Kin 203

What is a Skill?

The ability to bring about some end result with maximum certainty and minimum outlay of energy, or of time and energy.

Paul M. Fitts

The first person to question situations that require speed and accuracy (trade-off)

Franklin M. Henry

Shifted the science of sport-related skill from observational (descriptions) to experimental (measurable data)

What defines a skill?

1) Goal-oriented

2) Reproducible

3) Efficient

What do all skills involve?

1) Perception

2) Decision

3) Action

Open Skill

The environment is variable and unpredictable during the action (e.g open water swim)

Closed Skill

The environment is stable and predictable (e.g indoor archery)

Discrete Skill

Easily defined beginning and end, often a brief duration of movement (e.g one rep weight lift)

Continuous Skill

Has an arbitrary beginning and end, the movement flows for minutes or hours (e.g running laps)

Serial Skill

A group of discrete skills strung together to make up a new, more complicated skilled action. (e.g gymnastics routine)

Open Continuous

Setting with other people and environmental factors, movement lasts for minutes or hours (e.g open water swim)

Closed Continuous

Setting is stable and predictable, movement lasts for minutes or hours. (e.g running laps on a track)

Open Discrete

Setting with other people and environmental factors, movement with a clear beginning and end and is short duration (e.g shooting a 3-pointer in basketball while the game is in play)

Closed Discrete

Setting that is predictable and stable, movement with a clear beginning and end and is short duration (e.g serving a tennis ball)

How do we study skills?

Time (easy to measure)

Energy (difficult to measure)

Certainty

How to measure Discrete tasks?

Constant error

Absolute error

Variable error

Constant error

The signed difference of a score on a given trial compared to the target value; measures bias for that trial. aka. how far away it has missed its target on that trial.

[(∑Xi-T)/N]

Absolute error

The average absolute deviation of each of a set of scores from a target value; measures overall error. aka. tells you the magnitude of difference.

[(∑|Xi-T|)/N]

Variable error

The standard deviation of a set of scores about the subject’s own average (CE) score’ a measure of movement consistency. aka. how far off the trial score is from the average one they obtain

√[(∑Xi-CE)²/N]

How do we measure Continuous tasks?

Root Mean Square Error

Root Mean Square Error (RMSE)

The square root of the average of squared deviations of a set of values from a target value. (sensitive to large errors due to squaring, could cause an overestimate)

√∑Xi²/n

Stimulus identification (perception)

Sensory input is detected and identified.

Response selection (Decision)

Many alternate responses are generated and evaluated for selection before action.

Response programming (action)

Motor system is organized to produce movement aka. movement planning