KIN 330

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KIN 330

• Structural and Functional
• Analysis
• of Human Movement

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Structure of Class

• divided into three parts
• tissue
• movement patterns and analyses
• application of physics to movement

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What is Kinesiology?

• Components of Kinesiology

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What is Biomechanics?

• ...the application of physics and engineering
  principles to the study of motion.

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Components of Biomechanics

• Kinematics - the description of motion
• Kinetics - the study of forces on motion

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Who can use biomechanics?
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Biomechanics of Bone

• Purposes of skeletal system
• protection
• provides rigid links and attachments for muscles
• facilitates muscle action and body movement

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Bone

• metabolically active
• highly vascular
• responds to mechanical demands
• among the bodys hardest structures

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Distinguishing Features

• Organic component
• Inorganic component
• Interface of two components

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Mechanical Properties

• Functionally speaking
• strength
• stiffness

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Load/Deformation Curve

• Regions
• A - B Elastic Region
• B Yield Point
• B - C Plastic Region
• C Ultimate Failure Point

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Parameters displayed on curve

• load
• deformation
• energy

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Usefulness of L-D Curve

• determines the mechanical properties of the
  entire structure of the bone.
• Strength
• Stiffness

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Classification of Bone

• Depends on the extent of deformation before
  failure
• reflected in the fracture surfaces
• Brittle -
• Ductile -

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Bones behavior

• more brittle or more ductile behavior depending
  on
• age of bone
• rate at which bone is loaded

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Characteristic Unique to Bone

• Anisotropy
• bone exhibits different mechanical properties
  when loaded along different axes

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Types of Loading

• Forces are applied to bone using Newtons 3rd Law
  of Motion.
• These loads are equal in magnitude and oppositely
  directed.

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Types of Loading

• Tension
• loads applied outward along longitudinal axis of
  bone.
• Compression
• loads applied inward along longitudinal axis of
  bone.
• Shear
• loads applied parallel to cross-sectional surface
  of structure.

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Bone loads cont.

• Bending
• loads applied that cause bone to bend.
• Torsion
• loads applied that cause bone to twist about
  longitudinal axis.
• Combination
• two or more loads are applied to bone.

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Behavior of bone varies

• Rate of bone loading is important
• When loaded at higher rates
• bone is stiffer, sustaining higher load to
  failure, and
• bone stores more energy before failure.

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Clinical Importance of Loading Rate

• Influences the fracture pattern and amount of
  soft tissue damage at the fracture site.
• Three general categories of bone fracture.
• Low energy fracture
• High energy fracture
• Very high energy fracture

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Fractures caused by

• a single load that exceeds the ultimate strength
  of the bone, or
• repeated applications of a load of lower
  magnitude.

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Fatigue Fractures

• Produced by
• few repetitions of a high load, or
• by many repetitions of a relatively normal load.

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Factors affecting thefatiguing process

• Amount of Load
• Number of repetitions
• Frequency of Loading

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When do fatigue fractures occur?

• When remodeling process is outpaced by the
  fatigue process.
• Examples?
• Affect of muscle fatigue?
• Implications?

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Bone Remodeling

• bone remodels by altering its size, shape and
  structure to meet the mechanical demands placed
  on it.
• Wolffs Law

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Degenerative changes

• reduction in amount of cancellous bone,
• thinning of cortical bone,
• decrease in total amount of bone tissue, and
• slight decrease in the size of bone.
• Direct implications?

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Bone Summary

• Identify eight major points presented.

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