What does standing involve?
Standing alignment & ability to balance
What is balance?
- Ability to control the COM over the BOS
- Results from interaction between sensory & musculoskeletal systems
- Integrated & modified by CNS
What are the main sensory systems involved in balance?
- Vestibular: Info about head position & movement
- Kinaesthetic: Info about movement of body relative to BOS & limbs relative to each other
- Visual: Info about environment & orientation/movement of body
What are postural adjustments?
- Muscle activations that maintain balance (COM over BOS)
- Support head & body against gravity
- Stabilise body parts while others are moved
- Anticipatory or reactive
What is postural control important for?
- Independence
- Falls prevention
- Gait
- Predictor for achieving independent living after stroke
What are the important components of standing?
- Feet few cms apart
- Head balanced on level shoulders
- Weight evenly distributed
- Hips in front of ankles
- Hip, knee & ankle extension
What are the important components of reaching in standing?
- Shift head, arm, trunk & legs towards object by moving at ankles
- Load foot ipsilateral to direction of reach
What evidence is there for muscle activation in pushing & pulling?
- Compared normal activation of leg muscles during pulling & pushing on a handle in standing
- Pushing: Anterior leg muscles activated
- Pulling: Posterior leg muscles activated
- Muscles activated distal to proximal
- Clinical implications: Train in various directions
What evidence is there for lower limb activation during reaching in standing?
- Examined EMG patterns of lower limb during reaching tasks in normal participants
- EMG patterns varied with the task
- Muscle activity anticipatory & ongoing
- When holding on with hands, hand muscles turned on (not leg)
- Clinical implications: Train lots of different tasks, avoid holding on to ensure activation of leg muscles
What are the clinical implications of the research regarding muscle activation in standing?
Postural adjustments are:
- Anticipatory & ongoing
- Task & context specific
- Train balance as part of daily tasks
- Consider nature of external support (e.g. rails vs harness)
How is standing assessed?
- Observe standing alignment
- Observe balance in standing which reaching/looking in various directions
- Look for missing important components & adaptive strategies
How is standing measured?
- Functional reach test
- Step test
- Berg balance scale (may be too easy for some patients)
What are the common observable deviations in standing?
- Decreased hip & knee extension
- Excessive lateral pelvic shift to affected side
- Inability to make preparatory & ongoing postural adjustments during reaching
What are the common adaptive strategies in standing?
- Increased BOS
- Weight shifted to intact side
- Flexion at hips instead of DF at ankles when reaching forward
- Movement at trunk instead of hips & ankles when reaching sideways
- Shuffling & premature stepping
- Use of arms
- Voluntary restriction of movement
- Holding breath
What evidence is there for balance impairment after stroke?
- Balance impairment is common after stroke (83%)
- Correlated with severity of stroke, impairment & disability
What are the main research findings regarding stroke & standing balance?
- Greater postural sway
- Reduced weight through affected leg
- Smaller excursions of weight movement in direction of affected leg
- Effects seen in static & dynamic balance & in responses to external perturbations
What evidence is there for lateral shift in standing after stroke?
- Compared accuracy & speed of lateral shift over 12 weeks
- Stroke patients & healthy aged-match controls
- After 12 weeks, stroke patients had attained normal precision, but speed still reduced in both directions
What are the clinical implications of the research regarding lateral shift in standing after stroke?
- Hip abductors are main muscle group involved in lateral weight shift
- If abductors don’t turn on quickly, weight shift is too late & patient is at risk of falling
- Train hip abductors in strength & speed
- Train weight shift using cues
What interventions can be used for difficulty in standing?
- Impairments: Address impairments found in assessment
- Activity training: Improve standing alignment & ability to move COM over BOS
What are some activities that can be used as activity training for standing?
- Looking up at ceiling/behind shoulders
- Reaching in different directions
- Progress: Change BOS, increase reaching distance/speed, vary size/weight of target object, alter direction of reach
What evidence is there for balance training?
- Systematic review examining effects of balance training on standing balance after stroke
- One-on-one/group balance training effective in improving standing balance in all stages of stroke
What evidence is there for activity training for standing?
- Looked at effect of virtual reality in improving standing balance
- 40 mins PT 4 days/week for 4 weeks plus 30 mins virtual reality therapy
- Improved Berg balance, weight shift control, increase gait velocity & spatiotemporal factors
- But small study, further research needed (may be effective)
What evidence is there for use of biofeedback in standing training?
- Systematic review comparing biofeedback & usual physio in lower limb training after stroke
- Biofeedback more effective than usual physio in improving standing balance
What are the key points regarding standing balance?
- Important for function
- Impaired after stroke
- Normal standing balance is context specific
- Improves after stroke with training
