Chapter 2- Methodology for Studying Motor Performance Flashcards
**
classifications of motor skills
-discrete
-serial
-closed
-open
why is it important to classify motor skills
for communication within the field of motor learning
motor behavior depends on ___
the type of skill being performed
can a motor behavior be more than 1 type of skill
yes
**
discrete
-has a recognizable beginning + end
-goal-directed
example of discrete skills
throwing, striking a match, shifting gears
-dart throwing: goal is to hit the center hole to get max points
-kicking a ball: goal is to kick ball into net
-striking a match: goal is to light stick on fire
-shifting gears: goal is to go from park to first gear
**
serial
-discrete actions strung together
-neither discrete nor continuous
examples of serial skills
-playing piano
-assembly-line tasks
-gymnastics routine
**
continuous
-has no recognizable beinning + end
-behavior continues until movement is arbitrarily stopped
examples of continuous skills
-swimming
-steering a car
-tracking
-running
**
closed
-environment predictable
-consistent environment
-performer can effectively plan entire movement
-target is displayed for entirety of the task
examples of closed skills
-bowling
-brushing teeth
-writing
**
open
-environment unpredictable
-constantly changing environment
-performer cannot effectively plan entire movement
examples of open skills
-returning a punt
-catching a butterfly
-wrestling
in between open + closed skills
environment semipredictable
-steering a car
-fielding a bouncing ball
-carrying a pan of water
**
3 important considerations for movement
-ojectivity
-reliability
-validity
**
objectivity
-public verification- verified by professionals in the field
-2 observers evaluating same performance arrive at same/similar measurement
-sensitivity of measuring device- objective movements in lab setting
example of objectivity
clearing the high jump bar indicates the capability of the athlete to jump at least that much
**
reliability
extent to which the measurement is repeatable under similar conditions
-reliability can also be evaluating correlations between variables (variable A to variable B); measure of stability of a test under different applications
-more trials = more stability of performance = improved reliability
what 3 things can lack of reliability result from
-random technological error (stretch of tape)
-intra-subject variability (attention, fatigue)
-changes in environment (lab studies tend to be more artificial than natural- this minimizes variability of environment)
**
validity
extent to which a test measures what the researcher intends to measure
construct validity
the extent to which the measures taken actually reflect the underlying construct of interest
Muybridge
-attempted to look at aerial phases of horses; used 12 cameras to prove that all 4 hooves of the horse left the ground at the same time
-contributed to motion pictures
**
kinematics
describes movements of limbs/entire bodies during movement; looks at angles of joints + time relationship between these (location, velocity, acceleration)
location (in kinematics)
-limbs during movement
-cinematography to record based on landmarks of body
-use location of limb in space to quantify variables
velocity (in kinematics)
-slope/derivative of position curve at each moment
-rate of change in position
-maximum velocity + time of occurrence
acceleration (in kinematics)
-slope/inclination of velocity curve at each moment
-rate of change in velocity
**
electromyography (EMG)
measures electrical activity of muscles (in mV)
various ways to measure EMG
-pairs of electrodes placed on surface of a muscle -> do contractions -> get outputs recorded through different devices on a computer screen
-high density electrodes: a pad of electrodes swabbed over the muscle
(lots of recording sites)
-there are also recording sites/electrodes we can put under the skin, over the muscle, or even into the muscle to measure EMG
which muscle shows positive deflections in EMG
agonist
which muscle shows negative deflections in EMG
antagonist
**
raw EMG
the EMG we get straight from the recording
**
rectified EMG
gets rid of negative deflections to make it all positive
**
linear envelope
envelope over the tops of waves for EMG
integrated EMG (I-EMG)
the area under the curve of the rectified EMG signal
what do we use to get EMG signals into each shape
filters
**
low pass filter
allow low frequencies to pass; gets rid of medium/fast ones
**
high pass filter
allow high frequencies to pass; gets rid of medium/slow ones
