Transcript Energy System

Unit 1: Human Anatomy
Energy
Systems
Energy for
Muscular Activity
Woodland Christian High School
Energy Systems
How a Muscle Uses Energy
The ability to move, work or play sports is
dependant on supplying sufficient energy for
the duration of the activity.
To achieve muscle contraction, chemical
energy has to be converted into mechanical
energy. The source of this energy is stored
in the high energy phosphate bonds of ATP.
An ATP molecule consists of an adenosine molecule bonded
to three phosphate groups.
Adenosine
P
P
P
Woodland Christian High School
Energy Systems
How a Muscle Uses Energy
To release energy, a phosphate molecule breaks away from the
phosphate group to form adenosine diphosphate (ADP).
Heat
Adenosine
P
P
P
Hydrolysis
Adenosine
P
P
P
Energy
Breaking ATP into ADP
releases energy and allows
cross bridge formation to
occur inside the muscle.
Woodland Christian High School
Energy Systems
How a Muscle Uses Energy
A cell stores only a small amount of ATP. It can provide
energy for only 5 seconds of strenuous exercise. ATP has to
be continuously replenished since it is the only direct energy
source for muscle contraction. When ADP accumulates the
body begins the process of restoring ATP.
Adenosine
P
P
+
P
+
Energy
Adenosine
P
P
P
• To accomplish this synthesis, energy must be available;
• Energy is supplied through the breakdown of complex
molecules, such as fats and carbohydrates.
Woodland Christian High School
Energy Systems
How a Muscle Uses Energy
The production of ATP involves different energy systems
designated as anaerobic or aerobic each producing ATP at
a distinct rate and duration.
Anaerobic – without oxygen
Aerobic – with oxygen
The biochemical reactions in each system are complex, and
the body’s preference for anaerobic or aerobic metabolism
depends on several factors including the :
• type of muscle fibre involved in the activity;
• intensity and duration of exercise;
• level of training.
Woodland Christian High School
Energy Systems
Restoration of ATP
Woodland Christian High School
Energy Systems
The Three Energy Systems
Anaerobic
Energy systems that do not rely on the immediate use of oxygen.
There are two types of anaerobic energy systems.
Anaerobic Alactic
A short term energy of both fast and slow twitch muscle fibres
that does not require oxygen and does not produce lactic acid.
Anaerobic Lactic
A fast twitch muscle energy system which does not require
the immediate use of oxygen but does produce lactic acid
Aerobic
A slow twitch muscle energy system which is used in prolonged
continuous activity in the presence of oxygen and does not
produce lactic acid.
Woodland Christian High School
Anaerobic Alactic:
Energy Systems
ATP-CP System
An immediate - high energy phosphate system
Heat
Adenosine
P
P
P
Energy
Involves high power
output activities that
require an immediate
high rate of energy
production for a short
period of time
Involves activities such
as weight lifting, high
jump, long jump, shot
put, discus 50 metre
sprint, 25 metre swim
Woodland Christian High School
Anaerobic Alactic:
Energy Systems
ATP-CP System
As muscle contraction begins, the body may not be able to supply
ATP to the contracting muscle cells as rapidly as required.
Creatine phosphate serves as a quick available energy reserve
for muscles as it is broken down into creatine and phosphate.
CP CP
Adenosine
P
P
+
P
CP CP
Creatine
CP CP
ATP
Energy
The free phosphate ions bonds with ADP to produce ATP
and leave behind creatine. The new ATP molecule is
stored as potential energy. Creatine phosphate can only
support muscle contraction for another 3 to 4 seconds.
Woodland Christian High School
Energy Systems
Anaerobic Alactic Characteristics
• Only a small amount of ATP and CP is stored in muscle fibres;
• Uses very large amounts of energy in a short period of time;
• The rate of recovery is rapid. After a brief rest, the system
is recharged and ready for the next sprint;
• Oxygen is not required;
• Lactic acid is not produced;
• Provides energy for muscles for the first 5-10 seconds of
high intense activity;
• Uses both fast and slow twitch muscles;
• Work output is relatively high.
