L10B: Components of GMP Flashcards
What are the Three Invariant Features
that have been identified?
- Relative* timing (most critical, see text)
- Relative force
- Order of events
What is relative timing?
Internal rhythm of the skill
Relative timing of events/ actions/muscle activation is
invariant (fixed pattern) & remains constant within a GMP
“Relative” meaning % or proportion of overall duration of
skill for each component of the skill
Relative timing example…
150 ms
What is Relative force?
Amount of force produced by muscles remains in
constant proportion from movement to movement
Invariant Feature #3
What is Order of events?
Order of events, components (or muscles, if using the same muscles) is invariant or fixed
Summary
- I’ve introduced the idea of a generalized motor program, which helps satisfy storage and novelty problems inherent in the idea of storage of individual motor programs for every possible action permutation.
- GMPs are defined by their relative invariance (invariant features), meaning they contain a basic template or signature of a movement which is then parameterized or tuned to fit the individual context and the desired outcome.
- These invariant features are relatively consistent across a range of variables. Invariance is in the form of the order of elements, relative timing and relative force.
- Overall Movement time
should be Relative Timing
What are Parameters?
Features supplied to the GMP that are flexible & define how to produce unique events
Can be modified from one performance to another allows for variations in the response “Adaptable”
What are the 3 Parameters proposed for GMP?
- Movement Time (absolute duration)
- Movement Amplitude (absolute force)
- Effectors (muscle-selection)
What is Movement time?
Total time to perform motor skill
Increased or decreased (e.g., normal, faster,
slower speed). Relative time does not change.
What is Movement amplitude
(absolute force)?
Total force produced by muscles can be changed when we make movements bigger or aim for farther distances
Ex. Total force produced by muscles can be changed when we make movements bigger or aim for farther distances
How can we increase movement amplitude?
Force is directly proportional to acceleration… so we can ↑ movement amplitude by uniformly increasing the forces/accelerations of muscles
How do Effectors (muscle selection) affect GMP
Same GMP can be executed by different limbs or muscles depending on context
How do we select the parameters?
Primarily this has to do with selecting the appropriate force amount
What is the selection of parameters based on?
Selection of the parameter is based on past/ stored
relations between parameters & outcomes -“schema”
Parameter Selection
Throwing a ball (this is our selected GMP):
We have a desired outcome, so need to select the parameter
What is a Schema?
relation between parameters & outcomes.
We may have many schemas for various conditions
Schema Example
An applied example of a GMP
Total Movement Time
Dominant vs. Non-Dominant - Muscle Selection
Relative Fore Production - Movement Amplitude
All Parameters
An applied example of a GMP
Relative Timing
