Sport and the Body

Sport and the Body - Sport and the Body Glen Joe Exercise...

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Unformatted text preview: Sport and the Body Glen Joe Exercise Physiologist - Active Health Clinic Institute of Human Performance [email protected] Stanley Ho Sports Center , Sandy Bay Road, Henry Fok Health and Fitness Complex, Exercise Clinic, 1F Sport and the Body • (I) Advanced materials for sport equipment: optimizing sporting performance and making sport safer √ • (II) Sport Nutrition √ • (III) Sport and the Body – Notes posted on Blackboard before lecture Lab 2 Lab 3 Lab 4 Unit 1 Unit 2 Unit 3 (iii) Muscle Unit 4 (iv) Body Composition (I) Introduction to (ii) Aerobic Energy Sources (ii) Anaerobic Sources 1 • Anabolism: reactions in which smaller molecules are assembled to build larger ones. Require energy. Require Chemical reactions allow all foods to be converted to sources of potential energy…. •Catabolism: reactions in which large molecules are broken down to smaller ones. Usually release energy. Usually What is energy? • humans convert food into chemical energy via the energy rich compound adenosine adenosine triphosphate (ATP) • ATP = adenosine and 3 phosphates • ATP is a high energy compound • energy from ATP is utilized for all energy requiring processes in the cell 2 ATP How is it acquired? • we have only enough ATP stores to supply energy for a few seconds of maximum exercise. • so ATP needs to be continually resynthesized • we have 3 different systems for resynthesizing ATP – ATP-PCr (“immediate” energy) ATPimmediate” – Anaerobic Glycolysis (short-term, high intensity (shortenergy) – Aerobic Energy Production (long-term energy) (longhttp:// Success in many sports is dependent on brief, all-out, maximal efforts, e.g. • for all-out maximal efforts we rely almost allalmost exclusively on the high energy phosphates within the muscle – adenosine triphosphate (ATP) – phosphocreatine (PCr) 3 ATP-PCr system • PCr (phosphocreatine) = PC = CP (creatine phosphocreatine) (creatine phosphate) • rapid generation of ATP without oxygen • immediate source of energy for power events of less than 10 seconds • we have larger stores of PCr than ATP (4-6x) (4- ATP-PCr system ATP-PCr system • Using PCr helps maintain our ATP levels early in exercise and during short duration , very high-intensity exercise high- ATP-PCr system The most rapidly available sources of ATP because they – do not depend on a long series of chemical reactions – do not depend on an oxygen supply – are in the muscle 14 sec of maximal sprinting 4 Immediate Energy Stores • • • ATP ~ 5 mmol per kilogram of skeletal muscle PCr ~ 15 mmol per kilogram of skeletal muscle we have enough stored ATP and PCr to power a maximal effort for around 6 to 8 seconds • the body cannot sustain a maximal effort for longer than this time • so, in a 100m sprint the runner slows down towards the end of the race Short-Term, High-Intensity Energy • to continue high-intensity exercise for more than higha brief period ATP needs to be resynthesized • as our oxygen supply is inadequate to maintain very high-intensity exercise we rely on highanaerobic glycolysis for rapid ATP formation anaerobic Short-Term, High-Intensity Energy • anaerobic glycolysis is essential for: Anaerobic glycolysis • also called the “lactic acid system” system” • glycolysis – breakdown of glucose – glycogen is also broken down by this system (glycogenolysis) glycogenolysis) • anaerobic = without oxygen • muscle cells have a good supply of glycogen and glycolytic enzymes – well equipped for anaerobic energy production • glycolysis also occurs during “aerobic exercise” exercise” 400m run 100m swim last phase of 1500 m run 5 Anaerobic glycolysis Glycogen Anaerobic glycolysis • Benefits – rapid supplier of ATP if exercise lasts longer than 10 seconds • vital during short-term, high-intensity exercise shorthigh- – does not require oxygen • Disadvantages – CHO only fuel source – an inefficient use of glucose/glycogen • much lower ATP production per gram of glucose than via the aerobic pathway Lactic Acid Oxidative Breakdown 700 600 250 200 500 400 300 200 50 100 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Boy – 10y 53.8 kg 150 Power [W] Cadence [1/min] 100 Heart [1/min] Peak Power - 664 W Mean Power – 242 W 0 Time [Sec] 2000 1800 1600 1400 250 200 Girl – 17y 57kg Peak Power (power) - 1965 W Mean Power (capacity) - 568 W 1200 1000 800 600 400 200 0 150 Power [W] Cadence [1/min] 100 50 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time [Sec] 6 Comparison of ATP-PCr and Glycolytic Energy ATPSystems Characteristic Complexity Cellular location End products Rate of ATP production Capacity of ATP production e.g., sport ATP-PCr ATPSimple Cytoplasm ADP, Pi, Creatine High Low 100 m Glycolysis Moderate Cytoplasm Lactic acid No Moderate Moderate 800 m Oxygen requirement No 7 ...
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  • Spring '10
  • drtong
  • pH, Adenosine triphosphate, anaerobic glycolysis

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