Energy Systems
Aerobic System
Two Energy Systems
1. Aerobic
–
An energy system which is used in prolonged
continuous activity in the presence of oxygen
and does not produce lactic acid.
2. Anaerobic
–
Energy systems that do not rely on the
immediate use of oxygen. There are two types
of anaerobic energy systems.
3 Metabolic Pathways
Anaerobic Alactic (ATP-CP) or (ATP-PC)
Anaerobic Lactic (glycolysis)
Aerobic (cellular respiration)
• A slow twitch muscle energy system which is
used in prolonged continuous activity in the
presence of oxygen and does not produce lactic
acid.
The Aerobic System: Long-Term Energy
• Exercise performed at a ______________level relies
almost exclusively on the aerobic system for energy
production and requires the athlete to use
____________ as its source of energy.
o Most daily activities use energy provided by the aerobic
energy system
o The _________________________is the most important
energy system in the body.
• While this pathway cannot generate the speed of the
anaerobic, it does provide a great deal more
_____________________________________.
• Formula:
Key Nutrients
• Remember your Fats, Proteins and Carbs
because they are crucial for the fuel for the
aerobic system
The Aerobic System (Cellular Respiration)
• The aerobic system energy requires the metabolism of
Glucose
(Glycogen)
Oxygen
Fats
Proteins
Combine to produce
ADP + P
ATP
ENERGY
CO2
Using energy produces
Water
Cellular Respiration
• Involves 3 separate pathways
– Glycolysis
– Kreb’s Cycle
– Electron Transport Chain
Sub-Pathways – Cellular Respiration
Glycolysis –
• first stage
• Same as anaerobic lactic system (see previous
lesson)
Where Glycolysis changes with the Aerobic Systems:
• in the presence of oxygen, ________________is
converted to ________________ (co-enzyme)
– (rather than ___________________
– No lactic acid produced with aerobic at this time
• acetyl CoA then enters a more complicated pathway
known as the ____________________
Kreb’s Cycle-
• Central pathway for the metabolism of
____ and ____________
• series of __ reactions, __ ATP molecules
are produced at this stage, along with new
compounds
• capable of storing
____________________
• high energy electrons
are sent to a process
within the
_________________,
known as, the ____________
__________________
Electron Transport Chain-
• During the final stage of aerobic
respiration, ______________________are
produced,
• Electrons pass down the chain, highly
reactive molecules (free radicals) are byproducts
– these molecules may be a contributor to
long-term muscle fatigue
ATP Produced
Energy System
ATP
Glycolysis
Kreb’s Cycle
Electron Transport
Chain
Total
Aerobic Power: VO2max
Oxygen uptake
• The power of the aerobic system is generally
evaluated by measuring the maximum volume of
oxygen that can be consumed in a given amount
of time.
– This can be measured by determining the
amount of oxygen exhaled as compared to the
amount inhaled.
• As the intensity of work increases the capacity of
aerobic system reaches a maximum.
– You can only breath in and out so much
• The greatest rate at which oxygen (volume) can
be taken in and used during exercise is referred
to ____________________________or
(___________)
Aerobic Power VO2Max
Each person has his or her own maximal rate of oxygen
consumption (VO2 max).
•
• A normal VO2 max for most high school athletes would fall
somewhere between
• The VO2 max values of trained athletes will reach
The more active we are the higher the VO2 max will be in that
range.
The Effect of Training on the Aerobic System
A person’s ability to perform an activity is limited by
their maximal rate of oxygen consumption (VO2 Max).
The most efficient method for improving the aerobic
energy system is endurance training/exercise.
Long, slow distance training or exercise at the low end
of your _________________tends to use slow
twitch (ST) fibres. ST fibres are slower to fatigue and
are well suited for endurance activities.
The Effect of Training on the
Aerobic System
Endurance exercise consists of
Generally, the higher the intensity, the
greater the oxygen consumption. When
exercising the target heart rate (THR)
should be raised to 70% of max.
Finding your Target Heart Rate
The Effect of Training on the Aerobic System Con’t
Examples include: running, swimming or biking for 40 minutes or
more at a heart rate of 130-140 bpm
Note: A highly trained or elite athlete should be able to
sustain a heart rate of 85% of their VO2 max. This type of
training does not raise your anaerobic threshold.
Endurance training has four major effects on the aerobic
system:
Characteristics of the Aerobic System
The oxygen system is highly efficient. When
oxygen is used in muscle cells:
– it prevents the build-up of _______________
– an individual can work out longer before
_______________________________________
– it is able to remove lactic acid from muscles
allowing the muscle to continue to contract
allowing exercise to continue
– it promotes _________________of ATP for
energy when work output is low.
Characteristics of the Aerobic System
As the duration of activity increases, the
contribution of the aerobic system to the
total energy requirement increases.
Due to this, there are two limitations to the
aerobic system:
Using The Systems Together
While running at a comfortable pace you use both systems, but
the anaerobic: aerobic ratio is low enough that the lactate
generated is easily removed, and doesn't build up.
As the pace is increased, eventually a point is reached where the
production of lactate, by the anaerobic system, is greater than its
removal (anaerobic threshold).
Note: Depending upon the distance, and effort,
the body can use different proportions of
both of these systems. For example, the 800m
race is too long to be a sprint, but too
short to be a distance race. Therefore, it is
run at the cross-over between the aerobic
and anaerobic systems.
Training The Systems Together
The best method to train all of the systems together
is __________________. Interval work consists
of repeating a series of short, high intensity, runs
alternating with rest (recovery) periods.
Whichever method is used, the athlete must
continually push themselves into a lactate burdened
state which makes their body adapt. Regardless of
the race distance you are training for, 5k or
marathon, interval work will help you run faster.
Summary - The Energy Systems
• Energy for muscular activity depends on a
supply of ATP that can be broken down into
ADP and phosphate
• All of the body’s biochemical processes and the
three energy systems require ATP
• Trained individuals are able to use ATP and
remove lactic acid more efficiently than
untrained individuals
Roles of the Three Energy
Systems in Competitive Sport
Anaerobic Pathways
Primary
Energy
Source
Energy
System
Fuel
Duration
Sport Event
Aerobic Pathways
When the systems are used
ATP - CP System
Glycolytic System
Aerobic System
Feel the burn!