FINAL- STANDING AND BALANCE

Limit of stability (LOS)

amount of maximum excursion possible in any one direction without losing balance

12 degrees

normal adult anterior/posterior LOS

16 degrees.

normal adult medial/lateral LOS

sway envelope

path of the body’s movement during normal standing: consists of anterior/posterior, medial/lateral swaying

centered alignment

midpoint of sway between m/l and p/a

Static postural control (stability)

is also called steady state standing

dynamic postural control (controlled mobility)

weight shifting; necessary to control movements while standing

Static postural control (stability)

required to maintain undisturbed stance.

dynamic balance

ability to maintain postural control while in motion or while moving (balance)

dynamic balance

needed for ambulation

Anticipatory postural control

adjustments that occur in advance of the execution of voluntary movements.

Anticipatory postural control

Example: a person readies their posture before lifting a heavy weight or catching a weighted ball.

Reactive balance control

ajustments that occur spontaneously in response to unexpected changes in the COM or changes in surface

Reactive balance control

Examples: reacting to perturbations, or catching yourself when slipping

Fixed support strategies

use stabilizing movements at the ankles and hips without moving the feet

change-in-support strategies

involve stepping and/or reaching with the UEs to prevent a fall.

Adaptive balance control

ability to adjust or modify postural responses relative to changing task and environmental demands: balance Influenced by learning.

Head, arms, trunk (HAT)

should be over the LEs and within the BOS during all tasks and environmental conditions

somatosensory system

the tactile and proprioceptive system

dissociative movement

smooth, refined, and independent actions of muscle groups moving in isolation:

somatosensory system

responds to support-surface inputs about the relative orientation of body position and movement

somatosensory system

influence postural responses through the stretch reflexes, postural tone, and automatic postural reactions.

stretch reflexes, postural tone, automatic postural reactions

3 ways the somatosensory system influence postural repsonses

visual system

responds to visual cues about the environment and the relationship of the body to objects in the environment

visual system

provides input for optical righting reactions of the head, trunk, and limbs and contributes to upright head position and normal alignment of the head and body.

visual system

system that assists in regulating postural tone and guides safe movement trajectories.

vestibular system

responds to gravity acting on the head.

vestibular system

stabilizes gaze during movements of the head by using the vestibulo-ocular reflex (VOR)

vestibulo-ocular reflex (VOR)

how the vestibular system stabilizes gaze during movements of the head:

vestibulo-ocular reflex (VOR)

reflex that allows objects to remain stable in the visual field while the head moves in space.

vestibular system

provides input to labyrinthine righting reactions of the head, trunk, and limbs and contributes to upright head position and normal alignment of the head and body

vestibular system

allows one to remain upright in relation to gravity without the use of visual cues,

vestibular system

system allowing you to walk in the dark

vestibulospinal pathways.

vestibular system helps to regulate postural tone through:

vestibular system

acts to mediate conflicting information from the somatosensory and visual systems to accurately perceive movement in space.

synergies

functionally linked muscles that are constrained by the CNS to act cooperatively to produce an intended movemen

Ankle strategy

strategy requiring minimal movement of the hip and knee joints

Ankle strategy

small shifts of the COM by rotating the body about the ankle joints

Limit of stability (LOS)

ankle strategy movements are well within in the:

Hip strategy

translates the HAT segment forward and backward over the LEs

Hip strategy

larger shifts of the COM by flexing or extending at the hips

Hip strategy

strategy that approaches the LOS

change of support strategies

activated when the COM exceeds the BOS

change of support strategies

strategies that must be initiated that reestablish the COM within the LOS

stepping strategy, grasp strategy

2 type of change of support strategies

stepping strategy

involves realignment of the BOS under the COM achieved by stepping in the direction of the instability

grasp strategies

involve attempts to stabilize movement of the upper trunk

grasp strategies

keeps the COM over the BOS.

stepping strategy

realignment of the BOS under the COM

fixed support strategies

used before change in support strategies

Asymmetrical standing

weight borne primarily on one LE with little weight on the other LE results in increased ligament and bone stress on the weight-bearing side

Asymmetrical standing

the knee is usually fully extended on the stance limb

Asymmetrical standing

patient with stroke who stands with weight borne more on the less affected side has this standing and weight bearing impairment:

