Movement Analysis

• Lever Systems:

  A lever consists of:

  • A rigid structure (bone).
  • A force acting upon it (muscle) to produce a turning motion.
  • A fulcrum which is a fixed point (joint).
  • A load or resistance that is placed on the rigid structure (weight of body part and anything its carrying).
• First Class Levers:

  Fulcrum is in the middle of the effort and the load.

  • This type of lever is found in the neck when raising your head to head a football. The neck muscles are the effort, the neck is the fulcrum, and the weight of the head is the load.

  
• Second Class Levers:

  The load is in the middle between the fulcrum and the effort.

  • This type of lever is found in the ankle. When standing on tiptoe, the foot acts as the fulcrum, the weight of the body acts as a load, and the gasrocnemius is the effort. Used when taking off for a jump.

  
• Third Class Lever:

  The effort is in the middle between the fulcrum and the load.

  • During a bicep curl, the fulcrum is the elbow joint, the effort comes from the biceps contracting, the load is the weight of the forearm and any weight that it may be holding.

  
• 123, FLE.

  • First class lever - Fulcrum is in the middle.
  • Second class lever - Load is in the middle.
  • Third class lever - Effort is in the middle.
• Mechanical advantage of levers:

  Some levers operate with mechanical advantage. This means the lever can overcome a large load with little effort. It is very useful for joints which are weight bearing as they have to overcome the weight of the whole body.

  • Mechanical advantage = effort arm / resistance arm.

  The second class lever provides the most mechanical advantage.
• Planes and axes of movement:

  A plane is an imaginary flat surface running through the body. An axis is an imaginary line at right angles to the plane, about which the body rotates or spins.

  
• Planes of movement:

  • Sagittal plane - a vertical plane that divides the body into left and right sides. Flexion and extension occur at this plane. E.g. kicking a football, walking.
  • Frontal plane - Passes from side to side and divides the body into the front and back. Abduction and adduction occur in this plane. E.g. jumping jack, cartwheel.
  • Transverse plane - passes through the middle of the body and divides the body into top and bottom. Rotation occurs. E.g. pivoting in netball, spinning in skating.
• Axes of movement:

  • Transverse axis - runs from left to right through the centre of the body. E.g. performing a somersault.
  • Sagittal axis - runs from front to back through the centre of the body. E.g. performing a cartwheel.
  • Longitudinal axis - runs from top to bottom through the centre of the boy. E.g. performing a spin (skating).