122 Kinesiology Final - Motor Skills

4 characteristics of a motor skill

• there is a goal to achieve. (action has a purpose)

• performed voluntarily. (reflexes are not motor skills, trained reaction are)

• body and/or limb movement. (math - cognitive skill, hitting a gold ball - motor skill)

• need to be learned.

2 ways to measure motor performance

• performance outcome measures.

Measures the outcome or result of performing a motor skill.

A limitation is that this doesn’t tell you anything about how that outcome was achieved.

Ex. reaction time, movement time, amount of error.

• performance process measures.

Measures how aspects of the motor control system are functioning during the performance of an action.

Ex. muscles used, joint angles, nervous system activity.

Kinematics, kinetics, electromyography, coordination.

Motor skills can be classified on a continuum.

Reaction time

The time interval between the presentation of a signal and the initiation of a movement. Performance outcome measure.

Ex. the time between a starters gun and the initial force on the starting blocks in sprinting.

3 types of reaction time

• simple RT - one signal, one response

• choice RT - more than one signal, each with its own response

• discrimination RT - more than one signal, one response

2 parts to reaction time

• pre-motor time (PRMOT)

Time between the signal and the first change in EMG (electromyography) activity in the muscle. Represents time to: receive and interpret the signal, develop an action plan, and convey the information to muscles.

• motor time (MOT)

Time between first muscle EMG activity and observable movement.

Movement time (MT)

The time interval between the start of a movement and its completion.

How long it actually takes for the movement to occur.

Performance errors

Used to determine whether or not the goal of the movement was achieved.

3 types of performance errors

• absolute error (AE) - estimate the overall size of the error

• constant error (CE) - provides information on overall direction of error

• variable error (VE) - the standard deviation of performance

Kinematics

Motion qualities without regard to force.

3 types of kinematics

• displacement - change in position

• velocity - displacement per time

• acceleration - rate of change in velocity

Kinetics

Various internal and external forces acting on the body.

Electromyography (EMG)

Electrical activity in the muscle.

Coordination

Spatial and temporal relationships of limb segments.

3 one-dimensional systems of motor skill classification

• size of musculature

• distinctiveness of the movements

• stability of environment

Skills exist on a continuum.

Size of musculature

Precision of movement.

• gross motor skills

Involves large muscles, and precision of movement is not that important.

Smooth coordination of muscles is essential.

• fine motor skills

Require control of small muscles to achieve a goal.

Usually involve a high degree of precision of movement and hand-eye coordination.

Distinctiveness of movement

Defining the beginning and endpoints of movement.

• discrete motor skills - clearly defined beginning and end points

• serial motor skills - a series of discrete motor skills performed in a specific order

• continuous motor skills - no obvious beginning and end points

What stops a continuous motor skill

External forces determine the beginning and endpoints of the skill, rather than the skill itself.

• finish line

• stop light

• opponent

• fatigue

Stability of environment

• closed motor skills

Performed in a stable and predictable environment.

Self-paced, the object waits to be acted on by the performer.

• open motor skills

Performed in an ever-changing, unpredictable environment.

An externally-paced task, the performer needs to react to the environment.