Transcript Muscle tissue - Pulse Football Academy Education

Muscle Movements
 For
the following movements, identify the
major joint movements and the muscle
responsible
Muscle tissue
Muscle fibre type
Fibre types
 Skeletal
muscle can be distinguished on
the basis of the speed of contraction
 Type 1 – slow twitch
 Type 2 – fast twitch
 Human body contains both types
Fibre type determination – how
its done
Type I
fibres
Type II
fibres
Muscle fibre type
Muscle Fibre Type
Slow twitch
Fast Twitch
(Type 1)
(Type II)
Type IIa
Type IIb
(Intermediate)
(True fast twitch)
Slow twitch fibres (Type I)
 Characteristics:
• More capillaries per muscle fibre than fast twitch
therefore have a better blood supply
• More myoglobin than fast twitch fibres
• Myoglobin is a store for oxygen
• Red in colour due to the large amount of
myoglobin (red pigment)
• More mitochondria (ATP producers) and aerobic
energy producing enzymes
 Result?
• Slower contraction time than fast twitch
• A greater ability to use oxygen known as oxidative
potential so they are sometimes called SLOW
OXIDATIVE or SO fibres
Fast Twitch Fibres (Type IIa +
IIb)
 General
characteristics:
• Low aerobic capacity due to low numbers of
capillaries, smaller blood supply and smaller
mitochondria than slow twitch.
• Have high levels of glycolytic enzymes (anaerobic
energy producing enzymes)
• High ability to produce energy anaerobically by the
glycolytic system.
Fast twitch type IIa intermediate

Characteristics:
• Pink in colour due to moderately high levels of
myoglobin.
• Has high levels of oxidative and glycolytic
enzymes.
• A moderately well developed ability for aerobic and
anaerobic energy production
• Faster contraction speed than slow twitch.

Result?
• Because of their moderate contraction speed and
high levels of oxidative and glycolytic enzymes
type IIa fibres are often referred to as FOG (Fast
oxidative glycolytic)
Fast Twitch type IIb – true fast
twitch

Characteristics:
•
•
•
•
•
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Low levels of mitochondria
White in colour due to very low levels of myoglobin
Poor capacity for aerobic energy production.
High levels of glycolytic enzymes.
Very high capacity for anaerobic energy
production.
Result?
• Because of their fast contraction speed and their
high levels of glycolytic enzymes type Iib fibres are
often referred to as FAST GLYCOLYTIC or FG
fibres
Muscle fibre type and
contraction velocity
Type 1
Type 2a
Type 2b
Red
Red
White
Contract slowly
Contract rapidly
(but not as fast as
type 2b)
Contract rapidly
Aerobic
Aerobic
Anaerobic
Endurance-based
such as cycling
and long-distance
running
Middle-distance
such as ice
skating
Speed and
strength-based
such as sprinting
and rugby
Can contract
repeatedly
Exert minimal
force
Fairly resistant to
fatigue
Exert medium
Easily exhausted
Exert great force
Types of sport
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All types are used in all types of exercise
Type 1 particularly adapted to low-intensity
aerobic endurance work
particularly at the beginning of exercise,
regardless of intensity
Type 2 fibres adapt to high intensity anaerobic
exercise
Also employed during low intensity workouts as
you fatigue
Muscle fibre type and sports
performance
 Nature
vs nurture?
 Is sporting potential determined before we
are born?
 E.g. sprinters and long
distance/endurance sports
Think about it
 Every
athlete in the 100m Olympic final in
2004 was of African-Caribbean descent.
 Is this coincidence or do AfricanCaribbean athletes possess an advantage
in their type 2 concentrations?