Ch 74 - Gait Analysis Flashcards

1
Q

Define Kinetic gait analysis and kinematic gait analysis

A
  • Kinetic gait analysis: Study of forces generated during movement
  • Kinematic gait analysis: The study of motion irespective of masses or forces
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2
Q

Which gait are symmetric and asymmetric?

A
  • Symmetrical: walk, trot, pace
  • Asymmetrical: Canter, transverse gallop, rotary gallop
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3
Q

What are the 2 main phases of the gait cycle?

A
  • Stance phase
  • Swing phase
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4
Q

What is the ground reaction force?

A

The resultant force of all local forces acting on the foot/paw

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5
Q

What are the 9 quantites calculated for each foot fall on a force plate?
Which are most commonly used for analysis in dogs?

A

Three orthogonal components
- Fx, Fy, Fz - describes the direction of the force

Three spatial components
- x, y, z - describes the location of the force on the plate

Three orthogonal moments
- Mx, My, Mz

The direction of force is most commonly described, Fx (mediolateral), Fy (craniocaudal), Fz (vertical) with the vertical force Fz being most common

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6
Q

How do you calculate weight?

A

Weight = mass(kg) x acceleration of gravity on earth (9.81m/s^2)

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7
Q

What do the vertical force Fz and the craniocaudal force Fy represent?

A

Fz represents the vertical force of the leg and can be used to assed peak vertical force. Creates a bell chaped curve at a trot, M-shaped at a walk

Fy represents braking (positive value) and propulsion (negative value)

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8
Q

What is the impulse value?

A

The area under the forse-time curve and takes both force, and contact time into consideration

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9
Q

What change is expected regarding peak vertical force and impulse value with pain or lameness?

A

Both are reduced

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10
Q

What is represented by the rising and falling slope of a force-time curve?
What changes are expected with pain/lameness

A
  • Rising slope depicts the loading rate of the limb and falling slope depects the offloading rate of a limb.

Pain/lameness:
- RIsing slope is reduced (less steep, slower to lad limb)
- Falling slope is increased (more steep, fast offloading)

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11
Q

What number of photocells are required to measure velocity and acceleration?

A
  • Velocity - at least 2 photocells
  • Acceleration - At least three photocells

Placed 0.5m above gait platform, 0.5 - 3m apart

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12
Q

How do you calculate velocity?

A

Distance traveled (m) / time (change in time) in seconds

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13
Q

How do you calculate acceleration?

A

Change in velocity (m/s) /time (s)

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14
Q

What are some of the main differences of pressure walkways as appossed to force plate?

A
  • Force plates calculate a direct foce in three directions whereas pressure walkway only calculates pressure in a vertical direction
  • Pressure walkways can record infor for each individual limb, force plate only does one limb at a time

Cannot compare one to the other

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15
Q

During a trot, what is the average PVF of the thoracic limb and pelvic limb?

A
  • Thoracic limb 115% BW
  • Pelvic limb 72% BW
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16
Q

Which gait is the more sensitive and accurate for the detection of low-grade or mild lameness in dogs?

A

Trot - no overlap of footfalls

17
Q

What is symmetry index?

A

The use of an animals own limbs to serve as an internal control for comparison

18
Q

What is a normal level of asymmetry?

A

Has been repored as less than 3.2 or less than 6%

19
Q

What are some common sources of variability?

A
  • Handler
  • Trial repetition
  • Habituation
  • Changes in velocity, stance time or acceleration/deceleration
20
Q

What are the three joint rotations and the three joint translations in kinematic analysis?

A

Rotations:
- Flexion and extension
- Internal and external rotation
- Abduction and adduction

Translations:
- Mediolateral
- Proximodistal “joint distraction”
- Craniocaudal “drawer”

21
Q

What is parallax error and perspective error?

A
  • Parallax error: subject moves away from the optical axis of the camera
  • Perspective error: WHen subject moves out of calibrated plane of motion
22
Q

What are the 2 forms of markers that can be used for kinematic analysis?

A
  • Passive markers: Circular/spherical, non-reflective markers
  • Active markers: Light-emitting diodes.
23
Q

What point values are commonly assessed using kinematic analysis?

A
  • Range of motion
  • Maximal flexion or extension
24
Q

List some forms of complete waveform analysis of kinematic analysis

A
  • Fouriers analysis - can determine whether 2 gait cycles are similar. Deconstructs waveform into its component parts
  • Wavelet analysis
  • Generalised indicator function analysis - determines where in gait cycle the differences are occuring
25
Q

Define forward dynamics and inverse dynamics

A
  • Forward dynamics: The process of using forces and moments to directly calculate the resulting motion of an object
  • Inverse dynamics: The use of available kinetic and kinematic data for the indirect calculation of forces and moments
26
Q

Define joint moment and joint power as it relates to dynamics

A
  • Joint moment - net joint torque acting around a joint
  • Joint power - measure of mechanical energy generation and absorption across the joint
27
Q

What is parallax error and perspective error?

A
  • Parallax error: subject moves away from the optical axis of the camera
  • Perspective error: WHen subject moves out of calibrated plane of motion