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116 Cards in this Set

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Average normal stride duration
- 1 second for 5'4" (women)
- 1.1 seconds for 5'10" (men)
Average normal step duration
- 0.5 seconds for 5'4"
- 0.55 seconds for 5'10"
(half of stride duration)
Average normal step length
-0.65 meters for 5'4"
- 0.75 meters for 5'10"
Average normal degree of toeing out
7 degrees
What is the reference point for center for the foot?
2nd ray
Average normal cadence in normal walking
- 110 steps per minute in 5'4"
- 116 steps per minute in 5'10"
Average normal velocity of normal walking
about 80 meters per minute
List the 5 determinants of gait
- lateral pelvic tilt in the frontal plane
- knee flexion at midstance
- KAF interactions
- pelvic rotation in the transverse plane
- (physiologic valgus of the knee)
What's the deal with the 5 determinants of gait?
The are descriptors of things that normally happen to improve the effeciency of gait by keeping the COM as stable as possible
What are the 3 rockers in gait?
- heel, ankle, forefoot
Important concepts for the heel rocker
- from initial contact to flat foot
- "translate vertical GFR into forward progression of tibia through link of eccentric contraction of tibialis anterior"
Important concepts for the ankle rocker
- from foot flat to heel rise
- control rate of progression of body as tibia rotates over ankle under eccentric contraction of gastrocnemeus and soleus
Improtant concepts for the forefoot rocker
- from heel rise until the end of stance
- extend the period of ground contact via gastrocnemius to exploit GFR for swing initiation
List the 7 phases of the gait cycle
- loading response
- midstance
- terminal stance
- preswing
- initial swing
- mid swing
- terminal swing
Event that occurs at the beginning of double limb support
initial contact
% of gait cycle taken up by initial contact
less than 2%
What is the beginning and end of loading response
- begins with initial contact
- ends when other foot lifted for swing
Major event during loading response
shock is absorbed as weight is rapid transferred onto the outstretched limb
Interval of loading response in gait cycle (%)
0-10% of cycle
True or false, loading response includes initial contact?
true
Interval of mid stance in gait cycle (%)
10-30%
What is the beginning and end of mid stance?
- begins with other foot is lifted off ground
- ends when body weight over forefoot
Difference between early and late midstance?
early is from end of loading response to when swing leg passes stance leg
- early midstance is 10-20%
- late midstance is 20-30%
What key event occurs in the swing leg when the stance leg has COM over forefoot?
tibia of swing leg approaches vertical
What is the beginning and end of terminal stance?
- begins with heelrise
- ends when other foot strikes the ground
Major event of terminal stance
Body weight moves ahead of the forefoot
Interval of terminal stance in gait cycle (%)
30-50%
Pre-swing marks the beginning of
the second period of double stance
Pre-swing begins and ends with what?
- begins with initial contact of opposite limb
- ends with ipsilateral toe-off
Major event of pre-swing?
Rapid unloading of the ipsilateral limb as weight transfered to other limb
Perhaps a more appropriate name for preswing phase would be...
unloading
Interval of pre-swing in gait cycle (%)
50-60%
Initial swing begins and ends with
- begins with lift of the foot off floor
- ends with foot opposite stance foot
Two important objectives in pre-swing
- advancement of limb
- foot clearance of the floor
Interval of initial swing in the gait cycle (%)
60-73%
Midswing begins and ends with
- begins with swing foot opposite stance
- ends with tibia of swinging limb in vertical
How do you know when the tibia is vertical in midswing?
The hip and knee flexion postures are equal
Interval of midswing in the gait cycle (%)
73-87%
Terminal swing begins and ends with
- begins with vertical tibia
- ends with initial contact of foot
Major objectives of terminal swing
- complete limb advancement
- preparation for stance
Interval of terminal swing in the gait cycle
87-100%
General purpose of eccentric contractions in gait
slowing/decceleration, resisting gravity
General purpose of isometric contractions in gait
stabilization
General purpose of concentric contraction in gait
propulsion
Examples of eccentric contractions during gait
- gluteus medius mid-stance
- DF during loading response
- PF during terminal stance
- Hamstrings during swing
Examples of isometric contractions during gait
- abductors in mid-stance
- DF in swing for neutral ankle
- cocontraction at initial contact
What are the 3 concentric muscle contraction during gait?
- gastroc in pre-swing for PF
- DF in initial swing
- Hip flexors during preswing/initial swing
What's the role of the hamstrings in gait?
- slow down leg in terminal swing
- prep leg for loading
- stabilize the knee
Why so little muscle activity during mid-stance?
- momentum
- position of ground force reaction
Rectus femoris is good for:
hip flexion and knee extension
Sartorius is good for:
hip flexion and knee flexion
When does the most rear foot eversion occur?
Loading response
Rear foot eversion goes with...
Internal rotation
When one hip "dips" during ambulation, it's actually what movement?
adduction of contralateral hip
How can you locate the ground force reaction?
