6 Motor Performance Measurement

What is a performance outcome measure?

• A category of motor skill performance measurements that indicates the outcome or result of performance a motor skill

• How far? How fast? How long? How much error?

What is a performance production measure?

• A category of motor skill performance meause tha indicates perfomance of a specific aspect of motor control skills

• Kinematics, EEG, EMG, velocity, brain activity

What is the difference between kinematic and kinetic measures

• Kinematics: Displacement (position), velocity (speed), Acceleration (change in velocity), linear or angular

• Kinetics: internal and external forces, joint torque for the effect of force on rotation

What is EMG and what does it measure?

• Electromyography

• muscle activity

• bipolar

• use of 2 electrodes (bi)

What are some brain activity measures?

• EEG: measures electrical activity from the brain

• MRI: neuroimaging that uses magnetic fields to create images of brain structure

• MEG: detects brain activity through magnetic fields generated by neuronal activity

• TMS: uses magnetic fields to stimulate brain regions, producing neural activity.

• Product measure

What are teh 2 performance outcome measures?

Space and Time

Space

• Distance (throwing discus, long jump)

• Endpoint Accuracy (throwing a dart or horseshoe)

• Trajectory Accuracy (handwriting, balance beam)

Time

• Reaction Time (RT)

• Movement Time (MT)

• Response Time (RT+MT)

• Temporal Accuracy

Reaction Time (RT)

From onset of stimulus to onset of moment

Types of Reaction Time

• Simple RT- no choice

A sprinter in track at the beginning of a race

• Choice RT- 2 or more choices

Driving a car and coming to a stoplight

• Discrimination RT - go or no go

Avoiding an object when running

Movement Time (MT)

From onset of movement to completion of movement

Premotor and motor times is derived from

EMG

Premotor time

• Is the period of time between the onset of the “go” signal and the beginning of muscle activity

• consider an indicator of decision-making activity

Motor time

• Is the period of time from the increase in muscle activity until the beginning of observable movement

• Needed to overcome the inertia of the limb after the command

Error (measure of accuracy - spatial/temporal)

• provides a way to evaluate consistency and bias

• Consistency problems indicate a lack in acquiring the movement pattern

• Bias problems indicate difficulty in adaptation

One dimension movement

• Constant Error (CE)

• Absolute Error (AE)

• Variable Error (VE)

Constant Error (CE)

Measures bias (overshoot or undershoot)

Absolute Error (AE)

Measures magnitude (average distance from the target)

Variable Error (VE)

Scatter (how spread out misses are)

High CE vs Low CE

High AE vs Low AE

High VE vs Low VE

What are the types of error for two dimensional movements and for continuous skill?

• Radial Error (RE)

• Hypotenuse of right circle

• straight line distance

Continuous skills

• Root mean square error (RMSE)

• error in a pathway