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Energy systems. PHYSIOLOGICAL REQUIREMENTS OF PHYSICAL ACTIVITY. Foods Fuel and Energy Systems. Food Fuels our Body. 1. CARBOHYDRATES (Glycogen). 2. PROTEIN. 3. FATS. CARBOHYDRATES. Pastas. Cereals. Rice. Fruit/Veges. Breads. Sugar.
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PHYSIOLOGICAL REQUIREMENTS OF PHYSICAL ACTIVITY Foods Fuel and Energy Systems
Food Fuels our Body 1. CARBOHYDRATES (Glycogen) 2. PROTEIN 3. FATS
CARBOHYDRATES Pastas Cereals Rice Fruit/Veges Breads Sugar Carbohydrates are stored as Glycogen in Muscle & Liver CHO is the body’s preferred fuel during Exercise – breaks down easily, uses little oxygen
PROTEIN Fish Red Meat Poultry Eggs Dairy products GRAINS Protein is stored as MUSCLE and AMINO ACIDS around the body. 5-10% contribution to endurance events: Mainly used for growth/repair
FATS Butter Oils Margarine Nuts Cheese
Food that we ingest is stored and burnt to fuel our muscles This food must be converted into a chemical compound called ATP WithoutATP -Muscles cannot contract
ATP is used in all 3 energy systems. The type of energy system used and the interplay between them depends on the frequency, duration, intensity of the activity and fitness levels of the individual.
The 3 energy systems • The ATP – PC system • Alactacid system • Creatine phosphate system • Phosphagen system. • The Lactic Acid Systems • Anaerobic glycolysis system • Lactacid system • Aerobic System • Aerobic Glycolysis
For activity lasting: 0-10 SEC ATP-PC SYSTEM 10-30/40 SEC Anaerobic Glycolytic SYSTEM 2MINS + AEROBIC SYSTEM
ATP-PC SYSTEM CP instantly available, but runs out quickly Uses stores of CP (Creatine Phosphate) to REMAKE ATP Used for high intensity Jumps, Throws, Sprints Only have 10 seconds of CP in muscles If activity lasts longer than 10 sec, ATP must be REMADE by some other means…..
Anaerobic Glycolytic SYSTEM Body uses stored fuel of GLYCOGEN to REMAKE ATP Need Oxygen to do this properly About 2-3 hours of glycogen stored in body. Downside – by-product called Lactate. Hydrogen Ions also released which inhibit muscle contraction Happens because of lack of enough Oxygen to break down Glycogen 400m run, 800m at high intensity
Anaerobic Threshold • The exercise intensity at which lactic acid begins to accumulate within the blood • The point during exercise where the person begins to feel discomfort and burning sensations in their muscles • Lactic acid is used to store pyruvate and hydrogen ions until they can be processed by the aerobic system
AEROBIC SYSTEM Plenty of Oxygen available to remake ATP . So no LA or H+ is accumulated Used in longer, sub-max activities. Long run, swim, cycle. Like the LA system, the Aerobic uses Glycogen to remake ATP. Oxygen supply meets demand We use this system at REST (Now!) – except we burn… Will keep suppling ATP for as long as Fitness levels allow FAT!!!!
The Aerobic Oxidative System • The most important energy system in the human body • Blood lactate levels remain relatively low (3-6mmol/L bl) • Primary source of energy (70-95%) for exercise lasting longer than 10minutes provided that: a) working muscles have sufficient mitochondria to meet energy requirements b) sufficient oxygen is supplied to the mitochondria c) enzymes or intermediate products do not limit the Kreb’s cycle • Primary source of energy for the exercise that is performed at an intensity lower than that of the anaerobic oxidative system
Cori Cycle • Lactic acid is taken to the liver to be metabolized back into pyruvic acid and then glucose
During REST Any rest, short OR Long, CP is being replenished, so we can ‘sprint’ again. BUT, need 3 minutes rest to get all CP back! Any Lactate and Hydrogen Ions are removed from muscles & blood stream too.
Things to remember: All 3 turn on at once no matter what the activity. However, depending on intensity and duration of the activity, ONE system will contribute more than the other TWO. The 3 Energy Systems are not like TRAFFIC LIGHTS. One does not switch off and another goes on.
The Role of Three Energy Systems During an All-out Exercise Activity of Different Duration
Discussion Questions: 1. What are the differences between the 3 energy systems? 2. List one advantage and one disadvantage of each of the 3 energy systems. 3. Give an example of three activities or sports that use each of (a) the high energy phosphate system, (b) the anaerobic glycolytic system, and (c) the aerobic oxidative system as their primary source of energy (one sport for each energy system). • What is the most important source of fuel in the body for all types of energy production - a substance also known as the energy currency of the body? • 5. Describe how each of the three energy systems could be trained most efficiently.