Theories and Problems

Question 1

What is a theory?

Answer 1

1. Accurately describes a large class of observations.
2. Makes definite predictions about results of future observations. (hawking)

Question 2

What does motor learning and control theories focus on?

Answer 2

1. Explaining human movement behavior
2. Providing explanations about why people perform skills as they do.

Question 3

How does a theory have relevance to professional practice?

Answer 3

1. Provides the “why” basis for what practitioners do.

Question 4

What does motor control theory describe?

Answer 4

1. Describes and explains how the nervous system produces coordinated movement during motor skills performance in a variety of environments.

Question 5

What is science?

Answer 5

1. A tool to utilize and explain scientific experiments or observations to falsify claims about the world.

Question 6

Two types of control systems

Answer 6

1. Closed-Loop Control
2. Open-Loop Control

Question 7

Control System

Answer 7

1. How are you controlling different parts of your body?
2. Stimulus
3. Sensor or receptor
4. Afferent pathways
5. Integrating center
6. Efferent pathways
7. Target or Effector
8. Response

Question 8

Open and Closed Loop control System

Answer 8

1. Each has a central control center (executive)
2. Each include instructions form control center to effectors.

Question 9

Differences between the two systems?

Answer 9

1. Open loop
   a. Does not use feedback
   b. Control center provides all the information for effectors to carry out movement.
2. Closed loop
   a. Uses feedback
   b. Control center issues information to effectors sufficient only to initiate movement
   -Relies on feedback to continue and terminate movement

Question 10

Application of Closed Loop Control

Answer 10

1. Feedback and error are key
2. Untrained Skills
3. High attentional demands

Question 11

Application of open loop control

Answer 11

1. Pre-program responses
2. Quick and reactive
3. Low attention
4. No Feedback

Question 12

Cerebellum

Answer 12

1. Reference mechanism

Question 13

Open/Closed Loop continuum: Fitt’s law

Answer 13

1. Showed we could mathematically predict movement time (MT) for speed- accuracy skill
2. The MT increases with either increasing the movement amplitude (A) or decreasing the target width (W)

Question 14

Speed accuracy trade off

Answer 14

1. When both speed and accuracy are essential to perform the skill.

Question 15

Open-loop control: At movement initiation

Answer 15

1. The initial movement instructions sufficient to move limb to the vicinity of the target.
2. Speed, direction and accuracy are under CNS command

Question 16

Closed-loop control: At movement termination

Answer 16

1. Feedback information needed to terminate the movement
2. Feedback from vision and proprioception needed at end of movement to ensure hitting target accurately.

Question 17

Motor Program Based Theory

Answer 17

1. Cognitive based mechanism that controls coordinated movement

Question 18

Dynamical Systems Theory

Answer 18

1. Emphasizes the role of information in the environment and mechanical properties of the body and limbs in movement control/coordination.

Question 19

Generalized Motor Program (GMP)

Answer 19

1. Hypothesized memory based mechanism responsible for adaptive and flexible qualities of human movement.
   a. Proposed that each GMP controls a class of actions, which are identified by common invariant characteristics

Question 20

GMP Function

Answer 20

1. To serve as the basis for generating movement instructions prior to and during the performance of an action.

Question 21

Invariant Features

Answer 21

1. Characteristics that do not vary across performances of a skill within class of actions.
2. The identifying signature of a GMP

Question 22

Parameters

Answer 22

1. Specific movement features added to invariant features to adapt a specific situation
2. Characteristics can very from one performance of a skill to another.

Question 23

Dynamical Systems Theory (DST)

Answer 23

1. Describes the control of coordinated movements by emphasizing the roles of environmental information and dynamic properties of the body/limbs.

Question 24

Genesis of DST

Answer 24

1. DST was attempting to resole two problems associated with cognitive based theories.
2. Context-conditioned variability problem
3. Degrees of freedom problem

Question 25

Context-Conditioned Variability Problem: Cognitive based theories

Answer 25

1. Specific movement outcomes are dependent on specific commands found the motor program.

Question 26

Degrees of freedom problem

Answer 26

1. DOF: Number of ways in which a system can independently vary
   a. Same goal can be achieved by different movements.

Question 27

Solutions to the problems (Synergies)

Answer 27

1. Clustering of degrees of freedom into cooperating collectives.
2. Temporary and flexible assembled functional organizations that are defined over a group of muscles and joints and the convert those components into task specific coherent multiple degrees of freedom ensembles

Question 28

Freezing the degrees of freedom

Answer 28

1. Limiting the movement of limbs and joints.