Kin7

• Torque


  Force required to rotate an object around an axis, fulcrum or pivot

  
• Moment Arm


  Perpendicular distance from the point of force applied

  
• Torque


  Force (Fm) x Moment Arm

  
• Torque


  • It creates the movement of the lever system (bones)
  • Units: Newton. Meter (n. m)
• Torque


  • Force exerted on a bolt or screw when tightening or loosening it
• Torque


  Product of (Force applied x Perpendicular distance from the point of force applied)

  
• Torque Depends on


  • Amount of force
  • Angle of application of force
  • Length of the moment arm

  
• Joint ROM


  Does not always correlate with the amount of torque a muscle can create

  
• Greatest Torque/Moment Arm


  • Force applied at 90 degree angle to it's lever
• Moment arm


  Determines the quality of the torque
• Moment arm


  Changes with the angle of application of the force (angle of insertion)

  
• Barbell biceps curl exercise

  • It's much harder to move the bar when elbows are fully extended compared to 90°
• Patella


  • Increases the angle of application of the quadriceps tendon and therefore moment arm, thus increasing the amount of torque the quadriceps can create
  • Without the patella most of the quadriceps force would create more of a compression/joint stability moment

  
• Moment arm


  • Shortest distance from axis of rotation to the line of action of the force
  • The greater the distance of force arm, the more torque produced by the force

  
• Force arm length


  Inversely related to amount of force required to move a lever if resistance & resistance arm remain constant

  
• Resistance arm length


  Inversely related to amount of resistance that can be moved if force & force arm remain constant

  
• Force components & resistance components

  Directly related - if either of the resistance components increase, there must be an increase in one or both of force components
• External torque


  Product of the external force (gravity) and the external moment arm
• When the sum of the counterclockwise torques equals the sum of the clockwise torques, no turning will occur