Goes through the center of pressure
Muscle activity at initial contact
- DF (tib anterior)
- knee flexors
- hip extensors
- quads (stabilitation)
Muscle actions during loading response
- hip extensors
- knee extensors
- DF/PF
Muscle actions during early mid stance
- hip abduction
- knee extensors
- PF
Muscle actions during late mid stance
- hip abductors
- PF (eccentric)
Muscle actions during terminal stance
- hip flexion from ADDUCTORS
- knee flexion, off at end
- Massive/all PF
Muscle actions during pre-swing
- hip flexors
- min rectus femoris activity
- PF
Muscle actions during intial swing
- HIP FLEXION
- min short head biceps femoris activity
- DF
Muscle actions during mid swing
- Hip flex then ext
- small knee flexion
- DF to clear toe
Muscle actions during terminal swing
- HIP EXTENSION
- Knee flex then extend (stabilize)
- DF
Phases of the stair ascent gait cycle (and %)
- weight acceptance (0-14%)
- pull up (14-32%)
- forward continuance (32-64%)
- foot clearance (64-82%)
- foot placement (82-100%
In stair ascent, weight acceptance is analagous to ______ in normal gait
initial contact and loading response
In stair ascent,pull up is analagous to ______ in normal gait
mid-stance
In stair ascent, forward continuance is analagous to ______ in normal gait
terminal stance and pre-swing
In stair ascent, foot clearance is analagous to ______ in normal gait
initial swing and mid swing
In stair ascent, foot placement is analagous to ______ in normal gait
terminal swing
Breakdown of stance and swing during stair ascent cycle
stance 64%, swing 36%
Where does the power for forward continuance in stair climbing come from?
Plantar flexors
Key joint movements in weight acceptance in stair ascent
(relative movements)
- hip extends 10 degrees
- Knee extends 15 degrees
- ankle dorsiflexes 5 degrees
Key joint movements in pull up in stair ascent
(relative movements)
- Hip extends 25 degree
- knee extends 35 degrees
- ankle plantarflexes 10 degrees
Key joint movements in forward continuance in stair ascent
(relative movements)
- hip extends 25 degrees
- knee extends 25 degrees
- ankle plantar flexes 30 depgrees
Key joint movements in foot clearance in stair ascent
(relative movements)
- hip flexes 55 degrees
- knee flexes 85 degrees
- ankle dorsiflexes 30 degrees
Key joint movements in foot placement in stair ascent
(relative movements)
- hip extends 5 degrees
- knee extends 10 degrees
- ankle plantar flexes slightly
Key muscle contractions during stain descent
- eccentric quads and gluteal
"most dangerous" phase of stair ascent
Pull up
Phases of stair descent
Stance:
- weight acceptance
- lowering
Swing:
- foot clearance
- foot placement
What happens during weight acceptance phase of stair descent?
- slight hip flexion
- Knee flexion up to 50 degrees
- ankle moves to slight dorsiflexion
What happens during lowering phase of stair descent?
- controlled hip and knee flexion
- ankle dorsiflexion
What happens during foot clearance phase of stair descent?
(foot raised off higher step)
- hip and knee flexion
- little movement at the ankle
What happens during foot placement phase of stair descent?
(limb extends)
- hip and knee extension
- ankle PF
Definition of running =
no double support phase in gait cycle
When both feet are in swing phase this is called
flight
Proportions of gait cycle (general) in running
Swing phase is longer than stance
Compare forces in walking vs. running
2-3x body weight in running
Compare ROM of joints in walking vs. running
more ROM needed when running
Compare ROM of joints in stair ascent and descent
same
Which phase is longer in running vs. walking?
- running: swing
- walking: stance
Compare the duration of stance in running vs. walking?
- running: shorter
- walking: longer
Describe the double support period in running vs. walking?
- running: absent
- walking: present
Describe the duration of swing phase in running vs. walking?
- running: longer
- walking: shorter
Describe the floating period in running vs. walking?
- running: present
- walking: absent
Describe stride length in running vs. walking?
- running: longer
- walking: shorter
Describe stride frequency in running vs. walking?
- running: higher
- walking: lower
Describe position of body COM in running vs. walking?
- running: lower
- walking: higher
Describe linear and angular velocity of LE in running vs. walking?
- running: faster
- walking: slower
Describe Muscle activities in running vs. walking?
- running: greater
- walking: less
Describe the foot prgression line running vs. walking?
- running: 1 line along midline of body
- walking: 2 parallel lines
Describe the ground force reaction in running vs. walking
- running: 2-3 x body weight
- walking: ~90% of body weight
How does stance decrease in running?
The distance between the contact point of foot strike and the center of gravity decreases
What is the point of decreasing the distance between the contact point of foot strike and the center of gravity in running
- reduce stance
- facilitate propulsion
Is anterior foot strike more or less effecient?
- less because is moves the COM up
What muscle action decreases its % significantly when you move from running to sprinting?
ankle
When in the gait cycle are you the shortest?
double support
Effect of lateral pelvic tilt on COM
COM down
Effect of knee flexion in mid stance on COM
COM down
Effect of KAF interaction on COM
COM up
Effect of pelvic rotation of COM
COM up
When does lateral pelvic tilt in frontal plane occur?
single limb support
When does knee flexion (as determinant of gait) occur?
midstance
When are KAF interaction important as a determinant of gait?
- loading responce AND
- prewing
(= the beginning and end of stance)
When does pelvic rotation in the transverse plane (as a determinant of gait) occur?
progression of limbs during swing and stance
What is the role of physiologic valgus of the knee?
- places base of support more nearly under the COM to reduce lateral shift