Introduction to Balance and its concepts, Impaired balance and then management of impaired balance. Based on Therapeutic Exercise Foundations and Techniques

1. Exercise for Impaired
Balance
Chapter 8
Therapeutic Exercise
Foundations and Techniques
Prepared by:
Dr. Hazrat Bilal Malakandi, PT
DPT (IPMR, KMU), MSPT (KMU), CHPE (KMU)

3. Objectives of the lecture
• At the end of the lecture students will be able to
– Define balance and other key terms
– Describe limits of stability and its boundaries
– Describe the process of balance control
– Describe different sensory systems
– Define and describe sensory organization for
balance control
– Define different types of balance control
– Describe motor strategies for balance control

4. – Describe impaired balance and its causes
– Describe deficits with aging
– Enlist risk factors for falls in elders
– Perform examination and evaluation of
impaired balance
– Describe exercise for static balance control,
dynamic balance control, anticipatory balance
control, reactive balance control and balance
during functional activities
– Describe different factors affecting balance
– Describe Tai Chi for balance control

5. Background and
concepts

6. Balance and key terms definitions
• Balance
– Balance, or postural stability, is a generic term
used to describe the dynamic process by
which the body’s position is maintained in
equilibrium.
– Equilibrium means that the body is either at
rest (static equilibrium) or in steady-state
motion (dynamic equilibrium).
– Balance is greatest when the body’s center of
mass (COM) or center of gravity (COG) is
maintained over its base of support (BOS).

7. • Center of mass
– The COM is a point that corresponds to the center
of the total body mass and is the point where the
body is in perfect equilibrium.
• Center of gravity
– The COG refers to the vertical projection of the
center of mass to the ground.
– In the anatomical position, the COG of most adult
humans is located slightly anterior to the second
sacral vertebra or approximately 55% of a
person’s height.

9. • Momentum
– Momentum is the product of mass times velocity.
– Linear momentum relates to the velocity of the
body along a straight path.
– Angular momentum relates to the rotational
velocity of the body.
• Base of support
– The BOS is defined as the perimeter of the
contact area between the body and its support
surface; foot placement alters the BOS and
changes a person’s postural stability.

10. • Limits of stability
– “Limits of stability” refers to the sway
boundaries in which an individual can maintain
equilibrium without changing his or her BOS
– Changing depending on the tasks
– For normal adults, the anteroposterior sway
limit is approximately 12⁰ from the most
posterior to most anterior position.
– Lateral stability varies with foot spacing and
height; adults standing with 4 inches between
the feet can sway approximately 16⁰ from side
to side.

11. Boundaries of the limits of stability
while standing, walking, and sitting.

12. • Ground reaction force
– the contact between our bodies and the ground due
to gravity (action forces) is always accompanied by
a reaction from it, the so-called ground reaction
force.
• Center of pressure
– The center of pressure (COP) is the location of the
vertical projection of the ground reaction force.
– It is equal and opposite to the weighted average of
all the downward forces acting on the area in
contact with the ground.
– COP is a reflection of the body’s neuromuscular
responses to imbalances of the COG.

13. Balance Control
• Balance is a complex motor control task
involving
– the detection and integration of sensory
information to assess
• the position and motion of the body in space and
• the execution of appropriate musculoskeletal
responses to control body position within the
context of the environment and task.
• Balance control requires the interaction of
the nervous and musculoskeletal systems
and contextual effects

14. Interactions of the musculoskeletal and nervous
systems and contextual effects for balance control

15. Sensory Systems and Balance
Control
• Visual System
• Somatosensory system
• Vestibular system

16. Visual System
• The visual system provides information
regarding
1) the position of the head relative to the
environment
2) the orientation of the head to maintain level
gaze
3) the direction and speed of head movements
because as your head moves, surrounding
objects move in the opposite direction.

17. • Visual stimuli can be used to improve a
person’s stability when
– proprioceptive or vestibular inputs are unreliable
by fixating the gaze on an object.
• Conversely, visual inputs sometimes provide
inaccurate information for balance control,
such as
– when a person is stationary and a large object
such as a nearby bus starts moving, causing the
person to have an illusion of movement.

