LECTURE 7

1.  RIAZ AHMED PT

2.  one of the most common problems treated
by physical therapists.
 are thought to be common after stroke, and
they have been implicated in the poor
recovery of activities of daily living (ADL) and
mobility and an increased risk of falls.

4. “…the ability to maintain the body’s center of
gravity over its base of support with minimal
sway or maximal steadiness.”
(Emery et.al, 2005)
 a complex process involving the reception
and organization of sensory inputs and the
planning & execution of movement to
achieve a goal requiring upright posture

5.  is the set of functions which maintains man’s
upright during stance and locomotion by
detecting and correcting displacement of the
line of gravity beyond the BOS.

6.  Postural control – involves controlling the
body’s position in space for the dual purposes
of stability and orientation.
 Postural orientation –The control of relative
positions of the body parts by skeletal
muscles with respect to gravity and each
other.

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. It is determined by finding the
weighted average of the COM of each body segment.
 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.
Terminologies…

8.  Postural stability - The condition in which
all the forces acting on the body are balanced
such that the center of mass (COM)is with in
the stability limits or boundaries of BOS
Normal anterior/posterior sway – 12 degrees from
most posterior-anterior position.
Lateral sway - 16 degrees from side to side.
If sway exceeds boundaries, compensation is
employed to regain balance.

9.  Static balance - the base of support (BOS)
remains stationary and only the body center
of mass (COM) moves.The balance task in
this case is to maintain the COM within the
BOS or the limit of stability (the maximal
estimated sway angle of the COM).
 Maintaining a stable antigravity position
while at rest such as when standing and
sitting

10.  Automatic postural reactions - maintaining
balance in response to unexpected external
perturbations, such as standing on a bus that
suddenly accelerates forward.

11.  Dynamic balance - Maintaining balance
when a person is moving from point A to
point B, where both the BOS and COM are
moving, and the COM is never kept within the
BOS.
 is stabilizing 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

12. • Reactive control - in response to external
forces (perturbation).
• Proactive control – in anticipation of internal
forces imposed on the body’s own
movements.

14.  Balance control is very complex and involves
many different underlying systems.
 Postural control results from a set of
interacting systems that work cooperatively
to control both orientation and stability of
the body.

15. BALANCE
Anticipatory
Mechanisms
(internal)
Proactive
Mechanisms
(external)
Reactive
Mechanisms
Sensory
Systems
Body
Schema
Neuro-
muscular
Synergies
Musculo-
skeletal
Components

16.  Joint range of motion
 Spinal flexibility
 Muscle properties
 Biomechanical relationships among linked
body segments

17.  Motor processes (neuromuscular response
synergies)
 Sensory processes ( visual, vestibular, and
somatosensory systems)
 Higher-level integrative processes
• Mapping sensation to action
• Ensuring anticipatory and adaptive aspects of postural
control

18. ADAPTIVE POSTURAL
CONTROL
 Involves modifying sensory
and motor systems in
response to changing task
and environmental
demands
ANTICIPATORY POSTURAL
CONTROL
 Involves preparing the
sensory and motor systems
for postural demands
based on previous
experience and learning

20.  Body alignment
 Muscle tone
 Postural tone

21.  Minimize the effect of gravitational forces,
which tend to pull us off center
 The ideal alignment in stance allows the body
to be maintained in equilibrium with the least
expenditure of internal energy.

22. STANDING ALIGNMENT
 Head balanced on level
shoulders
 Upper body erect,
shoulders over hips
 Hips in front of ankles
 Feet a few cm (10 cm)
apart
SITTING ALIGNMENT
 Head balanced on level
shoulders
 Upper body erect
 Shoulders over hips
 Feet and knees a few cm
apart

23.  The force with which a muscle resists being
lengthened (Basmajian and De Luca, 1985)
 Keeps the body from collapsing in response
to the pull of gravity

24.  Increased level of activity in antigravity
muscles
 Activation of antigravity muscles during quiet
stance.
 Muscles that are tonically active during quiet
stance: gastrocsoleus, tibialis anterior,
gluteus medius,TFL, iliopsoas, and erector
spinae

25. Ankle strategy
Hip strategy
Stepping strategy
Weight shift strategy
Suspension strategy

26.  Used when displacements are small.
 Displaces COG by rotation about the ankle joint.
 Posterior displacement of COG – Dorsiflexion at
ankle, contraction of anterior tibialis, quadriceps,
abdominals.
 Anterior COG displacement – Plantar flexion at
ankle, contraction of gastrocnemius, hamstring,
trunk extensors.