Trunk extensor weakness

typically associated with a forward head position, rounded thoracic spine (kyphosis) with a flattened lumbar curve, creating a forward displacement of the COM near or at the anterior LOS

forward, anterior

Trunk extensor weakness is associated with (backward/forward) displacement of COM near or at the (anterior/posterior) LOS

kyphosis

is lordosis or kyphosis associated with Trunk extensor weakness?

forward head position

head position associated with Trunk extensor weakness

flattened

one word description of the the lumbar spine in Trunk extensor weakness

Trunk extensor weakness

results in flexed, stooped posture seen in many elderly people

elderly people

Trunk extensor weakness is seen in this population: flex and stooped posture

flexed-knee posture

increases the need for quadriceps activity

quadriceps, hip extensors, plantar flexors

flexed-knee posture increases the need for these 3 muscle groups:

flexed-knee posture

requires increased hip extensor and soleus activity for accompanying increases in hip flexion and dorsiflexion.

flexed-knee posture

increased hip flexion and dosirflexion in addition to the namesake joint action

lordosis, kyphosis

Excessive anterior tilt of the pelvis increases lumbar (kyphosis/ lordosis) and thoracic (kyphosis/ lordosis)

abdominals

muscle stretched in Excessive anterior tilt of the pelvis

iliopsoas

muscle shortened in Excessive anterior tilt of the pelvis

lumbar extensors

Excessive lumbar lordosis produces shortening of these muscles:

Excessive dorsal kyphosis

produces stretching of the thoracic trunk extensors and shortening of the anterior shoulder muscles.

Excessive cervical lordosis

produces shortening of the neck extensors

Genu valgus

produces medial knee joint stresses and pronation of the foot with increased stress on the medial longitudinal arch of the foot.

Pes planus

results in depression of the navicular bone and compressive forces laterally

Pes planus

increased weight is borne on the metatarsal heads

Pes cavus

results in increased height of the longitudinal arch with a depressed anterior arch and plantarflexion of the forefoot

Pes cavus

toe deformity (claw toes) may also be present.

Gastrocnemius-soleus weakness

results in limited sway and a wide BOS

Quadriceps weakness

results in unstable sway

Quadriceps weakness

knees are hyperextended (genu recurvatum) and the trunk may be inclined forward to increase stability.

active knee control

a patient without this compensates by keeping the hips slightly flexed, with increased lordosis.

LE spasticity

results in decreased function; the actions of the LE muscles and balance reactions are compromised.

LE spasticity

The LEs are typically adducted and internally rotated (scissoring position) with feet plantarflexed and inverted.

scissoring position

adducted and internally rotated LEs

Ankle strategy

small shifts in COM alignment or slow sway movements activates a:

dorsiflexion, plantar flexion

ankle strategies: the patient is instructed to sway gently forward and backward and then return to centered alignment using these 2 ankle motions

the ankles

the axis of motion for ankle strategies

hips, shoulders

Gentle perturbations applied to these 2 areas promote ankle strategies

dorsiflexors

ankle strategies: small displacement backwards activates the:

plantarflexors

ankle strategies: small displacement forwards activates the:

ankle synergies

Small weight shifts performed while standing on a split foam roller (flat side up) can also be used to activate:

the ankles

tipper boards and rocker boards stimulate actions at:

Hip strategy

Larger shifts in COM alignment or faster sway movements result in activation of a:

Ankle strategy

standing on a small BOS or on a compliant surface limits this strategy:

Ankle strategy

standing on a ladder or standing in the sand limits this strategy:

hip extensors, hip flexors

muscles that serve to realign the COM within the BOS in hip strategies

opposite

the upper trunk is moving (same/opposite) direction of the lower body in hip strategies

Hip strategy

instructing a patient to bring their buttocks to rest on the wall, then the shoulders to the wall, and return to standing is a way to practice this strategy:

stepping strategies

Larger shifts in which the COM exceeds the LOS result in activation of: (strategies)

stepping strategies

the patient leans forward until the COM exceeds the BOS to practice:

stepping strategies

stepping forward to prevent a fall is an example of:

backward step

Increased backward lean will result in a: