Transcript Energy systems.

Energy systems.
PHYSIOLOGICAL
REQUIREMENTS OF
PHYSICAL ACTIVITY
Foods
Fuel and
Energy Systems
A Maria Sharapova serve takes 1-2
seconds to perform. It’s fast & explosive.
She might do this hundreds of time over
a game. Plus she has to run fwd, bkwd
and sideways for 1-2 hours. Her Muscles
requires ENERGY to do this.
Where does this energy
come from?
Food Fuels our Body
1. CARBOHYDRATES
(Glycogen)
2. PROTEIN
3. FATS
CARBOHYDRATES
Cereals
Pastas
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
Eggs
Dairy
products
Poultry
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
Cheese
Nuts
Food that we ingest is stored and burnt to fuel
our muscles
This food must be converted
into a chemical compound
called ATP
Without ATP, Muscles
cannot contract
A.T.P.
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Adenosine triphosphate.
This is energy for muscle contraction.
Energy for movement of muscle fibres
is stored in the muscle as a molecule of
ATP.
Adenosine
Adenosine
P
P
triphosphate
P
To use the stored ATP


To release the energy, ATP is broken
down into ADP + Pi (Adenosine
diphosphate + Phosphate molecule)
The energy released allows for a muscle
contraction.
Adenosine
P
P
+
Pi
Energy
Resynthesis of ATP
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There is only enough stored ATP for about 12 contractions, soooo….we must resynthesise
ADP back into ATP.
Fuel and energy for this comes from CHO,
Fats, Proteins and Creatine phosphate.
These fuel sources resynthesise the free
Phosphate molecule (Pi) back to the ADP to
reform ATP.
CHO, Fats,
Proteins, CP
Adenosine
P
P
+
Pi
Resynthesises the ADP back to ATP
Adenosine
P
P
Pi
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
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The Lactic Acid Systems
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Alactacid system
Creatine phosphate system
Phosphagen system.
Anaerobic glycolysis system
Lactacid system
Aerobic System

Aerobic Glycolysis
ATP –PC system
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ATP breaks down to ADP + Pi to release
energy.
The ADP + Pi must be reformed to ATP
for continued muscle function.
PC provides the energy for the free Pi
to be re-attached to the ADP molecule
to form ATP.
ATP –PC system cont..
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PC stored in the muscles breaks down
anaerobically (without O2) to form Phosphate
and creatine. This releases energy for the
resynthesis of ATP.
It takes 2 PC molecules to resynthesise 1 ATP
molecule (one PC = 0.7 ATP).
NOTE: The resynthesis of PC (Phosphate + creatine = PC)
occurs in the recovery phase.
For activity lasting:
0-10 SEC
ATP-PC
SYSTEM
10-30/40 SEC
LACTIC
ACID
SYSTEM
30 + SEC- 2MINS
AEROBIC
SYSTEM
ATP-PC
SYSTEM
Used for high
intensity
Jumps, Throws,
Sprints
Uses stores of
CP (Creatine
Phosphate) to
REMAKE ATP
CP instantly
available, but
runs out
quickly
Only have 10
seconds of CP
in muscles
If activity lasts longer than 10 sec, ATP must be
REMADE by some other means…..
Summary
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Each ATP molecule is made up of an adenosine part
and three phosphate groups. When 1 mole (1) of
ATP is broken down, 7 to 12 Kcal (2) of energy is
released.
Besides ATP, there is still another high-energy
compound called phosphocreatine (PC) inside the
human muscle cells. When PC is broken down,
energy is released for the resynthesis of ATP.
Summary Cont…
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However, the total amount of PC stored in the human
body is also extremely limited. There are altogether
450 to 510 mM PC, or 4.5 to 5.1 Kcal of energy in the
human body. The energy released from the breaking
down of ATP is also required to resynthesize PC.
Nevertheless, this process will be carried out when
the human body is in the recovery stage.

The complete ATP-PC system can only supply 5.7 to
6.9 Kcal of energy, which can maintain about 10
seconds of maximal efforts.
Summary cont…
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The importance of the ATP-PC system is that it is the instant
energy source in the human body.

The ATP-PC system does not require oxygen in the muscles
for proper functioning. Besides, the required fuels (ATP and PC)
have already been stored in the muscle cells

The chemical reactions involved when PC is broken down are
fewer than the other two energy systems.

The ATP-PC system is particularly important for high-intensity
and high- speed activities that need to be completed in a few
seconds (e.g., starting, jumping, throwing, and weight lifting).
LACTIC ACID 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
AEROBIC SYSTEM
Like the LA system,
the Aerobic uses
Glycogen to
remake ATP.
Will keep suppling ATP
for as long as Fitness
levels allow
Used in
longer, submax
activities.
Long run,
swim, cycle.
Plenty of
Oxygen
available to
remake ATP .
So no LA or H+
is accumulated
Oxygen supply
meets demand
We use this
system at REST
(Now!) – except
we burn…
FAT!!!!
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:
The 3 Energy
Systems are not like
TRAFFIC LIGHTS.
One does not switch
off and another goes
on.
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.