Week 2.1: Analysis of Motor Performance Flashcards
Definition of a Motor Skill (Guthrie, 1952) vs. General Definition
“The ability to bring about some end result with maximum certainty and minimum outlay of energy, or of time and energy”
Task with specific goal, performed voluntarily, requiring body and/or limb movement that needs to be learned
-Are all movements motor skills??
No
-Reflexes are not (are not learned) ex. blinking, breathing, monosynaptic
Discrete vs. Continuous vs. Serial Skills
Discrete= Clear start and end (e.g., throwing a ball).
Continuous= No defined end (e.g., running, swimming).
Serial= Discrete actions strung together (e.g. playing piano, assembly line tasks, gymnastics routine)
Open vs. Closed Skills
Open= Unpredictable environment (e.g., soccer).
Closed= Predictable environment (e.g., darts).
Fine vs. Gross
Fine= small muscle groups
Gross= large muscle groups
Measuring Motor Performance- 3 Considerations
-Measuring changes in motor performance critical for evaluations and helps gauge amount of learning
-3 considerations:
1. Objectivity
2. Reliability
3. Validity
Why categorize motor skills?
To apply research findings and identify task-specific principles
Objectivity
Likelihood that two people or tools would come up with the same measure of performance. Highly dependent on the tool you use to measure
Reliability
How likely is it that the same tool will come up with the same measurement twice. Interaction between the tool
Validity
How well do these measurements in the lab translate to performance if the environment is changed (open vs closed) are the measures of performance actually valid?
How would you classify the skills used in motor learning and control research?
Discrete, closed and fine
Assessing Motor Performance- How far away is arrow from target?
Constant error- how far the arrow is away from the target on a single trial
-Target and performance must be measurable values
-Indicated the magnitude of the error
-Can be computed in more than on axis
-Sign gives direction of the error
Constant Error
*The amount and direction of bias away from the target
-Useful for providing feedback about tendencies or bias
-Limitation:
-Errors can cancel out
-If they make a large error to one direction but 4/5 are in the other direction it can be biases through the magnitude of error and can give someone a false idea of their error
-Overcome by taking more trials so impact of any one trial is decreased and feedback giving to the participant is more representative
Variable Error
*The variability in the movement outcome about the mean value
VE= /[(X-M)^2/n
-Square root of the sum of X-average performance, squared, divided by the
number of trials
-Does not care about where the target is just how consistent they are
-First summing the differences between the performance score and the person’s own mean
-Reflects the participant’s variability or consistency
Constant vs. Variable Error
CE= measures bias (accuracy)
VE= measures consistency (precision)
Total Variability
*Measure of overall error
-also known as RMSE (root mean square error)
-sum of the squared differences between the achieved position and the goal position
-similar to variable error with a reference to the target position (measures consistency around target values)
E^2 = VE^2 + CE^2
E= /[(x-T)^2/n
