Short duration high intensity activities early part of endurance activities Aerobic Endurance activities Training Decreases reliance on anaerobic systems Extends availability of glycogen M Ashcraft Sports and Nutrition Moderate intensity aerobic physical activity 5 times per week for 30 min each time Vigorous intensity aerobic activity 3 times per week for 20 min or more each time Exercise and Physical Fitness Muscle Strength Muscle Endurance Flexibility Cardiovascular Endurance Body Composition Energy Systems for Physical Performance Energy production systems Anaerobic Anaerobic Energy Systems Quick source of ATP Cellular ATP and creatine phosphate CP Lactic acid energy system Breakdown of glucose to lactic acid lactate Doesn t require oxygen Rise in acidity triggers muscle fatigue Oxygen energy system Breakdown of carbohydrate and fat for energy Requires oxygen Produces ATP more slowly Aerobic Energy Systems Factors Influencing Energy Costs Age Gender Size weight and body composition Activity level Type of activity Skeletal Muscle Fiber Types Type I slow twitch Red Muscle Aerobic energy system Posture endurance Walking standing habitual movements marathon runner Type II fast twitch White Muscle Anaerobic energy system Explosive short actions Sprinting jumping resistance Nutrition Requirements for Athletic Performance Appropriate body composition Muscle tissue fiber performance Muscle to fat ratio Adequate energy and nutrient intake pre and post performance Optimal recovery Hydration status M Ashcraft The Athlete s Diet No typical diet Meet DRIs for macro micro nutrients Adequate balance of essential nutrients and energy Before exercise Maintain hydration easily digested foods low in fat and fiber high in CHO moderate in protein During exercise After exercise Replace fluid losses provide CHO 30 60 g hr Adequate energy and CHO to replace glycogen and ensure rapid recovery Hydration Vegetarians may be at risk of low energy protein and micronutrients Carbohydrates Ergogenic Properties Normal blood glucose levels spare liver and muscle glycogen stores Glycogen loading delays the onset of fatigue Sources grains fruit vegetables and milk Amount Glycogen Loading 6 to 10 g kg body weight day Process of reducing activity while increasing CHO intake to maximize glycogen stores 7 d before competition Reduce training intensity 3 d before competition Reduce training to daily warm up of 10 to 15 minute Eat a CHO rich diet Fat Ergogenic Properties Use of fatty acids for energy delay exhaustion Preferred fuel source for low to moderate endurance activities Once glycogen stores are depleted High fat diets are not needed recommended to increase performance Recommendation Moderate fat intake 25 of total energy Extreme fat restriction limits protein iron zinc and essential fatty acids Mono and poly unsaturated sources Protein Ergogenic Properties Protein recommendations g kg day Sedentary adults 0 8 Endurance athletes 1 2 1 4 Strength athletes 1 6 1 7 Protein sources Lean meats fish low fat dairy egg whites Protein intake after exercise Helps replenish glycogen Aids in fast recovery Dangers of high protein intake Nitrogen by products Kidney function hydration status Branched Amino Acids Essential amino acids metabolized in skeletal muscle Trigger muscle protein synthesis by Transcription Formation of ribonucleic acid RNA from DNA M Ashcraft Arginine Creatine Translation mRNA ribosomes and specific amino acids bound to transfer RNA tRNA to attach amino acids to a lengthening protein chain Conditionally nonessential amino acid Precursor of creatine Changes into nitric oxide which causes blood vessel relaxation vasodilation In larger amounts it stimulates the release of growth hormone Believe to maintain muscle ATP levels Increase strength and possibly fat free body mass Water shifts Does not help endurance or sprinting performance Vitamins and Minerals Ergogenic Properties Vitamins and minerals do not appear to have any ergogenic value in amounts beyond the DRI Taken in amounts greater than the DRI will not improve performance and may be dangerous Vitamin E Antioxidant Stored in muscle and fat Maintains collagen in connective tissue Involved in energy production Needed for oxygen delivery and energy production Athletes have higher losses Improves oxygen capacity hemoglobin myoglobin Essential in nerve impulse transmission Essential for normal muscle function Essential to metabolism and component of ATP Helps maintain pH levels Sodium Potassium Chloride Maintain water balance and distribution Maintain normal cardiac rhythm Vitamin C B vitamins Iron Calcium Phosphorus Chromium Essential trace mineral in foods that helps metabolize carbohydrate fat and protein Improves glucose tolerance Increases glycogen synthesis Increases amino acid incorporation in muscle Alkalinization Bicarbonate Naturally part of body s buffering system to maintain normal pH Loading increases blood alkalinity More lactate can be cleared May delay fatigue Phosphates Increases potential for oxidative phosphorylation and creatine phosphate CP synthesis Enhances oxygen release to the cells Water Balance During Exercise Dissipates excess body heat Replace water loss due to sweating M Ashcraft Maintain blood flow Maintains blood pressure If dehydration exceeds 2 body weight physical performance is impaired Nutrition Supplements and Ergogenic Aids Many product claims Energy enhance performance change body composition Limited scientific evidence Potential side effects Many substances are banned for athletes Anabolic Steroids Banned for use in athletes Disproportional increase of fat free mass Side effects Breast development in men Liver cancer Severe acne Take Home Messages Exercise promotes health and reduces risk of chronic diseases Physical activity Exercise Types of muscle fibers Type I aerobic slow twitch Type II anaerobic fast twitch Energy systems Anaerobic ATP CP Lactate Aerobic Oxygen energy system Carbohydrates CHO Major source of energy in the athlete s diet during high intensity activities Should come from complex CHO Maintain glycogen stores and blood glucose levels Process of reducing activity while increasing CHO intake to maximize glycogen stores Major fuel source during low to moderate endurance activities High fat intake neither required nor recommended before during or after exercise Requirements increase in athletes vs sedentary people B vitamins iron zinc and calcium CHO loading Fat Proteins Water Most essential