Woodland Christian High School
Energy Systems
Characteristics of the
Anaerobic Alactic System
Energy System
Anaerobic Alactic
Type of Activity
short sprints used in baseball,
pole vault, long jump, triple jump
Range of Maximum Work Times
0 – 10 seconds
Oxygen Required
None
Lactic Acid Produced
None
Energy Source
End Products of Fuel Breakdown
Muscle Fibre Recruited
Work Output per Unit of Time
Chemical energy stored in muscles
Adenosine Triphosphate
Creatine and Phosphate
Adenosine Diphosphate
Creatine Phosphate plus energy
Fast and Slow Twitch
High
Woodland Christian High School
Anaerobic Lactic:
Energy Systems
The Lactic Acid System
If an athlete continues to work beyond 10 s, a second energy
system uses glucose to provide energy. Glucose, which is
stored in muscle cells and in the liver (glycogen), can provide
immediate energy without oxygen.
Lactic
Acid
Glucose
Energy
ADP + P ATP
When glucose is converted into energy lactic acid is
produced.
Woodland Christian High School
Energy Systems
The Effects of Lactic Acid
During intense exercise, lactic acid builds up in the blood
faster than it can be removed. As lactic acid build up an
athlete will reach their anaerobic threshold.
The anaerobic threshold
is the highest intensity of
workload at which lactate
clearance still keeps pace
with lactate production.
E X E R C I S E
Low
Slow twitch fibres dominate
I N T E N S I T Y
Moderate
Fast-twitch type A fibres are recruited
Once this level is reached
the intensity level must
decrease to reduce the
amount of lactic acid buildup
High
Fast-twitch Type B fibres dominate
Woodland Christian High School
Energy Systems
Anaerobic Threshold
Anaerobic threshold is the point
where a person begins to feel
discomfort and a burning sensation
in their muscles.
At the anaerobic threshold the muscle loses its ability
to contract resulting in muscle fatigue.
Woodland Christian High School
Energy Systems
The Effects of Lactic Acid
Lactic acid causes pH changes in the muscle fibres and
they can no longer respond to stimulation.
Lactic acid interferes with
cross-bridge bonding by
limiting the strength of
the fibre contraction.
A high production of lactic acid ultimately limits
continued performance in intense activities
Woodland Christian High School
Energy Systems
The Effects of Lactic Acid
When lactic acid accumulates, extreme fatigue sets in
and oxygen deficit develops.
• Oxygen deficit is the reason you must
breathe rapidly and deeply for a few
minutes after strenuous exercise.
• After you stop anaerobic exercise, your body needs
extra oxygen to burn up the excess lactic acid and return
your energy reserves to normal.
• Lactic acid cannot be removed until extra oxygen is
supplied to convert it to harmless, re-usable products.
Woodland Christian High School
Energy Systems
Characteristics of the
Lactic Acid System
• The energy source comes entirely from glucose;
• Oxygen is not required;
• Energy is provided for 10-60 or 120 seconds depending on
conditioning;
• Uses predominately fast twitch muscle fibres;
• Work output is moderate;
• Used in sports such as football, basketball and hockey.
Woodland Christian High School
Energy Systems
Characteristics of the
Lactic Acid System
Energy System
Anaerobic Lactic
Type of Activity
games such as football,
basketball, hockey
Range of Maximum Work Times
Oxygen Required
Lactic Acid Produced
Energy Source
End Products of Fuel
Breakdown
Muscle Fibre Recruited
Work Output per Unit of Time
10 seconds to 60 or 120 seconds
depending on conditioning
None or very little
Yes, accumulated faster
than it can be removed
Entirely carbohydrate
Lactic Acid
Predominately Fast Twitch
Medium
Woodland Christian High School
Energy Systems
Effects of Training on
the Lactic Acid System
At any level of work, the rate of lactic acid build-up is
decreased through training. Improvements in the
cardiovascular system deliver an increased blood flow to the
working muscle and,
• The individual can work out at a higher rate of activity
before lactic acid build-up begins.
• The individual is able to “handle” a higher level of lactic
acid.
• Trained individuals are able to remove lactic acid faster
from exercising muscles.
• The anaerobic threshold rises.
Woodland Christian High School
Energy Systems
The Aerobic System:
Long Term Energy
As the length of an exercise session continues the athlete
requires a steady power output over a long period of time
Exercise performed at a lower intensity level relies almost
exclusively on the aerobic system for energy production and
required the athlete to use oxygen as its source of energy.
