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Performance-Enhancing Substances. chapter 9. Performance- Enhancing Substances. Jay R. Hoffman, PhD; CSCS,*D; FACSM; FNSCA Jeffrey R. Stout, PhD, CSCS, FACSM, FISSN, FNSCA. Chapter Objectives.
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Performance-Enhancing Substances chapter9 Performance-EnhancingSubstances Jay R. Hoffman, PhD; CSCS,*D; FACSM; FNSCAJeffrey R. Stout, PhD, CSCS, FACSM, FISSN, FNSCA
Chapter Objectives • Provide reliable information to athletes on the risks and benefits of performance-enhancing substances. • Evaluate advertising claims for over-the-counter supplements marketed for performance benefits. • Describe the current status of research on performance-enhancing supplements.
Key Term • ergogenic aid: Any substance, mechanical aid, or training method that improves sport performance; for the purposes of this chapter, the term refers specifically to pharmacological aids.
Section Outline • Types of Performance-Enhancing Substances
Key Point • The distinction between a drug and a dietary supplement is linked to FDA approval for safety and effectiveness.
Types of Performance-Enhancing Substances • Definition of Products That Can Be Sold as Dietary Supplements • A product (other than tobacco) intended to supplement the diet that contains one or moreof the following dietary ingredients: • A vitamin • A mineral • An herb or other botanical • An amino acid (continued)
Types of Performance-Enhancing Substances • Definition of Products That Can Be Sold as Dietary Supplements (continued) • A product (other than tobacco) intended to supplement the diet that contains one or moreof the following dietary ingredients: • A dietary substance for use by humans to supplementthe diet by increasing the total dietary intake • A concentrate, metabolite, constituent, or extract (or combination of any ingredient identified above) (continued)
Types of Performance-Enhancing Substances • Definition of Products That Can Be Sold as Dietary Supplements (continued) • The product must also be intended for ingestion and cannot be advertised for use as a conventional food or as the sole item within a meal or diet.
Section Outline • Hormones • Anabolic Steroids • Dosing • Who Uses Anabolic Steroids? • Ergogenic Benefits • Muscle Mass and Strength • Athletic Performance • Psychological Effects • Adverse Effects (continued)
Section Outline (continued) • Hormones • Testosterone Precursors (Prohormones) • Human Chorionic Gonadotropin • Insulin • Human Growth Hormone • Efficacy • Adverse Effects • Erythropoietin • β-Adrenergic Agonists • β-Blockers
Hormones • Anabolic Steroids • The synthetic (man-made) derivatives of the male sex hormone, testosterone
Hormones • Anabolic Steroids • Dosing • Athletes typically use anabolic steroids in a “stacking” regimen, in which they administer several different drugs simultaneously. • The potency of one anabolic agent may be enhanced when it is consumed simultaneously with another anabolic agent. (continued)
Hormones • Anabolic Steroids • Dosing (continued) • Most users take anabolic steroids in a cyclic pattern, meaning that they use the drugs for several weeks or months and alternate these cycles with periods of discontinued use. • Often athletes administer the drugs in a pyramid (step-up) pattern in which dosages are steadily increased over several weeks. Toward the end of the cycle, the athlete “steps down” to reduce the likelihood of negative side effects.
Dose-Response Curve • Figure 9.2 (next slide) • Dose–response curve of anabolic steroids and changes in lean body mass
Figure 9.2 Reprinted, by permission, from Hoffman, 2002.
Hormones • Anabolic Steroids • Who Uses Anabolic Steroids? • Olympic athletes, professional athletes, collegiate athletes, and high school athletes have been reported to use steroids. • Many users are not involved in sports; they use steroids to improve appearance. • Ergogenic Benefits • Muscle Mass and Strength • Increases in muscle protein synthesis with steroid use are likely responsible for increases in lean body mass. • Changes occur in both recreationally trained and competitive athletes.
Fat-Free Mass • Figure 9.3 (next slide) • Changes in fat-free mass with anabolic steroid administration (200 mg/week nandrolone decanoate for eight weeks) and following drug cessation • *p < .05
Figure 9.3 Adapted, by permission, from Van Marken Lichtenbelt et al., 2004.
Hormones • Anabolic Steroids • Ergogenic Benefits • Athletic Performance • The purported ergogenic benefits commonly attributed to anabolic steroid use are increased muscle mass, strength, and athletic performance, but these changes depend on the training status of the individual.
Hormones • Anabolic Steroids • Psychological Effects • Anabolic steroid use is associated with changes in aggression, arousal, and irritability. • Adverse Effects • The medical problems related to anabolic steroids may be somewhat overstated. • Many of the side effects linked to abuse are reversible upon cessation. • Side effects differ between anabolic steroid use under medical supervision and consuming many drugs at high doses.
Hormones • Testosterone Precursors (Prohormones) • Although performance changes may not occur with prohormone use, athletes may be at higher risk for experiencing adverse side effects similar to those associated with anabolic steroid use.
Hormones • Human Chorionic Gonadotropin • When injected into men, HCG can increase testicular testosterone production. • Insulin • Insulin increases protein synthesis, but the side effect of hypoglycemia can be fatal.
