecule Glycogen Glucose Pyruvate Acetyl - CoA Kreb's cycle Electron Transport C + O2 CO2 + H2O + ATP 3 Energy Release From Fat The actual fuel reserves from stored fat represent approximately 80,000 to 100,000 kcal of energy in an average size male or female. In contrast, the carbohydrate energy reserve is less than 2,000 kcal, of which 1,500 kcal are stored as muscle glycogen, 400 kcal as liver glycogen, and about 80 kcal of glucose are in the blood. Energy Release From Protein Research findings indicate that protein breakdown above the resting level occurs during exercise of long duration when carbohydrate stores become low. It has been suggested as much as 15% of the energy during strenuous long duration exercise can come from protein. % phosphagen % glycolytic anaerobic anaerobic 5 seconds 10 seconds 30 seconds 60 seconds 2 minutes 4 minutes 10 minutes 30 minutes 60 minutes 120 minutes 85 50 15 8 4 2 1 Negligible Negligible Negligible 10 35 65 62 46 28 9 5 2 1 % aerobic 5 15 20 30 50 70 90 95 98 99 Aerobic Breakdown of Fatty Acids Less efficient than carbohydrate Fat in terms of energy Fatty acids per O2 used Beta oxidation Acetyl-CoA Kreb's cycle Electron Transport C + O2 CO2 + H2O + ATP Aerobic Breakdown of Proteins Protein" Amino acids Deamination Kreb's cycle Electron Transport Chain + O2 CO2 + H2O + ATP Relative contribution of aerobic and anaerobic energy during maximal physical activity of various durations. Duration of Maximal Exercise Seconds % anaerobic % aerobic Minutes 10 30 60 2 4 10 30 60 90 80 70 50 35 15 5 2 120 1 10 20 30 50 65 85 95 98 99 4 Phosphagen Energy Production Continuum Figure 6.5 in text The text graph shows this on logarithmic scale Lactic Lactate % Max Power Aerobic ATP-Creatine Phosphate System ATP !## #" ADP + Pi + ATPase CP !## #" C + Pi + Creatine Kinase General Characteristics of the Three Energy Systems Energy Energy For a max 1 second effort you do not really need to resynthesize much ATP – you have enough in the muscle already Table 6.3: Estimated Maximal Power Output and Capacity of the Three Energy Systems Energy System Power Moles ATP per minute Capacity Total moles of ATP available ATP-PC (phosphagen) Glycolytic Aerobic System 3.6 1.6 1.0 0.7 1.2 90.0 Aerobic Power ≈ 28% of Peak Phosphagen System Power Capacity and Power of the Three Energy Systems (Untrained Male Subjects) Energy System Phosphagen (ATP/PC) Anaerobic gylcolysis Aerobic (oxidative) ATP Production Capacity Power (total moles) (moles/min) 0.6 1.2 Theoretically Unlimited 3.6 1.6 1.0 Glycolytic System power ≈ 44% Peak Phosphagen Power (Some researchers report this value to be higher ≈ 60%) 5 Rankings of Rate and Capacity of ATP Production System ATP-PC (phosphagen) Anaerobic glycolysis Oxidation of carbohydrates Oxidation of fats and proteins Human Power Output Power Capacity rate of ATP production 1 capacity of ATP production 4 2 3 3 2 4 1 (energy systems) Graph from “Champion Athletes” Wilkie 1960 Time Motion Studies Energy Transfer in Exercise The energy systems previously discussed are related to all human activity. We now need to relate this information specifically to exercise. English 1st Division (Premier) Players Position and Distance Covered (in meters) Activity Mid-field Full-back Striker Centre-back Average Jog 4042 2907 2769 2908 3157 Cruise 2159 1588 1752 1596 1774 Sprint 1063 787 1068 829 937 Walk 2034 2293 2310 1774 2103 Back 507 670 498 652 582 Total 9805 8245 8397 7759 8552 6 Ajax Amsterdam Data Soccer Activity Walk Percentage of Total Match Time 20-30% Jog 30-40% Run 15-25% Sprint 10-15% (18%) Backwards 4-8% 4s ATP ATP-CP 10s 30s 3 min + 10 seconds 30 seconds 60 seconds 2 minutes 4 minutes 10 minutes 30 minutes 60 minutes 120 minutes Anaerobic ATP (in muscles) Anaerobic ATP + PC + Some muscle glycogen 4-20 seconds (ATP-PC/Glycolytic) Anaerobic Anaerobic (Glycolytic) Muscle glycogen 120-240 secs Aerobic + Glycolytic Muscle glycogen + a little from other fuels >240 secs Aerobic Muscle glycogen + Fatty Acids + Protein Performance Intensity Major Energy Time of Event System(s) Anaerobic Power Endurance 10 35 65 62 46 28 9 5 2 1 % aerobic 5 15 20 30 50 70 90 95 98 99 Types of Activity 0-6 seconds Very Intense ATP-CP Jumping, throwing, kicking, 50 metre sprints, base-running 6-30 seconds Intense ATP-PC and Glycolytic 100-200 metre sprints Glycolytic 600-800 metres run, ice hockey shifts, box lacrosse shifts, 100-metre swim 2-3 minutes Moderate Glycolytic and oxidative 800-100 metre runs >3 minutes Light Oxidative systems Running > 1000 metres, distance cycling, cross country skiing, swimming > 200-m Aerobic endurance 85 50 15 8 4 2 1 Negligible Negligible Negligible ATP + PC + Muscle glycogen 45-120 secs 30 seconds– Heavy 2 minutes % phosphagen % glycolytic anaerobic anaerobic 5 seconds 1-4 seconds Five Areas of the Energy Continuum Sustained Power Oxygen Predominate Energy Supplied By (Glycolytic/ATP-PC) Strength Power ATP-CP + glycolytic Classification 20-45 secs Predominant Energy Pathways 0s Duration Primary Metabolic Demand From Sports or Activity Phosphagen System Anaerobic Glycolysis Aerobic Metabolism Baseball High Low - Basketball High Moderate to High - Field Events High - - Field Hockey High Moderate Moderate Football (American) High Moderate