-
What is required for normal gait?
intact nervous system, muscular system, skeletal system
-
individual gait characteristics affected by?
genetics
environment
non-verbal communication
culture/ethnicity
emotional state
-
Reference foot: Initial contact
non-reference foot=?
preswing
-
reference foot loading response
non-reference foot=?
preswing
-
reference foot- midstance
non-reference foot=?
initial and midswing
-
reference foot-terminal stance
non-reference foot=?
terminal swing
-
reference foot-preswing
non-reference foot=?
initial contact--->loading response
-
reference foot-initial swing
non-reference foot=?
midstance
-
reference foot-midswing
non-reference foot=?
midstance
-
reference foot-terminal swing
non-reference foot=?
terminal stance
-
stride length =?
distance from 1 heel strike to the next heel strike of the same foot.
1 full gait cycle
4 feet
-
stance phase=?
when foot contacts surface until it leaves surface
60% of gait cycle
-
initial contact =?
moment foot contacts ground
-
loading response=?
weight transfered onto outstretched limb
1st period of double limb support
most demanding task-need shock absorber
-
midstance=?
body progresses over a single stable limb
single limb stance
-
initial contact--->midstance
restraining period
action of putting on brakes to slow the body down from swing
-
terminal stance
body moves ahead of the limb and weight is transferred onto the forefoot
begins with heel rise and continues until opposite LE contacts the ground
-
preswing (toe-off)
unloading of the limb occurs as weight is transferred to the opposite limb
double support
-
swing phase=?
moment toe leaves ground the ground and ends just before the heel makes contact with the ground
40% of gait cycle
-
inital swing=?
thigh advances as the foot comes up off the floor
from the time the foot leaves the floor until maximum knee flexion of the reference limb
-
initial swing--->mid swing
acceleration
advances the leg; toe leaves the ground until directly under the body
-
mid-swing=?
thigh continues to advance as the knee begins to extend; the foot clears the floor
-
terminal swing=?
knee extends, limb prepares to contact the ground for IC
deceleration
-
midswing-->terminal swing
deceleration
-
double limb stance
20% of gait cycle
heel of 1 foot and toe of other foot touch ground
decreases with increased speed
does not exist in running
-
step width=?
midline of 1 heel to midline of other heel
about 2-4 inches (8cm)
-
step length=?
IC of 1 foot to IC of opposite foot
1/2 of gait cycle
2 feet
-
stride time=?
amount of time 1 LE spends completing a gait cycle (swing and stance)
1-2 seconds per gait cycle
-
cadence=?
number of steps/minute
normal = 100-115
-
speed=?
normal person's walking speed
2.25-5 mph or 80 m/min
-
velocity=?
measure of distance over time
-
norma toe out
about 7-10d
-
qualitative kinematic analysis
movement without regard to forces involved in producing movement
-
kinetic gait analysis
assessment and analysis of the forces that act on the body or body parts during gait
for every external torque force body responds with internal torque force (muscle contraction, ligament resistance)
-
Newton's 3rd law of
every action has an equal and opposite reaction
ground force reactions= force from ground that strikes back once contact made
-
COG displacement in normal walking
sinusoidal curve
- total vertical displacement 2 inches
- -(summit)occurs midstance on 1 leg, mid swing on other leg
- -(valley) occurs at double limb stance in IC one 1 side and pre-swing on other
total horizontal displacement 2 inches
-
what are the 6 determinants of gait?
- 1. lateral displacement of the pelvis (shift over)
- 2.lateral pelvic tilt
- 3.pelvic rotation
- 4.knee flexion in stance (keeps COG f/ getting high)
- 5. knee mechanisms
- 6.foot mechanisms
-
Pelvic motions in gait?
normal lateral tilt ~ 2-4 inches
high point is during midstance low point during initial contact
normal pelvic rotation ~ 8 inches
-
Factors that control lateral COG displacement (4)
- 1. pelvic rotations
- 2.medial femoral angulation
- 3.knee genu valgus
- 4.inertia
-
factors that prevent COG from rising (2)`
- 1. lateral pelvic tilt
- 2.knee flexion and ankle PF in stance
-
factors that prevent COG from falling (1)
IC with knee extended (knee/foot mechanisms) horizontal pelvic rotation, terminal stance heel rise
-
opposite pelvic drop (lateral pelvic tilt)
~ 4 d of pelvic drop
downward tilt of pelvis toward swing side
decelerated by hip abductors on the opposite leg
-
collision at heel strike creates negative work...how do you compensate?
by positive work: muscular effort to keep from forward progression
-
good push off just prior to IC of swing leg can increase/decrease negative work of the collision?
decrease
-
Energy costs: answer by increase/decrease
narrow step widths
longer steps
faster steps
decrease
increase
increase
-
in early stance, the foot needs to act as a _______?
shock absorber
-
in preswing the foot needs to act as ______?
push off lever
-
decreased sensation =?
greater step width
increased energy expenditure
-
when in gait cycle are the major muscles groups active?
beginning and end of stance and swing
-
muscles the initiate movement are stretched beyond resting length first due to momentum....?
