Gait and Posture Flashcards
1
Q
Factors that impact movement
A
- Individual
- Task/action
- Environment
2
Q
Center of Mass (COM)
A
Point in space where there is equal distribution of mass
3
Q
Center of Pressure (COP)
A
The center of distribution of total force applied to the supporting surface
4
Q
Postural Control
A
Controlling the body’s position in space
5
Q
Postural Orientation
A
Ability to maintain:
- Appropriate relationship between body segments AND
- Appropriate relationship between the body and environment for a task
6
Q
Postural Stability
A
Ability to control COM in relationship to the base of support (BOS)
7
Q
Where does neural control of posture take place?
A
- Postural stability is not organized at the spinal level
- Controlled at higher centers, such as the brainstem and cerebellum
8
Q
Factors impacting motor control of the quiet stance
A
- Alignment
- Muscle tone
- Postural tone
9
Q
Alignment
A
Putting the body segments in a place that minimizes the effects of gravity
10
Q
Muscle tone
A
Keeps the body from collapsing under the force of gravity
11
Q
Postural tone
A
- An extension of muscle tone
- Focus is on the muscles designed to provide posture
- Antigravity muscle activation during quiet stance
12
Q
Muscles involved in postural control
A
- Erector spinae
- Iliopsoas
- Abdominals
- Gluteus medius
- Tensor fascia latae
- Biceps femoris
- Quads (?)
- Calves (gastroc/soleus)
- Tibialis anterior
13
Q
Perturbation
A
Displacement of the supporting surface
14
Q
Strategies to deal with pertubations
A
- Ankle
- Hip
- Step
15
Q
Ankle Strategy
A
- Used when perturbation is slow and low amplitude
- Head is in phase with the hips
16
Q
Muscles activated for ankle strategy in a forward sway
A
1) Gastrocnemius
2) Hamstrings
3) Paraspinals (erectors)
17
Q
Muscles activated for ankle strategy in a backward sway
A
1) Tibialis anterior
2) Quads
3) Abdominals
18
Q
Hip Strategy
A
- Restores balance in response to larger and faster perturbations or when BOS is restricted
19
Q
Muscles activated for hip strategy in a forward sway
A
1) Quads
2) Abdominals
20
Q
Muscles activated for hip strategy in a backward sway
A
1) Hamstrings
2) Paraspinals (erectors)
21
Q
Stepping Strategy
A
- Used when either the ankle or hip strategy is insufficient
- Alters the BOS
22
Q
Lifespan Posture
A
Emergence of skills requires development of postural activity to support the primary movement
23
Q
Types of Reflexes
A
- Primitive
- Postural
- Locomotor
24
Q
Primitive Reflexes
A
Survival and protection
25
Postural Reflexes
Reaction to gravity and changes in the equilibrium
26
Locomotor Reflexes
Resemble later voluntary locomotion movements
27
Postural Reflexes List
- Head and body righting
- Labyrinthine righting
- Pull-up
- Parachute
28
Head and Body Righting Reflex
-
| - Starting Date: ~ 2 months
29
Labyrinthine Righting Reflex
-
| - Starting Date: ~ 2 months
30
Pull-up Reflex
-
| - Starting Date: ~ 3 months
31
Parachute Reflex
-
| - Starting Date: ~ 4 months
32
Sequence of postural control development
Postural control development follows a cephalocaudal (head to foot) and proximodistal (midline to extremity) sequence
33
What causes lack of head control in infants?
- Lack of strength
| - Lack of organized muscle activity
34
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35
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36
Cognitive Systems in Postural Development
- Postural demands of younger children tax attentional resources more than for older children
- This may affect both postural and cognitive performance in dual-task situations
37
Why is balance so important in older populations?
Falls are a leading cause of injury death in older adults
38
Fall (clinical definition)
A situation in which the older adult falls to the ground or is found lying on the ground
39
Fall (research definition)
Movement of the center of mass outside the limits of the base of support
40
Spontaneous sway during quiet stance
- Acts as an indicator for assessing balance function
- Individuals at both ends of the age spectrum (6-14 & 58-80) have the most difficulty with sway during quiet standing
41
Sway Amplitude
The amount of displacement occurring during the quiet stance
42
Sway Velocity
The speed of displacement occurring during the quiet stance
43
Impact of Sway Amplitude vs Sway Velocity in Older Adults
- Sway velocity is significantly greater than sway amplitude for older adults with previous falls and those older than 80
- Measure the velocity of sway in a certain population may be a more sensitive measure of balance problems than amplitude of sway
44
Factors Impacting Instability in Association with Voluntary Movement
- Delayed onset of muscle responses
- Inability to activate postural muscles ahead of prime movers
- Inability to shut off muscle activity once activity completed
45
How to changes in the sensory systems contribute to declining stability as people age?