18. Somatosensory System
• The somatosensory system provides
information about the
– position and motion of the body parts relative to
• each other
• support surface.
• Information from mechanoreceptors are the
dominant inputs for maintaining balance
when support surface is firm, flat and fixed
•

19. Mechanoreceptors
– Muscle spindles and Golgi tendon organs
• sensitive to muscle length and tension
– Joint receptors
• sensitive to joint position, movement and
stress
– Skin mechanoreceptors
• sensitive to vibration, light touch, deep
pressure, skin stretch

21. Vestibular System
• The vestibular system provides information
– about the position and movement of the head
– with respect to gravity and inertial forces.
• Receptors in the semicircular canals (SCCs)
– detect angular acceleration of the head
– Sensitive to fast head movements
• Receptors in the otoliths (utricle and
saccule)
– detect linear acceleration and head position with
respect to gravity
– Responds to slow head movements

22. • The vestibular system can give no
information about the position of the body.
• The vestibular system uses motor
pathways
– originating from the vestibular nuclei for
• postural control and
• coordination of eye and head movements.

23. Sensory Organization for Balance
Control
• Somatosensory information has the fastest
processing time for rapid responses
– followed by visual and vestibular inputs
• When sensory inputs from one system are
inaccurate owing to environmental conditions or
injuries
– that decrease the information-processing rate
– the CNS must suppress the inaccurate input and
– select and combine the appropriate sensory inputs
from the other two systems.
• This adaptive process is called sensory
organization.

24. Types of Balance Control
• Static balance control
– to maintain a stable antigravity position while at
rest such as when standing and sitting
• Dynamic balance control
– to stabilize the body
• when the support surface is moving or
• when the body is moving on a stable surface
– such as sit-to-stand transfers or walking
• Automatic postural reactions
– to maintain balance in response to unexpected
external perturbations,
• such as standing on a bus that suddenly
accelerates forward

25. • Feedforward, or open loop motor control
– Utilized for movements that occur too fast to rely
on sensory feedback
• Anticipatory control
– Involves activation of postural muscles in
advance of performing skilled movements
• Closed loop control
– utilized for precision movements that require
sensory feedback
– e.g., maintaining balance while sitting on a ball or
standing on a balance beam

26. Movement systems

28. Motor Strategies for Balance
Control
• Three strategies
– Ankle Strategy (Anteroposterior Plane)
– Hip Strategy
– Stepping Strategy

29. Ankle Strategy
(Anteroposterior Plane)
• In quiet stance and during small perturbations
movements at the ankle act to
– restore a person’s COM to a stable position.
• For small external perturbations that cause loss of
balance in a forward direction
– muscle activation usually proceeds in a distal to
proximal sequence
– i.e. activation begins in gastrocnemius followed by the
hamstrings and finally paraspinal muscle.

30. • In response to backward instability
– muscle activity begins in the anterior tibialis
– followed by the quadriceps and abdominal muscles.

31. Hip Strategy
• Hip strategy is employed for
– rapid and/or large external perturbations
– movements executed with the COG near the limits of
stability
• The hip strategy uses rapid hip flx or ext
– to move the COM within the BOS.

32. • In response to a forward body sway
– muscles are typically activated in a proximal to distal
sequence
• Abdominals followed by activation of the
quadriceps.
• Backward body sway results in
– activation first of the paraspinals followed by the
hamstrings.

33. 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
• Example of a stepping strategy
– The uncoordinated step that follows a stumble
on uneven ground

34. Ankle, hip, and stepping strategies used
by adults to control body sway.

35. Factors Influencing Selection
of Balance Strategies
• Speed and intensity of the displacing
forces
• Characteristics of the support surface
• Magnitude of the displacement of the
COM
• Subject’s awareness of the disturbance
• Subject’s posture at the time of
perturbation
• Subject’s prior experiences

37. Impaired
balance

38. Impaired balance
• Impaired balance can be caused by injury
or disease to any structures involved in the
three stages of information processing. i.e.
– sensory input
– sensorimotor integration
– motor output generation

39. • Sensory input
– Proprioceptive deficits have been implicated as
contributing to balance impairments following
lower extremity and trunk injuries or pathologies
– Decreased joint position sense has been reported
in individuals with
• recurrent ankle sprains
• knee ligamentous injuries
• degenerative joint disease
• low back pain.

