Module 3- Metabolism and Nutrition Ergogenic Aids Module 3- Metabolism and Nutrition

Performance Enhancing Substances 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 What are some examples of other ergogenic aids?

Hormones Anabolic Steroids The synthetic (man-made) derivatives of the male sex hormone, testosterone 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 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

Table 9.1

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 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 Adverse 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 Illegal

Table 9.2

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 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 Adverse Effects There are no studies on the efficacy of HGH in athletic populations Anecdotal reports suggest impressive musculoskeletal performance changes in athletes using HGH (increased muscle mass, decreased body fat) Adverse Effects Although growth hormone used as replacement therapy for people with growth hormone or IGF-I deficiency can be effective and can have minimal adverse consequences, the dosages that are likely used by athletes may pose a significant risk for acromegaly (increased GH secretion by the pituitary gland leading to cardiovascular and kidney problems and gigantism)

Hormones Erythropoietin β-Adrenergic Agonists β-Blockers 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

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 Nutritional Muscle Buffers β-Alanine Sodium Bicarbonate Sodium Citrate

Dietary Supplements 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

Creatine 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

Creatine 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 adenosine diphosphate (ADP), especially during short-duration, high-intensity exercise Creatine supplementation has been shown to increase strength and improve training by reducing fatigue and enhancing postworkout recovery

Creatine Creatine Body Mass Changes Adverse Effects Prolonged creatine supplementation has been generally associated with increases in body weight, especially increases in fat-free mass (water weight?) 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 Adverse Effects 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 A central nervous system stimulant, caffeine is an ergogenic aid that may enhance performance in aerobic and anaerobic athletes alike

Dietary Supplements Stimulants Ephedrine Efficacy Adverse Effects 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