1. Behavioral Theories of Motor Control
Chapter 3

2. Coordination and Control
Degrees of freedom (problem) (Bernstein,1967)
Number of independent elements (nerves, muscles, and joint movement possibilities) that must come together into an organized movement pattern
Coordination (Sparrow, 1992; Turvey, 1990)
Process of constraining the system’s available degrees of freedom into a movement pattern
Control
Manipulation of those variables within the movement to meet the demands of a given situation
…..need both coordination and control in the acquisition and performance of motor skills (Vereijken, Whiting & Beek, 1992)

3. Command Center (theories regarding brain’s contribution to skilled movement)
Motor Program
Abstract representation of a movement plan
Stored in memory
Issues instructions that are carried out by the limbs and muscles
When a specific action is required, it is retrieved from memory and executed

4. Early Motor Program Theories
Proposed that for each movement to be made, a separate motor program existed and was stored in memory
2 problems:
Storage (would need limitless space in memory)
Novel responses (when you need to do something NEW)

5. Generalized Motor Program (GMP) (Schmidt,1985)
Represents a class of actions or pattern of movement that can be modified to yield various response outcomes
Invariant features
Relatively fixed underlying features that define a GMP
Parameters
Flexible features that define how to execute a GMP, easily modified from one performance to another

6. Invariant Features
Relatively fixed underlying features (eg.fingerprints)
Sequence of actions or components (e.g. order of actions to perform a tennis serve)
Relative timing
Internal rhythm of the skill (e.g.-arm movement in freestyle)
Relative force
Internal force relationship (changes proportionately as force increases or decreases)

7. Parameters Adaptable features of program
Easily modified from one performance to another to produce variations of a motor response (e.g. ability to throw to 1st base from various parts of the softball field)
Overall duration
Overall force
Muscle selection
For example, a soccer player can make a long or short pass, as the situation requires - same basic pattern but different outcome.

8. Schema (Schmidt, 1975,1985)
Rule or relationship that directs decision-making when a learner is faced with a movement problem - is the result of accumulated experiences
Developed by abstracting 4 sources of information each performance attempt
Initial conditions (limb/body/environmental conditions)
Response specifications (parameters e.g. speed/force required for the throw/ kick/ pass etc…)
Sensory consequences (sensory feedback - how it felt)
Response outcome (relative success of the action)

9. Motor Response Schema Recall schema
Responsible for organizing the motor program
Based on relationship with past experience of the action
Recognition schema
Responsible for the evaluation of a movement attempt
Both schemas can be ‘fine tuned’ with sensory feedback and external feedback (from the teacher/ instructor)

10. Open Vs. Closed Loop Systems
Open loop
Action plans generated by command center then carried out by the limbs and muscles without modification (feedback can only be used to vary a subsequent attempt at the movement action)
Closed loop
Command center generates action plan that initiates the movement
Feedback be used to modify on-going action
Action can be changed whilst it is occurring
Not possible in actions that involve speed

11. Evidence Supporting Motor Program Control
As complexity of the movement increases, RT increases (Henry & Rogers,1960)
Deafferentation studies involving surgical severing of sensory nerves (e.g. Polit & Bizzi, 1978)
Effects of unexpectedly blocking a limb during movement (Wadman, Dernier van der Gon, Geuze & Mol, 1979)
For example, baseball batter infers a specific type of pitch due to the type of wind-up demonstrated by the pitcher BUT the pitcher adjusts the way the ball leaves the hand, just prior to release - too late for the batter to adjust the motor program and therefore misses the ball!!

12. Dynamic System Theory
Argues that other theories ignore the fact that movement occurs in response to dynamic interaction of the mover and the environment
Alternatively, movement pattern is thought to emerge or self-organize as a function of the ever-changing constraints placed upon it

13. Constraints (Caldwell & Clark,1990)
The boundaries that limit the movement capabilities of an individual
Three types (or combination of each)
Organismic: can be structural e.g. height or functional e.g. cognitive ability
Environmental: eg. gravity, temperature, wind speed
Task: eg goals of the task, rules of the task, implements or machines required

14. Attractor States Systems prefer states of stability
When a change in constraints is imposed on a system, its stability is endangered
Deep basins = well learned = stable systems = difficult to change (Ennis, 1992)
Shallow basins = patterns not set = less stable = more susceptible to change

15. Phase Shifts Changes in behavior are the result of a series of shifts
Control parameters
Variables that move the system into new attractor states (e.g. direction, force, speed, perceptual information)
Rate limiters
E.g. cricket bat too heavy for the child)
Constraints that function to hinder or hold back the ability of a system to change

16. Dynamic System Theory Synopsis
The complexity of human behaviour leads to the Dynamic System Theory (DST) approach to understanding motor control
Teachers/ instructors need to:
Know individual learners’ capabilities;
Understand the complexity of the task to be taught;
‘Break down’ the task into developmentally appropriate stages;
Minimise or allow for constraints evident when teaching skills;
Understand the effect of ‘prior learning’ and ‘unlearning’;
Ensure the environment is conducive to learning;