40. – It is unclear whether decreased joint position
sense is due to changes in
• joint receptors or in
• muscle receptors.
– Somatosensory, visual, or vestibular deficits may
impair balance and mobility.
– Reduced somatosensation in the lower
extremities caused by
• peripheral polyneuropathies
– in the aged and in individuals with diabetes are
associated with
» balance deficits
» an increased risk for falls

41. • Visual loss or specific deficits in acuity, contrast
sensitivity, peripheral field vision, and depth
perception caused by disease, trauma, or aging
 can impair balance and lead to falls.

42. – Individuals with damage to the vestibular
system due to viral infections, traumatic brain
injury (TBI), or aging may experience
• vertigo (a feeling of spinning) and
• postural instability.
– Patients with severe bilateral loss of vestibular
function are unable to use hip strategies,
although ankle strategies are unaffected

44. • Sensorimotor Integration
–Damage to the basal ganglia,
cerebellum, or supplementary motor area
• impair processing of incoming sensory
information
• resulting in difficulty adapting sensory
information in response to environmental
changes.

45. –When stance is perturbed by platform
translations, patients with
• Parkinson’s disease tend to have a smaller
than normal amplitude of movement due to
co-activation of muscles on both sides of
the body,
• cerebellar lesions typically demonstrate
larger response amplitudes

46. • Biomechanical and Motor Output
Deficits
– Deficits in the motor components of balance
control can be caused by
• Musculoskeletal
– Poor posture, joint ROM limitations, decreased
muscle performance
• Neuromuscular system impairments
– impaired motor coordination, pain

47. – Postural malalignment
• such as the typical thoracic kyphosis of the elderly,
that shifts the COM away from the center of the
BOS
• increases a person’s chance of exceeding his or
her limits of stability
– Impaired ROM or muscle strength at one joint
can alter posture and balance movements
throughout the entire limb.

48. – In individuals with neurological conditions
(e.g., stroke, traumatic brain injury,
Parkinson’s disease)
• failure to generate adequate muscle forces due to
– abnormal tone
– impaired coordination of motor strategies
• may limit the person’s ability to recruit muscles
required for balance.

49. Deficits with Aging
• In persons over age 65, falls are common and
are a major cause of
– morbidity
– mortality
– reduced functioning
– premature nursing home admissions.
• Declines are found with aging in all
– sensory systems
• somatosensory, vision, vestibular
– three stages of information processing
• sensory processing, sensorimotor integration, motor
output

52. MANAGEMENT OF
IMPAIRED
BALANCE

53. Examination and Evaluation
of Impaired Balance
• The key elements include the following
– A thorough SE & OE
– History of falls
– Assessments to identify different impairments
contributing to balance deficits
• sensory input, sensory processing,
biomechanical and motor
– Assessment of Eye and Head Movement
Functions
– Assessment of Cerebellar Function
– Assessment of Walking Function

54. – Tests and observations to determine the
impact of balance control system deficits on
functional performance
– Environmental assessments to determine fall
risk hazards in a person’s home

55. Balance training
• Static balance control
• Reactive balance control
• Sensory organization
• Balance during functional activities

56. Static balance control
• Activities to promote static balance control
include
– sitting, half-kneeling, tall kneeling, and
standing postures on a firm surface.
• More challenging activities include practice
in the tandem and single-leg stance.

57. • Progress these activities by
– working on soft surfaces (e.g., foam, sand,
grass)
– narrowing the base of support
– moving the arms
– closing the eyes

58. Balance during
single leg
stance.

59. Provide resistance via handheld
weights or elastic resistance.

61. Add a secondary task to further
increase the level of difficulty

62. Dynamic balance control
• To promote dynamic balance control,
interventions may involve the following.
– Maintain equal weight distribution and upright
trunk postural alignment while on moving
surfaces, such as
• sitting on a therapeutic ball
• standing on wobble boards
• bouncing on a minitrampoline

64. – Progress the activities by movements such as
• shifting the body weight
• rotating the trunk
• moving the head or arms

65. – Vary the position of the arms from out to the
side to above the head
– Practice stepping exercises starting with small
steps, then mini-lunges, to full lunges.

