nutrition and energy systems

glycaemic index

-Ranking of carbohydrates based on their immediate effect on blood glucose (blood sugar) levels -Measured on a scale of 1-100 LOW GI FOODS Apples,Lentils, Kidney beans, Peanuts MODERATE GI FOODS Corn,Peas, White pasta, Sweet potatoes, Oranges, Oatmeal HIGH GI FOODS Pure glucose (GI 100), Honey, White bread, White rice, Carbo Shots

fuelling energy system

-The fuel source used for ATP production is based on the duration and intensity of exercise. -Low intensity - stored fats are the main energy source -As intensity of exercise increases, muscle glycogen contributes more- up to 90 minutes depending on intensity. Athletes "hit the wall" when muscle glycogen stores run out. :When muscle glycogen runs out, the stored liver glycogen kicks in to allow exercise to continue but performance starts to diminish. -Depletion of liver glycogen is referred to as "bonking" and affects the brain - decision making ability affected. -Fats now become the primary fuel source and intensity of exercise is reduced as fats are more difficult to break down -Depletion of fats results in protein being used as an energy source :This is only likely to occur in ultra endurance events -The lactic acid system is utilised when exercise is at a high intensity and uses glycogen as a fuel without Oxygen. Unfortunately this produces lactic acid and will only be the dominant supplier of energy for around 45 seconds.

carbohydrates

-When we ingest it is initially converted to glucose, giving a rise in insulin levels -Excess blood glucose is converted to glycogen -Glycogen - stored in muscle and in the liver for future use -An 80kg person on average stores 400g in the muscles and 100g in the liver RECOMMENDED DIETARY INTAKE OF NON ATHLETES -45-55% of total daily caloric intake -Approx 4.2g/kg daily ATHLETES -60% total daily caloric intake -Approx 7-8g/kg daily HEAVY TRAINING -70% total daily caloric intake -Approx 8-10g/kg daily :Energy yield - 17Kj per g supplies energy during -Rest -Low to moderate intensity activity -High intensity exercise

fats/lipids

:Represents body's most plentiful source of potential energy -80kg male (15% body fat) = 12kg (12000g) -Energy yield - 38kj per g = 452,000 Kj (stored as triglycerides in muscle cells and broken down into free fatty acids) are the major energy source during rest (60%) & light to moderate exercise but have little input during intense exercise. -Your body takes a long time to break fats down so tends not to use them when demands for energy are high. -Trained athletes are better able to break down and hence use them as a fuel source at higher intensities leading to glycogen sparing.

10seconds

ATP and CP combined lasts how long

anaerobic glycolysis

ATP is resynthesised by the breakdown of carbohydrate (glucose) Serves as the back up energy system for ATP - CP system and aerobic system Used for sustained sprint or muscular endurance activities usually lasting between 45 - 60sec 400m sprint 200m swim Require approximately 60-90min between events for optimal recovery Active recovery (ie slow walking included in recovery process) results in a faster removal of lactic acid than passive recovery

3-4minutes

ATP-CP suppliers recover in what time and trained athletes can recover this system quicker than untrained athletes

ATP

Food eaten (fats, carbohydrates (CHO) and protein) provides the energy required for the contraction of muscles (refer also to nutrition) The energy contained in CHO, fats and proteins cannot be used directly by the body Instead it is used to form a chemical compound called ATP (Adenosine triphosphate) and is stored in the muscle fibre This is the energy for muscle contraction The energy is stored as a molecule of ATP in the muscle, To release the energy, it is broken down into ADP + Pi (Adenosine diphosphate + Phosphate molecule) The energy released allows for a muscle contraction.

protein

Functions: 1.Growth of muscle tissue 2.Repair of muscle tissue 3.Production of red blood cells, hormones and antibodies 4.Contributes to ATP production when carbohydrate and fats stores are depleted (may occur in extreme circumstances, eg. starvation or during ultra endurance events such as the Hawaiian Iron-man. heacy training intake 1.5-2.0g/kg of body mass, meat, fish, poultry, eggs

food

Functions: 1.Provide energy to fuel the body 2.Growth and repair of tissue 3.Provide energy for metabolic function provides: - Proteins, CHO, fats, vitamins, minerals and water

daily energy requirements

NORMAL MALE :20 - 44 years old -2,700K.cal (up to 6000K.cal in some athletes) :55 - 74 years old - 2,300 K.cal :75+ - 2,100K.cal

frequency, duration, intensity

The type of energy system used and the interplay between them depends on the_____ of the activity and fitness levels of the individual

resynthesis of ADP to ATP

There is only enough stored ATP for about 1-2 contractions, Fuel and energy for this comes from CHO, Fats, Proteins and Creatine phosphate

nutrition

Utilisation of carbohydrates, fats and proteins as energy sources for physical activity and their role in the onset of fatigue

periods of growth, age, level of activity

daily energy requirements are affected by

55-60% carbs, 70% heavy training, 20-25% fats, 10-15% protein

diet should consist of

1-2seconds

how long does ATP last when stored in the muscles

7-8seconds

how long does CP last when stored in muscles

lactic acid system

is utilised when exercise is at a high intensity and uses glycogen as a fuel without O2. Unfortunately this produces waste and will only be the dominant supplier of energy for approximately 45sec

aerobic system

requires O2 slow speed of energy supply fuel source= carbohydrates and fats amount of ATP production=unlimited by products= CO2 H2O and heat duration= main source of energy 30+sec (point when oxygen supply has increased sufficiently to contribute ATP), Unlimited capacity to work unless insufficient fuel supply (food) cause of fatigue=unlimited activity=long duration

aerobic energy system

requires oxygen. ATP is resynthesised by the breakdown of carbohydrate, fat and protein All day, every day energy system. CHO are the preferred energy source during high intensity exercise as it costs the body less energy to produce ATP than fat. Stored glycogen in the muscles is broken down to glucose. When the glycogen in the muscles is depleted, glycogen in the liver is used. As long as you continue to provide your body with energy supplies, this energy system could last forever.

the lactic acid system

system is Anaerobic glycolysis system doesn't require O2 fast speed of energy supply fuel source= carbohydrates amount of ATP production= limited by products= lactic acid duration= main source of energy 10-30sec, peaks in output at 20sec, provides energy up to 2min cause of fatigue= lactic acid production activity=sprint endurance, sustained sprint

the ATP - CP system

system is part of anaerobic system, Creatine phosphate (CP) system, Phosphagen system. doesn't require O2 very fast speed of energy supply fuel source= creatine phosphate Amount of ATP production=limited no by products duration=main source of energy is 0-10sec, peaks in output at 5 sec and fatigues quickly cause of fatigue= limited supply ATP/PC activity=power based activities, sprinting, weightlifting, throwing, jumping recovers quickly 3-4 min