**
band pass filter
lets middle frequencies through; gets rid of slow/fast ones
**
Faraday cage
a formed enclosure made of conductive metal that reduces radio frequencies that interfere
-developed by Michael Faraday
-used in cars to stop cell signals from getting through that could cause car accident
**
electrooculography
measurement of eye muscle movements
**
saccades
rapid eye movement
**
occlusion methods
show how expert the subject is at a skill
-can be spatial or temporal
**
spatial occlusion methods
masking certain relevant/irrelevant parts of a display
**
temporal occlusion methods
used to stop a display at critical points during an action
**
electroencephalography (EEG)
recording of electrical changes that occur in brain as recorded from scalp
**
magnetoencephalography (MEG)
measures changes in magnetic fields involving brain activities
what do MEG + EEG provide
precise measures of mental event timing, but aren’t very good at localizing anatomic structures
neuroimaging techniques
-positron emission tomography (PET)
-single-photon emission computer tomography (SPECT)
-functional magnetic resonant imagine (FMRI)
-mangetic resonance imaging (MRI)
-diffusion tensor imaging (DTI)
-computerized axial tomography (CAT/CT scan)
**
positron emission tomography (PET)
-more detailed information about localization of brain structure + activity using positron-emitting isotope for clearer imaging
-patient is injected with radio-active substance which emits positrons that collide with tissue + emit
-shows cerebral blood flow/most active areas of brain
positron emission tomography (PET) is functional or structural neuroimagine
functional
**
single-photon emission computer tomography (SPECT)
gamma ray-emitting isotope for less clear but cheaper imaging
PET or SPECT is clearer? which is more expensive?
PET is clearer + more expensive
**
functional magnetic resonance imagine (FMRI)
-when specific part of brain is active in processing information, neural activity increases + thus oxygenated blood increases
-uses magnetic field + radiofrequency energy
-blood oxygen level dependent (BOLD) signal in 3D; uses different responses of oxygenated/unoxygenated blood to detect changes in blood flow; shows most active areas
-location + volume of active brain regions
functional magnetic resonance imaging (FMRI) is functional or structural neuroimaging
functional
**
magnetic resonance imaging (MRI)
-high-resolution structural scan that uses magnetic fields + radiofrequency energy
-hydrogen atoms respond by emitting energy, which is then used to construct an image
MRI is functional or structural neuroimagine
structural
CAT scan or MRI has better resolution
MRI
what is MRI typically used in combination with
FMRI
**
diffusion tensor imaging (DTI)
characterizes structural integrity + microstructural characteristics of key tracts + pathways
-we can use DTI to trace where the corticospinal tract is, which is useful in studying the relationship between the brain + behavior in pathological conditions that affect the CNS or neuromuscular system
**
computerized axial tomography (CAT/CT scan)
series of x-ray images of the head which are used to construct an overall image of the brain
-relatively low in resolution
-shows major structural problems like tumors
CAT/CT scan is high/low in resolution
low
CAT/CT scan is functional or structural neuroimagine
structural
**
transcranial magnetic stimulation (TMS)
-not a method to measure but rather STUDY brain function
-brief pulse sent via magnetic coil, temporarily affecting region of brain above where coil is positions
-excitatory/inhibitory
-often combined with FMRI to evaluate effects of stimulation on both behavioral + brain responses
**
target scoring
the way we describe the outcome of a movement
i.e. did I actually hit my target? was I “x” amount away from my target?
**
4 ways target scoring is assessed
-error
-time + speed
-movement magnitude
-performance on secondary tasks
**
error
target scoring
-performances may require the participant to perform an action with maximum accuracy
-performance measures represent the degree to which the target was not achieved- a measure of error
**
5 methods for combining scores into measures of error
target scoring
-constant error (CE)
-variable error (VE)
-total variability (E)
-absolute error (AE)
-absolute constant error (|CE|)
**
constant error (CE)
-measures average error in responding
-gives us the amount + direction of derivation relative to the target
-average error bias
-ex: how many inches away from bullseye was I? + in what direction?
