Explanation

1
Explanation

• To FLEX (bend the elbow) the biceps contract
  (shorten) and the triceps relax (lengthen).
• To EXTEND (straighten) the elbow, the biceps
  relax and the triceps contract.
• This above is called an antagonistic muscle
  action.
• The working muscle is called the prime mover or
  agonist.
• The relaxing muscle is called the antagonist.
• The prime mover is helped by other muscles called
  synergists.
• These contract at the same time as the prime
  mover.
• They hold the body in position so that the prime
  mover can work smoothly.

2
(No Transcript)
3
(No Transcript)
4
Tendons

• They connect muscle to bone.
• They are white, flexible and very strong.
• Tendons do not tear away easily due to them being
  embedded in the periosteum (surface of the bone).
• If they do tear, it is often a long and painful
  recovery.

5
Muscle Shape and Size

• Muscles come in many different shapes and sizes
  according to the job they have to do.
• Note the different shapes of tendons that go
  with them.