Motor Control Flashcards
Definition of Motor Control
The study of the nature and cause of healthy or abnormal movement
Time frame = milliseconds (ms) or seconds (s)
Shumway-Cook & Woollacott Model (Theory#1)
- Goal = accomplish a motor task
- Work on functional tasks
- Interaction b/w individual, task and environment
Horak’s Systems Model (Theory #2)
-Organized around a behavior or goal
- Interaction b/w…
1) Normal movement strategies (Typical) [Individual]
2) Compensatory strategies [Individual]
3) Musculoskeletal constraints [Individual]
4) Central set/predictive control [Individual]
5) Environmental adaptation
6) Behavioral goals
Typical Movement Strategies (individual)
Rolling Supine <> stand STS Gait Gait initiation Stair ascent & descent
Standing Neuromuscular Synergies
Ankle strategy
- surface = firm
- Small perturbations
Hip strategy
- Surface = softer or less firm
- Larger perturbations
Stepping strategy
- Surface = very pliable
- perturbations move COM beyond BOS
Important: can shift easily b/w 3 strategies!!!
Why is forward sway more than backward sway?
Ankle strategy
- Feet are longer in the front and shorter in the back
- Ankle strategy to recover 8-10deg of forward sway and 4-5deg of backward sway
- Recruits muscles from distal to proximal
Stepping Strategy
- Subjects were not told to keep their feet in place, they more frequently step, instead of using an ankle or hip strategy to restore balance
- Older adults more frequently and quicker step than young adults
Compensatory Strategies (individual)
- Individuals with neurological impairments have found the most appropriate, efficient and effective compensatory strategy given their constraints (*Best solution for what they have)
- Take away their compensatory strategy, PT responsible to help the patient replace it with a “typical” or other movement strategy in order to enable the patient to continue to accomplishment of the task
Compensatory vs. Recovery Focus: Early after injury
Focus on Recovery interventions
Other: Compensation interventions so patient is functional at home
Compensatory vs. Recovery Focus: Later, if recovery is limited
Focus on Compensation interventions
Compensatory vs. Recovery Focus: Next phase after injury
Focus on Recovery interventions
Musculoskeletal Constraints (individual)
- How much of the movement problem is due to musculoskeletal problems rather than neural constraints?
- Treat the musculoskeletal complaint and then re-exam the movement pattern
Ex) Ankle contracture = limited ability to utilize ankle strategy…So, use “early” hip or stepping strategy and treat the ankle contracture then re-assess balance ankle strategy
Central Set (individual)
-An internal model of one’s body dynamics and the dynamics of the external world
Ex) Predict that the trunk must accommodate for an upcoming UE movement (Feed-forward)
Predictive Control (individual)
-Knowing both your internal model (body) and the effects of the external world well enough to predict accommodations to future events
Ex) Predict the weight of a full cup of water
Anticipatory Mechanisms in Horak’s application to Balance
aka Central Set/Predictive Control
Feed-forward balance
-Anticipatory postural control
-Prior to voluntary movement that is potentially destabilizing in order to maintain stability during the movement
Ex) trunk reactions before reach
Feedback balance
- Compensatory or reactive postural responses
- Sensory feedback from unexpected external perturbations triggers postural responses
***We need to be able to do BOTH!!!
