PE - The muscular System (P1)

• Musculo-skeletal system


  The skeletal system and the muscular system working together
• Muscles


  • Needed to move bones
  • Attached to bones by tendons
• Muscle contraction


  1. Muscle shortens

  2. Pulls on tendon

  3. Pulls on bone

  4. Causes bone movement
• Muscle function


  Provide energy for body movement
• Heart


  Pumps blood carrying oxygen to muscles
• Muscle groups and their functions

  • Pectorals - adduction and flexion at shoulder
  • Deltoids - abduction, extension, circumduction at shoulder
  • Trapezius - extension at neck
  • Biceps - flexion at elbow
  • Quadriceps - extension at knee
  • Abdominals - flexion at waist
  • Triceps - extension at elbow
  • Latissimus dorsi - extension, adduction, rotation at shoulder
  • Gluteals - flexion, abduction, adduction at hip
  • Gastrocnemius - plantar flexion at ankle
  • Hamstrings - flexion at knee
• Antagonistic muscles


  • Pairs of muscles that work against each other
  • One contracts while the other relaxes, and vice versa
  • The contracting muscle is the agonist
  • The relaxing muscle is the antagonist
  • Each muscle is attached to bones by tendons
  • Only one of the bones connected at the joint actually moves
• Fixator muscles


  Muscles that help the agonist work properly by stabilizing the bone that doesn't move
• Antagonistic muscle pairs


  • Elbow flexion - agonist biceps, antagonist triceps
  • Elbow extension - agonist triceps, antagonist biceps
  • Knee flexion - agonist hamstrings, antagonist quadriceps
  • Knee extension - agonist quadriceps, antagonist hamstrings
  • Shoulder flexion - agonist front deltoid, antagonist back deltoid
  • Shoulder adduction - agonist latissimus dorsi, antagonist back deltoid
  • Shoulder abduction - agonist middle deltoid, antagonist latissimus dorsi
  • Shoulder extension - agonist back deltoid, antagonist front deltoid