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Chapter 25: Ergogenic Aids

EXERCISE PHYSIOLOGY

Theory and Application to Fitness and Performance, 5th edition

Scott K. Powers & Edward T. Howley

Presentation revised and updated by

TK Koesterer, Ph.D., ATC

Humboldt State University

(c) 2004 The McGraw-Hill Companies, Inc. All rights reserved.

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 effective ness 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

(c) 2004 The McGraw-Hill Companies, Inc. All rights reserved.

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

(c) 2004 The McGraw-Hill Companies, Inc. All rights reserved.

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

(c) 2004 The McGraw-Hill Companies, Inc. All rights reserved.

Ergogenic Aid

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

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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

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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

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Changes in Performance–the Placebo Effect

Fig 25.1

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Nutritional Supplements

• Little evidence that nutritional supplements improve performance

• Supplements include:– Protein– Creatine– Carnitine

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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

(c) 2004 The McGraw-Hill Companies, Inc. All rights reserved.

Oxygen Breathing

Fig 25.2

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Blood Doping

Fig 25.3

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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)

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Drugs• Amphetamines

– Catecholamine-like effect– Improve performance in fatigued subjects

only• No improvement in alert, non-fatigued

subjects

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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

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Factors Influenced by Caffeine That Might Improve Performance

Fig 25.4

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Mechanisms by Which Caffeine May Increase FFA Mobilization

Fig 25.5

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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

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Mechanisms by Which

Cocaine Can Kill

Fig 25.6

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The Effects of Nicotine

Fig 25.7

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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