Introduction to Gait

Question 1

Critical events in weight acceptance, single limb stance, and swing limb advancement

Answer 1

• WA: initial contact (heel contact/heel rocker) & loading response (knee flexion for shock absorption & controlled PF)
• SLS: midstance (ankle rocker controls tibial advancement) & terminal stance (heel rise, ankle PF concentric, & trailing limb 20º hip ext)
• SLA: preswing (ankle PF & passive knee flex 40º), initial swing (knee flex 60º & hip flex 15º), midswing (hip flex 25º & DF to neutral), & terminal swing (knee ext to neutral)

Question 2

Temporal variables in gait

Answer 2

• Stance time: time reference foot is on the ground
• Swing time: time reference foot is off the ground
• Double limb support time: time both feet are on the ground, occurs twice during gait
• Single limb support time: time non reference foot is swinging forward with reference foot on the ground
• Step time: time for one foot to step forward
• Stride time: time for one foot to step forward & the other foot to step forward

Question 3

Line of gravity through the body in standing

Answer 3

• anterior to ankle
• anterior to knee
• posterior to hip
• anterior to 2nd sacral vertebra
• straight through the ear hole

Question 4

Spatial variables of gait

Answer 4

• Stride length: distance for one step and the following step of the opposite foot
• Step length: distance that one foot steps forward
• Foot progression angle: degree of inward or outward angulation of the reference foot
• Step width: distance between the two feet/how far apart are the feet

Question 5

Four basic functions of normal gait

Answer 5

• Weight bearing stability: ground reactions forces at different phases
• Stance limb progression: heel rocker (forward progression from heel strike), ankle rocker (forward progression past 90º), & forefoot rocker (forward progression to heel rise)
• Shock absorption: ankle PF followed by knee flexion
• Energy conservation

Question 6

When does stance phase problems typically occur during gait

Answer 6

• entrance into midstance: initial contact, loading response, midstance
• exit from midstance: midstance, terminal stance, preswing

Question 7

When does swing phase problems typically occur during gait

Answer 7

• failure to achieve trailing limb posture at terminal stance/preswing
• inadequate knee flexion at preswing
• failure. of forward pelvic rotation to initiate swing on affected side to “crack the whip” (b/w preswing and midswing)
• “functionally long” swing limb

Question 8

Describe weight bearing stability

Answer 8

• muscles around the hip, knee, and ankle sequentially stabilize these joints as the body weight is transferred to the stance limb

Question 9

Describe initial contact 0% & muscles activated

Answer 9

• the instant the foot contacts the ground
• Hip 20º flexion
• Knee 0-5º flexion
• Ankle 0-5º DF
• hip extensors, quads, & pretibial muscles/DF

Question 10

Describe loading response 0-12% & muscles activated

Answer 10

• weight is rapidly transferred onto the outstretched limb
• hip stability, controlled knee flexion, & ankle PF
• Hip 20º flexion
• Knee 15º flexion
• Ankle 5-10º PF
• hip extensors & abductors, quads, pretibial muscles/DF

Question 11

Describe midstance 12-30% & muscles activated

Answer 11

• body progresses over single limb
• controlled tibial advancement
• Hip 0º
• Knee 5º flexion
• Ankle 5º DF
• hip abductors, quads initially, gastroc/soleus

Question 12

Describe terminal stance 30-50% & muscles activated

Answer 12

• body moves ahead of the stance limb
• controlled ankle DF with heel rise & trailing limb posture
• Hip 20º ext
• Knee 0-5º flexion
• Ankle 10º DF
• gastroc/soleus

Question 13

Describe pre-swing 50-62% & muscles activated

Answer 13

• rapid unloading of trailing limb as weight is transferred to opposite foot
• passive knee flexion to 40º & rapid ankle PF
• Hip 10º ext
• Knee 40º flexion
• Ankle 15º PF
• hip adductors

Question 14

Describe initial swing 62-75% & muscles activated

Answer 14

• thigh begins advancement as the foot comes up off the floor
• hip flexion 15º & knee flexion 60º
• Hip 15º flexion
• Knee 60º flexion
• Ankle 5º PF
• hip flexors, hamstrings, pretibial muscles/DF

Question 15

Describe mid swing 75-87% & muscles activated

Answer 15

• continued thigh advancement with foot clearance & begin knee extension
• hip flexion 25º, ankle DF 0º
• Hip 25º flexion
• Knee 25º flexion
• Ankle 0º
• hip flexors initially then hamstrings, pretibial muscles/DF

