Balance Flashcards
1
Q
Balance / Postural stability
A
Describes the dynamic process by which the body’s position is maintained in equilibrium
2
Q
Equilibrium
A
Body is either at rest (static equilibrium) or in steady-state motion (dynamic equilibrium)
3
Q
When is balance the greatest?
A
When the body’s COM or COG is maintained over its BOS
4
Q
Postural Orientation
A
The ability to maintain the appropriate alignment of body segments, and also refers to the body relationship to the environment for a task
5
Q
Postural Control
A
The control of the body’s position in space to maintain orientation and stability
6
Q
Center of Mass (COM)
A
A point that corresponds to the center of the total body mass and is the point at which the body is in perfect equilibrium
7
Q
How is COM determined?
A
By finding the weighted average of the COM of each body segment
8
Q
Center of Gravity
A
Vertical projection of the COM to the ground (most adults just anterior to S2)
9
Q
Momentum
A
Product of mass times velocity
10
Q
Linear momentum
A
Relates to the velocity of the body along a straight path
(sagittal or transverse plane)
11
Q
Angular momentum
A
Relates to the rotational velocity of the body
12
Q
Base of Support (BOS)
A
Perimeter of the contact area between the body and it’s support surface
13
Q
What alters the BOS?
A
Foot placement; changing a person’s postural stability
14
Q
Limits of Stability
A
Refers to the sway boundaries in which an individual can maintain equilibrium w/out changing his/her BOS
15
Q
Ground reaction force
A
Follows Newton’s law of reaction; the contact between our bodies and the ground due to gravity (action forces) is always accompanied by a reaction from it
16
Q
Center of Pressure (COP)
A
The location of vertical projection of the ground reaction force
Equal and opposite to weighted average of all the downward forces acting on the area in contact w/ the ground
17
Q
What does COP reflect?
A
The body’s neuromuscular responses to imbalances of the COG
18
Q
Balance is a complex process that emerges from what?
A
-Personal factors
-Environmental factors
-Postural control demands of the task
19
Q
Personal factors
A
-Physiological systems, cognition, and psychological factors
20
Q
What are the 3 systems that impact balance control?
A
-Nervous system (neurological)
-Musculoskeletal system
-Contextual effects
21
Q
NS provides
A
-Sensory processing
-Sensorimotor integration
-Motor strategies
-Adaptive mechanisms
-Anticipatory mechanisms
22
Q
Musculoskeletal contributions
A
-Postural alignment
-ROM flexibility
-Sensation
-Joint integrity
-Muscle performance
23
Q
Contextual effects
A
-Environment
-Support surface
-Gravity
-Lighting
-Task characteristics
24
Q
Cardiovascular system role
A
Contributes to balance by maintaining adequate brain perfusion to prevent loss of balance due to orthostatic hypotension or altered consciousness
25
Visual system Role
1) Position of head relative to environment
2) Orientation of the head to maintain level gaze
3) The direction and speed of head movement because as a person's head moves, surrounding objects move in opposite direction
26
When can visual stimuli be used?
To improve a person's stability when proprioceptive or vestibular inputs are not working properly
27
Somatosensory system Role
Provides info about the position and motion of the body and body parts relative to each other and the support surface
28
Muscle proprioceptors
Muscle spindles and GTOs
(sensitive to muscle length and tension)
29
Joint receptors
Pacinian and Ruffini
(sensitive to joint position, movement, and stress(
30
Skin Mechanoreceptors
(sensitive to vibration, light touch, deep pressure, and skin stretch)
31
What is the primary role of joint receptors?
To assist gamma motor system in regulating muscle tone and stiffness to provide anticipatory postural adjustments and counteract unexpected balance disturbances
32
Vestibular system Role
Provides info about the position and movement of the head with respect to gravity and inertial forces
33
Receptors in the semicircular canals (SCCs) detect...
angular acceleration of the head
34
Receptors in the otoliths detect...
linear acceleration and head position w/ respect to gravity
35
The SCCs are sensitive to ______ while otoliths are sensitive to ______.
Fast head movements (e.g. walking); slow head movements (e.g. postural sway)
36
How are visual, somatosensory, and vestibular systems organized for balance control?
Incoming sensory info is integrated and processed in the cerebellum, basal ganglia, and supplementary motor area
37
Which system has the fastest processing time?
