Transcript Food Fuel and Energy Systems an Introduction

Year 12 Physical Education
AREA OF STUDY 2
PHYSIOLOGICAL
REQUIREMENTS OF
PHYSICAL ACTIVITY
Foods
Fuel and
Energy Systems
WHAT YOU NEED TO KNOW AT THE END OF CHPT 4:
The Conversion of food to energy
Food fuels at rest and during exercise
The Glycemic Index
Energy for Muscular Contraction
The Aerobic and Anaerobic energy systems
The contribution of energy systems to various activities
The Energy System Interplay
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?
In the Tour De France, Alexander
Vinokourov rides 220km a day
Where does this energy
come from?
It takes 6 + hours, it’s
slower & less intense.
Like Sharapova’s serve, Vino’s
muscles require energy to ride for
this amount of time. And then do
it again tomorrow, and the next
day…etc…
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
Every muscle contraction
Ben Cousins performs
must have ATP available
to it…
ATP
Adeonsine Triphosphate
A
P
P
P
The energy for muscle
contraction is derived
when one of the 3
phosphate bonds is
broken
We end up with:
ATP
ADP + P + ENERGY
ATP is a very heavy compound, so we cannot
store much of it in our muscles.
Can only store about 1 SECOND
worth in muscle (allows 1 or 2
contractions to occur – eg Start
of 100m or a Netball shot)
For further contraction
to occur ATP must be
REMADE or produced
ATP
ADP + P + ENERGY
How is ATP remade?
The Body uses THREE DIFFERENT
ENEGRY SYSTEMS to do this.
For activity lasting:
0-10 SEC
ATP-PC
SYSTEM
10-30/40 SEC
LACTIC
ACID
SYSTEM
30 + SEC- 2MINS
AEROBIC
SYSTEM
ATP-PC & LACTIC ACID
SYSTEM ARE BOTH
CLASSIFIED AS ‘ANAEROBIC’
ENERGY SYSTEM
This means that the
muscles do not
need OXYGEN to
produce ATP
Energy. They use
STORED ENERGY.
The AEROBIC system takes
‘Time’ to become involved. It
cannot provide Oxygen quick
enough for short, fast activities.
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…..
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.