Question 16

Describe terminal swing 87-100% & muscles activated

Answer 16

• final knee extension in preparation for contact with ground
• knee extension to neutral
• Hip 20º flexion
• Knee 5º flexion
• Ankle 0º
• hamstrings & add/abductors, quads, pretibial muscles/DF

Question 17

Muscle activity during gait

Answer 17

• Erector spinae: control forward flexion of trunk after heel contact
• Rectus abdominus: stabilize pelvis & lumbar spine for initiation of hip flexion
• Hip rotators: internal rotators active during stance to move contralateral pelvis forward in horizontal plane; external rotators stabilize against the pull of internal rotators during early stance & are important for change of direction

Question 18

Energy conservation in gait for vertical displacement and side-to-side displacement

Answer 18

• Vertical = 5 cm
• Side-to-side = 4 cm

Question 19

Describe gait economy

Answer 19

• metabolic energy usage for a given sub maximal gait speed
• measured as a rate of O2 uptake
• customary range of speeds have a linear relationship
• fast walking speeds have a curvilinear relationship

Question 20

Describe the cost of walking

Answer 20

• O2 cost = rate of O2 uptake/consumption ÷ gait speed
• minimized. at preferred walking speeds
• higher cost with slow or fast walking

Question 21

Key considerations for gait analysis

Answer 21

• anticipatory dynamic balance
• reactive dynamic balance
• adaptability

Question 22

Common characteristics of hemiplegic gait

Answer 22

• poor control of flexor muscles during swing phase
• spasticity of the extensor muscles
• equinovarus deformity: ankle flexed down and inward
• stiff knee that hyperextends
• step to pattern on unaffected leg in swing
• shorten stance time on affected limb
• arm swing with opposite leg is absent
• may drag toe of affected limb
• contralateral trunk lean
• circumduction

Question 23

Post-stroke gait characteristics

Answer 23

• slow extended walker/circumduction
• ~11% normal walking speed
• quads too weak to support knee during stance phase
• Glut Max retracts femur into knee hyperextension
• ankle PF spasticity
• hip hike & circumduction
• usually require an assistive device

Question 24

Common deviations that go together during single limb stance (SLS)

Answer 24

• Excessive DF: increased knee flexion & hip flexion
• Excessive PF: knee hyperextension or extension thrust, forward lean at trunk, & backward rotation of pelvis

Question 25

Causes of extension thrust or hyperextension in loading response

Answer 25

- forefoot contact - weak quads - quad tone - absent/impaired proprioception at knee & ankle - intention to maintain limb stability

Question 26

Causes of extension thrust or hyperextension in single limb support

Answer 26

- Excessive PF: either due to lack of adequate DF ROM or PF tone - intentional to maintain limb stability in the absence of quads (polio)

Question 27

Common gait deviations in individuals with neurological disorders in the foot/ankle

Answer 27

- toe contact with the floor during swing or complete toe drag - inadequate DF in swing - initial contact with forefoot in early stance - medial-lateral instability in midstance

Question 28

Common gait deviations in individuals with neurological disorders in the knee

Answer 28

- inadequate knee flexion in swing - hyperextension of knee in stance to biomechanically compensate for weakness of the quads or lack of motor control-stability of the knee muscles - excessive knee flexion during stance

Question 29

Common gait deviations in individuals with neurological disorders in the hip

Answer 29

- hip rotated outward - hip hiking during swing phase - circumduction - inadequate flexion of the hip in early swing - inadequate extension of hip in stance - drop of non affected side of pelvis during affected side stance due to hip abductor weakness (trendelemburg)

Question 30

Common gait deviations in individuals with neurological disorders in the pelvis and trunk

Answer 30

- Pelvis: pelvic retraction on the hemiplegic side - Trunk: forward flexion of trunk to compensate for weak knee extensors during stance; lateral flexion of trunk to compensate for weak. hip abductors during stance

Question 31

Functional gait assessment (FGA) scoring

Answer 31

- Minimal detectable change: Clinically stroke MDC = 5 point change & percent change = 14.1% - Cutoff scores: stroke specific cutoff scores have not yet been established - Scores ≤22/30 were effective in predicting falls in community dwelling older adults - Scores ≤20/30 were optimal to predict older adults residing in community dwelling who would sustain unexplained fails in the next 6mo