Vestibular System
- Peripheral organ and nuclear degeneration
Deep Tendon Reflexes/Postural Muscle Strength
- Reflexes are reduced
- Postural muscles get weaker
46
Sensory Depravation and Sway
-
47
Positional relationship of the COM and BOS during gait
The COM must be projected outside the BOS to generate forward progression
48
Gait Analysis Considerations
- Human gait is the most common of all human movements
- Clinical investigators tend to look at output measures (stride length, cadence, etc)
- Neurological researchers focus on EMG
- Biomechanists analyze kinematics, reaction forces, moments of force, powers, energies, etc
49
Variables that describe the CAUSE of the gait pattern
- EMG
- Moments of force
- Power
50
Variables that describe the EFFECT of the gait pattern
- Kinematics
- Momentum
- Stride length
- Cadence
- Reaction forces
51
Phases of the Gait Cycle
- Stance
| - Swing
52
Components of the Stance Phase
- Initial contact (heel strike)
- Loading response (foot flat)
- Midstance
- Terminal stance (heel off)
- Preswing (toe off)
53
Components of the Swing Phase
- Initial swing
- Midswing
- Terminal swing
54
Relative Duration of Each Phase
- Stance Phase --> 60%
| - Swing Phase --> 40%
55
Double vs Single Support
- Initial contact (DOUBLE)
- Loading response (SINGLE)
- Midstance (SINGLE)
- Terminal stance (SINGLE)
- Preswing (DOUBLE)
- Initial swing (SINGLE)
- Midswing (SINGLE)
- Terminal swing (SINGLE)
56
When does push-off occur?
Terminal stance --> Preswing
57
Velocity
Distance traveled/unit of time
58
Step Length
Distance b/t heel of one foot and heel of the opposite foot
59
Step Width
Distance b/t center of heel on one foot and the other foot
60
Step Frequency
- AKA cadence
| - Number of steps/unit of time
61
Stride Length
Distance b/t heel of one foot and heel mark of same foot on next successive step
62
Relationship between stride length and cadence
Stride length and cadence are dependent on each other
63
Net Extensor Moment During Stance Phase
Various combinations of the extensor muscles can be used to prevent collapse
64
Balance during gait
- The body is in a continuous state of imbalance
| - HAT (head, arms, trunk) need to be controlled
65
Walking Speed and Gait
- Speed affects COM displacement
| - Slow speeds increase COM ML (medial-lateral?) deviation in healthy young adults
66
What is the goal of the swing phase?
Reposition the limb
67
What happens during swing phase?
- Hip flexion starts the swing
- Momentum sustains the swing once initiated
- Knee motions are constrained during swing
- Dorsiflexion occurs to prepare for heel contact
- Less variable than stance control
68
Cerebellum and Gait
- Regulation of the stepping pattern based on sensory information
- Spinocerebellar tracts: dorsal (muscle sensory afferents) and ventral (spinal motor neurons of CPG) are active
69
Role of cortical areas of the brain
"Perception and action" pathways
70
Contributions to Emergence of Locomotion
- Limited locomotor pattern generator at birth
- Optic flow modulations for head control at birth
- Modulation of stance at 5-6 months
- Voluntary control
- Motivation increases at onset of creeping
71
Sequence of Rudimentary Locomotor Abilities
- Crawling
- Creeping
- Walking
72
Crawling
Body drag (6-8 months)
73
Creeping
Abdomen clears the ground (8-10 months)
74
Walking
```
With support (9-10 months)
Alone (well) (12-14 months)
Backward (14-18 months)
Stairs (up and down) (2-4 years)
Perfected (5 years)
```
75
Change in arm position while walking over time
- Base of support narrows
- Foot contact changes (flat-foot and toes out)
- Foot angle changes (plantar to dorsi)
- Double knee-lock variation is acquired
76
Gait in the 1st year
- High step frequency
- Absence of reciprocal arm swinging between upper and lower limbs, flexed knee in stance
- Increased hip flexion, pelvic tilt and hip abduction, relative foot drop in swing
- Plantar flexion during foot strike
77
Gait at 2 years
- Reciprocal arm swing in 75% of children
- Pelvic tilt, abduction, and ER of hip decreased
- Ankle dorsiflexion increases
78
Gait after 2 years
Push-off begins at the end of stance
79
Gait during years 2-7
Muscle amplitudes and durations reduce, becoming similar to adults
80
Gait after 7 years
Walking very similar to adults
81
Normal gait in older adults
No defined standards to conclude "normal" gait in older adults
82
Changes in gait for older adults
- 10-20% reduction in gait velocity and stride length
- Increased stance width
- Increased time spent in double support phase
- Bent posture
