Nutrition and Ergogenics



Nutrition and Ergogenics





3.1 General

Nutrition guidelines are established every 5 years by the U.S. Department of Agriculture and the U.S. Department of Health and Human Services (http://www.nalusda.gov/fnic/dga/dguide95.html). The Food Guide Pyramid (http://www.nal.usda.gov:8001/py/pmap. htm) offers a general guide for a healthy diet (see Table 3.1).








Table 3.1 Nutrition Guide for Optimum Performance

















Eat a high carbohydrate diet.


Taper by decreasing the intensity and/or duration of practice for 1-2 d before competition.


Eat a carbohydrate meal 3-4 hr before competition.


Maintain adequate fluid intake before and during competition.


Avoid sugar less than 1 hr before competition.


After exhausting exercise, eat carbohydrates.


Eat foods containing adequate vitamins and minerals.



Banned Drugs



  • For the most current list of drugs banned by the National Collegiate Athletic Association (NCAA) and the International Olympic Committee, check the websites:



    • http://www.ncaa.org/sports_sciences/drugtesting/banned_list.html


    • http://www.olympic.org/ioc/e/org/medcom/medcom_antidopage_e.html



3.2 Creatine

Prim Care 2005;32:277; Ped Clin North Am 2002;49:435, 2002; 49:829; Clin Sports Med 1999;18:651; Nut Aspects of Ex 1999;18:651; Phy Sportsmed 1999;27:47

Pathophys:



  • Short-burst, intense exercise rapidly consumes ATP.


  • Phosphocreatine serves as an energy buffer, transferring its phosphate group to ADP to regenerate ATP.


  • There is 4-6× more creatine phosphate (CP) than ATP stored in cells.


  • Both of these energy sources are depleted within 6-10 secs of intensive exercise, and they are replenished primarily through breakdown of carbohydrates and fats.


  • Ergogenic effects:



    • Creatine stores in muscle are increased through the ingestion of creatine (at most about 20%).


    • Increasing the supply of creatine phosphate provides more energy to exercising muscle.


    • Creatine improves performance in short-duration, repetitive, and intense exercise. Improvement in cycling, swimming, kayaking, rowing, weight lifting, jumping and sprinting ability have been shown.


    • Creatine increases total body mass and fat-free muscle mass (0.5-2.0 kg).


    • Creatine decreases lactic acid levels in the blood during sprints.


    • Conversely, creatine does not improve isometric strength, power, or aerobic endurance.


    • Middle-aged athletes may benefit more than younger athletes.


    • Men seem to benefit more than women from creatine use.


    • Simultaneous training exercise is required for a beneficial effect.



  • Creatine use with exercise results in increases in muscle mass. Type I (slow twitch, aerobic), type IIA (intermediate, anaerobic), and type IIB (fast twitch, anaerobic) muscle mass are increased.


  • Caffeine reduces the efficacy of creatine.


  • Large carbohydrate intake augments muscle uptake of creatine.


  • Best effects seen in subjects with lower initial creatine stores (vegetarians)

Sx: Muscle cramps (25% of users), strains, decrease urine output, diarrhea.

Cmplc: There are some reports of association with exertional rhabdomyolysis (J Am Board Fam Pract 2000;13:134) and heat injuries probably related to poor hydration, cardiac arrhythmia, cardiomyopathy, DVT, seizure, and use of other ergogenic substances.

Lab: UA, BUN/Cr or other labs indicated by presentation.

Rx:



  • A loading dose of 0.3 gm/kg of body weight per day (0.14 gm/lb of body weight per day) divided over 4-5 doses/d is taken for 5-7 d.


  • A maintenance dose of 0.03 gm/kg of body weight per day (0.014 gm/lb of body weight per day) is subsequently taken.


  • Naturally available creatine is found in beef, dairy products, and fish.


  • Not recommended for adolescents.


3.3 Anabolic Steroids

Prim Care 2005;32:277; Ped Clin North Am 2002;49:829; Clin Sports Med 1999;18:667; Am J Sports Med 1993;21:468; Clin Sports Med 1998;17;299


Cause: Oral or injectable supplementation.

Epidem: 6.6% of HS male seniors; mean age to start 14; also used by the recreational athlete looking for rapid gains.

Pathophys:



  • Testosterone is produced in the testes and adrenals.


  • Androstenedione is produced in the adrenal gland and testes then converted in the liver to testosterone.


  • Testosterone affects almost all body tissues by decreasing tissue breakdown and increasing tissue production.


  • Excess testosterone is peripherally converted to estrogen, resulting in feminization in males (Ann Pharm 1992;26:520).


  • Size and strength gains through anticatabolic, anabolic, and motivational effects.



    • Anticatabolic: displacement of cortisol from receptors resulting in less wasting and negative nitrogen balance.


    • Anabolic effect: induce protein synthesis; stimulation of endogenous HGH.


    • Motivational: aggressiveness to train hard.


  • Effects are reversed as soon as the steroids are stopped.

Sx: Significant improvement in performance more than indicated by level of training; muscle hypertrophy; aggressiveness and mood swings to include paranoia, mania, and hypomania; risk-taking behaviors; premature cardiovascular disease.

Si: Muscular hypertrophy; acne; striae; elevated BP; gynecomastia; gonadal atrophy, and impaired spermatogenesis; clitorimegaly; male pattern baldness.

Cmplc: Sudden death, myocardial infarction, increased low-density lipoproteins (LDLs), decreased high-density lipoproteins (HDLs), hypertension, concentric cardiac hypertrophy, hypercoagulability, decreased spermatogenesis, decreased testicle size, prostate hypertrophy, prostate cancer, voice alterations, liver damage and cancer, premature epiphyseal closure with resulting short stature, weaker tendons (Achilles and patellar tendon rupture), electrolyte
imbalances, insulin resistance, skin pathology, aggression, depression, paranoia, HIV, and hep B and C.

Lab: Sperm count, electrolytes, glucose, serum lipids, coagulation studies, liver function tests, PSA (over 40 or 50 years of age), an electrocardiogram, and possibly an echocardiogram if indications of ventricular hypertrophy are present; screening for hep B, hep C, and HIV is recommended for any athlete using injectable drugs. Urine screen is done to measure testosterone: epitestosterone ratio; >6 is a positive test.

Rx:



  • Stop supplementation.


  • Management of poststeroid depressive sx and dependence sx.


  • Multidisciplinary management approach.


3.4 Human Growth Hormone

Prim Care 2005;32:277; J Clin Endo and Met 1999;84:3591; Am J Sports Med 1993;21:468

Cause: Supplementation by injection.

Epidem: Unknown.

Pathophys:

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Jul 21, 2016 | Posted by in SPORT MEDICINE | Comments Off on Nutrition and Ergogenics

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