• Most daily activities use energy provided by the
aerobic energy system
• The oxygen energy system 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 efficiency and endurance.
Woodland Christian High School
The Aerobic System:
Energy Systems
Long Term Energy
The aerobic system energy requires the metabolism of
Glucose
stored in
muscles
Fats
Proteins
Oxygen
combine to produce
ADP + P  ATP
Energy
CO2
using energy produces
Water
Woodland Christian High School
Energy Systems
Characteristics of the
Aerobic System
The oxygen system is highly efficient. When oxygen is
used in muscle cells:
• it prevents the build-up of lactic acid;
• an individual can work out longer before lactic acid
build-up begins;
• it is able to remove lactic acid from muscles allowing
the muscle to continue to contract allowing exercise to
continue;
• it promotes the re-synthesis of ATP for energy when
work output is low.
Woodland Christian High School
Energy Systems
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:
 The system requires a continuous supply
of oxygen and fuel sources necessary
for the aerobic metabolism.
 The use of ATP must be relatively slow
to allow the process to meet the energy
demands.
Woodland Christian High School
Energy Systems
Characteristics of the
Aerobic System
Energy System
Aerobic
Type of Activity
long distance running, cross
country skiing, swimming
Range of Maximum Work Times
Oxygen Required
120 seconds plus
Yes
Lactic Acid Produced
Depends on intensity
Energy Source
Mixture of fat and
carbohydrate
End Products of Fuel Breakdown
Muscle Fibre Recruited
Work Output per Unit of Time
CO2 and H2O
Slow twitch and
some fast twitch
Low
Woodland Christian High School
Energy Systems
Aerobic Power
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. The greatest rate at which
oxygen can be taken in and used during exercise is referred
to maximal oxygen consumption or (VO2max)
Woodland Christian High School
Energy Systems
Aerobic Power – Max VO2
Each person has his or her own maximal rate of oxygen
consumption (VO2 max)
• The maximal rate at which oxygen can be
used is genetically determined.
• The VO2 max values of trained athletes will
reach 65-75 for males and 50-60 for females
• A normal VO2 max for most high school athletes
would fall somewhere between 30 and 50 range.
The more active we are the higher the VO2 max will
be in that range.
Woodland Christian High School
Energy Systems
Max VO2 Standards for 2.4 km Run
Time
Max VO2
Time
Max VO2
8:00
65.2
10:45
48.9
8:15
64.9
11.00
47.6
8:30
63.2
11.15
46.1
8:45
61.3
11:30
44.7
9:00
59.1
11.45
43.2
9:15
57.9
12:00
41.7
9:30
56.7
12:15
40.3
9:45
55.6
12:30
38.9
10:00
53.1
12:45
37.4
10:15
51.8
13:00
36.2
10:30
50.1
13:15
35.1
Woodland Christian High School
Energy Systems
Max VO2 Standards for Beep Test
Woodland Christian High School
Energy Systems
Max VO2 Norms
Female (values in ml/kg/min)
Age
Very
Poor
Poor
Fair
Good
Excellent
Superior
13-19
<25.0
25.0 - 30.9
31.0 - 34.9
35.0 - 38.9
39.0 - 41.9
>41.9
20-29
<23.6
23.6 - 28.9
29.0 - 32.9
33.0 - 36.9
37.0 - 41.0
>41.0
30-39
<22.8
22.8 - 26.9
27.0 - 31.4
31.5 - 35.6
35.7 - 40.0
>40.0
40-49
<21.0
21.0 - 24.4
24.5 - 28.9
29.0 - 32.8
32.9 - 36.9
>36.9
50-59
<20.2
20.2 - 22.7
22.8 - 26.9
27.0 - 31.4
31.5 - 35.7
>35.7
60+
<17.5
17.5 - 20.1
20.2 - 24.4
24.5 - 30.2
30.3 - 31.4
>31.4
Male (values in ml/kg/min)
Age
Very
Poor
Poor
Fair
Good
Excellent
Superior
13-19
<35.0
35.0 - 38.3
38.4 - 45.1
45.2 - 50.9
51.0 - 55.9
>55.9
20-29
<33.0
33.0 - 36.4
36.5 - 42.4
42.5 - 46.4
46.5 - 52.4
>52.4
30-39
<31.5
31.5 - 35.4
35.5 - 40.9
41.0 - 44.9
45.0 - 49.4
>49.4
40-49
<30.2
30.2 - 33.5
33.6 - 38.9
39.0 - 43.7
43.8 - 48.0
>48.0
50-59
<26.1
26.1 - 30.9
31.0 - 35.7
35.8 - 40.9
41.0 - 45.3
>45.3
60+
<20.5
20.5 - 26.0
26.1 - 32.2
32.3 - 36.4
36.5 - 44.2
>44.2
Reference: The Physical Fitness Specialist Certification Manual, The Cooper Institute for Aerobics Research, Dallas TX, revised 1997 printed in Advance Fitness Assessment & Exercise Prescription, 3rd Edition, Vivian H. Heyward, 199
Woodland Christian High School
Energy Systems
VO2 Max in Athletes
and Non-Athletes
VO2 max varies greatly
between individuals and
even between elite
athletes that compete in
the same sport.
