Transcript Physiology of Fitness

Physiology of Fitness
Energy systems and their role in
sport and exercise
Learning Outcomes
• List the 3 main energy systems and their cellular fuel
• Describe the 3 energy systems giving sports related
examples
• Explain why some sports require more of one energy system
than another
• Measure and record the body’s responses to different types
of exercise
• Explain the recorded measurements
• Produce a short magazine article describing the three main
energy systems using examples.
Actin & Myosin
• The key terms to remember
• What are the
from that clip are:
contractile proteins
• ATP
in muscle?
• Actin & Myosin
http://www.youtube.c
om/watch?v=gJ309
LfHQ3M
http://www.physics31
10.org/images/240_
actin.gif
• ADP + Creatine Phosphate
• Myosin
Contractile
proteins
• Actin
• When ATP is released onto
myosin the chemical bond
breaks releasing a lot of
energy causing actin and
myosin filaments to contract
ie muscle contraction
What is ATP?
• ATP is a protein
(Adenosine) with 3
phosphates attached
to it
• When chemical bonds
are broken, energy is
released and ATP
becomes ADP
(Adenosine
diphosphate Di=2)
• The energy from this
breaking is used to
make muscles contract
The release of energy from ATP
Energy Systems
• What are the 3 main
energy systems that
convert chemical fuel
from food into energy?
1. Creatine Phosphate
System
2. Lactic Acid System
3. Aerobic Energy
System
What is this?
The mitochondrion,
shown here, is a tiny
cellular structure that turns
chemical fuel into cellular
energy ie ATP.
Creatine Phosphate System
Creatine Phosphate System
CP System
(immediate energy)
• Here ATP is made without
the presence of oxygen.
• When exercise intensity is
high, or energy needs are
instantaneous, creatine
phosphate stored in your
muscle is broken down to
provide energy to make
ATP.
• Explosive work can be
achieved, but only for short
periods of time at maximum
intensity, as the supply of
creatine phosphate is very
limited, up to 10 seconds.
Activity
List as many sports activities
as possible that use mainly
the CP system.
Creatine Phosphate System
Primary energy source:
Stored ATP, CP
Duration of activity:
7-12 s
Sporting events:
Weight lifting, high jump, long jump, 100m
run, 25m swim
Advantages:
Produce very large amount of energy in a
short amount of time
Limiting factors:
Initial concentration of high energy
phosphates (ATP, PC)
Creatine Phosphate System
Training The CP System
a) Interval training: eg 1min low intensity 1min high intensity
& repeat
- 20% increase in CP (creatine phosphate) stores
- no change in ATP stores
- increase in ATPase function (ATP -> ADP+P)
- increase in CPK (creatine phosphokinase) function
(CPK breaks down CP molecule and allows ATP
resynthesis)
b) Sprint training:
- increase in CP stores up to 40%
- 100% increase in resting ATP stores
Lactic Acid Energy System
Lactic Acid Energy System
• high intensity exercise
• up to 2 minutes.
• ATP is made by the
partial breakdown of
glucose and glycogen.
This is caused by
anaerobic glycolysis
• It’s an anaerobic
process (no O2)
• Where does the body store
glycogen?
– Muscles
– Liver
• What is the by-product of
anaerobic glycolysis?
– Lactic acid
• http://www.youtube
.com/watch?v=JLa
VIPlPm6g&feature=
related
Lactic Acid Energy System
Primary energy source:
Stored glycogen, blood glucose
Duration of activity:
12 s – 3 min
Sporting events:
800m run, 200m swim, downhill ski racing,
1500 speed skating
Advantages:
Ability to produce energy under conditions of
inadequate oxygen
Limiting factors:
Lactic acid build up, H+ ions build up
(decrease of pH)
Lactic Acid Energy System
Lactic Acid Energy System
Anaerobic Threshold
• The exercise intensity at which lactic acid begins to
accumulate within the blood
• The point during exercise where the person begins to feel
discomfort and burning sensations in their muscles
• Lactic acid is used to store pyruvate and hydrogen ions until
they can be processed by the aerobic system
Lactic Acid Energy System
• The primary source of substrates is carbohydrate
Carbohydrates:
– primary dietary source of glucose
– primary energy fuels for brain, muscles, heart,
liver
Aerobic Energy System
Primary energy source:
Glycogen, glucose, fats, proteins
Duration of activity:
> 3 min
Sporting events:
Walking, jogging, swimming,
walking up stairs
Advantages:
Large output of energy over a long
period of time, removal of lactic acid
Limiting factors:
Lung function, max.blood flow, oxygen
availability, excess. energy demands
Aerobic Energy System
Aerobic Energy System
Aerobic Energy System
•The most important energy system in the human body
•Blood lactate levels remain relatively low (3-6mmol/L bl)
Primary source of energy (70-95%) for exercise lasting
longer than 10 minutes provided that:
a) working muscles have sufficient mitochondria to meet
energy requirements
b) sufficient oxygen is supplied to the mitochondria
c) enzymes or intermediate products do not limit the Kreb’s
cycle
•Primary source of energy for the exercise that is
performed at an intensity lower than that of the anaerobic
oxidative system
Aerobic Energy System
• Long term energy,
system for light
exercise and every day
movements.
• Uses O2
• The production of
energy in the aerobic
system does not start
instantly.... Why?
• In groups discuss this
and write down your
agreed answer
Answer:
It takes a few minutes
for the heart to deliver
oxygenated blood to
the working muscles.
Long, continuous
moderate exercise
produces energy using
this system.
Types of Sport that use each system
• Remember, energy at any given time
is derived from all 3 energy systems.
• However the emphasis changes
depending on:
– the intensity of the activity
– the efficiency of your aerobic fitness
Energy Systems Summary
1. Creatine Phosphate energy system ...
for very short high intensity exercise
• ADP + Phosphocreatine
ATP + creatine
• requires no O2 but only enough stored for
about 10secs e.g. power lifting...
2. Lactic Acid Energy System: short-term
energy system
• Glucose
• Glycogen
2 ATP + 2 lactic acid + heat
3 ATP + 2 lactic acid + heat
requires no O2 but produces energy for high
intensity exercise for up to 60 – 90 secs e.g. 400m
race..
Energy Systems Summary
3. Aerobic Energy System: long-term energy
system
– Glucose +O2
– Fatty acids + O2
38 ATP + CO2 + water + heat
129 ATP + CO2 + water
+ heat
Activity
Produce a magazine article that
describes and explains the body’s
energy systems to a football coach.
1. What are the differences between the 3 energy systems?
2. List one advantage and one disadvantage of each of the 3
energy systems.
3. Give an example of three activities or sports that use each of
(a) the creatine phosphate system, (b) the lactic acid system,
and (c) the aerobic system as their primary source of energy
(one sport for each energy system).
4. What is the most important source of fuel in the body for all
types of energy production - a substance also known as the
energy currency of the body?