wk 3 - kinematics and visual gait analysis

Question 1

motion that occurs in sagittal plane and how to view

Answer 1

-dorsiflexion/plantarflexion -of ankle, midtarsal, metatarsophalangeal and interphalangeal joints.

-flexion/extension of knee and hip

view this plane from side on.

Question 2

motion that occurs in frontal plane and what occurs during them

Answer 2

movement occurring away or towards the midline of the body

varus: position of distal body part towards midline
valgus: position of distal body part away from midline
inversion: movement of the distal segment towards midline
eversion: movement of distal segment away from midline
lateral flexion- trunk
hip abduction/adduction

view this front on or behind a person

Question 3

common frontal plane deformities

Answer 3

knee position
genu varum - bow legged
genu valgum- knee knocking

foot posture
varus- rolling on the outside of foot (inverted)
valgus- rolling on inside of foot (everted)

hips
trendelenburg sign - pelvic dip

Question 4

excessive hip drop is called

Answer 4

trendelenburg sign. weak glute muscles to stabilise pelvis during swing phase

Question 5

motion that occurs in transverse plane

Answer 5

abduction, adduction of foot

internal and external rotation of hip/knee/ankle

pelvic tilt or rotation of hip

view looking up or down

Question 6

pronation occurs in what planes and what movements

Answer 6

all 3 planes and includes movements eversion, dorsiflexion and abduction

Question 7

supination is what

Answer 7

inversion, plantar flexion and adduction

Question 8

what is internal rotation of the tibia coupled with? and what does this cause

Answer 8

pronation of the foot which shortens the limb during early stance phase

Question 9

what is external rotation of the tibia coupled with? and what does this cause

Answer 9

supination of the foot which the forefoot stays in contact with the ground longer due to midtarsal joint

-foot is functionally longer

Question 10

define the study of kinematics

Answer 10

a description of motion of body segments and joints in terms of
angles
positions
velocities
accelerations

(not force)

Question 11

3 types of motion and what the simplified motions are

Answer 11

1. translation
   the body moves without turning, a straight line on the body shifts but remains parallel to start
2. fixed-axis rotation
   the body turns about a stationary point in a plane
   The movement paths are circular arcs
   about the fixed axis
3. Combined motion*
   The body moves so that all points change
   position and all lines turn ie. the body
   translates and rotates

simplified:
linear- translational
angular- rotational

Question 12

how kinematic data are reported (relative/absolute angles)

Answer 12

joint angles are reported in relation to the anatomical position (relative angles not absolute)

10 degrees dorsiflex not 100

flexion/dorsiflexion/adduction/internal rotation/inversion= positive angles

extension/plantarflexion/abduction/external rotation/eversion = negative angles

Question 13

pros/cons of observational (visual) gait analysis

Answer 13

-inexpensive
-no equipment
-quick and easy assessment

-human eye can only visualize movements not forces or any specific data
-bias toward treatment outcomes
-high speed visual stimulus for the eye (can use video)
-change of walk when being watched
-typically only view from 1 plane (frontal)

Question 14

pros of 2D video analysis 4

Answer 14

Can enhance visual gait observations
* Easy to use
* Inexpensive, simple & quick analysis
* No time consuming marker placement

Question 15

limitations of 2D analysis 3

Answer 15

• only accurate when the camera is positioned perpendicular to the plane of action, and viewing from the correct plane the action occurs in (parallax error)
• the movement must occur within the calibrated plane, related to camera distance (perspective error)
• Cannot measure all three planes of motion
  simultaneously.

Question 16

pros/cons of 3d video analysis (2) (3)

Answer 16

gold standard for research applications
* Cameras are infrared and capture rate over 100 Hz

• Requires multiple cameras (at least 6) and a large gait lab
• Expensive and time consuming analysis
  -marker placement and camera placement can be inaccurate and lead to error

Question 17

what is the parallax error

Answer 17

an angle being more or less than what it really is because of the viewing angle not being perpendicular or in the correct plane of action

Question 18

perspective error

Answer 18

apparent change in length/height as object moves out of calibrated plane, related to camera distance from object