In previously sedentary
people, training at 75%
of aerobic power, for
30 minutes, 3 times a
week over 6 months
increases VO2 max an
average of 15-20%
Woodland Christian High School
Energy Systems
Improving VO2 Max
Genetics plays a major role in a person’s VO2 max and
heredity can account for up to 25-50% of the variance
seen between individuals. The highest ever recorded VO2
max is 94 ml/kg/min in men and 77 ml/kg/min in women.
Both were cross-country skiers
The extent by which VO2 max can change with training
also depends on the starting point. The fitter an
individual is to begin with, the less potential there is for
an increase and most elite athletes hit this peak early in
their career. There also seems to be a genetic upper limit
beyond which, further increases in either intensity or
volume have no effect on aerobic power. This upper limit is
thought to be reached within 8 to 18 months.
Woodland Christian High School
Energy Systems
VO2 Max as a
Predictor of Performance
In elite athletes, VO2 max is not a good predictor of
performance. The winner of a marathon race for example,
cannot be predicted from maximal oxygen uptake.
Perhaps more significant than VO2 max is the speed at
which an athlete can run, bike or swim at VO2 max. Two
athletes may have the same level of aerobic power but one
may reach their VO2 max at a running speed of 20 km/hr
and the other at 22 km/hr.
While a high VO2 max may be a prerequisite for performance
in endurance events at the highest level, other variables
such as anaerobic threshold are more predictive of
performance.
Woodland Christian High School
Energy Systems
Oxygen Deficit
While exercising intensely the body is sometimes unable to
meet all of its energy needs. Specifically, it is unable to take
in and absorb enough oxygen to adequately 'feed' the muscles
the amounts of energy needed to adequately perform the tasks
the athlete is requesting from the body.
In order to make up the
difference without sacrificing
output, the body must tap into
its anaerobic metabolism.
This where the body uses both
aerobic and anaerobic energy
production. While not hugely
detrimental, oxygen deficits
can grow to a level that the anaerobic energy system
cannot cover. This can cause performance to deteriorate.
Woodland Christian High School
Energy Systems
Oxygen Debt
Oxygen debt refers to post exercise
oxygen consumption where the body
needs to pay back its debt incurred
above after the exercise is over
You will notice that even after you are
done racing you will continue to breath
hard.
At this point your body is still trying
to repay the oxygen debt that was
created when you were working hard.
Woodland Christian High School
Energy Systems
Effects of Training on
the Aerobic System
The performance of any activity requires a certain rate of
oxygen consumption. A person’s ability to perform an activity
is limited by their maximal rate of oxygen consumption;
Therefore, 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 target heart rate
tends to use slow twitch fibres.
Walking, jogging or any other light exercise,
uses mainly slow-twitch fibres to do the
work. ST fibres are slower to fatigue and
are well suited for endurance activities.
Woodland Christian High School
Energy Systems
Effects of Training on
the Aerobic System
Endurance exercise consists of repeated, sustained effort of
long duration several times per week;
Generally, the higher the intensity, the greater the oxygen
consumption. When exercising the target heart rate (THR)
should be raised to 70% of max. Examples include:
running, swimming or biking for 40 minutes or
more at a heart rate of 130-140 bpm
Notes: 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.