27.  Employed when ankle motion is limited,
displacement is greater, when standing on
unstable surface that disallows ankle strategy.
 Preferred when perturbation is rapid and near
limits of stability.
 Post. Displacement COG – Backward sway,
activation of hamstring and paraspinals.
 Ant Displacement COG – Forward sway,
activation of abdominal and quadricep muscles.

28.  If displacement is large enough, a forward
or backward step is used to regain
postural control

29.  The movement strategy utilized to control
mediolateral perturbations involves shifting
the body weight laterally from one leg to
other.
 Hips are the key control points of weight shift
strategy. they move the COM in a lateral
plane primarily through activation of hip
abductor and adductor muscles.

30.  This strategy is observed during balance tasks
when a person quickly lowers his or her body
COM by flexing the knees, causing associated
flexion of the ankles and hips.

35. The maintenance of balance is based on an
intrinsic cooperation between the
 Vestibular system
 Proprioceptive
 Vision
 Postural control does not only depends on
the integrity of the systems but also on
the sensory integration with in the CNS,
visual and spatial perception, effective
muscle strength and joint flexibility

36.  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.
 Provide a reference for verticality
 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.

38.  Since most individuals can keep their balance
when vision is occluded
 In addition, visual inputs are not always an
accurate source of orientation information
about self-motion.
 Visual system has difficulty distinguishing
between object motion, referred to as
exocentric motion, and self-motion, referred
to as egocentric motion.

39.  Provides the CNS with position and motion
information about the body with reference to
supporting surfaces
 Report information about the relationship of
body segments to one another
 Receptors: muscle spindles, Golgi tendon
organs, joint receptors, and cutaneous
mechanoreceptors

40.  A powerful source of information for postural
control
 Provides the CNS with information about the
position and movement of the head with
respect to gravity and inertial forces,
providing a gravitoinertial frame of reference.
 Distinguish exocentric and egocentric
motions

41. SEMICIRCULAR CANAL
 Sense angular acceleration
of the head
 Sensitive to fast head
movements ( those that
occur during gait or
imbalance such as slips,
trips, and stumbles)
OTOLITH ORGANS
 Signal linear position and
acceleration
 Source of information
about head position with
respect to gravity
 Respond to slow head
movements (those that
occur during postural sway)

42.  Vestibular, visual, and somatosensory inputs
are normally combined seamlessly to
produce our sense of orientation and
movement.
 Incoming sensory information is integrated
and processed in the cerebellum, basal
ganglia, and supplementary motor area.

43.  Somatosensory information has the fastest
processing time for rapid responses, followed
by visual and vestibular inputs
 When sensory inputs from one system are
inaccurate the CNS must suppress the
inaccurate input and select and combine the
appropriate sensory inputs from the other
two systems.

48.  Injury to or diseases of the structures (e.g. eyes,
inner ear, peripheral receptors, spinal cord,
cerebellum, basal ganglia, cerebrum)
 Damage to Proprioceptors
 Injury to or pathology of hip, knee, ankle, and
back have been associated with increases
postural sway and decreased balance
 Lesions produced by tumor , CVA, or other
insults that often produced visual field losses

49.  Patients with muscle weakness and poor control
lack effective anticipatory, ongoing, and
reactive postural adjustments and therefore
experience difficulty in:
 Supporting the body mass over the paretic lower
limb
 Voluntarily moving the body mass from one lower
limb to another
 Responding rapidly to predicted and unpredicted
threats to balance

50.  Changing the base of support
 Restricting movement of body mass
 Using hands for support

51.  Wide BOS
 Shuffling feet with inappropriate stepping
 Shifting on the stronger leg

52.  Stiffening the body with altered segmental alignment
 Moving slowly
 Changing segmental alignment to avoid large shifts in COG
 standing reaching forward - flexing at hips instead of
dorsiflexing ankles
 standing reaching sideways - flexing trunk sideways
instead of moving body laterally at hips and feet
 sitting reaching sideways - flexing forward instead of to
the side
 in standing - not taking a step when necessary.

