Muscles

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Muscles

• Every movement of your body depends on muscles.
  There are three different types of muscles
• INVOLUNTARY MUSCLE (SMOOTH) - is found in the
  bodys internal organs. It performs its function
  without any conscious control, but usually quite
  slowly. E.g eyelids blinking, breathing

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• VOLUNTARY OR SKELETAL MUSCLE
• (also known as striped or striated muscle)
• Mainly found attached to the skeleton, capable
  of rapid contraction which cause skeletal
  movement. It is under our conscious control.
• CARDIAC MUSCLE
• Is only found in the heart and is also
  involuntary. It never stops working until we die.
  It pumps blood from our heart around the body.

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Voluntary Muscle - How They Perform

• FRONT
• DELTOIDS - create abduction at the shoulder and
  raise your arm sideways, e.g. swimming arm
  action.
• PECTORALS - create adduction at the shoulder
  across the chest, e.g press ups.
• BICEPS - allows flexion at the elbow, e.g.
  chin-ups.
• ABDOMINALS - allow you to flex your trunk, e.g.
  sit -ups.
• QUADRICEPS - makes extension of the leg possible
  at the knee, e.g. squats, kicking.

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• BACK
• TRAPEZIUS - allows shrugging of the shoulders,
  raising and lowering the head.
• LATISSIMUS - adduction at the shoulder behind
  your back, e.g. rope climb.
• TRICEPS - creates extension at the elbow, e.g.
  press-ups, throwing.
• GLUTEALS - allow extension, abduction and
  adduction at the hip (gluteus maximus is the
  biggest Gluteal). E.g. squats, jumping.
• HAMSTRINGS - these allow flexion of the knee,
  e.g. sprinting (leg action recovery)
• GASTROCNEMIUS - allows you to stand on your
  tiptoes, by creating extension at the ankle, e.g.
  sprinting (start).

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TASK Name all the muscles
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• Muscle Attachment
• Voluntary muscles are attached to your skeleton
  by TENDONS, usually across a synovial joint.
  These are fibrous and INELASTIC.
• The point where the muscle tendon attaches to the
  fixed or stationary bone is called the ORIGIN.
• The point where the muscle tendon attaches to the
  moving bone is called the INSERTION.
• As muscles contract they shorten. This makes the
  joint move.
• WHEN A MUSCLE CONTRACTS THE INSERTION MOVES
  TOWARDS THE ORIGIN.

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• HOW MUSCLES WORK
• Muscles can only create movement in one direction
  - by becoming shorter. This means that you need
  two muscles at every joint to allow movement in
  two directions.
• Therefore MUSCLES WORK IN PAIRS. For example,
  when your biceps CONTRACT it makes your elbow
  flex pulling your forearm up. To allow your elbow
  to extend, you need your triceps to CONTRACT and
  pull your arm back down. Meaning the biceps are
  RELAXING.

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• Muscles working in opposite directions like the
  above example are said to be working
  ANTAGONISTICALLY.
• The muscle doing the work and creating the
  movement is called the AGONIST or PRIME MOVER.
  The muscle which is relaxing and letting the
  movement take place, is called the ANTAGONIST.
• When you flex your elbow, e.g. during a bicep
  curl. The bicep is the AGONIST and the tricep is
  the ANTAGONIST.
• When other muscles assist the prime mover in
  creating a movement, these other muscles are
  called SYNERGISTS. E.g. deltoids doing a press-up.

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• Types Of Muscle Contraction
• 1. ISOMETRIC CONTRACTION
• the muscles stay the same length as it works and
  so no movement occurs.
• The muscles in the vertebral column contract
  isometrically to maintain our posture
• 2. ISOTONIC CONTRACTI0N
• the muscles changes its length as it works
• shortening is called CONCENTRIC CONTRACTION and
  lengthening under tension is called ECCENTRIC
  CONTRACTION.

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Fibres

• All muscles have fast and slow twitch fibres or a
  mixture of the two. The proportions are
  inherited.

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• FAST TWITCH FIBRES
• Produce powerful contractions very quickly
  (explosive)
• These fibres become fatigued in a short time
  (8-10 seconds)
• Great for sprinting, fast bowling, weight
  lifting, discus etc.

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• SLOW TWITCH FIBRES
• Produce less powerful, slower contractions.
• Become fatigued less quickly.
• Ideal for endurance events. E.g. marathon
  running.