Chapter 25 Ergogenic Aids

1. Chapter 25Ergogenic Aids EXERCISE PHYSIOLOGY Theory and Application to Fitness and Performance, 6th edition Scott K. Powers & Edward T. Howley

2. Objectives • Define ergogenic aid • Explain why a “placebo” treatment in a “double-blind design” is used in research studies involving ergogenic aids • Describe, in general, the effectiveness of nutritional supplements on performance • Describe the effect of additional oxygen on performance; distinguish between hyperbaric oxygenation and that accomplished by breathing oxygen-enriched gas mixture

3. Objectives • Describe blood doping and its potential for improving endurance performance • Explain the mechanism by which ingested buffers might improve anaerobic performances • Explain how amphetamines might improve exercise performance • Describe the various mechanisms by which caffeine might improve performance

4. Objectives • Identify the risks associated with using chewing tobacco to obtain a nicotine “high” • Describe the risks of cocaine use and how it can cause death • Describe the physiological and psychological effects of different types of warm-ups

5. Ergogenic Aid • A substance, appliance, or procedure (e.g., blood doping) that improves performance

6. Ergogenic Aids • Research design concerns • Placebo • Look-alike substance containing nothing that will improve performance • Athlete’s belief in a substance may influence performance • Double-blind studies • Neither the investigators nor the subjects are aware of who is receiving the treatment

7. Research Design Concerns • Amount of substance • Too little or too much may show no effect • Subject • May be effective in trained but not untrained subjects and vice versa • Task • Endurance vs. short-term events • Large-motor vs. fine-motor activities • Use • May enhance short-term performance but compromise long-term performance

8. Changes in Performance –the Placebo Effect Fig 25.1

9. Nutritional Supplements • Little evidence that nutritional supplements improve performance • Supplements include: • Protein • Creatine • Carnitine

10. Aerobic Performance • Oxygen breathing • Before or after exercise: no effect on performance • During exercise: improved performance • Blood doping • Infusion of RBCs in effort to increase hemoglobin concentration and oxygen carrying capacity of blood • Effective in improving VO2max and endurance performance

11. Oxygen Breathing Fig 25.2

12. Blood Doping Fig 25.3

13. Anaerobic Performance • Blood buffers (sodium bicarbonate) • Improves performances of 1-10 minutes duration or repeated bouts of high-intensity exercise • No benefit for tasks of less than one minute • Optimal dose • 0.3 g•kg body weight-1 (with 1 liter of water)

14. Drugs • Amphetamines • Catecholamine-like effect • Improve performance in fatigued subjects only • No improvement in alert, non-fatigued subjects

15. Drugs • Caffeine • May improved performance at muscle, nervous system, or the delivery of fuel to muscle • Can elevate blood glucose and increase fat utilization • Effect is variable and dose-related • Effect may be diminished in regular users

16. Factors Influenced by Caffeine That Might Improve Performance Fig 25.4

17. Mechanisms by Which Caffeine May Increase FFA Mobilization Fig 25.5

18. Drugs • Cocaine • Powerful stimulator of cardiovascular and central nervous systems • May cause sudden death • Nicotine • Can stimulate both sympathetic and parasympathetic nervous systems • Cardiovascular or GI effects • Known to cause diseases of the mouth, including oral cancer

19. Mechanisms by Which Cocaine Can Kill Fig 25.6

20. The Effects of Nicotine Fig 25.7

21. Physical Warm-up • Causes both physiological and psychological changes that are beneficial to performance • Increased muscle temperature, arousal, focus on event • Warm-up activities • Identical to performance • Directly related to performance • General warm-up

22. Chapter 25 Ergogenic Aids