Gait Test 1 Flashcards

1
Q

Joint Reaction Force

A

2 bones compressed

Equal & opposite to ground reaction force in loading

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2
Q

Center of Pressure

A

Origin of ground reaction force (location of average weight bearing force)
- Commonly used to indicate postural stability

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3
Q

COP Excursion

A

Measure of balance

Trace of center of pressure as someone stands on force plate

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4
Q

Equations for:
Force
Pressure
Torque

A
F = mass*accel
P = F*Area
T = Force * moment arm
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5
Q

Support Moment

A

Sum of sagittal plane moments at ankle, knee, and hip
Total external torque demand on LE
Force required to support body in a certain position

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6
Q

Biomechanical Influence of backward trunk lean

A
  • Hip flexion torque down (less glut max/hamstrings)
  • Knee flexion torque up (more quads), more loading at knee
  • Ankle PF torque up (more DF action)
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7
Q

4 functions of locomotor unit during gait that are needed to walk normally

A
  • Shock absorption
  • Stance stability
  • Forward progression
  • Energy conservation
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8
Q

Shock Absorption achieved by 2 things…

A

Passive - bone & cartilage
Active - eccentric muscle contractions absorb energy
(primarily eccentric quads)

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9
Q

Heel Rocker - 3 functions

A

Loading response, Due to normal heel strike

  • Drives foot to floor
  • Propels tibia forward, creates forward momentum
  • Facilitates knee flexion
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10
Q

Ankle rocker

A

Midstance

Tibia forward –> COM translates over BOS

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11
Q

Forefoot rocker

A

Pivots on metatarsal heads, late stance

Lets COM progress beyond BOS

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12
Q

Center of mass oscillation during gait cycle

A

COM oscillates 4 cm medial/lateral and 2 cm up/down
Highest in midstance, lowest in double limb support
M/L shift over stance limb during single limb support

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13
Q

Locked position of midtarsal joints

A

Supination

supinated foot = rigid, pronated foot flexible

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14
Q

Purpose of pronation in loading response/midstance (3)

A
  1. Unlocks MT joints, turning foot into mobile adaptor –> shock absorption
  2. More contact with floor –> stability
  3. Facilitates tibia IR –> unlocks knee allowing 20º flexion
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15
Q

Purpose of supination in midstance/terminal stance (2)

A

Locks MT joints turning foot into rigid lever –> facilitates forefoot rocker

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16
Q

Dynamic control of foot pronation in loading response (4)

A

Eccentric inverters decelerate pronation of foot. Foot will continue to flatten if weakness

  1. Tib Post
  2. Tib Ant
  3. Flexor Hallucis Longus
  4. Flexor Digitorum longus
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17
Q

Dynamic control of supination in mid/terminal stance (3)

A
Concentric invertors
1. Tib post
2. Flexor hallucis longus
3. Flexor digitorum longus
Not tib ant. because it also does DF
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18
Q

Influence of wide heel shoes on rearfoot mechanics

A

Shoes with wide lateral heel increase pronation torque because it moves the contact point laterally

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19
Q

Influence of flared heel on heel rocker mechanics

A

Increases PF torque

Increased demand on dorsiflexors –> potential cause of shin splints, tib ant overuse

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20
Q

Screw Home Mechanism

A

Due to curvature of condyles
In open chain NWB:
Tibia IR a few degrees before flexion, tibia ER a few degrees to lock into extension

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21
Q

Proximal control of femur rotation (3)

A
  1. Gluteus maximus
  2. Piriformis
  3. Deep external rotators
    Weakness/poor control of ER –> will see leg roll in more
22
Q

Initial Contact - Objectives & Critical Events

A

Heel contact (heel rocker) needs:

  • 0º ankle
  • 0º knee
  • 20º hip flexion
23
Q

Loading Response - Objectives and Critical Events

A

Shock Absorption - 20º Knee FL + 4-6º pronation
Forward Progression - 0-5º ankle PF
Weight-bearing Stability - maintain 20º hip Fl + pronation

24
Q

Mid Stance - Objectives and Critical Events

A

COM over BOS - ankle DF to 5º, knee ext to 0, hip ext to 0

Single limb stability - knee ext, hip ext

25
Q

Terminal Stance - Objectives & Critical Events

A

COM progress beyond BOS - all 4 critical!
- 10º ankle DF + supination + 0º knee + 20º hip ext
(normal stride length - 20º hip Ext)

26
Q

Pre Swing - Objectives & Critical Events

A

Initiate Limb Advancement - hip flexion from 20º ext to 0º –> facilitates knee flexion

27
Q

Initial Swing - Objectives & Critical Events

A
  • Limb Advancement - 0 to 10º hip flexion

- Foot Clearance - 40 to 60º knee flexion

28
Q

Mid Swing - Objectives & Critical Events

A
  • Limb Advancement - hip flexion (10 to 20º) + knee extension (60 to 30º Fl)
  • Foot Clearance - ankle dorsiflexion from 5º PF to 0º
29
Q

