Biomechanical Principles Influence Movement

• Linear Motion


  Movement in a straight line
• Linear Motion

  • 50m swim
• Angular Motion


  Circular movement around a central point
• Angular Motion


  • Gymnast on bars
• Projectile Motion


  Movement along a curved path under the action of gravity
• Projectile Motion


  • Javelin throw
• Distance


  Path travelled from one location to another
• Displacement


  Location measured with respect to a known point
• Speed


  Distance traveled over time, scalar quantity (no direction)
• Speed


  • Rate at which a body moves from one place to another
• Velocity


  Rate of change of displacement, vector quantity (magnitude + direction)
• Speed describes only the magnitude of how quickly a body is moving. It is a scalar quantity.
• Velocity describes both magnitude and direction of the body's movement. It is a vector quantity that measures the displacement divided by the time taken to get from point A to point B.
• Speed

  Describes only the magnitude of how quickly a body is moving
• Velocity


  Describes both magnitude and direction of the body's movement
• Speed measures how fast a body moves over a distance regardless of direction. It only considers magnitude.
• Velocity measures both the speed and direction of a body's movement. It specifies how fast and in what direction the body is moving, considering displacement.
• Acceleration


  Rate at which velocity changes over time
• Positive acceleration


  Increase in velocity
• Negative acceleration


  Decrease in velocity
• Momentum


  Quantity of motion a body possesses
• Momentum


  • Once in motion, stays in motion; more speed = more distance to stop
• Center of Gravity


  Point where all weight is equally distributed, axis of rotation when moving/rotating
• Base of Support


  Region of the body in contact with the surface applying reactive force
• Line of Gravity


  Imaginary vertical line through the center of gravity, represents the direction gravity acts on the body
• Flotation & Center of Buoyancy

  Ability to maintain a stationary position on the surface of water, factors: Center of Gravity, Body Density (mass/volume)
• Fluid Resistance


  Force exerted when a body or object moves through water or air
• Lift


  Force operating at right angles to drag
• Applied Forces


  Generated by muscles, applied to surfaces (e.g., running track)
• Reaction Forces


  Equal and opposite forces exerted in response to applied forces (e.g., runner on a track)
• How the Body Absorbs Force

  • Producing force over a larger area reduces impact
  • Flexing joints minimizes force (e.g., landing from a jump)
  • Changing impact from direct to oblique lessens force (e.g., turning head while being punched)
  • Using equipment to absorb force instead of body parts (e.g., boxing gloves)
  • Increasing the time of force absorption (e.g., catching a cricket ball)
• Newton's Laws


  • Objects in motion stay in motion unless acted on by an external force
  • Force = Mass x Acceleration
  • For every action, there is an equal and opposite reaction