Postural Control

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Postural Control

• Definition
• Function
• Neurophysiology
• Systems Model
• DONG-EUI MEDCAL CENTER
• AHN BYUNG UG

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The terms balance, equilibrium and postural
controlare used as synonyms for the same concept
of the mechanism by which the human body prevents
itself from falling or loosing balance.

Ragnarsdottir 1996
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Postural Control

• controlling the bodys
• position in space
• for the dual purposes of
• stability and orientation
• 
  Shumway-Cook and Woollacott 1995

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POSTURAL ORIENTATION

• This involves
• The ability to maintain the appropriate
  alignment between body segments.
• The appropriate relationship between the body
  and the environment.
• Requires establishing a vertical orientation to
  counteract the forces of gravity.
• Creates a reference frame for perception and
  action with respect to the external

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INTERNAL REPRESENTATION

• It is thought that an internal representation of
  body posture exists within the CNS.
• This is often referred to as the Postural Body
  Schema.
• Body Schema incorporates body geometry, kinetics

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BODY SCHEMA

• ? DEFINITION
• A postural model one has of oneself, having to
  do with how one perceives the position of the
  body and the relationship of body parts. It is
  believed to be the basis for all motions
• 
  (Barbara Zoltan 1991)

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POSTURAL STABILITY

• This involves
• Maintaining the bodys center of mass within
  oundaries of space, referred to as stability
  limits.
• Stability limits are boundaries of an area of
  space in which the body can maintain its
  position without
• changing its base of support.

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STABILITY LIMITS

• Stability limits are not fixed but may change
  according to
• the task
• the individual
• the environment
• Postural action can be viewed as a motor skill
  that
• emerges from the interaction between
• the individual, the task and the environment.

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Postural Control . allows us to

• Maintain a variety of positions / postures
• Loose and regain midline - displacements
• Provide a reference frame and stability to
  selectively move our eyes, head or limbs.
• Move from one position to another
• Carry out cognitive tasks whilst moving i.e.
  dual tasks
• Function independently within a changing
  environment

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GRAVITY

• Is a modality of afferent information.
• It is a constant downward force with which man
  must develop the ability to interact in order to
  move selectively. Balance and agonistic activity
  is developed through exposure to gravity (BBTA
  2002).

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Systems control of posture

• Ascending
• Descending
• Peripheral
• Posture is safeguarded by multiple inputs and
  outputs.
• It reflects the care that evolution has
  bestowed on the capability to adjust the body to
  the direction of gravity, and parts of the body
  in relation to each other. (Brooks 1986)

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• Appropriate alignment of
• body segments
• Appropriate muscle activation
• Orientate in midline
• Interactive with BOS
• Linear acceleration
• against gravity

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Aim to Optimise the System of postural Control
Musculoskeletal Component
Systems Model of Postural Control
Neuromuscular Synergies
Adaptive Mechanisms
Individual Sensory Systems
Anticipatory mechanisms
Sensory Strategies
Internal Representation
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• Musculoskeletal
• Muscle length
• Joint range of
• movement
• Compliance
• Alignment
• Strength

• Neuromuscular
• Normal tone
• Reciprocal innervation
• Patterns of movement / coordination
• Appropariate level of activation / timing / force

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Anticipatory Mechanisms
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Balance Strategies
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SUMMARY

• Control of posture and movement requires
  initiation and planning at the highest level,
  control and updating from the middle level, and
  execution and regulation of the task at the
  lowest level.
• However it must be stressed that interaction
  between these levels is constant and ongoing,
  providing information in both direction.

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CORE STABILITY

• The co-activation of the abdominals and
  multifidus to stabilize the trunk and head during
  self initiated or facilitated limb activities