Presentation on theme: "15 Ergogenic Aids and Sport chapter. Did You Know... ? The placebo effect refers to when your body’s expectations of a substance determine your body’s."— Presentation transcript:
Did You Know... ? The placebo effect refers to when your body’s expectations of a substance determine your body’s response to it. While the effect is psychological in origin, the body’s physical response to the substance is real.
The Placebo Effect on Muscular Strength Gains Data from G. Ariel and W. Saville, 1972, "Anabolic steroids: The physiological effects of placebos," Medicine and Science in Sports and Exercise 4: 124-126.
Amphetamines Increase mental alertness, blood pressure, heart rate, blood glucose and FFA levels, and muscle tension Decrease sense of fatigue Redistribute blood flow to skeletal muscles May enhance speed, power, endurance, concentration, and fine motor coordination May be addictive and can trigger cardiac arrhythmia or death
Beta-Blockers Prevent the binding of norepinephrine and decrease sympathetic nervous system activity May improve accuracy (for shooting sports) Decrease aerobic capacity but have no effect on strength, power, or muscular endurance Prolonged use can cause bradycardia, heart blockage, hypotension, bronchospasm, fatigue, and decreased motivation
Caffeine Increases mental alertness, concentration, catecholamine release, and mobilization and use of FFA by the muscles Decreases fatigue and lowers perception of effort Improves endurance performance; may improve sprint and strength performance Can cause nervousness, insomnia, and tremors and can lead to dehydration
Diuretics Increase urine production and excretion Used for weight reduction and to mask other drugs during drug testing Cause weight loss (water loss) Can lead to dehydration, impaired thermoregulation, and electrolyte imbalances
Hormonal Agents Anabolic steroids Human growth hormone Oral contraceptives
Anabolic Steroids Are nearly identical to male sex hormones; synthetic form maximizes building effects Increase muscle mass and strength Can cause testicular atrophy, reduced sperm count, and prostate and breast enlargement in men Can cause breast regression, masculinization, and menstrual disruption in women Cause personality changes, liver damage, and cardiovascular disease
Percent Changes in Body Size, Body Composition, and Strength When Athletes Used Anabolic Steroids and a Placebo
Relationship Between Total Dose of Steroid and Change in Fat-Free Mass (in kg) From an article published in Metabolism, vol. 34, G.B. Forbes, "The effect of anabolic steroids on lean body mass: The dose response curve," pp. 271-573, Copyright 1985.
Human Growth Hormone Secreted naturally by pituitary; synthetic form used by some athletes Difficult to detect synthetic from natural in drug testing Proven to increase lipolysis and blood glucose levels Can cause acromegaly, enlargement of internal organs, muscle and joint weakness, diabetes, hypertension, and heart disease
Blood Doping Artificial increase in total volume of red blood cells (often via transfusion) Improves endurance performance by increasing blood’s O 2 -carrying capacity Increases VO 2max, time to exhaustion, and measurable performance Can cause blood clotting, heart failure, and transfusion complications.
Changes in VO 2max and Running Time to Exhaustion After Reinfusion of Red Blood Cells Adapted, by permission, from F.J. Buick et al, 1980, "Effect of induced erythrocythemia on aerobic work capacity," Journal of Applied Physiology 48: 636-642..
Improvements in Running Times After Reinfusion of Red Blood Cells Adapted, by permission, from L.L. Spriet, 1991, Blood doping and oxygen transport. In Ergogenics - Enhancement of performance in exercise and sport, edited by D.R. Lamb and M.H. Williams (Dubugue, IA: Brown & Benchmark), 213-242. Copyright 1991 Cooper Publishing Group, Carmel, IN.
Erythropoietin Natural hormone produced by the kidneys to stimulate red blood cell production Can be cloned and administered to increase red blood cell volume Increases VO 2max and time to exhaustion Can cause blood clotting and heart failure due to increased blood viscosity.
Oxygen Supplementation Breathed by athletes to increase oxygen content of blood Can improve performance if administered during exercise, but not before or after Too cumbersome to be practical No serious risks known
Bicarbonate Naturally part of body’s buffering system to maintain normal pH Loading increases blood alkalinity so that more lactate can be cleared (delay fatigue) Ingesting 300 mg per kg body weight can increase performance in all-out exercise bouts between 1 and 7 minutes Can cause gastrointestinal cramping, bloating, and diarrhea
Concentrations of (a) Blood Bicarbonate and (b) Blood Hydrogen Ion With and Without Ingestion of Sodium Bicarbonate Adapted, by permission, from D.L. Costill et al., 1984, "Acid-based balance during repeated bouts of exercise: Influence of HCO 3," International Journal of Sports Medicine 5: 228-231.
Phosphate Loading is thought to increase phosphate levels throughout the body, which then increase potential for oxidative phosphorylation and PCr synthesis, enhance oxygen release to the cells, and improve cardiovascular response to exercise and buffering and endurance capacities. Studies are divided on results of phosphate loading. No risks are yet known.
Amino Acids L-tryptophan and BCAA Proposed to increase endurance performance by delaying fatigue Studies are inconclusive on effects on performance
Time to Exhaustion on a Cycle Ergometer at 70% of VO 2max Adapted, by permission, from G. van Hall et al., 1995, "Ingestion of branched-chain amino acids and tryptophan during sustained exercise in man: Failure to affect performance," Journal of Physiology 486: 789- 794..
Creatine Supplement to better maintain muscle ATP levels Shown to increase strength and possibly fat-free body mass Not shown to help endurance performance, sprint running, or sprint swimming performance