Download energy analysis

ENERGY ANALYSIS
ENERGY
BALANCE
Neutral
-------Positive
+
Negative
-
DESCRIPTION
If the amount of energy in food intake exactly equals the
amount of energy expended by the muscles in performing
external work and internal functioning, then bodyweight
remains constant.
If the amount of energy in food intake is greater than the
amount of energy expended by means of external work and
internal functioning, the bodyweight increases.
Conversely, if the energy derived from food intake is less
than the body’s immediate energy requirements, the body
must use stored energy to supply energy needs, and
accordingly, bodyweight decreases.
ADENOSINE TRIPHOSPHATE
WHAT IS ADENOSINE TRIPHOSPHATE?
¨ Adenosine Triphosphate (ATP) is a high-energy molecule that is the immediate and
essential source of energy for muscle contraction.
WHY DO MUSCLES NEED ATP?
¨ Without ATP, muscles cannot contract. However, muscle contains only a small
amount of ATP, about enough to expend energy at maximal rate for only one second.
If muscle contraction is to continue, additional ATP must be supplied.
¨ The faster you want your muscles to contract, the more rapidly you must replenish
ATP. The purpose of the 3 Energy Systems is to supply this additional ATP, but the
rate at which they can supply it varies.
WHAT IS ADENOSINE DIPHOSPHATE?
¨ ADP is the resulting molecule after ATP has released its energy.
¨ The broken down ADP molecules can be re-synthesised (reformed) through the arrival
of Creatine Phosphate (CP).
WHAT IS CREATINE PHOSPHATE?
¨ Creatine Phosphate is produced naturally by the body, and is also available in small
quantities in the muscles.
¨ Its primary function is to re-synthesise ADP back into ATP, which it is able to do so for up to around 4.5 seconds of intense physical activity.
ENERGY SYSTEMS
ATP-CP SYSTEM (0 - 4.5 SECS)
¨ The ATP-CP Energy System consists of mobilising ATP and CP within the first few
seconds of exercise to supply energy. This system is completely anaerobic.
¨ Both ATP and CP are in very short supply within the muscles, and there is only
enough available CP to re-synthesise ADP back into ATP for an additional 4-5
seconds of exercise (maximal exertion) at one time.
LACTIC ACID SYSTEM (4.5 - 90 SECS)
¨ The Lactic Acid Energy System is where the body uses carbohydrates for fuel in the
absence of oxygen (anaerobic).
¨ A process called Anaerobic Glycolysis facilitates the breakdown of Glucose into ATP
within the Mitochondria.
¨ As you move from the ATP-CP System into the Lactic Acid System, the rate of
Anaerobic Glycolysis increases to help meet your need for additional ATP.
¨ Through a series of chemical reactions in the muscle cell, the formation of Lactic Acid
is associated with fatigue processes within the muscle cell, so there is a limit to this
energy system during exercise.
OXYGEN SYSTEM (90 SECS +)
¨ The Oxygen Energy System is where the body uses oxygen to breakdown carbs and /
or fats during exercise into ATP within the Mitochondria.
¨ Although the Oxygen system cannot produce ATP as rapidly as the two Anaerobic
systems, it is capable of producing greater quantities of ATP.
¨ If a steady exercising pace is maintained, the body can then ‘learn’ how to mobilise fat
as a primary fuel, burning in the ‘fire’ of oxygen and carbohydrate.
ENERGY SYSTEMS TERMINOLOGY
TERM
DEFINITION
Aerobic
Glycolysis
The breakdown of Glucose into ATP within the Mitochondria using the Oxygen Energy System.
Anaerobic
Glycolysis
The breakdown of Glucose into ATP within the Mitochondria using the Lactic Acid Energy System.
Fast-Glycolytic
Type II b
White ‘Fast-Twitch’ Anaerobic Muscle Fibre Type.
Fast-Oxidative
Type II a
Pink ‘Intermediate’ Muscle Fibre Type that can adapt aerobically
or anaerobically.
Haemoglobin
Respiratory protein molecules, designed to transport oxygen via
Red Blood Cells (Erythrocytes).
Mitochondria
An organelle that produces ATP.
Pyruvic Acid
The chemical precursor of lactic acid - derived from the initial
stage of Anaerobic Glycolysis.
Slow-Oxidative
Type 1
Red ‘Slow-Twitch’ Aerobic Muscle Fibre Type.
RATE OF ENERGY EXPENDITURE
The chart below is based upon a 70 Kg individual - with average
physical activity and lean tissue %.
FORM OF ACTIVITY
ENERGY EXPENDITURE
(KCAL / HOUR)
Sleeping
65
Awake - lying still
77
Sitting at rest
100
Standing relaxed
105
Walking slowly on level (2.6 mph)
200
Carpentry - painting a house
240
Cycling on level (5.5 mph)
304
Shovelling snow / sawing wood
480
Swimming
500
Jogging (5.3 mph)
570
Rowing (20 SPM)
828
Walking upstairs
1100
THE MEASUREMENT OF ENERGY
HOW IS ENERGY MEASURED?
¨ Energy can be measured in either joules or calories.
¨ A joule (J) can be defined as the energy used when 1 kilogram (kg) is moved 1 metre
(m) by the force of 1 Newton (N).
¨ A calorie (cal) can be defined as the energy needed to raise the temperature of 1 gram
of water from 14.5 to 15.5ºC.
¨ In practice, both units are used, just as different units are used to measure liquids, e.g.
pints and litres.
¨ One calorie is equivalent to 4.184 joules.
¨ People use large amounts of energy so nutritionists use larger units.
¨ 1 kilojoule (kJ) = 1,000 joules
¨ 1 megajoule (MJ) = 1,000,000 joules
¨ 1 kilocalorie (kcal) = 1,000 calories or 1 Calorie (Cal)
¨ To convert from one unit to another: 1 kcal = 4.184 kJ
¨ 1 MJ = 239 kcal
¨ Therefore, a 1000 kcal diet provides 4.184 MJ or 4184 kJ.
Copyright WABBA Qualifications 2009. All Rights Reserved.