2 general categories of measuring motor performance
performance outcome measures
performance production measures
performance outcome measures
measures the result/outcome of a skill ex: distance thrown, speed, reaction time
performance production measures
inform us about how the nervous system, muscular system, and limbs are acting to produce the performance outcome ex: EEG, EMG, force, limb kinematics
types of performance outcome measures
-reaction time (RT) -movement time (MT) -response time
reaction time (RT)
indicates how long it takes to prepare and initiate movement
movement time (MT)
the interval of time between the initiation of a movement and the completion of the movement
response time
the time interval involving both reaction time and movement time; the time from the onset of a signal to the completion of a response -aka: RT + MT
types of reaction time
-simple reaction time -choice reaction time -discrimination reaction time -fractionated reaction time
simple reaction time
the reaction time that involves 1 signal/stimulus and 1 response
choice reaction time
the reaction time that involves more than one signal & each signal requires its own specified response
discrimination reaction time
the reaction time that involves more than one signal but only one response--which is to only one of the signals--the other signals require no response
reaction time related to movement and response time
-reaction time does NOT predict movement -movement time does NOT predict reaction time -RT and MT are SEPARATE motor abilities -when comparing individuals, they may have differing rates of both RT and MT
fractionated reaction time (FRT)
-requires the use of EMG to partition into 2 parts:
premotor time (PRMOT)
motor time (MOT) -allow researchers to identify if changes in movement RT are due to cognitive processes or mechanical features of the limb(s)
premotor time (PRMOT)
time that elapses between the presentation of a stimulus and the first change in EMG(muscle) activity
motor time (MOT)
begins with 1st change in EMG activity and ends when movement begins
error measures for 1 dimensional actions
absolute error constant error variable error
absolute error
a measure of error without regard to direction ex: distance from target
constant error
signed deviation from the target (biases) ex: directional biases (given + or - )
variable error
an error score that represents the variability of performance consistency -standard deviation of a series of constant error scores
error measures for 2 dimensional actions
radial error root-mean-squared error (RMSE)
radial error
use the pythagorean theory to solve
root-mean-squared error (RMSE)
-error measure for continuous skills -indicates the amount of error between the performance curve produced and the criterion performance curve for a specific amount of time -ex: tracking
kinematic measures
-kinematics: the description of motion without regard to force or mass; displacement
-displacement: describes changes in spatial location as a person carries out a movement
-velocity: rate of change in an object position with respect to time
-acceleration: change in velocity during movement
kinetic measures
-kinetics: force as the cause of motion -measuring tools: force plate, strain gauge
EMG
(electromyography) -measures electrical activity in muscles
EEG
(electroencephalography) -measures brain activity
PET
(position emission tomography) -used for measuring the concentration of positron-emitting radioisotopes within different body tissues
fMRI
(functional magnetic resonance imaging) -visualizes brain function through change in fluid flow (cerebrospinal fluid, blood)
lesions
remove portion of brain matter to see its effect on function (performed on lab animals or people with lesions already such as stroke victims)