How Muscles Affect Movement (AQA GCSE Physical Education (PE))

How Muscles Move the Skeleton

• At each joint, multiple different muscle groups work together to cause movement in two or more directions

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

• Muscles often work together in pairs to create movement in two directions:

  • 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

• When muscles contract it can result in different outcomes:

  • Isometric muscle contractions do not cause movement because the muscle length does not change

    • An example of this is tensing a muscle when holding a lifted weight still, or holding a plank by keeping the body in a fixed position

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

    • Concentric contraction is when the muscle shortens

    • Eccentric contraction is when the muscle lengthens