Musculoskeletal System

• Joints 


  A place where two or more muscles meet and create movement
• Ball and Socket Joint 


  Allows movement in all directions

  Movements: Extension, Flexion, Adduction, Abduction, Rotation
• Hinge Joint 


  Only allows forward and backwards movement

  Movements: Flexion, Extension (Plantarflexion and Dorsi-Flexion at the Ankle)
• Plane


  An imaginary flat surface that divides the body into two sections
• Axis 


  An imaginary straight line around which something turns
• Sagittal Plane + Transverse Axis 


  Divides body into left and right

  Movements go forwards or backwards (flexion at the knee)
• Transverse Plane + Frontal Axis 


  Divides body into top and bottom

  Movements which require rotation or twisting
• Transverse Plane + Longitudinal Axis


  Divides body into front and back

  Movements towards or away from the midline of the body
• Antagonist Muscle Pairs 


  Muscles are paired to create movement

  One muscle will contract while the other relaxes
• Agonist 


  The prime mover in a muscle pair

  Creates the movement between muscles and bones
• Antagonist 


  The muscle which relaxes

  Facilitates the contraction of the agonist
• Isometric Contractions


  Muscle contractions which do not create movement

  The muscle will contract without lengthening and shortening

  Relies on tension and holding position
• Isotonic Eccentric Contractions 


  The muscle lengthens under tension

  Acts a break against movement during negative work
• Isotonic Concentric Contractions 


  The muscle shortens under tension
• Newtons First Law


  An object will remain in its state of motion unless another force acts on it

  Inertia is the resistance to this changing force
• Newtons Second Law 


  The rate of momentum depending on force

  The higher the force the faster the acceleration
• Newtons Third Law 


  To every action there is an equal and opposite reaction
• Power (W) = Force x Distance/Time
• Force (F) = Momentum / Time