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Articulate !
Line up, each person will choose one of
these cards and then describe the word on
there!
Table who gets
most answers wins!
Learning Outcomes
• Compare the two types of skeletal muscle
found in the body.
• Identify sports which show preference of one
muscle type to the other.
• Debate on the potential racial problems the
genetic information has arisen.
Muscle Fibres
• 2 types of muscle fibres;
– Type 1 slow-twitch muscle fibres
– Type 2 fast-twitch muscle fibres
• Many differences between them , key ones are
– Slow (1) contract slower, contract for longer,
predominantly used aerobic respiration, so many
mitochondia, large blood supply and major fuel
source are fats
– Fast (2) contract fast, for short periods of time,
[predominantly use glycolysis, so fewer
mitochondria, smaller blood supply and major
fuel is glycogen and creatine phosphate.
See table 7.1 p115
Which sport suits which muscle
type?
– Slow (1) contract slower, contract for longer,
predominantly used aerobic respiration, so many
mitochondia, large blood supply and major fuel
source are fats
– Fast (2) contract fast, for short periods of time,
[predominantly use glycolysis, so fewer
mitochondria, smaller blood supply and major
fuel is glycogen and creatine phosphate.
Which sport suits which muscle
type?
– Slow (1) contract slower, contract for
long distance
running, cycling, longer, predominantly used aerobic
cross country
respiration, so many mitochondia, large
ski-ing,
blood supply and major fuel source are
fats
Weightlifting,
200m sprint,
100m hurdles
– Fast (2) contract fast, for short periods of
time, [predominantly use glycolysis, so
fewer mitochondria, smaller blood supply
and major
fuel is glycogen and creatine phosphate.
Demonstrate your knowledge
• Answer the questions
• Extension Question
• How could you tell the difference between
fast (II) twitch muscle and slow (I) twitch
muscle? Think about their properties....
Myoglobin
• Haemoglobin in rbc store O2
• Myoglobin in muscle (protein) cells store O2
• Myoglobin has higher affinity than haemoglobin,
thus able to receive O2 from blood supply.
• O2 need more in slow twitch muscles – why?
Mainly aerobic pathway, so more O2 needed, hence more
blood capillaries.
Distribution of Fibre Types
• All muscle composed of
Slow Twitch (I) ST and
Fast Twitch (II) FT fibres
• Most individuals possess
between 45 and 55% ST
• Distribution varies from
muscle to muscle within an
individual;
Eg. posture mainly ST
eye ball mainly FT
Does it difference if you’re black or
white?
• Alan Wells, 100m gold
Olympic medallist winner
in 1980.
• Current Scottish record
holder with time of 10.1s
August 2012 BBC Interview with
Gabby Logan.
Gabby Logan “Describe his
emotions when he won the
Olympic 100m final in Moscow in
1980”. Eventually Alan Wells
said: "Well, that was the last time
a white man was in the Olympic
final. And I managed to win it as
well."
Does it difference if you’re black or
white?
• Incontestable statement – but any truth to it?
• Jon Entine book enflamed racism in sport.
• 494 of the 500 fastest times, only 1 in top
71 are white (Christophe Lemaitre)
• ACTN3 gene predominant fast-twitch
muscle fibres and that the "sprint" version
of this gene.
Does it difference if you’re black or
white?
• ACTN3 is more common among Jamaicans than
other populations, 98 per cent of Jamaicans
have the relevant gene, so, too, do 82 per cent
of Europeans!
• Kenyans (who win distance
events but have virtually no
success in sprinting) have an
even higher frequency of the
relevant gene than Jamaicans!
• So not just genetic then?
• Cultural and nurture of training!
Odd one Out
Choose one and justify your choice ...
Myoglobin
Glycolysis
Lactic Acid
metabolism
Proteins
ATP synthase
ATP
Fast Switch
Type I muscles fibres
Citric Acid Cycle Electron Transport
Chain
Citric Acid Cycle Creatine phosphate
system
Fats
Carbohydrates
Phosphorylation Dehydrogenase
Catabolic
Phosphofructokinase
SQA Arrangements p26-7
• The two different types of skeletal muscle fibres
are slow twitch (type 1) muscle fibres and fast
twitch (type 2) muscle fibres.
• Slow twitch muscle fibres contract more slowly,
but can sustain contractions for longer. These
muscle fibres are good for endurance activities
like long distance running, cycling or crosscountry skiing. Slow twitch muscle fibres rely on
aerobic respiration to generate ATP and have
many mitochondria, a large blood supply and a
high concentration of the oxygen storing protein
myoglobin. The major storage fuel of slow twitch
muscles fibres is fats.
• Fast twitch muscle fibres contract more
quickly, but cannot sustain contractions for
as long as slow twitch muscle fibres. These
muscle fibres are good for activities like
sprinting or weightlifting. Fast twitch muscle
fibres can generate ATP through glycolysis
only and have few mitochondria and a lower
blood supply than slow twitch muscle fibres.
The major storage fuels of fast twitch
muscles fibres are glycogen and creatine
phosphate.