9. WITHIN OUR SKELETAL MUSCLE WE ACTUALLY HAVE 2 TYPES
OF MUSCLE FIBRE CALLED FAST AND SLOW TWITCH FIBRES,
RELATED TO THE SPEED IN WHICH THEY CONTRACT.
Slow Fibres: Walk long distances
Fast fibres: React quickly when needed
10. RED in colour, as they have a good blood supply
They are suited to
endurance work and are
slow to fatigue - Due to
having a dense network of
blood vessels.
11. They also contain many
MITOCHONDRIA (Energy
producing organelles within
cells), making them more
efficient at producing
energy using OXYGEN (O2).
Type 1 – Slow Twitch Fibres
12. FAST TWITCH FIBRES
CONTRACT TWICE AS
QUICKLY AS SLOW TWITCH
FIBRES AND THICKER IN
SIZE.
They have a poor blood supply, meaning they
are whiter in appearance and will fatigue
quicker due to lack of OXYGEN (O2)
Type 2a and type 2b – Fast Twitch Fibres
13. Their FASTER, HARDER contractions make them
suitable for producing fast and powerful
contractions. E.G: Sprinting and Weightlifting
Type 2a and type 2b – Fast Twitch Fibres
14. TYPE 2 (A)
Work at slightly lower intensities, but higher than
slow twitch fibres are capable of. For example, a
400m runner would utilise Type 2a fibres.
15. Type 2 (b)
These fibres work when a person is working close to their maximum
intensity. For example, a 100m runner would use these type of fibres, or an
Olympic lifter performing a fast lift.
16.
17. Type 1 and Type 2b fibres will always retain
their distinctive features. However, Type 2a
can take on characteristics of Type 1 and
Type 2b depending on the training (they do
not change their fibre type).
Bursztyn (1997): well trained middle- distance athletes
will have 80% slow twitch fibres and well trained
sprinters may have up to 75% fast twitch fibres
18. How do muscles work?
Muscles can only pull
Muscles are attached to bones by tendons
Muscles pull when they contract
When the muscle contracts it pulls on the bone causing movement
19. How do muscles work?
• The bone act like levers and the joints are the fulcrum
• Muscles get shorter and fatter when they contract.
• Muscles usually work as pairs pulling in opposite directions
– these are called antagonistic muscles.
20. The biceps and triceps work together
as an antagonistic pair to move the
elbow joint.
To flex the elbow, the biceps (the
flexor) contracts and the triceps (the
extensor) relaxes.
To extend the elbow, the actions are
reversed so that the triceps contracts
and the biceps relaxes.
The muscles of the upper arm
21. The quadriceps and hamstrings in the legs are another
antagonistic pair. Can you answer the following questions?
Which joint do they move?
What types of movement are produced?
Which is the flexor and which is the extensor?
Identify the origin and insertion of each muscle.
quadriceps
hamstrings
Quad & Hamstring movement
23. The fixators hold the scapula
still by increasing tension, but
keeping the same length. In
the same way that a guy rope
holds a tent up.
24. E.g. Walking is automatic takes no real cognitive effort
learned & needs concentration for toddlers.
With constant practice:
1. Neural networks & motor neuron/muscle pathways
become fast and effortless,
2. No conscious thought to achieve the fluid sequence
of motor activity that produces optimal walking
behaviour.
25. Eccentric - Involves controlling
the weight on it’s way down
Concentric - Contraction to
push weight away from the
body
26. WHERE A MUSCLE CONTRACTS, BUT
DOES NOT CHANGE IN LENGTH.
THE MUSCLE IS ACTIVE IN HOLDING A
STATIC POSITION
THIS IS EASY TO TRAIN, BUT SOON
LEADS TO FATIGUE