Terminal Swing - Objectives & Critical Events

A
  • Limb Advancement - 20º hip flexion maintained + knee extension (30º to 0º)
  • Prepare for heel contact - ankle 0º maintained
  • (Normal stride length) - 20º hip fl, 0º knee ext
30
Q

Ankle position arc through gait cycle (IC –> T Sw)

A

0º - 5º PF - 5º DF - 10º DF - 20º PF - 5º PF - 0º - 0º

31
Q

Knee position arc through gait cycle (IC –> T Sw)

A

0º - 20º - 0º - 0º - 40º - 60º - 30º - 0º

All degrees are flexion

32
Q

Hip position arc through gait cycle (IC –> T Sw)

A

20º Fl – 20º Fl – 0º – 20º Ext – 0º – 10º Fl – 20º Fl – 20º Fl

33
Q

Kinematics vs Kinetics

A

Kinematics = study of motion (translational, rotary, curvilinear)

Kinetics = study of forces
Statics (equilibrium) & dynamics

34
Q

Agonists in loading response

A
  • eccentric Dorsiflexors (control 5º PF)
  • eccentric Vasti (20º knee flexion)
  • isometric hip extensors (maintain 20º FL)
35
Q

Agonists in mid stance

A
  • Ecc. plantar flexors- gastroc & soleus (do 10º DF)
  • Conc. Vasti –> no activity in late midstance (20º knee ext)
  • Conc. hip extensors (20º hip ext)
36
Q

Agonists in terminal stance

A
  • Ecc. plantar flexors (big DF torque, 5º DF)

- Hip extension passively resisted by anterior capsule

37
Q

Agonists in pre swing

A

Conc. plantar flexors (residual from TS- do 30º PF)

Conc. hip flexors (Rec fem & Add longus) - 20º flexion also flexes knee

38
Q

Agonists in initial swing

A
Concentric dorsiflexors (15º DF)
Conc. biceps femoris short head (20º knee flexion)
Conc hip flexors - Iliopsoas (10º hip flexion)
39
Q

Agonists in mid swing

A
  • Concentric Dorsiflexors (5º DF)

- Conc. hip flexors - Iliopsoas (10º hip flexion)

40
Q

Agonists in terminal swing

A
Isometric dorsiflexors (hold ankle at 0º)
Concentric vasti (30º knee extension)
Hip extensors: (maintain 20º flexion)
- isometric glut max & add magnus, eccentric hamstrings
41
Q

Changes during development of gait - 9 mo to 7 years

  • Velocity
  • Cadence
  • Stride length
  • SLS (% GC)
A
  • velocity- steady increase
  • cadence decreases
  • stride length lengthens as legs grow
  • time in single limb stance increases up to about 40% of gait cycle
42
Q

9 mo - 15 mo standing posture

A
  • Wide BOS
  • Hip ABD & slight flexion
  • Excessive femoral anteversion
  • Knee varus
  • Tibia IR
  • Heel everted
43
Q

9 mo - 15 mo Gait Characteristics

A
  • Wide BOS, good m/l stability
  • Full foot initial contact
  • Low stride length, high cadence
  • Foot drop in swing b/c tibialis anterior not strong enough yet
44
Q

Co - contraction in development of gait

A

Activating both sides of the joint - energy inefficient but increases dynamic stability

  • 9 mo to 15 mo
  • co-contracting quads & hamstrings in stance
  • Gastroc / tib ant in swing
45
Q

18 mo - 24 mo

Standing Posture

A
  • Decreased BOS (more strength & stability)
  • Decreased hip ABD, knee varus, and anteversion (still higher than adults)
  • Heel still everted
46
Q

Age at which heel strike begins

A

24 months

47
Q

18 mo - 24 mo gait characteristics

A
  • Eccentric muscle control - emerging knee flexion in loading response
  • Decreased co-contraction
48
Q

Age of emergence of knee valgus

A

3 to 3.5 years

49
Q

3 - 3.5 yo gait characteristics

A
  • adult-like kinematics and EMG patterns

- Joint torques lower than normal

50
Q

Too much dorsiflexion/lack of heel rise in terminal stance is a sign of what?

A

Weak calves

51
Q

Center of mass changes from 9 mo to 7 yrs

A

Babies - very high COM, thoracic area

7 y o - L3, still higher than adults

52
Q

Common gait characteristics in the elderly (6)

A
  • Decreased velocity, stride length, & cadence
  • Decreased SLS time
  • Increased BOS
  • Foot flat initial contact
  • decreased foot clearance, more hip & knee flexion to compensate
  • decreased maximal ROM