Postural Control

DefinitionFunction

NeurophysiologySystems Model

DONG-EUI MEDCAL CENTERAHN BYUNG UG

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

Ragnarsdottir 1996

Postural Control

‘controlling the body’s

position in space

for the dual purposes of

stability and orientation

Shumway-Cook and Woollacott 1995

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

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

BODY SCHEMA

▪ DEFINITION “A postural model one has of oneself, having to d

o 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)

POSTURAL STABILITY

This involvesMaintaining the body’s 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 it’s position without changing it’s base of support.

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.

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

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).

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)

Appropriate alignment of

body segments

Appropriate muscle activation

Orientate in midline

Interactive with BOS

Linear acceleration

against gravity

Aim to Optimise the System of postural Control

Musculoskeletal

Component

Neuromuscular

Synergies

Individual

Sensory

Systems

Sensory

Strategies

Internal

Representation

Anticipatory

mechanisms

Adaptive

Mechanisms

Systems

Model

of

Postural

Control

Musculoskeletal• Muscle length• Joint range of

movement• Compliance• Alignment• Strength

Neuromuscular• Normal tone• Reciprocal innervation• Patterns of movement / co

ordination• Appropariate level of activ

ation / timing / force

Anticipatory Mechanisms

Balance Strategies

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.”

CORE STABILITY

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