Zeno's Arrow Paradox:

1
Zeno's Arrow Paradox

• If everything when it occupies an equal space
  is at rest, and if that which is in locomotion is
  always occupying such a space at any moment, the
  flying arrow is therefore motionless.

2
New Zealand Sea Lion (Phocarctos hookeri) Running
mechanics in relation Male Age Class

• Juvenile (1-3 yrs old), Sub-adult (4-5yrs old)
  and Adult (6yrs and up)

Supervisor Dr. Chris Lalas
3
In the Beginning..

• there was nothingWell nothing running
• Then came the Acanthostega gunnari and Running
  mechanics was born
• The Field had a bit of a slow down for some 365
  million years
• Until Edward Muybridge came along and revitalized
  the science

4
By filming a horse
The most recognizable image from the field of
Running Mechanics
5
Present Understanding of

• Two basic principles in Running Mechanics
• Upside Down Pendulum (leg)
• Spring (Tendon and muscle)

High potential energy
High kinetic energy
Hoyt D.F. et al 2006
6
The Inverted Pendulum Spring
BIEWENER A.A 2006
7
Two gaits determined by Center of Mass

• When looking at the way a subjects Center of
  Mass (CM) moves there are two distinct forms of
  transport
• The Walk where Potential energy and Kinetic
  energy fluctuate between each other
• The Run Potential and Kinetic energy Fluctuate
  in sync, and are stored as elastic energy or
  spring energy (tendon)

BIEWENER A.A 2006
8
A Typical Terrestrial Runner

• Small plantar
• Long legs
• Stiff back
• Narrow trunk

9
Atypical Terrestrial Runner

• Larger planters
• Short legs
• Flexible Spine
• Round trunk

10
Why study a running sea lion?

• Natural selection pushes all runners to a
  standard design as illustrated earlier
• Marine Mammals have two distinct environments
  they need to move through
• Water is 800 times denser and 60 times more
  viscous than Air
• Terrestrial
• Primary Resistance Gravity
• Water
• Primary Resistance Drag and Buoyancy
• These opposing demands force the advancement of
  non-standard solutions
• Wobbling found in penguins
• Spinal flexion found in otters and river rats

11
Other Possible aspects

• There are two different questions that are asked
• How will an animal normally perform?
• How well is an animal capable of performing?
• The first Question is generally answered by
  filming wild animals
• This leads to difficulties in quantifying results
• The second is generally done in a controlled
  environment on a trained animal
• This opens the question of was the animals
  behavior altered by the process of captivity and
  training
• By initiating a territorial response will the
  animals perform as well as a trained sea lion?

Beentjes M.P. 1990
12
Hypothesis

• Ho Age will not affect gait characteristics or
  stride choice
• Ha Age will affect gait characteristics or stride
  choice

13
Methods

• Video Capture Two Filming methods Side view
  and Front view Two possible Errors Parallax and
  Non-Perpendicular Track
• Sea lion Prep Dots at joints and plantar
• Video Prep and Analysis Video Editing,
  digitizing and then software analysis
• Statistical Analysis

14
Two Filming treatments
Camera
Tom
Sea Lion
Sea Lion
Tom
Camera
Front view
Side view

• Side filming for standard Gait analysis, Foot
  contact, stride length, speed
• Head On Filming To quantify non-standard
  wobbling in the Z axis

15
Video Capture

• Filming Must be Perpendicular to the camera to
  enable the software to accurately calculate the
  geometry
• The Camera is set up as far away as possible and
  zoomed in to lower disturbance and decrease
  parallax error

vectors
vectors
16
Sea Lion PreparationPainting Sea LionsArt or
Science

• The Sea lion will have several dots applied to
  its fur to facilitate the digitizing process and
  prevent bias
• These dots will be applied at the shoulder
  (pivot) and the wrist (plantar) on both hind and
  fore limbs
• To measure wobble two dots will be placed on
  the chest of the animal

17
Video Preparation and AnalysisAlso known as
connect the dotHundreds of times over

• For the software to analysis the video digital
  dots are added to the markers on the animal, for
  every frame
• These dots are used to accurately measure, speed
  and angles when referenced to known lengths in
  the field of view

18
StatisticsAlso known as nap time

• Will need three groups of 8 individuals, planning
  on 30 individuals for each filming treatment,
  side and head on
• Speed, foot contact, stride length will be
  analyzed in reference to age groups
• The data will also be compared to terrestrial,
  semi-aquatic and aquatic mammal studies

19
Possibilities

• 3D Camera
• One lens, Multiple angles The lens has two paths
  that are used alternately and used to build a 3d
  image
• One lens, One laser While the camera is filming
  a second lens is recording laser light or IR
  image to get a depth for each pixel
• Multiple lenses One main lens to record the
  picture and several smaller lenses (Bug Eye) to
  build a 3d image giving depth info for main image
• All do the same thing, capture the distance of a
  object from the camera
• This would solve several difficulties, but
  presents other problems

20
Questions

• Run Abe Run

21
Science!