2 issues of constant error (CE)
-the average value can be different/smaller than any of the individual values
-it doesn’t consider the variability of the responses
**
variable error (VE)
measures the inconsistency/variability in movement outcome
-ex: if all outcomes are consistent in landing at the bottom of the target, they are not necessarily accurate in hitting the bullseye
1 issue with variable error (VE)
it doesn’t consider the accuracy of the responses
**
if given a bullseye with a lot of variability scattered around the target, this is constant error (CE) or variable error (VE)
variable error
**
if given a bullseye with all the bullets in the same place but far away from the target, this is constant error (CE) or variable error (VE)
constant error
**
who is better to train- someone with constant error (CE) or variable error (VE)
constant error; they just need to make an adjustment to be more accurate
**
total variability (E)
-root mean square error
-measures overall error
-indicates total amount of spread of the movement around the target
-overall measure of success in achieving the target
**
what makes up total variability (E)
E = CE + VE
1 issue with total variability (E)
when CE is different from the target, E will represent the combination of this error in bias plus variability about CE
describe the graph for total variability (E)
the one shown in class where there was variability above and below the genreal line
**
issues with reporting data as total variability (E)
-wecould have some issues with how we report this data- average could look really good but in reality there is variability
-SO, we must be transparent in the way we report error
**
absolute error (AE)
measures the average error in responding (overall accuracy in performance, average absolute deviation) between movement + target
-used by most early researchers (today we use E to present accuracy + variability)
1 issue with absolute error (AE)
the mathematical properties that can explain the bias + variability of responses to the error aren’t straightforward
**
absolute constant error (|CE|)
-a transformation of CE
-measures the average error in responding
1 issue with absolute constant error (|CE|)
the sign is taken away from the average of responses; not for each individual trial
**
time and speed
target scoring
-assumption: the performer who can accomplish more in a set time/can produce a bgiven amount of action in less time = skillful
-measure of time is reduced with practice but at the cost of quality in movement/accuracy (just because you can do something faster, doesn’t mean better; more prone to make mistakes)
2 methods for measuring time + speed
-reaction time (RT)
-movement time (MT)
**
sum of RT + MT
RT + MT = response time
**
reaction time
a measure of the time from arrival of a sudden, unanticipated signal to the beginning of the response to it
how is reaction time useful to research motor skills
-measures are components of real life tasks, so high face validity
-measures time for mental events (stimulus processing, decision making, movement programming)
**
movement time
the interval from the initiation of response to the completion of the movement
-high external validity in practical settings
**
movement magnitude
target scoring
-magnitude/size of behavior produced (i.e. distance discus is thrown or amount of weight lifted)
-movement magnitude is not just maximal force production- requires precise timing of forceful contractions + accurate coordination of core + participating limbs
what experiment references movement magnitude
Wulf’s ski setup
Wulf’s ski setup
-task: subject must thrust their hips/body in different directions very ballistically with fast, explosive force
-measures how far subject can thrust to move their body from 1 location to another on the ski simulator
-if they can thrust hips back + forth- they are successful; doesn’t necessarily mean they are thrusting at max capacity
**
performance on secondary tasks
target scoring
-no basic methods of measurement will be sensitive to skill differences among individuals, or to differences in skill caused by an independent variable
-sometimes the 2 subjects you are comparing are equally good at doing something; or sometimes the task is too easy where the chances of making a mistake are very low
-we can add different variables to indicate how well someone is at the primary task
-involves tasks for which differences in performance aren’t evident; use statistics/measures of skills during critical events or evaluate secondary tasks that will co-occur with the primary task- to measure the primary task
-mathematics during different conditions of driving
-reaction time tasks to evaluate limited capacity to process information
-physiological measures of effort- pupil diameter, heart rate + variability