Woodland Christian High School
Energy Systems
Effects of Training on
the Aerobic System
Endurance training has four major effects on the
aerobic system:
• Improved delivery of oxygen and nutrients to the muscles
• Increase the size and number of mitochondria in muscle
fibres
• Increased activity of enzymes involved in the aerobic
pathway
• Preferential use of fats over glucose during exercise which
saves the muscles limited store of glycogen
Woodland Christian High School
Energy Systems
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. The anaerobic threshold is the point
where lactate (lactic acid) begins to
accumulate in the bloodstream.
Note: Depending upon the distance, and effort,
the body can use different proportions of
both of these systems. For example, the
800 m 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.
Woodland Christian High School
Energy Systems
Training the Systems Together
The best method to train all of the systems together is
interval training. Interval work consists of repeating a series
of short, high intensity, runs alternating with rest (recovery)
periods.
Whichever interval training method is used,
the athlete must continually push themselves
into a state where lactic acid builds, forcing
their body’s to adapt.
Regardless of the race distance you are
training for, 5k or marathon, interval
work will help you run faster.
Woodland Christian High School
Energy Systems
Interval Training
Pushing the body past the 'comfortable' speed of
running increases aerobic capacity, trains the fast
twitch muscles to operate at a higher/faster level and
makes the athlete more tolerant of lactic acid build up.
The result of interval training is that a
runner who can comfortably run a sixminute/mile pace and runs their intervals
at a five-minute/mile pace will be able to
increase their steady comfortable pace
under an six-minute/mile pace.
Woodland Christian High School
Roles of the Three Energy
Systems in Competitive Sport
Energy Systems
Energy
Pathways
Primary
Energy
Source
Anaerobic Pathways
Aerobic Pathways
ATP produced without the
presence of oxygen
ATP produced with the
presence of oxygen
Energy
System
Immediate
Alactic
Short-term Lactic
Long-term Oxygen
Fuel
ATP and CP
Glycogen + glucose
Glycogen, glucose, fat and protein
Duration
0s
10s
Sprinting
100 m dash
Throwing
Jumping
Sport
Event
Weightlifting
Ski jumping
Diving
Vaulting in
Gymnastics
40s
70s
2 min
Track 200-400 m
100 m Swim
500m
Speedskating
800 m track
Most gymnastics
events
Gymnastic
floor
exercise
Cycling (track)
Alpine skiing
50 m swim
Cycling 1000
m pursuit
6 min
25 min
Middle distance track,
swimming, speedskating
1000 m canoe
Boxing
Wrestling
Rowing
1 hr
2hr
3hr
Long Distance track
swimming, canoeing,
speedskating
Cycling
road racing
Marathon
Triathlon
Figure skating
Cycling, pursuit
Most team Sports/Racquet Sports
Woodland Christian High School
Energy Systems
Energy System
Summary
Anaerobic Alactic
Anaerobic Lactic
Aerobic
short sprints used in
baseball, pole vault
long jump triple jump
games such as football,
basketball hockey
long distance running
cross country skiing
swimming
0 – 10 seconds
10 to 60 or 120 seconds
(depending on conditioning)
120 seconds plus
Oxygen Required
None
None or very little
Yes
Lactic Acid
Produced
None
Type of Activity
Range of
Maximum Work
Times
Yes, accumulated faster
than it can be removed
Depends on intensity
Energy Source
Chemical energy stored
in muscles, ATP and CP
Entirely carbohydrate
Mixture of fat and
carbohydrate
End Products of
Fuel Breakdown
Adenosine Diphosphate
Creatine Phosphate
plus energy
Lactic Acid
CO2 and H2O
Fast and slow twitch
Predominately fast twitch
Slow twitch and
some fast twitch
High
Medium
Low
Muscle Fibre
Recruited
Work Output per
Unit of Time
Woodland Christian High School
Energy Systems
Summary
• 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
• Endurance training can significantly improve the
aerobic system
Woodland Christian High School
Energy Systems
Example of Interval Training
Anaerobic Alactic Capacity/Power (sprints):
E:P ratio 1:3-6, >130%Vo2 max. 5-30sec. work.
Time Phase - maintain all year
1. 10 x 80-100m strides, 90-95% effort. Jog return recovery.
2. 5 x 4 x 100m strides, 95-100% effort, 2min./4 min. recovery.
3. 6-10 x 20-30m hills, max effort, 1 1/2-2 min. recovery.
Woodland Christian High School