wk 3 - kinematics and visual gait analysis Flashcards
motion that occurs in sagittal plane and how to view
-dorsiflexion/plantarflexion -of ankle, midtarsal, metatarsophalangeal and interphalangeal joints.
-flexion/extension of knee and hip
view this plane from side on.
motion that occurs in frontal plane and what occurs during them
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
common frontal plane deformities
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
excessive hip drop is called
trendelenburg sign. weak glute muscles to stabilise pelvis during swing phase
motion that occurs in transverse plane
abduction, adduction of foot
internal and external rotation of hip/knee/ankle
pelvic tilt or rotation of hip
view looking up or down
pronation occurs in what planes and what movements
all 3 planes and includes movements eversion, dorsiflexion and abduction
supination is what
inversion, plantar flexion and adduction
what is internal rotation of the tibia coupled with? and what does this cause
pronation of the foot which shortens the limb during early stance phase
what is external rotation of the tibia coupled with? and what does this cause
supination of the foot which the forefoot stays in contact with the ground longer due to midtarsal joint
-foot is functionally longer
define the study of kinematics
a description of motion of body segments and joints in terms of
angles
positions
velocities
accelerations
(not force)
3 types of motion and what the simplified motions are
- translation
the body moves without turning, a straight line on the body shifts but remains parallel to start - fixed-axis rotation
the body turns about a stationary point in a plane
The movement paths are circular arcs
about the fixed axis - 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
how kinematic data are reported (relative/absolute angles)
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
pros/cons of observational (visual) gait analysis
-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)
pros of 2D video analysis 4
Can enhance visual gait observations
* Easy to use
* Inexpensive, simple & quick analysis
* No time consuming marker placement
limitations of 2D analysis 3
- 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.
pros/cons of 3d video analysis (2) (3)
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
what is the parallax error
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
perspective error
apparent change in length/height as object moves out of calibrated plane, related to camera distance from object
marker placement do what, and what is the problem with them
for 3D analysis, 3 markers define each body segment
error:
-placement error
-movement of skin/soft tissue error
common sources of error in kinematic data collection
perspective error
parallax error
Marker placement
soft tissue movement
specifcally with the foot and ankle, what errors/challenges occur in kinematics
- motion analysis have difficulties tracking several markers close together
- complex bony structures/motions- difficult to quantify
- perspective error- zoom in on foot, miss the rest of the lower limb
what is the average degree for anterior pelvic tilt in standing and walking, when does peak anterior tilt occur, when does posterior tilt occur
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
hip motion in the sagital plane. what movements occur in which phases? what deg and when does the hip reach full extension and flexions?
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
what degree minimum is important at the hip for foot clearence - sagittal plane
15 degrees of hip flexion minimum, impacts ground/toe clearance if the degree is shortened
at initial contact, knee is extended to what degree? - sagittal plane
full extension to 10 degrees flexion
the faster the gait, the greater the knee flexion
the knee experiences two waves of flexion, the first wave is approx what degree? the second wave is approx what degree? - sagittal plane
first- 20 degrees (transition between loading response and mid stance)
second- 60 degrees (during initial swing an assists foot clearance)
what causes more knee flexion- sagittal plane
increase in speed, to absorb shock
what are the 4 arcs of motion for the ankle - sagittal plane
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
when is toe clearance sensitive to the knee and ankle movements?
during initial swing, toe clearance is sensitive to knee flexion
during mid swing, toe clearance is sensitive to ankle dorsiflexion
what degrees is the first metatarsophalengeal joint at the initial contact, mid stance, terminal stance and pre swing - sagittal plane
IC- 15 degrees (dorsi)
MS- neutral
terminal- 15-20 (dorsi)
preswing- 50 (dorsi)
why is some pelvic obliquity okay?
serves as a shock absorber and limb length adjustment
what happens to the tibia during single support?- frontal plane and why is it important
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
what does the subtalar joint do at initial contact, loading response, mid stance, terminal stance- frontal plane
inverted (sup) at initial contact
everts (pronates) until foot flat through loading response
inverts (supinates) through late midstance/terminal stance
when does maximum pelvic rotation occur? and what is the range of motion in degrees- transverse plane
initial contact and terminal swing
approx 10
what does pelvic rotation contribute to
step length
what occurs at the knee during initial contact, loading response and terminal stance?- transverse plane
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
what usually occurs for angle of gait (toe in, toe otu) during walking - transverse plane
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