53.  holding on to support
 grabbing

56.  Romberg tests: measure static balance while standing with
eyes open and eyes closed
 Unipedal stance test: timed one-leg stance test that
provides simple measure of static balance; two conditions:
eyes open, eyes closed
 Clinical test of sensory integration of balance: evaluates the
contributions of the visual, proprioception, and vestibular
sensory systems to balance

57.  Functional reach tests: measure maximum distance one
can reach beyond an arm’s length without losing balance or
moving the feet
 Timed up and go tests: assess dynamic balance and agility
of older adults
 Star excursion balance test: provides a significant challenge
to athletes and physically active individuals

62.  The clinical test of sensory integration on
balance test (CTSIB) also called as foam and
dome test.

64.  Balance cannot be trained in isolation from
the actions which must be relearned.
▪ In training walking, standing up and sitting
down, reaching and manipulation… postural
adjustments are also trained, since acquiring
skill involves in large part the fine tuning of
postural and balance control.

65.  Postural adjustments are specific to each
action and the conditions under which it
occurs.
 It cannot be assumed that practice of one action
will transfer automatically into improved
performance in another.

66.  Progressive complexity is added by
increasing the difficulty under which goals
must be achieved, keeping in mind the
various complex situations in which the
patients will find themselves in the
environment in which they live, both inside
and outside their homes, and the precarious
nature of balance.

67.  As control over balance and confidence
improves, tasks are introduced which require
a stepping response, and responses to
external constraints such as catching a
thrown object and standing on a moving
support surface

68.  Use a gait belt any time the patient practices
exercises or 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.

69.  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 equipment
(such as treadmills and stationary bikes).
 Ensure that the floor is clean and free of debris.

71.  A variety of mode can be used to treat balance
impairment
 Begin with weight shifts on a stable
surface
Gradually increase sway
Increase surface challenges (mini-tramp,
etc.)

72.  Rehabilitation balls ,foam rollers ,foam
surfaces are often used to
• Provide uneven or unstable surface for
exercise
• Sitting balance ,trunk stability, and weight
distribution can be trained on a chair, table,
or therapeutic ball
 Pool is an ideal palace for training balance

73.  Awareness of posture and the position of the
body in space is fundamental to balance training
Begin in supine or seated position
Over sessions, use a variety of arm positions,
unstable surfaces, single leg stances, etc.
Training both Static posture & Dynamic
posture
 Mirrors can provide postural feedback –Visual
feedback

74.  Adding movement patterns to acquired stable
static postures increases balance challenge.
 Add ant./post. sway to increase stability limits
 Trunk rotations and altered head positions alter
vestibular input.
 Stepping back/forward assists in re-stabilization
exercises.

75.  From simple to complex involves
• BOS – Advance from wide to narrow base
• Posture – Stable to unstable posture (sway)
• Visual – Closing of the eyes
• COG – Greater disruption to elicit hip or stepping
strategy
 Progress to more dynamic activities, unstable surfaces,
and complex movement patterns
 Frequency,intensity,and duration

77.  Normal postural activity forms necessary
background for normal movement and for
functional skills
 Flaccid stage – balance exercises in sitting
 Stage of spasticity – practice symmetrical
weight bearing in standing, weight shifting,
bending of knees and hips

78.  For stability
 Combination of isotonics
 Stabilizing reversals
 Rhythmic stabilization

79.  Analysis of task
• Individual
• Task
• Environment
 Practice of missing components
• Strategy training
• Impairment and strategy level
 Practice of whole task
• Functional level
 Transference of learning

80.  Vary postures
 Vary support surface
 Incorporate external loads

83.  Moving support surfaces
 Move head, trunk, arms, legs
 Transitional and locomotor activities

86.  Reaching
 Catching
 Kicking
 Lifting
 Obstacle course

88.  Standing sway
 Ankle strategy
 Hip strategy
 Stepping strategy
 Perturbations

89.  Reduce visual inputs
 Reduce somatosensory cues

90.  acute stage post-stroke
 Head and trunk movements
 Reaching actions
To progress:
 Increasing distance to be reached
 Varying speed
 Reducing thigh support
 Increasing object weight and size to involve both upper limbs
 Adding an external timing constraint such as catching or
bouncing a ball

91.  Head and body movements
 Reaching actions
 Single limb support
 Sideways walking
 Picking up objects

93. The following main aspects should be developed:
 Antigravity support or weight bearing on the feet
 Postural fixation of the head on the trunk and on the
pelvis in the vertical
 Control of anteroposterior weight shift of the child’s
COG
 Control of lateral sway from one foot to the other.
 Tilt reactions in standing
 Saving from falling (strategies)

94. Training should check:
 Equal distribution of weight on each foot
 Correction of abnormal postures
 Building up of the child’s stability by decreasing
support
 Delay training in standing and walking if the child is
not ready
 Weight shift leading to stepping
 Training lateral sway
 Training on different surfaces

95.  Read Kisner’s Chapter onTechniques to
improve balance.

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