Introductory Terminology: Lecture 1 Flashcards
Motor control
Ability to regulate or direct the mechanisms essential to movement
- CNS and PNS
- coordination
- use of sensory information
- personal perception
- past experiences
- environment
- motor development
Reflex theory of motor control
Complex behavior was explained through the combined action of individual reflexes chained together.
Does not explain movement that occurs in absence of a sensory stimulus nor novel movements
Reflex-based neurofacilitation approaches:
- PNF
- quick stretch
- contract relax
- tapping
(retraining motor control through techniques designed to facilitate and/or inhibit different movement patterns)
Hierarchical theory of motor control
Organization control is top down; each successively higher level exerts control over level below it
Vertical hierarchy: lines of control do not cross; never bottom-up control
Cannot explain dominance of reflex behavior in certain situations in normal adults
Explains disordered motor control in patients with neurologic disorders
Ecological theory of motor control
The perception/action system actively explores the environment to satisfy its goals
- assess environmental properties in relation to our own characteristics
- action is dependent on how well an individual fits within environmental constraints
- action facilitates perception and perception facilitates action
Perception-action coupling
The linking together of information and actions or movements
Perception
- detection and utilization of critical information for the control of action
- Ex: hand-eye coordination
Action
- various movements that are regulated by the perceived information
- Ex: stepping off the bottom stair without vision (anticipatory)
Motor program-based theory
Retraining movements are important to functional tasks, not just specific muscles in isolation
Responsible for adaptive and flexible qualities of human movement
Each motor program controls a class of actions
The basis for generating movement prior to and during the performance of an action
Motor programming theory
“Schema theory”
Memory based mechanism that controls coordinated movement
Central motor program:
- more flexible than a reflex
- activated by sensory stimuli or central processes
If stimulus is absent, a concept for a central motor pattern remains
Systems theory
Dynamic systems theory
Emphasizes environmental information, mechanical and dynamic properties of the body/limbs in movement control/coordination
Behavioral changes are not always continuous, linear progressions but are often sudden or abrupt
Behavior is organized by the interactions among task, environmental, and organism constrains
Behavior self-organize in response to constraints
Small amount of variability indicates highly stable, energy efficient behavior
Open loop system
the control center sends the effectors all the movement instructions they need to perform a skill from beginning to end
control center –> instruction –> effectors
Closed loop system
Includes feedback as part of the system
The control center sends movement instructions to the effector that enable them to initiate the performance of a skill
Feedback from effectors and other sources provides the control center with the information needed to give the effectors the instructions to continue and end the movement
control center –> instruction –> effector –> information –> control center –> loop
Degrees of freedom
Number of independent elements in a system and the ways each element can act
More than 100
Problem –> How to control degrees of freedom to make a complex system act in a specific way?
- Freeze: reduce movement degrees of freedom
- Free: increase movement degrees of freedom
Synergies
Groups of muscles (and joints) acting as functional units; patterning of body and limb motions relative to environmental objects/events
- play role in solving degrees of freedom problem
- ensure flexible and stable performance of motor tasks
- develop through practice and experience
Summary of motor control theories
Motor program-based theory, dynamic systems theory BEST
motor control theory cannot focus exclusively on movement information specified by CNS
Theory hybrid could explain control of coordinated movement
Motor abilities as individual difference variables
If 2 people have the same
- amount of practice
- level and amount of instruction
- motivation to perform the skill
Then motor abilities will influence the level of performance success each person can achieve
General motor ability hypothesis
- Many motor abilities are highly related
- A person can be described as having global motor ability
Specificity of motor ability hypothesis
- Many motor abilities are relatively independent
- Each person varies in the amount of each ability
- A person’s motor ability can be described by a profile of amount of each specific motor ability
Fleishman’s taxonomy of motor abilities
- multi-limb coordination
- control precision
- response orientation
- reaction time
- speed of arm movement
- rate control (anticipating obstacles, conditions)
- manual dexterity
- finger dexterity
- arm-hand steadiness
- wrist, finger speed
- aiming
Reaction time
From “go” to initiation of response
- simple (one target, one finger)
- choice (multiple targets, respective fingers)
- discrimination (multiple targets, one finger)
RT + MT = response time
Movement time
From initiation of response to termination of response
RT + MT = response time
Regulatory conditions
Features of the object or environment to which movements must conform to achieve action goal
Spatial and temporal aspects of the movement are regulated
Non-regulatory conditions
Features of the object or environment that have no effect or an indirect effect on movement; movement does not have to conform to these features
Intertrial variability
Variations in the regulatory conditions from one trial to the next
Closed motor skills/environment
Stationary support surface, object, and/or other people/animals
The performer determines when to begin the action
Predictable (closed)
- gymnastics
- typing
- cutting vegetables
Open motor skills/environment
Involves a supporting surface, object, and/or other people/animal in motion
Environmental features determine when to begin the action
Unpredictable (open)
- soccer
- wrestling
- chasing a rabbit
Motor skill performance outcome measures
Indicates the outcome or result of performing a motor skill
Does not tell us about the movements that led to the outcome
Does not provide information about the activity of various muscles involved or how the nervous system was involved
Ex: jump height; throwing accuracy; TUG time
Motor skill performance production measures
Indicate the activity of specific aspects of the motor control system during the performance
Ex: high jump technique; angle of each joint of the arm during a throw; TUG movement analysis
Characteristics of Gentile’s Taxonomy
Each category puts different demands on the performer
Skill complexity is the basis for taxonomy organization
Complexity increases when a motor skill involves one or more of the following
- open environment
- trial-to-trial variability
- object manipulation
- body transport
Practical uses of Gentile’s Taxonomy
Guides evaluation of motor performance capabilities, limitations, deficiencies
Provides a systematic basis for selecting progressions
Chart an individual’s progress
Manipulative vs. non-manipulative
maintaining/changing position of moveable objects
Bimanual coordination skills
Motor skills that require simultaneous use of two arms
Symmetric:
- rowing a boat, jumping rope
Asymmetric:
- playing a guitar
- driving stick shift
Temporal and spatial coupling of the two arms when initially performing an asymmetric bimanual skill
- practice required to disassociate the two limbs
Discrete motor skills
specified beginning and end points, usually require a simple movement
Serial motor skills
involve a continuous series of discrete skills
Continuous motor skills
no recognizable beginning or end points; usually involve repetitive uninterrupted movements
