Fundamentals of Gait Flashcards
Why evaluate Gait?
- most common physical activity
- inability to walk limits participation
- disease/trauma disrupts precision, coordination, speed, and versatility [Decrease efficiency Increase energy cost]
- abnormal gait effects lower extremities
- insight to prederred movements/advanced movements
Clinical indications for Gait Analysis
painful unstable inability to walk quick inability to walk efficient inability to walk distances
Basic functions of Locomotor Unit during gait
- shock absorption- impact forces
- stance stability- active or passive (frontal/sag planes)
- forward progression
- energy conversation
above pelvis is passenger (no big impact), below pelvis is locomotor!
Passive shock absorption
Bones and Cartilage– non-contractile
results in hitting ground harder
ex: flat footed heavy walking
Active shock absorption
Muscles–Eccentric muscle contractions
absorbs energy and is a smoother process
ex: knee ~20 degrees +/- 5 flexion
in gait eccentric contraction of quads :)
Passive Stance Stability
vector aligned w/ joint centers
decreased torque (decreased lever arms) minimum muscle activity
COM over joint centers
Dynamic Stance Stability
walking is mostly dynamic
muscles are active to stabilize system
lever arms constantly changing=changing torque!
Sagital vs. Frontal plane regarding Gait Stability
Frontal- unstable
Sagital- more stable
inherately good sagiatl control-> most muscles have sagital action
frontal plane relies heavily on DYNAMIC stability!!
Forward Progression
1.Heel rocker
Loading response phase
Ant Tib controls
!!creates INSTABILITY and need for DYNAMIC stability!!
normal: heel first contact
pivot point- calcaneus hits, tibia rocks forward!
flat foot: no foward progression= compensations
ppl w/ balance issues- scared tendency
Forward Progression
2.Ankle rocker
Midstance
Calf controls
Allows COM to translate over foot!!
!pivot point: ankle joint!
tibia moves over flat foot
action: ankle dorsiflexion
Forward Progression
3.Forefoot/Toe Rocker
!Pivot point: metatarsal heads!!
!Allows COM to move over BOS!
creates a fall
heave to catch yourself-> need shock absorbers
Forward Progression
4.Forward fall of bodyweight
mini fall-> creates small impact force
Forward Progression
5.Swing limb momentum
other limb moves forward
5 stages of forward progression
- heel rocker
- ankle rocker
- forefoot/toe rocker
- forward fall of bodyweight
- swing limb momentum
if any are bad- lowers stability, increases energy expen
Energy conservation of gait
minimizes displacement of center of mass and muscle activation
Normal vs. abnormal gait energy conservation
normal: very small; unilateral, forward movement
excessive displacement: increase energy to walk
COM decreases at both feet on ground; increases single limb support
COM shifts as transition medial to lateral
What is a phase
portion of given movement cycle
ex: loading response
ex: mid stance
What is an objective
basic requirement of given phase
ex: shock absorption
ex: ankle rock
What is a critical event
joint or segment motion or positions that are require to accomplish objective for given phase
ex: measureable angle 20 deg of knee flex
ex: 10 degree dorsiflex
Objective of LOADING RESPONSE
shock absorption- (knee flexion)
forward progression- heel rocker
weight bearing stability-( hip)
Objective of MID STANCE
progression of COM over BOS- ankle rocker- dorsiflexion
Single limb stance stability
Objective of TERMINAL STANCE
progression of COM beyond BOS- forefoot rocker
Objectives of PRE-SWING
initiate limb advancement- transition phase (hip)
Objective of INITIAL SWING
limb advancement
foot clearance- trip/hitting foot happens here or mid swing
Objective of MID-SWING
continued limb advancement
continued foot clearance
Objective TERMINAL SWING
complete limb advancement
prepare limb for stance
Start-finish of gait cycle is?
first heel contact on reference foot to the next heel strike of same foot
~1 second
Percentage of Swing vs. Stance
60% stance- reference foot IN CONTACT with floor
40% swing- reference foot NOT in contact with floor
Three parts of STANCE w/ percentages
Initial double limb support- 10% BOTH on ground
Single limb support- 40% ONE on ground
Terminal double limb support- 10% Both on ground
Parts of initial double limb support
Loading response- 10%
Parts of single limb support
Mid-stance- 20% (foot flat)
Terminal stance- 20% (heel off ground)
Parts of terminal double limb support
Pre-swing- 10%
Parts of SWING w/ percentages
Initial: 13/3%
Mid: 13.3%
Terminal: 13.3%
- Loading Response
Ipsilateral (ref) INITIAL contact—->Contralateral TOE OFF
refernce contact; opposite toe off
- Mid-stance
Contralateral TOE OFF—> Ref heel rise or contralat VERT TIB
swing limb tib is vertical
flat foot single limb support
ANKLE rocker
- Terminal Stance
Ipsolat heel rise or VERT TIB on swing leg—> Contralat INITIAL contact
heel off ground single limb support
FOREFOOT rocker
- Pre-swing
contralat INITIAL contact—> ipsilat toe off
terminal double limb support
- Initial swing
ref toe off —> point where swing limb (ref) foot crosses stance limb foot (contralat)
- Mid swing
swing limb cross stance limb—> tibia vertical on swing limb
- Terminal swing
vertical tibia on swing—> ref foot initial contact
Stride charachteristics
velocity
cadence
stride length
ALL interrelated
Gait velocity
indicates walking ability- most common outcome measure–> measure over 10 m
DISTANCE/TIME
avg. is 80m/min (3 mph)
speed is a function of stride length and cadence
Cadence
STEPS/MIN
men: 108 steps/min
women: 116 steps/min
men less because longer stride length
count heal contacts (regardless of side)
Step vs. stride length
step: initial heel contact on 1 side to contact of other side
stride: initial contact on one side to next contact on that SAME side
(2 steps=stride)
tall people have longer strides but in turn usually slower cadence
if avoid heel rocker-> increase cadence and decrease stride length
