How Muscles affect movement

• • Each joint has muscles called prime movers, which are the muscles most responsible for the action of the joint
• Agonist

  Muscles CONTRACT and therefore SHORTEN, pulling the bone at the joint and causing the movement, this can also be called the prime mover
• Antagonist

  Muscles RELAX during a movement and therefore lengthen
• Isometric

  • Muscle contractions do NOT cause movement because the muscle length does not change
  • E.g —> holding a plank by keeping the body in a fixed position
• Isotonic

  involves the lengthening or shortening of muscles, leading to movement at a joint
• Concentric contractions

  The muscle shortens
• Eccentric contraction


  The muscle lengthens