hip flexors (lift and bring forward)
-
much of the muscle activity in gait is eccentric to decelerate motion or resist the force
DF (control)
-
GFRF in IC-->LR
posterior to ankle which creates a PF moment = eccentric
-
DF in midstance-->terminal stance
inactive
-
DF in preswing-->midswing-->terminal swing
concentric
helps to clear foot from hitting ground
-
calf muscles in gait
not active in IC-->LR
-
GFRF in late LR-->Midstance-->terminal stance-->Psw
anterior to ankle= DF moment
-
calf muscles in late LR-->to midstance=
eccentric---restrains forward movement
-
calf muscles in terminal stance-->preswing
concentric= need push off
-
quads in IC-->LR
controls knee flexion
eccentric
-
GFRF in knee during IC-->LR
posterior= flexion moment
-
quads in LR--> midstance
knee extension
concentric contraction
-
quads in midstance-->terminal stance
silent/inactive
begin contracting again in last half of swing
=concentric
to prepare for IC and stablilize
-
hamstrings in IC-->LR
help prevent increased hip flexion stabilize for extension
eccentric
-
GFRF in hip during IC-LR
anterior to hip joint
creates flexion moment
-
hamstrings in midstance
inactive
-
when are hamstrings active in gait
toward end of swing phase
decelerate forward swing of leg
in MSw-->TSw-->LR=eccentric
-
glute max in gait
most active during IC and immediately after LR
controls hip flexion=eccentric
-
GFRF in hip
anterior
creates flexion moment
-
glute max inactive during?
midstance and rest of stance phase
-
hip flexors are silent in?
ic-midstance
midswing-terminal swing
stance phase
-
hip flexors are active when?
just before preswing-->midswing
short burst of activity in initial swing to mid swing
concentric contraction
-
hip abductors are active when?
midstance
IC-->midstance
eccentric contraction
-
GFRF falls medial to hip jt =?
adduction moment
-
hip abductors contribution in gait?
control lateral pelvic tilt on swing side
-
hip abductors are also active with what other muscles?
glute max and quads
-
erector spinae in gait
stabilize trunk in LR
-
Abs in gait
internal and external obliques active throughout gait cycle at low level
-
posterior deltoid
decelerate arm during foward arm swing and initiate backward swing
-
@ IC what type of moment is at the ankle
PF
-
what muscles are active at the ankle?
DF=eccentric
-
what is the moment at the knee at IC-->LR
flexion
-
what muscles are active at the knee?
quads=eccentric
-
what is the moment at the hip during IC-->LR
flexion
-
what muscle are active at the hip?
glute max, hamstrings=eccentric
-
Muscles active in IC
quads, hamstrings, DF
-
muscles active in LR
quads, glute max
-
muscles active in midstance
quads, soleus, gastoc
-
muscles active in terminal stance
soleus, gastoc
-
muscles active in pre-swing
adductor longus, rectus femoris
-
muscles active in initial swing
hip flexors, DF
-
muscles active in mid swing
hip flexors, DF
-
muscles active in terminal swing
hamstrings, quads, DF
-
Effects of DF weakness/poor timing?
1-deviation w/o compensation results in IC--LR ____
2- with compensation in IC _____
3- deviation w/o compensation in swing _____
4-with compensation in swing ______
1- foot drop
2-flat foot or toe contact
3-foot drop/toe dragging
4-steppage gait (may circumduct, hip hike, vault walk)
-
other anomalies during IC
1-toes contact first =?
2-flat foot contact=?
1- PF contracture, antalgic heel
2-fixed DF
-
PF muscle weakness/poor timing
1-IC--Tst=?
2-Tst--Psw=?
1-excessive DF, uncontrolled tibial advance compensation-step to gait
- 2-decreased opposite step
- compensation-whole foot lifted off ground
-
why do some people drop their pelvis on the affected side at the last moment of stance? (midstance--terminal stance)
don't have PF to push you up and forward-fall off the flat foot
have rapid uncontrolled movement of the tibia over the foot
-
quads:
1-with weakness/poor timing--
2-swing--
1-excessive knee flexion or trunk lean forward with strong PF-causes knee to hyperext (can use hand to extend knee)
2-mid swing--terminal swing--inad terminal knee extension
-
why does a person with quad weakness exhibit knee hyperextension?
knee hyperext and hip extension the GFRV is anterior to the knee and posterior to the hip stabilizing these joints
== hang on ligaments
-
hamstrings:
1-with weakness/poor timing
2-deviations
- 1-affects swing phase most
- -decreases the ability to slow the forward swing of the leg
- 2-rapid/uncontrolled knee extension/hip flexion
- -lands with a harsh heel
-
phase most affected by glute max weakness/poor timing
early stance phase
-
deviations of glute max (3)
1-backward throwing of trunk and pelvis just after IC on affected side with knee hyperext (no hip flexion moment)
2-forward protrusion of the affected hip due to trunk motion--increased hip flexion and anterior pelvic tilt
3-tightly extended/hyperextended knee in midstance resulting in elevation of the hip during full weight bearing
-
hip flexors:
1-with weakness/poor timing
2-deviations
1-swing phase most affected
2-circumduct/hip hike
- -backward throwing of the trunk and pelvis as a unit followed by pelvic flexion
- -whole deviation last from terminal stance/preswing to midswing
-
Biomechanics of normal hip:
center of mass is _____to hip
causes a ______moment at the hip joint
pelvis on swing side is pulled _____
resisted by action of the _____ and _____ on stance side
hip joint acts as a (1st, 2nd, 3rd) class lever?
