Muscles and Movement

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Muscles and Movement
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How Muscles Work

• A voluntary muscle usually works across a joint.
• It is attached to bones by tendons.
• When a muscle contracts, usually just one bone
  moves.
• (EG When the biceps in the arm contracts, the
  radius moves but the scapula does not).

TENDON
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Origin and Insertion
(1)

• The origin is where the muscle joins the
  stationary bone (1).
• The insertion is where it joins the moving bone
  (2).
• When a muscle contracts the insertion moves
  towards the origin.

(2)
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Muscles Working in Pairs
Biceps contract
Biceps Relax
Triceps Relax
Triceps Contract
Flexion
Extension
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