balance theory and assessment Flashcards
what is centre of gravity?
-the point about which the mass of all body segments is evenly distributed
what is newtons first law?
-the body is in a state of equilibrium when the projection of its centre of gravity ir centre of mass (COG) falls within its base of support
what is the base of support (BOS)?
the surface area of the part which is involved in the support of the object
when is balance achieved - in relation to the BOS and COM/COG?
Balance is achieved when the COM falls inside the BOS
what is important for postural control of standing balance?
-body alignment
-muscle tone - background muscle tone
what is postural sway?
a term used to describe the unconscious, small movements that happen around the body’s center of gravity in order to maintain balance.
why does postural sway happen?
-2/3 of our body mass is located 2 thirds of body height above the ground
-major challenge to our control system
-allows pressure to be distributed across larger SA on the feet (ie prevents single pressure point)
what is postural control?
the act of maintaining, achieving or restoring a state of balance during any posture or activity
define static balance
the maintenance of a specified posture
define dynamic balance
-voluntary mvt
-reaction to an external disturbance such as a trip, a slip or a push
what 3 input ‘ systems’ does our brain receive in relation to neurophysiological control of balance?
-visual
-vestibular - inner ear
-somatosensory - ligament, joint receptors, muscle spindles
what are the visual inputs?
-reference to the external environment
-if we move we can tell how much we have moved
-we can see how high up we are
-not absolutely necessary for balance & postural control
what do the semicircular canals provide input about?
-angular acceleration of the head
-controls the vestibular ocular reflex (VOR)
What inputs do the utricle and saccule provide to the brain?
the utricle and saccule detect linear position and acceleration - esp slow movements
what is the vestibular ocular reflex?
-The Vestibuloocular reflex (VOR) very well contributes to the maintenance of clear vision.
eg When we move our head to the sides, to maintain a clear vision the eyeballs don’t move along with the head but moves towards the opposite side. These movements of the eyeballs help to fix the gaze on the object and thus we see it clearly[1].
compare exocentric vs egocentric mvt
-egocentric mvt - -object motion
-egocentric mvt - self motion
what information do the somatosensory inputs provide to the CNS?
-info about the body’s position and motion with reference to supporting surfaces
-info about the relationship of body segments to one another
what are the different proprioceptors in the MSK system?
-muscle spindles
-golgi tendon organ
- joint receptors
-cutaneous mechanoreceptors
what are Golgi tendon organs?
sensory mechanoreceptors located within tendons
what are examples of individual factors that influence balance?
-proprioception
-agility
-strength
-vision
-sensation
-age
-body size
what are reactive (compensatory) postural control strategies?
refers to the body’s ability to react to unexpected perturbations or disturbances to maintain balance and stability
- eg being pushed
what is anticipatory (predictive) postural control stategies?
Anticipatory postural control involves the proactive adjustment of posture and muscle activity in anticipation of an expected perturbation or movement.
-eg how you walk on ice or snow
what is the ankle strategy in relation to postural control strategies?
-involves controlled movements primarily at the ankle joint to counteract perturbations and maintain balance.
-It is typically employed when the body’s center of mass is shifted or destabilized within the base of support, such as a slight lean forward or backward.
what is the hip strategy?
Definition: The hip strategy involves controlled movements primarily at the hip joint to counteract perturbations and maintain balance.
It is typically employed when the magnitude or velocity of the perturbation exceeds the corrective capabilities of the ankle strategy alone,
what are equilibrium reactions as a type of postural control strategy?
-using arms and trunk to realign the centre of mass
what is a change-in-support reaction in relation to postural control strategies?
-BOS moves so COM intersects
-ie there is a new base of support
Describe 5 conditions are likely to present the physiotherapist with balance problems?
-vertigo - vestibular problem
-Parkinson’s - not somatosensory, movements are too slow / small
stroke - sensory loss and impaired motor output
-ankle fracture/ injury - somatosensory and muscle weakness
-concussion - vestibular problem
what 3 components should be included in a clinical balance assessment ?
-static
-dynamic - anticipatory (task involving movement), reactive (giving them a little nudge or lean and release)
what are examples of testing static balance?
-observation of postural sway
-timed test - single leg stance, tandem stance, eyes open and closed
-clinical test of the sensory integration of balance
what are examples of testing dynamic balance?
-observation of reaching out of base of support
-functional tests - give a set of tasks to do - see how well they can do them
-Y balance test
what is the clinical test of the sensory integration of balance?
- timed test that measures the influence of the visual, vestibular & somatosensory on standing balance
describe the single leg stance test
-measure of postural stability
-test performed with eyes open and closed
-30 secs hold
-best of 3
-static test (not involving active mvt)
describe the ‘Y balance test’
-test of dynamic anticipatory single leg balance
-moving but in a SL stance
-used in sports for screening injuries risk
-non stance leg reaches 3 directions
-tests somatosensory component
what 3 directions does the non stance leg reach in the Y balance test?
- anterior
-posteromedial
-posterolateral
what is the functional reach test?
a test for assessing dynamic balance
describe the timed up and go test
- used for clinical assessment of balance and mobility in older people with neurological conditions
-there is cut off points to predict falls
what is the berg balance scale?
-determines a patient’s ability (or inability) to safely balance during a series of predetermined tasks.
-14 tasks
-each task graded on 5 point scale
what is the tinoetti balance test?
-assesses a person’s perception of balance and stability during activities of daily living and their fear of falling.It is a very good indicator of the fall risk of an individual
what is the BESTest ?
quantitative assessment tool that aims to identify the disordered systems underlying the postural control responsible for poor functional balance
what kind of populations can the BESTest be used in?
-Neurological conditions eg Parkinson’s, Stroke, Cerebellar Ataxia, Neuropathies, Head injury, Multiple Sclerosis, Cerebral palsy
-Vestibular disorders,
-Cognitive Impairments
-Elderly.