1-medial
2-rotary
3-down
4-glute med, glute min
5-1st class lever
-
hip abductors:
weakness/poor timing
phase affected most is stance
-
deviations of hip abductors
--uncompensated glute med gait
increased lateral pelvic tilt on unaffected side, IC of affected side
-IC of unaffected side- lateral protrusion of affected hip sliding of entire trunk/pelvis toward affected side
often results in steppage gait
-
deviation of the hip abductors
--compensated glute med gait
-dropping of pelvis on unaffected side, IC of affected side--
-medial devation of affected hip instead of a protrusion
-lateral flexion over affected hip with dipping of the shoulder on same side
decreased steppage gait
-
biomechanics of uncompensated glute med gait:
-glute med is unable to overcome the force (resistance) of body weight being pulled down by gravity
-what happens? during what phase?
-hip _____is increased on ______side (stance side)
-hip will appear more protrude and weak during _____
-pelvis drops during swing phase
-adduction .....affected side
-stance
-
biomechanics of compensated glute med gait:
-COG is moved ___ (medial to lateral) to compensate and decrease pain
-______in resistance lever means glut med and min do not have to work as hard to hold pelvis up and pelvis wont drop
decreased glute med force + decreased body weigh force = _______resultant force on hip jt
lateral trunk flexion over _____
-movement of the entire pelvis _______
-decreased/increased stance phase time on involved/affected stance side
-closer
-reduction
-decreased
-affected side
-laterally
-decreased stance phase time
-
Unilateral stance biomechanics
gravity and tension of adductors creates a rotary force between femoral head and acetabulum that is greater than body weight
-
implications for using a cane during ambulation:
decreases:
force need to stabilize pelvis by weak hip abductors
rotary movements at hip
pain
-
what does the cane do during gait?
upward force which raises the hip during swing phase--opposes downward force of bodyweight which decreases hip abductors work on stance side
changes hip from 1st class lever to 2nd class lever
-
key points of gait:
-more weight on cane =
-countertorque by _____ decreases need for abductors
-both affect the body weight from pulling the pelvis __
-___________ by placing weight on cane
= _______compressive forces on hip and results in ______ pain
less force required by abductors
lats
down
decreasing force of body weight
less compressive forces
decreased pain
-
other possible causes of gait deviations besides muscle weakness?
decreased ROM
excessive ROM
pain
abnormal tone
contractures
-
knee surgeries...how does it impact gait?
decreased stance, force, compensated glut med gait
-
Genu valgus
stressed/stretched structures
compressed stuctures
stressed structures-medial
compressed-lateral
-
genu varus
stressed/stretched structures
compressed structures
stressed-lateral
compressed-medial
-
genu recurvatum (hyperextension)
structure stressed/stretched
structures compressed
stressed-posterior capsule, muscles/ligs, poor position of patella
compressed- anterior structures, hamstrings?
-
what happens with a knee flexion contracture greater than 20d?
decreased stance time
decreased knee movement
possible compensated glut med gait
-
when the knee is restricted near full extension what happens?
leg length discrepancy
increased energy expenditure
decreased walking speed
-
gait resulting from pain = antalgic
-occurs during stance phase
-step length on non affected side decreased
-decreased walking velocity and cadence
-dampening of IC and terminal stance/preswing
-exhibit compensated glut med gait
-
foot pain results in.....
dampen terminal stance--preswing
-flat foot gait
-pick up foot as a unit
-
heel pain results in.....
dampen IC or avoidance
pain in IC--terminal stance
decreased stance time
possibly compensated glut med gait
-
leg length discrepancy can result in.....
vaulting
circumduction
hip hiking
steppage gait
abducted gait
-
vaulting
definition and deviation
definition-excessive vertical displacement of the body on stance leg to compensate for longer limb
deviation-increased PF during late stance of shorter leg head bobs up and down
-
circumduction
definition and deviation
longer leg abducts during swing phase only but will come back to midline for stance phase
-
hip hiking
pt will shorten longer leg in swing by hiking hip up with quadratus lumborum, erector spinae, abs
-can also be done to compensate hip flexor weakness or extensor spasticity in the swing leg
-
steppage gait
definition/deviation
purpose/cause
definition/deviation-excessive hip and knee flexion during swing phase
purpose/cause-compensates for DF weakness
can also be seen in hamstring weakness of swing phase when hamstrings can't decelerate leg
-
abducted gait
def/deviation
reasons for use
def/deviation-continuous abduction of long LE in all phases of gait
wide base gait
- reasons-leg length discrepancy
- -increased stability
- ITB or hip abductor shortness
- -neuro dysfunction
-
functional ambulation
includes use of aids, transfers, distances to cross street or to get from 1 part of house to another, safe, secure
|
|
