STANDING BALANCESTANDING BALANCE

Kate RamadgeKate Ramadge

PhysiotherapistPhysiotherapist

NSW PAR Day NSW PAR Day

3030thth March 2007 March 2007

What are:What are:

Standing balanceStanding balance

The ability to stand without using undue muscle activity,

to move about in standing,to perform a wide variety of motor

tasks,and to move in and out of the standing position.

What are:What are:

Postural adjustmentsPostural adjustments

Muscle activation patterns to control of the motion of several body segments relative to each other,

to ensure the upcoming movement does not destabilise the body’s equilibrium.

Contributors to PA’sContributors to PA’s Vision Vision

Vestibular systemVestibular system

Postural adjustmentsPostural adjustments- - strengthstrength

- timing of muscle activity- timing of muscle activity- co-ordination of multiple muscles- co-ordination of multiple muscles

ProprioceptionProprioception

Postural Adjustments:Postural Adjustments:Task & Context SpecificityTask & Context Specificity

Cordo & Nashner (1982)Cordo & Nashner (1982)

A. Person pulls on handle:

Gastrocs

Hamstrings

Biceps last

Anticipation

Internally generated

B. Handle is pulled:

Gastrocs

Biceps

No anticipationExternally imposed

C. Handle is pulled and trunk supported:

Biceps only

Leg muscles not required as posturalsupport

D. Handle and floor are pulled:

Biceps delayed

Postural Adjustments: Postural Adjustments: Essential featuresEssential features

Context specificContext specific Modified by task being performedModified by task being performed

AdaptiveAdaptive not reflex behaviour not reflex behaviour

Muscle actions change with alterations in base Muscle actions change with alterations in base of supportof support

AnticipatoryAnticipatory: muscle activation occurs in : muscle activation occurs in anticipation of changes in centre of massanticipation of changes in centre of mass

Vision over-rides proprioceptionVision over-rides proprioception

Vision Over-rides Proprioception

A. Wall moves away from person

B. Person perceives this as falling backwards

C. Person falls forward to compensate

Lee and Aronson (1974)

Training Postural AdjustmentsTraining Postural Adjustments

Train specific tasksTrain specific tasks

eg reaching in sitting, standing eg reaching in sitting, standing

Patients need to learn which muscles Patients need to learn which muscles to activate to activate in anticipationin anticipation of a change of a change in COGin COG

Need to train specific muscle actions Need to train specific muscle actions for specific tasksfor specific tasks

Training Postural AdjustmentsTraining Postural Adjustments

Patients need to practise in safety but with Patients need to practise in safety but with the opportunity challenge their postural the opportunity challenge their postural adjustmentsadjustments

Eg. Standing next to a wall without hand Eg. Standing next to a wall without hand support support insteadinstead of holding onto parallel bars of holding onto parallel bars

Postural adjustments occur in the joints Postural adjustments occur in the joints adjacent to support surfaces adjacent to support surfaces (Slijper & Latash, (Slijper & Latash, 2000)2000)

(So, (So, whenwhen should we issue a frame?) should we issue a frame?)