1. Name: Calena Smith
Topic: The effect of aerobic exercise
on muscle fibre function

2. Key Words
Aerobic Exercise
Muscle
Muscle fibre
A.T.Pase
Mitochondria
Myoglobin
Slow twitch
Fast Twitch

3. Definition of terms
• Aerobic Exercise: is physical exercise that
intends to improve the oxygen system.
• Aerobic means "with oxygen", and refers to
the use of oxygen in the body's metabolic or
energy-generating process. Many types of
exercise are aerobic, and by definition are
performed at moderate levels of intensity for
extended periods of time.

4. Muscle
• an organ that, by cellular contraction,
produces the movements of life

5. Muscle fibre
• any of the cells of skeletal or cardiac muscle
tissue which is an elongated contractile cell
that forms the muscles of the body
• are mainly composed of the proteins, actin
and myosin.

6. A.T.Pase
• Enzymes that cause the conversion of A.D.P to
release energy

7. Mitochondria
• are known as the powerhouses of the cell.
They are organelles that act like a digestive
system that takes in nutrients, breaks them
down, and creates energy for the cell.

8. Myoglobin
• is a protein and has oxygen bound to it, thus
providing an extra reserve of oxygen so that
the muscle can maintain a high level of
activity for a longer period of time.

9. Slow Twitch
• Muscle fibers that produce energy by
converting fats into energy aerobically.

10. Fast Twitch
• Muscle fibers that produce energy by breaking
down glycogen in the absence of oxygen. They
produce rapid contractions, but create lactic
acid as a by-product.

12. Types of Muscle Fibre
there are two main type of muscle fibre:
• Type I – often called slow-twitch or slow fibre
or highly-oxidative muscle fibres
• Type II – often called fast-twitch or Fast fibers
or low-oxidative muscle fibres

13. Slow Twitch Muscle Fibre
• contain more mitochondria
• smaller in size
• have better blood supply
• contract more slowly

14. more fatigue resistant than
their fast-twitch brothers.
 produce energy, primarily,
through aerobic metabolism of
fats and carbohydrates.

15. Type 1 Muscle Fibre
are only aerobic and contain an
abundance of mitochondria (where
the Krebs cycle occurs).
The major source of energy for Type
I is fat through the Krebs cycle.

16. They also contain large amounts of
myoglobin: a pigment similar to
haemoglobin that also stores
oxygen – that provides an
additional store of oxygen for
when oxygen supply is limited

17. Type II has three subgroups:
Fast Oxidative Glycolytic
Fast Glycolytic
Indeterminate

18. Fast Oxidative Glycolytic -
Aerobic
burns glucose
mitochondria present but not as
many as type I

19. Fast Glycolytic
• Anaerobic
• burns glucose
• no mitochondria

20. produces lots of lactic acid which
can enter mitochondria of type I
or IIa
heart muscle can utilize all the
lactic acid it can get. Any lactic
acid left over enters the liver and
is reconstitued into glucose.

21. Indeterminate
undifferentiated fibers -can
become type IIa or IIb

22. The effect of aerobic exercise on
muscle fibre
Increase blood capillaries to muscle
fibre
Increase in number and size of
mitrochrondria
Increase enzymic action (A.T.Pase)

23. Exercise suitable for slow twitch
muscle fibre
• Marathon
• Cross country cycling
• Swimming
• Skating
• Skiing
• Triathlon, Decathlon, Heptathlon
• Running