Gait analysis Flashcards
Why evaluate gait?
= most common physical activity performed by humans
= inability to walk limits ones ability to participate in society
=Abnormalities in gait can cause decreased efficiency and increased energy cost
How do abnormal gait patterns affect LE?
- joint stress (bone and cartilage)
- Soft tissue strain (ligament and tendon)
- Muscle overuse
Clinical indications for Gait analysis?
- pain, instability, inability to walk quickly/efficiently/over distances
Functions of locomotor unit in gait?
- Shock absorption
- Stance stability (passive and active)
- Forward progression
- Energy conservation
define shock absorption?
contacting the ground creating an impact force (passively and actively) –> GRF
example of passive shock absorbers?
Bone and cartilage
example of active shock absorbers?
eccentric muscle contraction
How can one determine if gait is more passive or more active?
loading response ! (phase in the gait cycle)
which muscle group is the primary shock absorber in walking?
quadriceps
When does passive stance stability occur? Saggittal
it is when the Center of Mass is directly aligned over the Base of Support –> therefore least amount of muscular effort.
Where is the COM in relation to the majority of the gait cycle?
the COM is majorly behind the (reference limb) foot and the force vector behind the ankles.
When does “dynamic stability” occur?
When there is an internal response from our muscles TO an external torque.
How about stance stability in the frontal plane?
people are inherently unstable ( ie single limb stance) –> more muscular control required
define forward progression?
the transition of COM over a distance
list the stages of forward progression
- heel rocker
- ankle rocker
- forefoot rocker
- forward fall of bodyweight
- swing limb momentum
what happens in heel rocker forward progression?
- strike with heel –> first initial contact (creating a pivot point about the calcaneous) –> thereby rocking the tibia forward
- overall creates instability
what happens in ankle rocker forward progression?
- when foot is flat on the ground, the ankle dorsiflexes allowing COM to move over the foot
what happens in forefoot/toe rocker forward progression?
- heel comes off the ground –> allows the COM to progress beyond the BOS
- essentially a continuation of ankle rocker
what happens in forward fall of body weight?
- it sets up the contralateral leg to begin heel rocker stage due to COM goes beyond the foot
what happens in Swing limb momentum?
limb swings forward helping the COM forwardly progress
define how to conserve energy in terms of gait:
- Keep the COM stable as possible, not moving excessively –> this is the best way to walk
(less muscular effort)
When is the COM at its peak?
- during the single limb stance
when is the COM at its lowest?
- during double limb stance
Movement analysis language?
phase
objective
critical event
define a phase
- a portion of a given movement cycle
objective
- the basic requirements of a given phase
critical event
- joint or segment motions or positions that are required to accomplish an objective for a given phase
what is the breakdown percentage of stance and swing of the 7 stages of the gait cycle
60% stance
40% swing
what defines “stance” in the gait cycle?
- when the reference foot is in contact with the floor
what defines “swing” in the gait cycle?
- when the reference foot is NOT in contact with the floor
What is the breakdown of the stance section in the gait cycle?
- initial double limb support 10%
- single limb support 40%
- Terminal double limb support 10%
what is the breakdown of the swing section in the gait cycle?
- initial swing 13.3%
- mid swing 13.3%
- terminal swing 13.3%
Objectives of loading response?
- Shock absorption (met via crit event knee flexion)
- forward progression ( met via heel rocker event)
- weight bearing stability ( crit event at the hip)
Objective of mid stance?
- Progression of COM over BOS ( ankle rocker)
- Single limb stance stability
objective of terminal stance?
- Progression of COM beyond BOS ( forefoot rocker)
objective of pre swing stance?
- Initiate limb movement
objective of initial swing?
- limb advancement
- foot clearance !!!!!
objective of mid swing?
- continued limb advancement
- continued foot clearance
objective of terminal swing?
- complete limb advancement
- prepare limb for stance
what are the characteristics of stride?
- velocity
- stride length
- cadence( rhythm)
What does velocity in gait?
- ones walking ability
- speed tells functional ABILITY of walking
what is the average velocity of walking?
80m(eters)/min (3 mph)
Stride length is proportional to _____?
leg length
Define stride length?
initial heel contact to the next heel contact of the ipsilateral leg
define step length?
heel contact of ipsilateral limb to the heel contact of the contralateral limb
what is cadence measured in?
____ steps/ min
convert 108 steps/min to strides
54 strides/min ( divide by 2)
convert 220 steps/min to strides
110 strides/ min
the equation for velocity
velocity = Stride length x .5 cadence
Bobby’s stride length is 1.64m, while he is able to step 100 steps/ min…. what is his velocity?
1.64 m x ((.5)(100))
