Week 2 Flashcards
motor skill definition by guthrie, 1952
the ability to bring about some end result with maximum certainty and minimum outlay of energy, or of time and energy
general definition of a motor skill
task with a specific goal, performed voluntarily, requiring body and/or limb movement
- needs to be learned
are all movements motor skills?
no, reflexes are not motor skills
ex. blinking and breathing are not motor skills
components of a motor skill
- perceiving relevant environmental features (defining goal positions and outcomes)
- deciding what to do and the timing of the action (planning and programming how to achieve goal)
- producing the muscular activity required to generate the movement goal (sending commands and adjusting commands as needed)
classification of skills
motor skills are classified on a continuum
3 continuums of motor skills
- discrete vs. continuous
- open vs. closed
- fine vs. gross
discrete skill
start and end point are clear and recognizable
examples of discrete skills
- penalty shot in soccer
- free throw in basketball
- shifting gears
serial movement
set of discrete movements strung together
- skills in between have a clear start and end
example of serial movement
- gymnastics routine
- playing piano
- assembly-line tasks
continuous movement
- repetitive for longer period of time
- no clear start and end
example of continuous movement
- running
- walking
- swimming
open skills
unpredictable environment
examples of open skills
- football
- catching a butterfly
- wrestling
closed skills
environment is predictable
examples of closed skills
- bowling
- archery
- darts
- writing
- brushing teeth
between open and closed skills
semipredictable environment
examples of semipredictable environment
- steering a car
- fielding a bouncing ball
- carrying a pan of water
what traits define success in an open skill?
adaptibility
what traits define success in a closed skill?
planning and programming
fine motor skill
smaller muscle groups
gross motor skill
bigger muscle groups
gross and fine motor skills
classified depending on type of musculature used for the skill performance
where are finer skills often used?
in the laboratory settings because of space and measurement tools
measuring motor performance
critical for evaluations and helps us gauge the amount of learning
3 considerations when measuring motor performance
- objectivity
- reliability
- validity
objectivity
likelihood that 2 individuals/tools could come up with the same measurement of performance
- highly dependent on tools used
reliability
interaction between tool and measure should be as reliable as possible
validity
how well do these measurements translate to perform if we change the environment
ex. closed to open
tools used in motor learning and control research?
sensorimotor exploration laboratory
what are some ways we assess motor performance (archery or darts)?
assess accuracy as a measure of how far they are from target
how can we measure how far the arrow is from the target?
target and performance must be measurable values
constant error
indicates the magnitude of the error
- can be computed in more than one axis
- sign gives the direction of the error (over, under, left and right)
mean constant error (CE)
average error in the response
CE = sum (x - T)/n (number of trials)
what to do with CE if the target is 0
just average of trials
what is constant error useful for providing feedback about?
tendencies or bias
- give people direction about their bias
what are the limitations of constant error?
- errors can cancel out if someone is positive, negative, positive, negative
- can be biased by magnitude of error
variable error
reflects the participants variability or consistency
- does NOT depend on whether the performer was close to the target (not concerned with target position)
how is variable error computed?
by first summing the differences between the performance score and the persons own mean
what does constant error measure?
accuracy
what does variable error measure?
precision/consistency
which athlete would you rather have- consistency or accuracy?
more consistency/precision over accuracy
total variability
measure of overall error
- also known as Root Mean Square Error (RMSE)
RMSE
sum of the squared differences between the achieved position and goal position
- similar to VE with reference to target position
which error is the best measure of player performance?
variable error
when the CE is close to zero, what is the relationship between the total variability and VE?
they’re equal, or they become more similar as constant error decreases
total variability
accounts for the bias and variability
absolute error (AE)
absolute deviation between the performers movements and the target
- used a lot in early research
AE
- complex mathematical relationship between CE and VE
- not as clear as total variability (E)
absolute constant error (ICEI)
transformation of CE
- just removing the sign of CE
- sign is taken away after the averaging and computation is completed
when would absolute CE be useful?
- when using a target
- stops things from cancelling out (bias)
- gets rid of bias when summarizing a group
measuring performance in a continuous task
can compute the difference between performed trajectory and target trajectory
- and RMSE to measure deviation over a sampling variable (usually time)
common sampling variable
time
RMSE equation
square root of the average of ideal-actual meaasure squared over number of trials subtract 1
movement characteristics - biomechanics
biomechanics and rehabilitation is ofter concerned with the quality of movement
what does movement characteristics - biomechanics examine
- loading
- muscle activation patterns
- joint reaction forces
purpose of movement characteristics - biomechanics
- preventing injury
- making movements more efficient
movement characteristics - motor control
motor control and learning if often concerned with error and performance
what does movement characteristics - motor control examine
endpoint variables and strategies (kinematics)
- examines if you can do test or not, don’t care about quality
how can movements be characterized?
by looking at kinematics
kinematics
concerned with motion rather than the forces that created that motion
kinematic markers
can be used to describe movements
- position information (where limb is in place)
- velocity information (rate of change of position)
- acceleration (rate of change of velocity)
temporal and temporal-kinematic variables
also used to describe movement
- reaction time
- movement time
- time to/after kinematic markers
why are kinematics useful?
- give a researcher/teacher/coach detailed information about current performance and improvements in actions
- can provide detailed and understandable feedback to participants
- neuronal firing patterns reflect direction and speed of upcoming actions
kinematics in the brain
neuronal firing patterns in motor related areas in the brain predict the kinematics of movements
- posterior parietal cortex
- motor cortex
reaction time
measure of the time from arrival of a stimulus to the beginning of the response
- stimulus is UNANTICIPATED
what was reaction time traditionally used for?
used as a proxy for cognitive function
what are some ways we can control for anticipation?
- vary the time the stimulus is presented so you can’t expect the time the signal will start
- go and stop stimulus
- make stimulus ambiguous
2 components of reaction time
- premotor RT
- motor RT
premotor RT
occurs when no muscle activity when stimulus is presented
motor RT
muscle activity but response hasn’t overtly begun
- no movement yet
movement time
time interval from the initiation of the response to the completion of the movement
- precision of units depend on the skill
response time
RT + MT
what different processes may be studied using RT and MT?
- processes to initiate a movement
- processes to complete a movement
***different processes may underlie correcting a movement as well - changes MT
movement measuring devices
- KINARM
- markerless capture
- markered motion capture
what relationship are we often concerned with?
relationship between movement characteristics and performance
correlations
measures both direction and strength of a relationship
correlation coefficient (R)
- number indicates- increased R = strong relationship
- sign indicates- direction
R2
measures the shared variance (can convert to a percentage by multiplying by 100)
regression
allows to predict one variable from another
simple regression
fit a linear model to data that we have collected
does correlation always = causation?
NO
what is an indirect way of measuring capability in a motor task?
measuring performance on a dual cognitive task
dual cognitive task
- attention is a limited capacity resource
- the less attention a task takes, the more the performer has mastered it
dual cognitive task study results
- experimental group improves in all basketball-related tests compared to the control group
- no differences in ERP data
- suggests very little underlying changes
limitations to dual cognitive study
experimental group has more exposure than control group
- could influence performance
is there any real scientific basis for these new cognitive-motor performance sports training devices?
there could be, but not necessarily for sport performance
