Energy Systems - Horton High School

Metabolism – process of turning carbs, fats and proteins into energy to be used
by our body.
Glucose – the body processes food and turns it into glucose sugar molecules. It
is then transformed into glycogen, the usual form in which the body stores
carbohydrates in our muscles and liver for energy use.
ATP – AdenosineTriPhosphate, the common energy molecule for all living things.
ATP is like the gas our muscles use for energy. Glucose/Glucogen is converted
to ATP before our muscles can use it for energy.
Lactic Acid – a waste product produced during energy conversion during the
Anaerobic/Lactic phase. It causes muscle fatigue.
Alactic – energy produced with no lactic acid waste
Anaerobic – energy produced without the need for oxygen.
Aerobic – energy produced with oxygen
ATP is the molecule that muscles use to release
energy for movement
All 3 energy phases work to produce ATP for
energy during exercise but do it in different
ways and produce different amounts of ATP
A = Adenosine atom
 D = Di or means 2 atoms
 T = Tri or means 3 atoms
 P = Phosphate atom
 C = Creatine atom
 Example - ATP refers to a molecule
made up of:
1atom adenosine, 3 atoms phosphate
This process is called Anaerobic (without oxygen) and Alactic
(no lactic acid produced) because it does not require O2 nor
does it produce the lactic acid waste during energy
Adenosinediphosphate (ADP) molecule combines with
Phosphocreatine(PC) molecule to produce 1ATP molecule and
1Creatine molecule. Both ADP and PC can be found stored in the
This ATP can be used for quick energy but for only a few seconds
because only small amounts of PC are stored in the muscles and are
used up quickly.
takes about 4 to 5 minutes of rest for the body to replace the PC
stores to the muscles.
•Important in short sprints or power weight lifting, high jump, etc.
PC = Phospho Creatine
ADP = Adenosinediphosphate
PC and ADP molecules stored in our
muscles in small amounts
PC + ADP => ATP + C
One ATP molecule produced plus a
creatine atom
Glucose stored in muscles is combined with ADP and
Phosphate to create ATP energy molecules and Lactic Acid
as a waste product.
Creates twice the amount of ATP energy as Phase 1.
Able to produce ATP energy without oxygen but due to lactic
acid build up muscles fatigue after 2 to 3 minutes.
Oxygen will work to break down the lactic acid waste during
the next energy phase which is aerobic and allows the
muscles to continue to perform.
Important energy for many sports such as hockey, soccer,
basketball that require short but repetitive bursts of energy.
Glucose molecules are stored in muscles is shown as
6 Carbon atoms + 12 Hydrogen atoms +6 Oxygen atoms
Glucose combines with 2 molecules of Adenosine
Phosphate and 2 free phosphate atoms to produce
ATP and 2 Lactic Acid molecules (waste)
Lactic Acid molecule is shown as C3H6O3
3 Carbon atoms + 6 Hydrogen atoms + 3 Oxygen atoms
C6H12O6 + 2ADP + 2P => 2C3H6O3 + 2ATP
2 ATP molecules formed (twice as much as Phase 1) but
with Lactic acid waste
After 2 – 3 minutes of exercise the build up of lactic acid
impedes muscle performance and a third aerobic form of
energy production takes over called aerobic.
Oxygen is combined with Glucose, ADP and Phosphate to
produce 18 times more ATP energy than phase 2. Carbon
Dioxide and water waste is a by product.
This energy system can produce energy for long durations
and is limited only by the body’s store of glucose and its
ability to provide oxygen to the muscles.
Moderate exercise (jogging, repetitive sporting activity,
etc) can be sustained for up to about 1 – 2 hours. Until the
energy stores in the body are used up.
Good cardio vascular fitness increases VO2 uptake and
improves ones ability to sustain energy production during
the aerobic phase.
Oxygen combines with Glucose to
produce ATP without Lactic acid
 Carbon Dioxide molecule is shown as
CO2. Given off as waste in this process.
C6H12O6+6O2+36ADP+36P => 6CO2+36ATP+6H2O
36 ATP produced with water and carbon dioxide
waste. Much more energy than phase 1 or 2
Anaerobic Threshold refers to a point during
aerobic exercise when your CV system cannot
keep up to the demand for oxygen to produce
Max VO2 (the amount of oxygen you can
deliver to the muscles in one minute)
People with high levels of CV fitness have
greater Max VO2 and a higher Anaerobic
Threshold. It would take more effort before
they reached this point.
Exceeding the threshold requires the body to
begin producing energy from phase 2 with
lactic acid build up.
See the next slide for an example
In the first 10 seconds energy is anaerobic and alactic
 In the next 2 – 3 minutes energy is anaerobic and lactic
 From the 3 min to about the 1:30 min mark energy is
aerobic (no lactic acid build up)
 The last 15 min the runner exceeds the anaerobic
threshold and the extra energy is produced by the
anaerobic and lactic system. This leads to exhaustion
from lactic acid build up around the muscles
Phase 1 is limited to about 10 – 15 seconds as it quickly uses
up its store of PC molecules
Phase 2 is limited to about 3 minutes as lactic acid waste acts
to inhibit muscle contraction. It takes the oxygen in phase 3
to break down lactic acid and restore muscle ability.
Phase 1 and 2 produce instant energy for explosive/quick
Phase 3 is good for long duration exercise at moderate rates.
It uses oxygen to produce ATP molecules from glucose and
ADP. While it produces much more energy than phase 1 or 2
it is limited by the amount of oxygen getting to the muscles, if
exercise exceeds the VO2 intake, energy must be created by
phase 2 leading to lactic acid build up and muscle fatigue.
Phase 1 produces 1 ATP molecule
 Phase 2 produces 2 ATP molecules
 Phase 3 produces 36 ATP molecules
Phase 3 aerobic energy produces vastly
more energy than the first 2 energy
systems. So long as there is enough
oxygen and glucose stores one can
continue to exercise
How is Lactic Acid a factor in the NHL when the puck
is iced? If you don’t know the icing rule ask around
and find out. Why do coaches sometimes use their
time outs during this play?
Use the example of a cross country runner who gets in
a foot race with another runner the last K of a 7 K race
to answer the question below. Explain why the runner
with the higher Anaerobic Threshold has the better
chance of winning.
Answers should be about one paragraph and well written.

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