Chapter 2: Kinematic Concepts for Analyzing Human Motion

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Chapter 2Kinematic Concepts for Analyzing Human
Motion

• Basic Biomechanics, 4th edition
• Susan J. Hall
• Presentation Created by
• TK Koesterer, Ph.D., ATC
• Humboldt State University

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Objectives

• Identify describe reference positions, planes,
  and axes associated with the human body
• Provide examples of linear, angular, general
  forms of motion
• Define appropriately use directional terms
  joint movement terminology
• Explain how to plan conduct an effective
  qualitative human movement analysis
• Identify describe uses of available
  instrumentation for measuring kinematics

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Forms of Motion

• Most human movement is general motion
• A complex combination of
• Linear and
• Angular motion components

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Forms of Motion

• Linear Motion
• May also be thought of as motion along a line
  that may be straight or curved, with all parts of
  the body moving in the same direction at the same
  speed, also known as translatory motion, or
  translation.
• Rectilinear along a straight line
• Curvilinear along a curved line

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Forms of Motion

• Angular motion involving rotation around a
  central line or point
• Axis of rotation imaginary line perpendicular
  to the plane of rotation and passing through the
  center of rotation

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General Motion

• A combination of translation and rotation
• Most human movement activities are categorized as
  general motion

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Mechanical Systems

• Before determining the nature of a movement, the
  mechanical system of interest must be defined.
• System a body or group of bodies whose motion
  is being analyzed

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Standard Reference TerminologyAnatomical
Reference Position

• Erect standing position with all body parts,
  including the palms of the hands, facing forward
  considered the starting position for body segment
  movements

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Standard Reference TerminologyDirectional Terms

• Superior
• Inferior
• Anterior
• Posterior
• Medial
• Lateral

• Proximal
• Distal
• Superficial
• Deep

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Standard Reference TerminologyAnatomical
Reference Planes

• Cardinal planes 3 imaginary perpendicular
  reference planes that divide the body in half by
  mass
• Sagittal plane
• Frontal plane
• Transverse plane

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Standard Reference TerminologyAnatomical
Reference Axes

• An imaginary axis of rotation that passes through
  a joint to which it is attached
• Mediolateral or frontal axis
• Anterioposterior or sagittal axis
• Longitudinal axis

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Joint Movement Terminology

• In anatomical position, all body segments are
  considered to be positioned at zero degrees.
• Sagittal Plane Movements
• Frontal Plane Movements
• Transverse Plane Movements
• Other Movements

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Sagittal plane movements
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Frontal Plane Movements
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Transverse Plane Movements
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Other Movements
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Spatial Reference Systems

• Used to standardize the measurements taken
• Cartesian Coordinate system
• Movements primarily in a single direction, or
  planar, can be analyzed using a two-dimensional
  Cartesian
• X (horizontal) direction
• Y (vertical) direction
• 3-dimensional by adding a z-axis

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Cartesian Coordinate System
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Qualitative Analysis of Human Movement

• Requires knowledge of the specific biomechanical
  purpose of the movement and the ability to detect
  the causes of errors
• Qualitative refers to a description of quality
  without the use of numbers.

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Prerequisite Knowledge for a Qualitative Analysis

• Kinematics
• Performance outcome
• Analysts should be able to distinguish the cause
  of a problem from symptoms of the problem or an
  unrelated movement idiosyncrasy
• Experience in performing a motor skill does not
  necessarily translate to proficiency in analyzing
  the skill.

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Planning a Qualitative Analysis

• What are major questions to be answered
• Determine the optimal perspective(s)
• Analysts viewing distance
• Number trial or executions
• Performers attire
• Nature of surrounding equipment
• Visual observation or video camera

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Conducting a Qualitative Analysis

• Continuous process of
• formulating an analysis
• collecting additional observations
• formulating an updated analysis
• Detecting biomechanical errors
• Characteristics of the performer
• Other factors that can affect performance
• Auditory information
• Feedback from the Performer
• Observation skill

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Tools for Measuring Kinematic Quantities

• Cinematography Videography
• Standard video 30 pictures per second
• Higher rates available
• Clarity of images
• Number of cameras to capture information
• Computer-linked equipment digitizing

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Measuring Kinematic Quantities

• Other Movement Monitoring Systems
• Real-time tracking of LEDs
• Computer-linked cameras track targets
• Other Assessment Tools
• Goniometer or Electrogoniometer
• Photocells, light beams, and timers
• Accelerometer

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Summary

• Teachers of physical activities, clinicians
  coaches all routinely perform qualitative
  analyses to assess, correct, or improve human
  movements
• Both knowledge of the specific biomechanical
  purpose of the movement and careful preplanning
  are necessary for an effective qualitative
  analysis

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The End