Somatosensory-->Visual-->Vestibular
38
Steady-state control
Maintain a stable upright posture while at rest (e.g., sitting, standing), or when the support surface is moving or the body is moving on a stable surface (e.g., sit-to stand transfers, walking)
39
Reactive control
Recover balance in response to unexpected external perturbations that displace the BOS (e.g., standing on a bus that suddenly accelerates forward or tripping on an object on the ground); or when forces displace body segments that move the COM (e.g., a strong wind striking the body)
40
Anticipatory control
Maintain stability by compensating for destabilization associated with voluntary movements, such as postural transitions and navigation
Involves activation of postural muscles in advance of performing skilled movements, such as activation of posterior leg and back extensor muscles before a person pulling on a handle when standing or planning how to navigate to avoid obstacles in the environment
41
Anticipatory postural adjustments (APAs)
Proactive postural changes that occur before and at the onset of a movement to reduce destabilization caused by the movement
42
Adaptive control
Improve balance performance with experience. People have noticeably exaggerated reactions when they first experience an unpracticed perturbation to balance, called a “first trial reaction
43
Closed-loop control
Used for precision movements that require sensory feedback (e.g., maintaining balance while sitting on a ball or standing on a balance beam)
44
Open-loop control
Used for movements that occur too fast to rely on sensory feedback (e.g., reactive responses) or for anticipatory aspects of postural control
45
What are the motor strategies for balance?
Fixed-support (ankle and hip strategy) & change-in-support (stepping)
46
Fixed-support
Maintain the same BOS and keep the COM within the limits of stability provided by the BOS
47
Change-in-support
Change the initial BOS to establish a new stability limit to recover balance
48
Factors Influencing Selection of Balance Strategies
Speed and intensity of the displacing forces
Characteristics of the support surface
Magnitude of the displacement of the center of mass
Single versus multiple tasks
Person’s awareness of the disturbance
Person’s posture at the time of perturbation
Person’s prior experiences (well learned task versus new
49
Ankle Strategy (Anteroposterior Plane)
Rotation of the body about the ankles like an inverted pendulum acts to restore a person’s COM to a stable position
50
Weight-Shift Strategy (Lateral Plane
Shifting the body weight laterally from one leg to the other where hips are the key control points
51
Suspension Strategy
Observed during balance tasks when persons quickly lower their body COM by flexing the knees, causing associated flexion of the ankles and hips
52
Hip Strategy
For rapid and/or large external perturbations or for movements executed with the COG near the limits of stability, hip strategy uses rapid hip flexion or extension to move the COM within the BOS
53
Stepping Strategy
If a large force displaces the COM beyond the limits of stability, a forward or backward step is used to enlarge the BOS and regain balance control
54
Balance During Quiet Stance
In quiet stance, the body sways like an inverted pendulum about the ankle joint
An ankle strategy is utilized in which ankle muscles (i.e., ankle plantar flexors/dorsiflexors, invertors/evertors) are automatically and selectively activated to counteract body sway in different directions
55
Balance Related to Perturbation
Perturbations to balance in standing can be either:
internal from voluntary movement of the body OR external through forces applied to the body.
Both involve activation of muscle synergies, but the response timing is proactive and anticipatory for internally generated perturbations and reactive for externally generated perturbations
56
Balance During Whole-Body Lifting
Most common way that balance is challenged during everyday life is when lifting boxes or other large objects that are resting on the floor or at a level that is low relative to the person’s COM; may result in a fall, slip, or back injury
57
What are some of the factors of lifting?
-COM shifts
-Anticipated weight and momentum
-Loss of balance
-Liftings style
-Lifting instructions
58
What is the balance goal during gait?
to move the body outside the BOS by letting the body fall forward and yet prevent a fall.
To accomplish this goal, a person must be able to maintain balance and posture of the upper body
Trunk and hip muscles keep the upper body balanced, and extensor muscles of the lower extremities prevent vertical collapse
59
What can cause impaired balance?
