Week 2

Question 1

What are the 4 characteristics of human action? (Sheridan, 1984)

Answer 1

Flexibility of movement
- The ability to accomplish a task using a variety of musculoskeletal resources

Uniqueness of movement
- Movements are not identical

Consistency of movement
- Close similarity over a series of performances

Modifiable try of movement
- The explanation for a persons ability to alter a movement during its performance

Question 2

What is motor equivalence?

Answer 2

Capability of the motor system to perform a particular task, and produce the same movement outcome, in a variety of ways

Question 3

What is serial order?

Answer 3

Capability of the motor system to structure movement commands in such a way as to reliably produce movement elements in their desired sequence.

Question 4

What is degrees of freedom?

Answer 4

The number of independent elements or components in a control system and the number of ways each component can act.

Question 5

What is the degrees of freedom problem?

Answer 5

There are multiple ways for a person to perform a movement in order to achieve the same goal.

Question 6

Define coordination

Answer 6

Effectively and efficiently patterning body movements by constraining the available degrees of freedom to achieve the goal of a skill.

Question 7

Define control

Answer 7

Arriving at total body movement based upon the degrees of freedom for each segment

Question 8

What is an open loop system

Answer 8

Feedback is not used either to continue or correct movement, the instructions contain all the necessary information. Feedback is produced and available but is not needed or there isn’t enough time to use it after movement has been initiated.

Question 9

What is a closed loop system?

Answer 9

Initial instructions and additional feedback, either to continue or correct movement. Feedback is afforestation information sent by various sensory receptors. Feedback updates control centre about the correctness of movement while in progress.

Question 10

What are the 5 psychological theories?

Answer 10

1. Reflex theory
2. Hierarchical theory
3. Motor programming theories
4. Systems theories
5. Ecological theories

Question 11

What is reflex theory?

Answer 11

• Reflexes are the building blocks of complex behaviour

- Complex behaviour can be explained through the combined action of individual reflexes that are chained together

Question 12

How does reflex theory work?

Answer 12

Requires a receptor, a conducting nervous pathway and an effector.
The reflex arc consists of the receptor, the conductor and the effector

Question 13

What are some limitations of reflex theory?

Answer 13

• Does not explain spontaneous and voluntary movement
• Doesn’t explain and predict movement that occurs in absence of a sensory stimulus
• A stimulus can result in varying responses
• Does not explain novel (new) movements.
• Does not explain fast movements too rapid for sensory feedback

Question 14

Reflex theory and clinical implications?

Answer 14

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Question 15

What is hierarchical theory?

Answer 15

• The nervous system is organised as a hierarchy
• ## Control is top down

Question 16

What are some current concepts of hierarchical theory?

Answer 16

• The importance of elements of hierarchical organisation
• Each level of the nervous system can act on other levels depending on the task
• Reflexes are not considered the sole determinant of motor control (one of many processes important for movement)

Question 17

Limitations of hierarchical theory

Answer 17

• Cannot explain the dominance of reflex behaviour in certain situations.
• Assumes that all lower level behaviours are primitive, immature and non adaptive.

Question 18

What are motor programming theories?

Answer 18

• Explores physiology of actions, rather than reactions
• Central motor pattern. What remains when a stimulus is removed from a motor response
• One can remove the stimulus and still have a patterned response
• More flexible, can be activated by either sensory input or central processes.