Question 19

marker placement do what, and what is the problem with them

Answer 19

for 3D analysis, 3 markers define each body segment

error:
-placement error
-movement of skin/soft tissue error

Question 20

common sources of error in kinematic data collection

Answer 20

perspective error
parallax error
Marker placement
soft tissue movement

Question 21

specifcally with the foot and ankle, what errors/challenges occur in kinematics

Answer 21

1. motion analysis have difficulties tracking several markers close together
2. complex bony structures/motions- difficult to quantify
3. perspective error- zoom in on foot, miss the rest of the lower limb

Question 22

what is the average degree for anterior pelvic tilt in standing and walking, when does peak anterior tilt occur, when does posterior tilt occur

Answer 22

approx 10 degrees- tilt is forward not side.
peak anterior tilt in terminal stance
posterior tilt during pre swing

usually minimal (2-3deg) when walking

Question 23

hip motion in the sagital plane. what movements occur in which phases? what deg and when does the hip reach full extension and flexions?

Answer 23

extension during stance phase
flexion during swing.

these are the 2 main arcs of motion during the gait cycle for the hip

begins approx 20 degrees flexion at initial contact, moves to approx 15 degrees extension before opposite contact and back to 20 flexion mid swing until initial contact again

Question 24

what degree minimum is important at the hip for foot clearence - sagittal plane

Answer 24

15 degrees of hip flexion minimum, impacts ground/toe clearance if the degree is shortened

Question 25

at initial contact, knee is extended to what degree? - sagittal plane

Answer 25

full extension to 10 degrees flexion

the faster the gait, the greater the knee flexion

Question 26

the knee experiences two waves of flexion, the first wave is approx what degree? the second wave is approx what degree? - sagittal plane

Answer 26

first- 20 degrees (transition between loading response and mid stance)

second- 60 degrees (during initial swing an assists foot clearance)

Question 27

what causes more knee flexion- sagittal plane

Answer 27

increase in speed, to absorb shock

Question 28

what are the 4 arcs of motion for the ankle - sagittal plane

Answer 28

heel rocker- initial plantarflexion (approx 5 degrees)

ankle rocker- rapid dorsiflexion at mid stance while tibia advances over stationary foot

forefoot rocker- in terminal stance, dorsiflexion as tibia continues to advance

toe rocker- in pre swing following contralateral initial contact, rapid ankle plantarflexion occurs

during swing phase the ankle returns to neutral (this is to gain ground clearance) through dorsiflexion

Question 29

when is toe clearance sensitive to the knee and ankle movements?

Answer 29

during initial swing, toe clearance is sensitive to knee flexion

during mid swing, toe clearance is sensitive to ankle dorsiflexion

Question 30

what degrees is the first metatarsophalengeal joint at the initial contact, mid stance, terminal stance and pre swing - sagittal plane

Answer 30

IC- 15 degrees (dorsi)
MS- neutral
terminal- 15-20 (dorsi)
preswing- 50 (dorsi)

Question 31

why is some pelvic obliquity okay?

Answer 31

serves as a shock absorber and limb length adjustment

Question 32

what happens to the tibia during single support?- frontal plane and why is it important

Answer 32

varus position as body weight is transferred onto stance leg

important when assessing someone with a positional deformity as it will differ between stance and single limb stance

Question 33

what does the subtalar joint do at initial contact, loading response, mid stance, terminal stance- frontal plane

Answer 33

inverted (sup) at initial contact
everts (pronates) until foot flat through loading response
inverts (supinates) through late midstance/terminal stance

Question 34

when does maximum pelvic rotation occur? and what is the range of motion in degrees- transverse plane

Answer 34

initial contact and terminal swing

approx 10

Question 35

what does pelvic rotation contribute to

Answer 35

step length

Question 36

what occurs at the knee during initial contact, loading response and terminal stance?- transverse plane

Answer 36

IC- knee is slightly externally rotated
LR- internal rotation coupled with STJ pronation occurs
by the end of loading response the knee and limb has reached peak internal rotation
TS- external rotation coupled with supination of STJ at terminal stance, pre swing, and swing phase

Question 37

what usually occurs for angle of gait (toe in, toe otu) during walking - transverse plane

Answer 37

usually remains externally positioned throughout gait cycle, further external rotation during single limb support and small amount of internal rotation during pre swing
external rotation in initial swing
internal rotation in terminal swing