PRINCIPLES OF BIOMECHANICS

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PRINCIPLES OF BIOMECHANICS

• BUILDING BLOCKS OF EXERCISE

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SEVEN PRINCIPLES

• Grouped into four(4) categories
• Category 1 Stability
• Category 2 Maximum Effort
• Category 3 Linear Motion
• Category 4 Angular Motion
• Pages 231 234 in textbook

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Stability - Principle 1

• Proper stability balance are essential to
  efficient movement.
• See notes on stability from earlier in unit.

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Max Effort - Principle 2

• Production of maximum force requires the use of
  all possible joint movements that contribute to
  the tasks objective.
• With more joints coming into play, the more
  muscles there will be to contract leading to
  greater force being exerted.

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Principle 2

• Example Throwing a ball
• Use as many body joints as possible

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Max Effort - Principle 3

• Production of maximum velocity requires the use
  of joints/muscles in order from largest to
  smallest.

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Principle 3

• Example Use legs to shoot in basketball
• Bend from legs to generate more force

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Linear Motion Principle 4

• The greater the applied impulse or force, the
  greater the increase in velocity.
• The harder you hit an object, the farther it will
  travel.

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Principle 4

• Principle of Impulse crouch before you take off
  to jump.
• Reverse Impulse absorbing forces when catching
  an object or landing after a jump. ( in order to
  lessen the load on joints and disperse the large
  forces at work)

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Linear Motion Principle 5

• Movement usually occurs in the direction
  opposite that of the applied force.
• Examples Resistance of water in swimming,
  pushing off floor before jumping, etc.
• Related to Newtons 3rd Law (Reaction)

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Angular Motion -Principle 6

• Angular motion is produced by the application of
  a force acting at some distance from an axis.

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Angular motion
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Principle 6

• Angular velocity increases closer the object is
  to the axis of rotation.
• Examples figure skating spinning, diver
  spinning, throwing a curve ball.

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Angular Motion -Principle 7

• Angular momentum is constant when an athlete or
  object is free in the air (or airborne).

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Applying PrinciplesCase 1

• You are coaching a peewee football team and you
  notice that one of your 50kg linemen is getting
  knocked down very easily and often. As a result,
  your 9-year old all-star quarterback has suffered
  his 5th concussion and is forced to eat all of
  his meals through a straw.

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Case 1

• Principle 1 Work on stability of linemen.
• Principle 3 Large to small muscles when
  pushing off opponent.
• Principle 4 Hit opponent harder to protect
  quarterback.
• Anything else?

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Applying PrinciplesCase 2

• When Silken Lauman was a young rower she pulled
  the oars with her arms and then pushed with her
  legs, causing her boat to not travel as fast as
  she would like. Somehow she became one of the
  best rowers in the world.

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Case 2

• Principle 3 Largest to smallest muscles.
  Generate force from legs and then arms.
• Principle 5 Resistance of oars in watermore
  efficient strokes.
• Anything else?

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Applying PrinciplesCase 3

• Ben Johnson could run the 100m in 10 seconds.
  After pumping his body full of steroids, he cut
  his time to a world record time of 9.79 seconds
  in 1988.

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Case 3

• Principle 4 Greater applied force, greater the
  reaction. Push off ground harder with steroids.
• Principle 5 Movement occurs in opposite
  direction of applied force. Push off starting
  blocks harder with steroids.
• Anything else?