1. April 7, 2006 The Lactic Acid System and Aerobic Systems for Energy Production During Exercise David L. Gee, PhD www.cwu.edu/~geed

2. Lactic Acid System n Anaerobic glycolysis n Uses muscle glycogen, blood glucose, liver glycogen as substrates (not FAT or PRO) n High rate of ATP energy production n Primary fuel in sprint-type activities (a few seconds - few minutes)

6. Lactic Acid System n Important when: n Activity longer than a few seconds creatine-P depleted/limited n Activity too intense for aerobic metabolism oxygen delivery limited –limited rate of O 2 : uptake in lung transport and delivery to muscle cell transport and delivery to mitochondria

7. Lactic Acid System n Lactic acid is the end product n Low total energy capacity lactic acidosis Inhibits glycolytic enzymes n Training effects improved aerobic capacity reducing lactate production improved removal of lactate n Ergogenic aids bicarbonate loading

8. Oxygen Energy System

9. Oxygen Energy Systems n Aerobic carbohydrate metabolism glycolysis, Krebs cycle, electron transport system n lower rate of ATP energy production n high total energy capacity n primary source of energy for higher intensity endurance events (~< 30 min)

10. 09.06 Aerobic Respiration Overview Slide number: 2 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Glucose Plasma membrane Extracellular fluid Mitochondrion Cytoplasm

11. Glucose Plasma membrane Extracellular fluid 09.06 Aerobic Respiration Overview Slide number: 4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mitochondrion Cytoplasm PyruvateGlycolysis ATP NADH Acetyl-CoA

12. Glucose Plasma membrane Extracellular fluid 09.06 Aerobic Respiration Overview Slide number: 6 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mitochondrion Cytoplasm PyruvateGlycolysis ATP NADH ATP H2OH2O O2O2 Electron transport system ATP NADH CO 2 Krebs cycle NADH Acetyl-CoA

13. Oxygen Energy Systems n Fat oxidation Beta-oxidation, Krebs cycle, Electron transport system n Lowest rate of ATP-energy production n Highest total energy capacity n Primary source of energy during lower intensity endurance events (~>30 min)

14. Oxygen Energy Systems n Protein oxidation Amino acid oxidation, Krebs cycle, Electron transport system n Low rate of ATP-energy production n Limited total energy capacity n significant source of energy during long endurance events

16. % Contribution of Aerobic and Anaerobic Energy Sources