EF205 Scientific Foundations of Exercise and Fitness

1. EF205 Scientific Foundations of Exercise and Fitness Unit 3

2. Today’s Agenda Quick Review and Look Ahead Lecture Summary and Q & A

3. Quick Review • What did we study last week?

4. Quick Review • What did we study last week? • Why knowledge of anatomy is important • Different types of joints and movements at those joints • Important facts about muscles • Types of muscle actions

5. Why Do We Need to Understand Energy Metabolism?

6. Why Do We Need to Understand Energy Metabolism? • ATP is used for muscle contraction • Adaptations to exercise training involve aspects of energy metabolism. • Different activities will require different energy systems and thus the body must be supplied with the correct fuels. This is why the interaction between Nutrition & Exercise is so important.

7. Energy • Energy is the capacity to perform work • Energy can come from a number of different forms (Chemical, Electrical, Electromagnetic, Thermal, Mechanical, Nuclear) • The energy we derive from food is stored in a high-energy compound - ATP

8. Where do we get Energy from?

9. Where do we get Energy from? • CHO provides about 4 kcal of E per gram • Fat provides about 9 kcal of E per gram • Protein can also provide energy--about 4 kcal per gram.

10. Aerobic vs. Anaerobic Metabolism • Aerobic metabolism: • The production of ATP with oxygen • Anaerobic metabolism: • The production of ATP without oxygen

11. Practically Speaking Anaerobic refers to activities that are high in intensity, but short in duration

12. Practically Speaking Aerobic refers to activities that are low-to-moderate in intensity and longer in duration.

13. Difference If energy demand exceeds oxygen delivery, you are performing anaerobic exercise If oxygen delivery meets or exceeds energy demand, you are performing aerobic exercise

14. Anaerobic ATP Production • Two pathways: • ATP-PC system • Anaerobic glycolysis • The ATP-PC and glycolytic systems are major contributors of energy during the early minutes of high-intensity exercise.

15. ATP-PC System • Simplest of the energy systems • This process is rapid • Does not require oxygen (O2) and is therefore anaerobic. • Can only sustain maximum muscle work for 3-15 seconds.

16. Glycolysis No oxygen is required for this system. • It is an Anaerobic System • Lactic Acid will eventually prevent the muscles from contracting. • 2ATP from Glucose • 3ATP from Glycogen

17. Aerobic Metabolism The oxidative system involves breakdown of fuels with the aid of oxygen This system yields much more energy that the ATP-PC or glycolytic systems

18. Aerobic Metabolism • The process produces carbon dioxide and water as by-products. • Oxygen is required for this system • It is an Aerobic System. • The waste products are easily removed from the body • 38ATP from Glucose (39 from Glycogen)

19. Interaction of Energy Systems

20. Interaction of Energy Systems

21. Energy Used When Exercising • When exercising some muscles work aerobically (with oxygen), which means they can use fat or carbohydrate as a fuel. Others work mainly anaerobically for which they can use only carbohydrate. The diagram summarizes what happens when exercising:

22. Muscle Fibers • Some are more aerobic, some are more anaerobic • Type I (slow oxidative)—mostly aerobic, contract slowly, produce little force, resist fatigue • Type IIa (Fast oxidative glycolytic)—fast contracting, produces a great deal of force, but also resists fatigue • Type Iix (fast glycolytic)—contract quickly, produce great force, but fatigue quickly

23. What type of muscle fibers do you have? • Avg male and female • ~52% Type 1 • ~33% Type IIa • ~13% Type IIx • This differs greatly across overall population • Cannot convert fast twitch fibers to slow twitch or vice versa with endurance training • However, muscle fibers can take on aerobic characteristics

24. Fat and Protein Metabolism • ATP production from fatty acid sources is important in many forms of exercise. • Protein metabolism can provide energy, but it accounts for less than 5 percent of total ATP production during exercise.

25. True or False Only low intensity exercise causes you to burn fat and lose weight so you should avoid high intensity exercise if you want to lose fat

26. True or False Only low intensity exercise causes you to burn fat and lose weight so you should avoid high intensity exercise if you want to lose fat FALSE!

27. What factors influence caloric expenditure?

28. What factors influence caloric expenditure? • Type of activity • Intensity of activity • Weight of individual • Fitness level/efficiency of individual • Other factors: music, size of muscles, etc

29. What is VO2 Max? • An interaction between your cardiovascular system and respiratory systems • Is the point at which oxygen uptake does not increase even with increases in work load

30. How do we measure/test CV Fitness? • Graded Exercise Test (GXT)--Workload is progressively increased until the client is exhausted and cannot continue • Requires exercise physiology lab with trained personnel • Replaced by submaximal tests which don’t require expensive equipment

31. Submaximal Tests and Field Tests • Give good estimate of VO2max • Monitoring heart rate is necessary • Good for testing large numbers of people at one time • Require little equipment • Common tests: • Rockport Walk Test • YMCA step test • 1.5-mile run-walk test

32. Facts about VO2Max • Endurance training can increase VO2max by 5-25% • CC skiers have some of the highest VO2max’s (~80ml/kg/min-1) • Women’s VO2 values are ~15% lower than men’s • Genetics accounts for ~40% of VO2max • Aging decreases VO2max by 1%/year • Disease (CV and Pulmonary) negatively effects VO2max

33. Quiz Hints • Respiratory Exchange Ratio • Facts about VO2max • Metabolic pathways • Blood lactate levels

34. Wrap Up Summary Q & A