Gait Flashcards
What is a gait cycle?
Heel strike to ipsilateral heel strike
I.e.- left gait cycle = time left heel hits ground to the time the left heel hits the ground again
What is a step?
Heel strike to contralateral heel strike
So right step = right heel strike to the left heel strike
What is stride length?
Distance between ipsilateral foot contacts
What is step length?
Distance between contralateral foot contacts
What is step width?
Distance between heel centers of contralateral feet (BoS)
What is foot angle?
Angle formed between long axis of foot and line of progression– angle between where foot is pointed and the center line
What is cadence
Steps per minute
What is stride time
Time to complete gait cycle
I.e. Left foot IC to next left foot IC
What is step time
Time for completing a step (left foot IC to right foot IC)
What is single limb support time
Amount of time only one foot on ground
How is walking speed calculated
Distance/time
Spatial-temporal descriptor
Initial swing/Terminal swing
Which is speeding up or slowing down?
Initial = acceleration Terminal = deceleration
Goals of muscles in gait
- Keep CoG at minimum
- Decrease vertical/lateral CoG excursion
- Decrease energy expenditure
Least stabile position in gait
30-50 percent– single leg stance, highest and most lateral CoG
(Unsure of exact percentages but the single leg stance times– so like 30 and again at 80)
What side does lateral pelvic tilt occur at?
Side of unsupported (swing) leg– keeps CoG from rising too high
Relative adduction of stance hip is controlled by
Abductors of stance leg
Purpose of knee flexion at midstane
Prevents further rise in CoG
Forward rotation happens on _____ side
Swing
Backward rotation occurs on _____ side
Stance
Total pelvic rotation during gait
8 degrees
Purpose of pelvic rotation in gate
Lengthens legs to prevent excessive CoG excursion
If your hips didn’t rotate, your legs wouldn’t really advance you
Kinetic energy lowest at _____, greatest at _______
Lowest = midstance Greatest = double limb
Potential energy highest at ______, lowest at ______
Highest at midstance
Lowest at double limb
Highest when CoG is highest, lowest when CoG is lowest
Tilt ______ with speed
Increases
Hip at initial contact
30 degrees of flexion– moves into extension as trunk moves over foot
Peak hip extension
Terminal stance
Knee at IC
5 degrees of flexion
Knee during loading response
20 degrees of loading
When does knee move towards extension
Terminal stance
Peak knee flexion?
Pre to mid swing
At initial contact– ankle is
Neutral to slight PF
DF in midstance
10 degrees
Plantarflexion mainly occurs
During push-off and into initial swing
In swing, ankle….
Neutral DF!!!!!
Pelvic drop during loading
Contralateral
Hip during loading
Adducts
Ankle– initial contact, stance, rest of stance/swing
Inversion IC, Eversion stance, Inversion rest of stance/swing
Supination-pronation-supination
Foot transforms from what to what in each gait cycle?
From flexible/shock absorber
To a rigid elver
Eversion in stance…
Adds flexibility to midfoot
Late stance STJ
Arch rises, STJ supinate to add rigidity and prepare foot to support large loads
Pelvis rotation IC – stance – swing
Contralateral posterior, contralateral anterior, ipsilateral anterior
-hip internally/externally rotates in response to this rotation
Shoulder girdle rotates ______ direction of pelvis
Opposite
Restriction in trunk motion
Increases energy expenditure
Max shoulder extension
Heel contact
Max flexion of shoulder
Double limb support
Shoulder moves in opposite direction of hips/trunk
Vertical GRF in walking gait
Double hump– IC and push off
A/P GRF in walking gait
Posterior in IC, then anterior in push off
Sagittarius plane internal moments at IC
Hip extensor moment
Knee flexor moment
Dorsiflexor moment
Sagittal plane internal moment at foot flat
Hip extensor
Knee extensor
DF
Sagittal plane internal moment at midstance
Hip flexor
Knee flexor
PF
Sagittal plane internal moment in heel off
Hip flexor
Knee flexor
Dorsiflexor
Toe flexor
Sagittal plane internal moment in toe off
Hip flexor
Knee extensor
Plantarflexor
Toe flexor
Summary of joints at initial contact
Flexed hip, minimally flexed knee, neutral / pf ankle
External moments at initial contact
Hip flexed/adducted, knee extended, ankle plantarflexed
Muscle activity at initial contact
Hip extensors
Pre-tibials to control DF (ant tib , ext digitorum, ext hallucis)
Critical event at loading response
- shock absorption by quads/hip extensors
- restrained ankle PF
Muscle activity at loading response
- Pretib muscle slow foot drop rate (eccentric)
- Quads limit knee flexion (most action here–eccentric)
- Gluts/adductor magnus prevent further flexion
- Hip abductors control pelvic drop/hip adduction
Phase of greatest muscle activity and why?
Loading response– most amount of eccentric contraction by multiple muscle groups.
Critical events in midstance
- forward progression
- knee extension increases stability
- pelvic stabilization maintains upright trunk
External moments in midstance
Ankle Df
Knee flexion
Hip flexion
Hip adduction
Muscle activity in midstance
Eccentric gastroc/soleus
Eccentric glutes and adductor
Quads-knee stability
Critical events in terminal stance
- body wt advances beyond area of support
- free forward fall of body
External moments in terminal stance
Dorsiflexion
Knee flexion
Hip extension to hyperextension
Muscle activity in terminal stance
Strong gastroc/soleus (soleus advances tibia!!)
Critical event in pre-swing
Knee flexion
Moments at pre-swing
ankle df
Hip extension
Knee extension
Muscle activity in pre-swing
Gastroc slowly decreases activity
Critical events in initial swing
Knee flexion
Hip flexion
Muscle activity in initial swing
Iliacus, sartorial/gracious for hip flexion
Pre-tibial- begin lifting the foot
Critical events in mid-swing
Ankle dorsiflexes to clear floor (it’s in neutral though!)
Hip flexion for limb advancement
Muscle activity in mid-swing
Minimal pre-tib and hip flexion
Hamstrings begin firing at the end
Critical events in terminal swing
Hip decelaration
Knee deceleration
Knee extension
Ankle DF
Muscle activity in terminal swing
HS restrain hip flexion, control tibial momentum
End: quads fire to complete knee extension
Pre-tibials ensure control of dorsiflexion
Weakness examples in abnormal gait
Disuse atrophy
Neuro impairment
Sensory loss issue in gait
Proprioception
Impaired motor control examples
Spasticity
Timing
Sequencing
Pain in abnormal gait will cause
Tissue limits
Swelling
Arthritis
Consequences of excessive PF in stance
Limits progression
Shortened stride length
Reduced gait velocity
Consequences of excessive plantarflexion in swing
Obstructs limb advancement (toe drag)
Consequence of inadequate knee flexion in loading response
Reduces shock absorption
Consequences of inadequate knee flexion in pre-swing
Difficult toe-off
Greater hip flexion required
Consequences of inadequate knee flexion in initial swing
Toe drag
Consequence of inadequate knee flexion in mid swing
Limited hip flexion will also occur
Inadequate hip extension in midstance
Forward trunk lean
Lumbar spine lordosis
Flexed knees
Consequences of inadequate hip extension in terminal stance?
Possible anterior pelvic tilt
Shortened step length
Possibly increased knee flexion
