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Transcript of Energy Systems ©Subject Support 2010.. Learning Objectives To understand the different energy...
Energy Systems
©Subject Support 2010.
Learning Objectives
To understand the different energy systems
To understand each energy systems use in sport and exercise
REMEMBEREnergy can be defined as the
capacity to do work!
Grading Criteria
P7 – Describe the three different energy systems and their use in sport and exercise activities
M4 – Explain the three different energy systems and their use in sport and exercise activities
D2 – Analyse the three different energy systems and their use in sport and exercise activities
Unit Content
Energy systems – Phosphocreatine; Lactic Acid; Aerobic energy system
Amount of ATP produced by each systems
Sports that use these systems to provide energy
Recovery time
Energy Systems
©Subject Support 2010.
• ATP-PC System (anaerobic)
• Lactic Acid System (anaerobic)
• Aerobic Energy System
Energy Systems
The use of each system depends on the intensity and duration of each activity:If the activity is short in duration (less than
10 seconds) and high intensity, we use the ATP-PC system
If the activity is longer than 10 seconds and up to 3 minutes at high intensity, we use the lactic acid system
If the activity is long in duration and submaximal pace, we use the aerobic system
Energy Continuum
Sometimes we need to use all three systems to regenerate ATP because the demands of an activity are varied. For example, in rugby:A short sprint to tackle a player uses the ATP-
PC systemA long sprint the length of the pitch to score
a try uses the lactic acid systemPositional play will use the anaerobic system
Adenosine Triphosphate (ATP)
ATP is vital for muscle contraction it is the only form of useable energy in the body
The body only has enough ATP stored for 1 explosive act (about 3 seconds)
After that there is none leftThen energy has to be created by other
means
ATP (1 explosive act) = ADP (adenosine phosphate)
ADENOSINE PHOSPHATE PHOSPHATE PHOSPHATE
High energy bond
ADENOSINE PHOSPHATE PHOSPHATE
PHOSPHATE
ENERGY
ATP – Adenosine TriPhosphate
ADP – Adenosine DiPhosphate
Phosphocreatine Energy System (ATP/PCr System)
ADP + Creatine Phosphate (PCr) = ATPLasts about 10 secondsHigh intensity maximum workExtremely efficientDoes not need oxygenHas no waste products
Think 100 meters
ATP-PC SystemAdvantages
Phosphocreatine stores can be regenerated quickly (50% replenishment in 30 s; 100% in 3 mins)
No fatiguing by-products Creatine supplementation extends the time that the ATP–
PC system can be utilisedDisadvantages
There is a limited supply of phosphocreatine in the muscle cells, i.e. it can only last for 10 s
Only 1 molecule of ATP can be regenerated for every molecule of PC
PC regeneration can only take place in the presence of oxygen (i.e. when the intensity of the exercise is reduced)
Lactic Acid Energy System
ADP + Glucose = ATPWhen PCr runs out, the muscles call
upon stores of glucose (glycogen).Lasts between 10-60 seconds.Has a waste product called pyruvic acidIf not enough oxygen is breathed in to
break pyruvic acid down (oxygen debt) it converts into lactic acid
This is also called anaerobic glycolysis
Think 400m
Lactic Acid Energy System
Carbohydrate in Food
Glucose in bloodstream
Glycogen in Liver
Glucose in Muscle
Glycolysis2 ATP
Pyruvic Acid
Lactic Acid (1) Lactic Acid (1)
AN
AE
RO
BIC
Mus
cle
Sar
copl
asm
Acetyl Coenzyme A
+ O2
Lactic Acid System
AdvantagesATP can be regenerated quite quickly because few chemical reactions are involved.In the presence of oxygen, lactic acid can be converted back into liver glycogen, or used as a fuel by oxidation into carbon dioxide and water.It can be used for a sprint finish (i.e. to produce an extra burst of energy).
Lactic Acid SystemDisadvantages
Lactic acid is the by-product! The accumulation of acid in the body denatures enzymes and prevents them increasing the rate at which chemical reactions take place.Only a small amount of energy (5%) can be released from glycogen under anaerobic conditions (as opposed to 95% under aerobic conditions).
Aerobic Energy System
Starts similar to the Lactic Acid systemADP + P + Glucose = ATP + Pyruvic AcidAs oxygen is present the pyruvic acid
does not convert into lactic acid but into another 34 molecules of ATP
Long term low intensity exerciseCarbon dioxide (CO2) and water (H2O0
are waste products of this systemThink long distance running
Aerobic Energy System
The aerobic system of energy production needs oxygen.
Breaks down carbohydrates & fats into CO2, H20 and ENERGY
Takes approx 3 mins to extract 95% of energy from glucose molecule
This supplies the body with a prolonged and steady supply of energy.
O2
Aerobic Energy System
Immediate energy production, therefore comes from the other two anaerobic systems used.
Heart rate and ventilation rate increase during exercise. The vascular system distributes more oxygenated blood to our working muscles.
Within 1-2 mins the muscles are being supplied with enough oxygen to allow effective aerobic respiration
ATP (1 burst of energy) =ADP
ADP+ PCr = ATP (3-10s of work) = ADP
ADP + Glucose= ATP (10-60s of work) = ADP + Pyruvic Acid
(No oxygen = lactic acid)
ADP + P + Glucose = ADP + Pyruvic Acid
+ Oxygen =34 ATP + CO2 + H20
AE
RO
BIC
Mus
cle
Mito
chon
dria
Pyruvic Acid
Glycolysis 2 ATP
Acetyl CoA
Citric
Acid
+ Oxaloacetic Acid
AN
AE
RO
BIC
Mu
scle
Sa
rco
pla
sm
Krebs Cycle
2 ATP
Carbon Dioxide
Hydrogen
Electron Transport Chain
O2
Electron Transport Chain
The Aerobic System
Advantages More ATP can be produced — 38 ATP from the
complete breakdown of one glucose molecule. There are no fatiguing by-products (only carbon
dioxide and water). Stores of of glycogen and triglyceride are
plentiful, so exercise can last for a long time.
The Aerobic System
Disadvantages This is a complicated system so it cannot be used
immediately. It takes time for enough oxygen to become available to meet the demands of the activity and ensure glycogen and fatty acids are completely broken down.
Fatty acid transportation to muscles is low and fatty acids require 15% more oxygen to break them down than glycogen.
Food Fuels
Food is the basic form of energy for ATP regeneration. The main energy foods are: carbohydrates — stored as glycogen and
converted into glucose during exercise glycogen — a complex sugar supplied from
muscle or liver stores glucose — a simple sugar supplied from the blood fats — stored as triglycerides in adipose tissue
under the skin and converted by the enzyme lipase to free fatty acids when required
When are These Fuels Used During Exercise?
The intensity and duration of exercise play a huge a role in determining whether fats or carbohydrates are used.
The breakdown of fats to free fatty acids requires more oxygen than that required to breakdown glycogen. It is also a much slower process.
Therefore, during high-intensity exercise when oxygen is in limited supply, glycogen will be the preferred source of energy.