Hormones • Human Growth Hormone • Efficacy • There are no studies on the efficacy of HGH in athletic populations. • Anecdotal reports suggest impressive musculoskeletal performance changes in athletes using HGH.
Key Point • The anabolic potential of human growth hormone (HGH) and its ability to reduce body fat have contributed to the rise inHGH use among athletes.
Hormones • Human Growth Hormone • Adverse Effects • Although growth hormone used as replacement therapyfor people with growth hormone or IGF-I deficiency canbe effective and can have minimal adverse consequences, the dosages that are likely used by athletes may pose a significant risk for acromegaly.
Hormones • Erythropoietin • Injections of EPO are associated with elevations in both hematocrit and hemoglobin. • Health risks include increased risk of blood clotting, elevations in systolic blood pressure, a compromised thermoregulatory system, and dehydration during aerobic endurance events. • β-Adrenergic Agonists • β-adrenergic agonists can increase lean mass and decrease stored fat. • β-Blockers • β-blockers reduce anxiety and tremors during performance.
Key Point • More research is needed to examine the effect of many ergogenic aids in athletic populations. Athletes should not miscon-strue a lack of scientific information as an indication of safety.
Section Outline • Dietary Supplements • Essential Amino Acids • β-Hydroxy-β-Methylbutyrate • Nutritional Muscle Buffers • β-Alanine • Sodium Bicarbonate • Sodium Citrate • L-Carnitine • Creatine • Importance of Creatine to Exercise • Creatine Supplementation (continued)
Section Outline (continued) • Dietary Supplements • Creatine (continued) • Ergogenic Benefits • Body Mass Changes • Adverse Effects • Stimulants • Caffeine • Efficacy • Adverse Effects • Ephedrine • Efficacy • Adverse Effects • Citrus Aurantium
Dietary Supplements • The sport supplement industry throughout the world has exploded, with more than 600 sport nutrition companies marketing over 4,000 products that produce annual sales of more than $4 billion in the United States alone.
Dietary Supplements • Essential Amino Acids • EAA can augment muscle protein synthesis in healthy human subjects. • β-Hydroxy-β-Methylbutyrate (HMB) • It is believed that HMB has both anabolic and lipolytic effects, but research is limited. Recent studies do not support HMB supplementation in resistance-trained athletes.
Dietary Supplements • Nutritional Muscle Buffers • β-Alanine • Sodium Bicarbonate • Sodium Citrate • L-Carnitine • Studies examining L-carnitine’s role as an ergogenic aid for increasing lipid oxidation have not shown clear efficacy. • L-carnitine may enhance recovery from exercise.
Dietary Supplements • Creatine • Importance of Creatine to Exercise • The ability to rapidly rephosphorylate ADP is dependent upon the enzyme creatine kinase and the availability of creatine phosphate (CP) within the muscle. • Creatine Supplementation • Creatine supplementation increases the creatine content of muscles by approximately 20%, but there is a saturation limit. • Ergogenic Benefits • Studies consistently show significant ergogenic benefits.
Key Point • Creatine, in the form of creatine phosphate (CP; also called phosphocreatine [PCr]), has an essential role in energy metabolism as a substrate for the formation of adenosine triphosphate by rephosphorylating adeno-sine diphosphate (ADP), especially during short-duration, high-intensity exercise.
1RM Squat Strength • Figure 9.4 (next slide) • Changes in 1RM squat strength in experienced collegiate American football players ingesting creatine, creatine plus β-alanine, or a placebo • * = significantly different (p < .05) compared to placebo
Figure 9.4 Adapted, by permission, from Hoffman et al., 2006.
Key Point • Creatine supplementation has been shown to increase strength and improve training by reducing fatigue and enhancing postworkout recovery.
Dietary Supplements • Creatine • Body Mass Changes • Prolonged creatine supplementation has been generally associated with increases in body weight, especially increases in fat-free mass. • Adverse Effects • Controlled studies have been unable to document any significant side effects from creatine supplementation. • Concerns include gastrointestinal disturbances and strain on the kidneys.
Dietary Supplements • Stimulants • Caffeine • Efficacy • Increases time to exhaustion • Effects on sprint or power performance unclear • Adverse Effects • Many adverse effects, including anxiety, gastrointestinal disturbances, restlessness, insomnia, tremors, heart arrhythmias, and increased risk for heat illness • Is physically addicting
Key Point • A central nervous system stimulant, caffeine is an ergogenic aid that may enhance perfor-mance in aerobic and anaerobic athletes alike.
Dietary Supplements • Stimulants • Ephedrine • Efficacy • Effective only when it is taken in combination with caffeine • Improves aerobic endurance performance • Adverse Effects • Many adverse effects, including death • Banned by most sport governing bodies, including the International Olympic Committee
Dietary Supplements • Stimulants • Citrus Aurantium • Is thought to contribute to appetite suppression, increased metabolic rate, and lipolysis • When combined with caffeine and other herbal products, significant improvements in time to fatigue have been reported • On NCAA list of banned performance-enhancing drugs