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Chapter 2
Kinematic Concepts
for Analyzing Human
Motion
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
McGraw-Hill/Irwin
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
What is anatomical reference position?
• erect standing
position with all
body parts facing
forward
• considered the
starting point for all
body segment
movements
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-2
Directional terms:
superficial: toward the surface of the body
superior: closer to the head
proximal: closer to the trunk
lateral: away from the
midline of the body
posterior: toward
the back of the body
deep: inside the body away from the surface
medial: toward the midline of the body
anterior: toward the front of the body
distal: away from the trunk
inferior: farther away from the head
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-3
Reference planes:
• sagittal plane - in which forward and
backward movements occur
• frontal plane - in which lateral movements
occur
• transverse plane - in which rotational
movements occur
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-4
Reference axes:
Longitudinal axis - directed vertically and around which rotational
movements occur
Anteroposterior axis – directed along the sagittal plane
and around which rotations in the frontal plane occur
Mediolateral axis – directed along the frontal plane and
around which rotations in the sagittal plane occur
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-5
Forms of motion:
Linear motion: motion along a line
• Rectilinear motion: (along a straight line)
• Curvilinear motion: (along a curved line)
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-6
Forms of motion:
Angular motion: rotation around an axis
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-7
Forms of motion:
Angular motion
Curvilinear motion
Rectilinear motion
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-8
Forms of motion:
General motion: a combination of linear and
angular motion (includes most human
motion)
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-9
What is a mechanical system?
• a body or portion of a body that is
deliberately chosen by the analyst
• examples: throwing arm, kicking leg, the
trunk during performance of a lift, the
entire body during performance of a
maximal vertical jump
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-10
What movements occur in the sagittal plane?
Flexion
Extension
Dorsiflexion
Hyperextension
Plantar flexion
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-11
What movements occur in the frontal plane?
Radial
deviation
Abduction
Ulnar
deviation
Adduction
Lateral flexion
Elevation
Depression
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
Eversion
Inversion
2-12
What movements occur in the transverse
plane?
Horizontal
adduction
Pronation Supination
Medial
rotation
Lateral
rotation
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
Horizontal
abduction
2-13
Spatial Reference Systems
• useful for standardizing descriptions
of human motion
• most commonly used is the Cartesian
coordinate system
• human body joint centers are labeled
with numerical x and y coordinates
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-14
Spatial Reference Systems
Y
(x,y) = (3,7)
(0,0)
X
Cartesian coordinates of the hip
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-15
Spatial Reference Systems
y
x=y=+
x=+
y=+
x
(0,0)
x=y=-
x=+
y=-
Coordinates can be both positive and
negative.
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-16
Qualitative Analysis:
Prerequisite Knowledge
• What is the purpose of the skill?
• What are the causes of performance errors?
• How can knowledge be gained?
• experience in performing the skill
• reading available literature
• attending conferences and workshops
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-17
Qualitative Analysis:
Planning
• What is the question to be answered?
• From what perspectives (angle and viewing
distance) should the movement be
viewed?
• How many observations should be taken?
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-18
Qualitative Analysis:
Planning
• What plans should be made for:
• performer attire
• lighting conditions
• background
• use of video
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-19
Qualitative Analysis:
Conducting the Analysis
Identify
Question/Problem
Viewing Angle
Viewing Distance
Performer Attire
Refine Question
Make Decisions
Use of Video
End Analysis
Communicate
with Performer
Environmental
Modifications
Collect
Observations
Visual
Auditory
From Performer
Interpret Observations From Other Analysts
Basic Biomechanics, 6th edition
By Susan J. Hall, Ph.D.
2-20