66. – Progress the exercise program to include
hopping, skipping, rope jumping, and hopping
down from small stool while maintaining
balance.
– Perform arm and leg
exercises while
standing with
• normal stance
• tandem stance
• single leg stance

67. Balance while standing on
wobble boards
Balance while standing on
wobble boards with arm
movements

68. Balance while standing
on wobble boards with
arms above the head
One-legged stance with
resisted shoulder extension
using elastic resistance

69. Anticipatory Balance Control
• Have the patient practice anticipatory
balance control by performing the
following.
– Reach in all directions to touch or grasp
objects, catching a ball, or kicking a ball.
– Use different postures for variation (e.g.,
sitting, standing, kneeling) and throwing or
rolling the ball at different speeds and heights.

70. Multisensory training and its effects on
balance control in children with CP

71. – Use functional tasks
• in different postures at varying speeds
• maneuver through an obstacle course.

72. • Balance when
standing while
reaching and
catching the ball
overhead.

73. Reactive Balance Control
• Have the patient train reactive balance
control with the following activities.
– Gradually increase the amount of sway when
standing in different directions
– To emphasize training of the ankle strategy,
have the patient practice while
standing on one leg with the
trunk erect.

74. – To emphasize training of the hip strategy
• Walk on balance beams or lines drawn on the floor
• Perform tandem stance and single-leg stance with
trunk bending
• Stand on a mini-trampoline

75. – To emphasize the stepping strategy, have the
patient practice stepping up onto a stool

76. – To increase the challenge during these
activities, add anticipated and unanticipated
external forces. For example,
• have the patient lift boxes that are identical
in appearance but of different weights
• throw and catch balls of different weights
and sizes
• while on a treadmill, suddenly stop/start the
belt or increase/decrease the speed.

77. Balance During Functional Activities
• Focus on activities similar to the functional
limitations identified in the evaluation.
– For example, if reaching is limited, the patient
should work on activities such as
• reaching for a glass in a cupboard
• reaching behind
• catching a ball

78. • Perform two or more tasks simultaneously
– increases the level of task complexity
• Practicing recreational activities the patient
enjoys, such as golf, increases motivation
for practice while challenging balance
control

79. Functional
balance during a
golf swing

82. Health and Environmental Factors
• Low Vision
• Sensory Loss
• Medications

83. • Low Vision
– encourage regular eye examinations
– Wearing a hat and sunglasses in bright
sunlight
– making sure lights are on when walking about
the house at night
– avoid using bifocal glasses when walking
because
• Single lens glasses are safest for improving depth
perception and contrast sensitivity, especially on
stairs

84. • Sensory Loss
– For individuals with sensory loss in the legs
• caution them to take extra care
– when walking on soft carpet or uneven ground
• use a cane or other device if necessary
– wear firm rubber shoes with low heels
– Regular medical examinations
• blood glucose levels
– Seek medical attention if they experience any
symptoms of dizziness.

85. • Medications
– Patients should be educated about the
influence of certain medications
• such as sedatives and antidepressants
– if such medications are used at night as a
sleep aid
• patients should take extra precautions when
getting up to use the bathroom

86. Tai Chi for Balance Training
• Popular traditional Chinese exercise
• Consisting of a sequence of whole-body
movements that are performed
– in a slow, relaxed manner with an emphasis on
• awareness of posture alignment and
• synchronized breathing
• The slow, continuous, even rhythm of the
movements facilitates
– sensorimotor integration
– awareness of the external environment

87. • Continuous weight shifting from one leg to
the other facilitates
– anticipatory balance control
– motor coordination
– lower-extremity strength
• Finally, the large dynamic, flowing and
circular movements of the extremities
promote joint ROM and flexibility.