Gait Analysis Flashcards
what is gait
- pattern of movement of the limbs during locomotion over a solid substance
normal human gait strives to maintain? while moving the body along desired path
- weight bearing stability
- conserving energy
- absorbing shock of floor impact
2 reasons why we should measure walking gate
- to find out how we walk (what is normal and why)
- to understand walking as a baseline measure to understand
- -> healthy vs unhealthy
- -> ages
- -> genders
- -> races
gait analysis involves measures of?
kinetics, kinematics, EMG
pressure mats and insoles hep determine?
- estimates of COP when walking
what measurement type gives us the most detailed info about kinetics
- force plates
combining kinematics and kinetics can allows us to use what?
inverse dynamics to calculate joint forces, torques and muscle forces
name four methodologies of kinematics
- passive marker systems: use reflective markers and multiple cameras
- active marker systems: use active markers that are triggered to illuminate (electromagnetic systems track position of coordinates and orientation of sensors)
- electrical goniometers: electrical device measuring joint angles (simple cheap)
- accelerometers, gyroscopes, magnetometer
name the 5 steps of the stance phase in order
- initial contact
- loading response
- mid stance
- terminal stance
- pre swing
the stance phase is what percentage of the gait cycle
62%
name the 3 steps of the swing phase in order
- initial swing
- mid swing
- terminal swing
what percent of the gait cycle is the swing phase?
38%
when is the first double support and when is the second double support?
- initial contact
- terminal stance/pre swing
what 3 steps of the stance phase involve single leg support
- loading response, mid stance, terminal stance
the 2 periods of double stance together take up what percentage of the gait cycle
25%
initial contact. begins and ends when? what percent?
- instantaneous point when leading foot touches the ground, 0 %
loading response. what percent?
- body weight transferred onto stance limb (0-10%)
midstance. what percent?
- contralateral foot leaves the ground and body weight travels along the length of the foot until forefoot (10–30%)
Terminal stance. begins and ends when? what percent?
- begins with heels rise, ends when opposite foto contacts the ground (30-50%)
preswing. begins and ends when? what percent?
begins with opposite foot contact, ends with ipsilateral toe off, stance limb unloaded and body weight transfered onto opposite limb (50-60%)
terminal contact?
instant when the foot leaves the ground
initial swing. begins and ends when. what percent?
- begins moment the foot leaves the ground and continues until max knee flexion (60-70%)
midswing. begins and ends when, what percent
- following max knee flexion and ends when tibia in in vertical position (70-80%)
terminal swing. begins and ends when.
- tibia passes over perpendicular and knee fully extends in preparation for heel contact (85-100%)
the joint moment is determined by?
- the muscle moment
- the amplitude and line of action of the Ground reaction force
3 functional tasks of walking
- weight acceptance
- single limb support
- limb advancement
explain the inverted pendulum
during the single limb support the body (c of G) vaults over the extended limb with minimal energy expenditure
- -> anytime your in the middle stance you shouldnt need alot of muscle/ leg support
- -> during double limb support there is a redirection of the whole body ( C of G) over the extended limb and the inverted pendulum continues on the other side (major energy expenditure)
6 determinants of gait/ help conserve energy
- pelvic rotation
- pelvic obliquity
- knee flexion in stance phase
- ankle mechanism
- foot mechanism
- lateral displacement of body
what does pelvic rotation allow?
allows us to have longer step length and minimizes the movement of the COG
what does pelvic obliquity do?
vertical movement of the trunk is less than that of the hip because the pelvic tilt is about the anteroposterior axis, allows COG to be kept more steady
what is the knee mechanism in stance phase?
bends shortening the leg mid stance so the COG does not move up
what s the ankle mechanism
heel hits first so the COG stays level and then leg lengthens as ankle beds and body comes forward
what is the foot mechanism
heel rises and knee bends to keep COG level
lateral displacement of the body allows what?
closer together the feet are the less lateral displacement of the body and side to side movement of the COG at the hips,
2 things you can look for when comparing normal to abnormal gait
- change in swing to stance ratio
- left/ right asymmetry
4 common abnormalities
- lateral trunk bending
- anterior trunk bending
- posterior trunk bending
- leg length discrepancy
what is lateral trunk bending?
what is the purpose of this move?
- bending the trunk towards the side of the supporting limb during the stance phase
- to reduce the forces int he abductor muscles and hip joint during single leg stance
4 common causes of lateral trunk bending
- painful hip
- hip abductor weakness
- leg length discrepancy
- abnormal hip joint
what is anterior trunk bending?
what is its purpose?
- flexes the trunk forward early in the stance phase
- used to move the COG forward moving LOA in front of the knee producing an extension movement
a common cause of anterior trunk bending
- poor quad strength, dont want to bend your knee. so leaning forward helps bend knee
what is posterior trunk bending?
what is its purpose?
- back bend early in stance
- LOA brought to external force behind the axis of hip joint creating a hip extensor movement
a common cause of posterior trunk bending
weak gluts
4 gait abnormalities of leg length discrepancy
- circumduction: swing leg outward
- hip hiking: pelvis lifted on side of swinging leg
- steppage: exaggerated knee and hip flexion to lift foot higher than usual during swing
- vaulting: stance phase modification, go up on toes of stance phase