Injury or disease to any structures involved inn the 3 stages of information processing:
-Sensory input
-Sensorimotor integration
-Motor output generation
60
Sensory input Impairements
Proprioceptive deficits following lower extremity and trunk injuries or pathologies
Recurrent ankle sprains, knee ligamentous injuries, degenerative joint disease, and low back pain (LBP)
61
Sensorimotor Integration Impairments
Damage to the basal ganglia, cerebellum, or supplementary motor area impairs processing of incoming sensory information
Difficulty adapting sensory information in response to environmental changes and disrupted anticipatory and reactive postural adjustments
62
Biomechanical and Motor Output Impairments
Can be caused by musculoskeletal (i.e., poor posture, joint ROM limitations, and decreased muscle performance) AND/OR neuromuscular system (i.e., impaired motor coordination and pain) impairments
63
Deficits With Aging
Falls are common in persons over age 65, directly leading to morbidity, mortality, reduced functioning, and premature nursing home admissions
64
Risk Factors for Falls Among Older Adults
History of falls
Multiple medications
Gait, balance, and mobility deficits
Visual deficits
Other neurological impairments
Muscle weakness
Heart rate and rhythm abnormalities
Postural hypotension
Foot and footwear problems
Environmental hazard
65
Deficits From Medications
increased risk of falling among older individuals who take four or more medications and among those taking certain medications due to dizziness or other side effects
66
Balance training: Static
Observations of patient maintaining different postures; Romberg Test; sharpened (tandem) Romberg; Single-Leg Stance Test; Stork Stand Test
67
Balance training: Dynamic
Observations of patient standing or sitting on unstable surface or performing postural transitions and functional activities; Five Times Sit to Stand Test (5TSTS)
68
Balance training: Anticipatory (feedforward)
Observations of patient catching ball, opening doors, lifting objects of different weights; Functional Reach Test; Multidirectional Reach Test; Star Excursion Balance Test (SEBT); Y-Balance Test (YBT)
69
Balance training: Reactive (feedback)
Observation of patient’s responses to pushes (small or large, slow or rapid, anticipated and unanticipated); Pull Test; Push and Release Test (PRT); Postural Stress Test
70
Balance training: Sensory organization
Modified CTSIB, Balance Error Scoring System (BESS)
71
Balance training: Balance during functional activities
Berg Balance Scale (BBS); Timed Up and Go Test (TUG); Tinetti Performance-Oriented Mobility Assessment (POMA); Balance Evaluation Systems Test (BESTest) or mini-BESTest; Four Square Step Test (FSST); Functional Gait Assessment (FGA); Community Balance and Mobility Scale; High-Level Mobility Assessment (HiMAT); Dizziness Handicap Inventory (DHI)
72
Balance training: Safety during gait, locomotion, or balance
Observations; home assessments; Falls Efficacy Scale; Activities-Specific Balance Confidence (ABC) Scale
73
Safety During Balance Training
Use a gait belt any time the patient exercises or practices activities that challenge or destabilize balance.
Stand slightly behind and to the side of the patient with one arm holding or near the gait belt and the other arm on or near the top of the shoulder (on the trunk, not the arm).
Perform exercises near a railing or in parallel bars to allow patient to grab when necessary.
Do not perform exercises near sharp edges of equipment or objects.
Have one person in front and one behind when working with patients at high risk of falling or during activities that pose a high risk of injury.
Check equipment to ensure that it is operating correctly.
Guard patient when getting on and off exercise equipment.
Ensure that the floor is clean and free of debris.
74
Health and Environmental Factors
-Low Vision
-Sensory loss
-Medications
75
Where is the best setting option for an exercise-based falls prevention program and WHY?
Home setting;
(1) the person functions most often in this environment, and therefore the training takes place in the location where falls are most likely to occur
(2) the person may participate more fully to their physical capacity without the stress and fatigue that may be associated with transportation issues.
76
Otago Home Exercise Program
5 warm up and 17strength and balance exercises delivered by a PT at home for 6 visits over a period of 1 year
77
Supervised Group Program
Multimodal group exercise programs incorporating muscle strengthening (resistance), gait, balance, coordination, and functional exercises.
The more effective programs for improving balance are carried out x3 per week for at least 3 months and include dynamic exercises in standing
78
Ankle sprains
Single-leg balance training on unstable surfaces are recommended in the postacute phase of rehabilitation for ankle sprains for their potential to improve static and dynamic balance control
Also, incorporate activities that require recruitment and coordination of the hip and trunk musculature
79
ACL Injuries
Proprioceptive and balance training programs either alone or in combination with neuromuscular training that includes lower extremity plyometrics, trunk stabilization and strengthening, and sport-specific functional training have been shown to reduce the incidence of ACL injuries
Progress from firm to unstable surfaces
80
Low Back Pain
interventions designed to improve neuromuscular control of the trunk
