160 likes | 367 Views
Chapter 16. Ergogenic Aids for Fitness and Athletics. Ergogenic aids function. By improving the capacity of the muscles and/or the oxygen transport and utilization systems to do work By removing or reducing inhibitory mechanisms to allow the use of previously untapped reserves.
E N D
Chapter 16 Ergogenic Aids for Fitness and Athletics
Ergogenic aids function • By improving the capacity of the muscles and/or the oxygen transport and utilization systems to do work • By removing or reducing inhibitory mechanisms to allow the use of previously untapped reserves Visit The Physician and Sports Medicine: Ergogenic Aids at www.physsportsmed.com/issues/1997/04apr/eichner.htm
Amphetamines • Mimics the activity of the sympathetic nervous system • May improve swimming, running, weight throwing performance, reaction time, and balance, but conflicting results
Caffeine • Central nervous system stimulant • Diuretic • Mental stimulant • May impair motor performance • Increases endurance performance in cycling, running, and swimming
Anabolic steroids • Synthetic cholesterol-based drugs that resemble hormones • Popular with strength and power athletes as well as body builders • Increase strength, muscle mass, and body weight Visit NIDA Research Report—Steroid Abuse and Addiction at www.nida.nih.gov/ResearchReports/Steroids/AnabolicSteroids.html
Growth hormones • A naturally occurring polypeptide secreted by the anterior pituitary gland • Can now be synthesized • Used by strength and power athletes to increase muscle size and strength
Sodium bicarbonate • Naturally occurring buffer of acids in the blood • Used to reduce fatigue-causing effects of lactic acid build-up
Creatine • Synthesized primarily in the liver from amino acids • Found in meat and fish • Stored in skeletal muscle as phosphocreatine, used as a fuel source for high intensity exercise • Creatine loading increases phosphocreatine stores in muscles to delay onset of fatigue in high intensity, short-term activities • In resistance training it increases body weight, fat-free weight, and muscle mass Visit Creatine Supplementation at www.rice.edu/~jenky/sports/creatine.html and Sports Science Creatine Review at www.sportsci.org/traintech/creatine/rbk.html
Pyruvate • 3-carbon metabolite of carbohydrate metabolism • Intermediate in glycolytic energy production pathway • May provide additional substrate for the Krebs cycle, increase aerobic production of ATP, and improve endurance
Beta-hydroxy-beta-methylbutyrate (HMB) • Metabolite produced from the breakdown of the amino acid leucine • Used in resistance training to increase muscle mass and strength and decrease fat weight • Being studied for effect on muscle damage from long-distance running
Phosphate loading • Oral administration of sodium phosphate • Potential ways it may affect performance • Elevations in serum and intracellular phosphate • Increased availability of phosphate for oxidative phosphorylation and creatine phosphate synthesis • Increased red cell anaerobic glycolysis and efficiency • Elevation in red cell 2,3-diphosphoglycerate (2,3-DPG) • Enhanced myocardial and cardiovascular efficiency • Possible increase in anaerobic threshold
Blood doping • The process • 8 to 12 weeks prior to an endurance competition, two pints of blood are removed. • Red blood cells (RBC) are separated and frozen • Athlete continues to train and body restores RBC count to normal levels • During week prior to competition, the RBCs are reinfused • Results • An increase in RBC concentration and thus improved oxygen transport capability
Blood doping (cont.) • Ethical questions surrounding blood doping • Con: increases performance in artificial and unfair manner • Pro: same advantage enjoyed by athletes who train at high elevations to compete at sea level
Erythropoietin • Drug used for anemia and kidney disease • Stimulates bone marrow to produce red blood cells (RBC) • Improves performance is manner similar to blood doping
Carbohydrate loading • Increases amount of glycogen stored within muscles and so delays the onset of fatigue during endurance activities • Classic carbohydrate loading • 15% carbohydrate for first three days and 70% for last three days • Sherman’s moderate carbohydrate regime • 50% carbohydrate for the first three days and 70% for the last three.
Aid Anecdotal effect Research-proven effect Major side-effects Banned Pyruvate Improves performance in endurance activities, weight loss, lowers cholesterol High doses improve submaximal endurance performance High doses: Gastrointestinal distress, diarrhea N HMB Increases muscle mass and strength and decreases fat weight Increases isometric strength, concentric and eccentric isokinetic peak torque, and fat-free weight More research needed N Phosphate loading Enhances endurance performance Conflicting results None reported N Blood doping Enhances endurance performance Enhances endurance performance None reported Y Erythropoietin Enhances endurance performance Enhances endurance performance Elevated blood pressure, flu-like symptoms, possible heart attack, stroke, pulmonary edema Y Carbohydrate loading Enhances endurance performance Enhances endurance performance None N