2OverviewNow that we’ve looked at response preparation, what happens during the response programming stage?
3Early Motor Program Theories Proposed that for each movement to be made, a separate motor program existed and was stored in memoryTwo problems:Storage: Hard drive (brain) could run out of spaceNovel responses: How do you respond to an action never done before?
4Command CenterDecision> appropriate plan retrieved from memory> instructions to rest of body for action
5Open Loop Systems Open loop Action plans generated by command center then carried out by the limbs and muscles without modificationCommand CenterActionMechanical Example:Sending
6Closed Loop Systems Closed loop Command center generates action plan that initiates the movementFeedback is used to modify on-going actionCommandCenterActionFeedbackMechanical Example: Thermostat
7Slow Vs. Rapid Movements Motor control uses both open and closed loop systemsMovements are planned in advance, initiated & executed with little modification (remember the fake in PRP?)If a rapid movement, feedback will be used for the next attemptFor slower movements, open loop begins the movement and closed loop will continue to completion
8Problem: How does a person do a novel motor skill? Motor Program Abstract representation of a movement planStored in memoryIssues instructions that are carried out by the limbs and muscles
9Generalized Motor Program (GMP) Represents a class of actions or pattern of movement that can be modified to yield various response outcomesInvariant featuresRelatively fixed underlying features that define a GMPParametersFlexible features that define how to execute a GMP
10Fixed vs. Flexible Features Write your name with the following:Your dominant handYour non-dominant handPen in your mouthPressing very hardPressing very softWrite quickly, then slowlyWhich aspects were fixed? Flexible?
11Invariant Features Relatively fixed underlying features Sequence of actions or componentsRelative timingInternal rhythm of the skill : the amount of time to write each letter of your name will stay the same whether writing fast or slowRelative forceInternal force relationship: The amount of force given to write each letter stays proportionally the same whether pressing hard or soft
12Parameters Adaptable features of program Easily modified from one performance to another to produce variations of a motor responseOverall duration: Fast or slowOverall force: Hard or softMuscle selection: Writing with hand or foot?
13Review QuestionWhen swimmers use hand paddles or when baseball hitters swing heavier bats, does this manipulate invariant features or parameter features?When might such an action hinder the development of correct technique?What signs would you look for to avoid this problem?
14SchemaRule or relationship that directs decision-making when a learner is faced with a movement problemDeveloped by abstracting 4 sources of information for each performance attemptInitial conditions present at start of movementResponse specifications: parameters used in the execution of the movementSensory consequences: what did the action feel like?Response outcome: how successful was the response?
15Schema DevelopmentFor each movement attempt the four sources of information are stored in memory brieflyFeedback from the attempt verifiesHow successful was the performance?Do I need to change the movement?With each additional attempt, the strength of the schema increases when you compare one attempt to the next
16Motor Response Schema Recall schema Recognition schema Responsible for organizing the motor programWhat do I need to do?>What conditions exist?>What parameters & invariant features are required?>Execute the responseRecognition schemaResponsible for the evaluation of a movement attempt : Was the movement correct?Error signal updates the recall schema
17Dynamic System TheoryMovement pattern is thought to emerge or self-organize as a function of the ever-changing constraints placed upon it
18ConstraintsDefined as the boundaries that limit the movement capabilities of an individualThree typesOrganismic: structural or functionalBody type, wt, htPsychological, cognitive, emotionalEnvironmental:wind, light, flat surface, grassyTask
19Task Constraints The goal of task: a certain movement Rules that may limit the movementOne must serve the tennis ball within an area on the baselineImplements or machinesUsing a walker, using weight machines, using a ball
20Attractor States Systems prefer states of stability When a change in constraints is imposed on a system, its stability is endangeredDeep basins = stable systems = difficult to changeShallow basins = less stable = more susceptible to change
21Phase Shifts Changes in behavior are the result of a series of shifts Control parametersVariables that move the system into new attractor states: gaining leg strength to perform a skill betterRate limitersConstraints that function to hinder or hold back the ability of a system to change :Adult learner, fear
22So what happens when a skill performance needs to change? Practice strategies need to create instability in a deep attractor basinAs the skill moves through the phase shift, it will become a combination of the old and new waysAt some point it will be neither the old or new and performance effectiveness is reducedEventually through practice, a new attractor state is formed, and eventually a new deep basin
23Key Point Movement patterns prefer state of stability New movements self-organize and emerge with phase shifts where attractors stabilize and destabilize as a function of the control parameters
24Practical Application Explain how orthotics function from a dynamic system perspective
25Exit Slip How do the recall and recognition schema work together? How are phase shifts indicative of behavioral change?