Low Ice Hockey High Moderate Moderate Lacrosse High Moderate Moderate Marathon (42 km) Low Low High Soccer High Moderate Moderate Tennis High Moderate - Volleyball High Moderate - Wrestling High High Moderate Weight Lifting High Low Low 7 Average VO2 max (ml/kg.min) for Non-Athletes and Athletes Average VO2 max (ml/kg.min) for Non-Athletes and Athletes From Chapter 5 – you shouldMale see a high Group or Sport Age Female positive correlation between a sport 38-46 with Non-athletes 10-19 47-56 a high demand on the oxidative system 20-29 43-52 33-42 and the athletes VO260-69 max. 31-38 22-30 Baseball Cycling Football Gymnastics Ice Hockey Rowing 18-32 18-26 20-36 18-22 10-30 20-35 48-56 62-74 42-60 52-58 50-63 60-72 47-57 36-50 58-65 Oxygen Deficit Group or Sport Age Male Female Skiing – Alpine 18-30 57-68 50-55 Skiing – Cross-country 20-28 65-95 60-75 Soccer 22-28 54-64 - Speed Skating 18-24 56-73 44-55 Swimming 10-25 50-70 40-60 Weight Lifting 20-30 38-52 - Wrestling 20-30 52-65 Oxygen Debt O2 Deficit O2 Deficit Steady State O2 consumption VO2 (l/min) VO2 Rest Time Resting VO2 Oxygen Debt after Anaerobic Exercise O2 Deficit O2 Debt Exercise “Rapid” portion of debt O2 Debt O2 Debt Exercise TIME Recovery Recovery Oxygen Debt O2 Deficit VO2 max TIME Exercise TIME “Slow” portion of debt Recovery 8 Figure 6.11 Lactate threshold and the onset of blood lactate (OBLA) Recommended Recovery Times after Exhaustive Exercise Recommended Recovery Time Recovery Process Minimum Maximum Restoration of ATP & CP 2 min 3 min Repayment of alactate O2 debt 3 min 5 min Restoration of O2-myoglobin 1 min 2 min Restoration of muscle glycogen 10 hr 46 hr (prolonged) 5 hr 24 hr (intermittent) Removal of lactate from 30 min 1 hr (exercise-rec) muscle and blood 1 hr 2 hr (rest-recover) Repayment of lactate O2 debt 30 min 1 hr Lactate does not cause muscle soreness Despite the commonly held belief that lactic acid (lactate) causes muscle soreness this has been discredited. Delayed onset muscle soreness is likely caused by damage to muscle fibers and associated connective tissue. Ice Hockey Post-Game Recovery A light bike ride before/after exercise is a great way to warm-up or cool down along with stretching. Also, riding after a game helps to "flush out" lactic acid and other waste your muscles produce during activity; A cool-down flush ride should last around 10-min (often up to 30-min); Get your heart rate up around 140 bpm (Level II) for 5 min, then back off to a easy spin (Level I); You don't want to go hard enough to produce any more lactic acid (lactate); Stretch!!! This quote from” Paul Goldberg, of the Colorado Avalanche, February 1st, 2006. Blood Markers Getting a ball in the face also causes soreness! If we take a blood sample from a runner the day after a marathon, especially an ultra-marathon, we find that the levels of an enzyme called creatine kinase are very high. This is a marker of muscle damage as this particular enzyme "leaks" from damaged muscle. The "damage" is in the form of minute tears or ruptures of the muscle fibres. We can see this trauma to the muscle if a sample of muscle is examined microscopically. 9 Blood Markers (cont.) However, it is not just the muscle that is damaged. By measuring hydroxyproline, it is possible to show that the connective tissue in and around the muscles is also disrupted. What this shows is that stiffness results from muscle damage and breakdown of connective tissue. Muscle Fatigue and Lactate Lactic acid does not actually exist as an acid in the body but rather as “lactate. Producing lactate is a beneficial process since it allows the regeneration of a coenzyme that ensures that energy production is maintained and exercise can continue (see text). Lactate also does not cause an increase in acidity (acidosis) within the muscle. When ATP is broken down to release energy for muscular contraction a hydrogen ion is released. This increases acidosis. Muscle Fatigue & Calcium Channels Leaked calcium also stimulates an enzyme that attacks muscle fibers and also leads to fatigue and possible damage. However, as very high acidity could also cause damage to the cells the calcium leaks may be a protective mechanism to prevent muscle cell damage due to excessive acidity. Stretching and DOMS There is no statistically strong evidence that stretching reduces post exercise muscle soreness. Intense stretching can cause muscle soreness. Muscle Fatigue and Hydrogen Ions ATP-derived hydrogen ions are primarily responsible for increases in acidity in the muscle. High acidity is one factor that contributes to acute muscular discomfort experienced during and shortly after intense exercise. However, recent evidence suggests fatigue is caused by calcium leaking into muscle cells from release channels within the muscle. Calcium helps control muscle contractions but after extended high-intensity exercise, channels in the muscle cells begin to leak calcium, which leads to weakened muscle contractions. Neural Fatigue There is also the issue of Central Nervous System (CNS) fatigue. During intense repeated bouts of strenuous exercise neurotransmitters get depleted and reduces physical and cognitive performance. Central and peripheral fatigue factors are discussed in text Chapter 6. 10