Understanding Movement Preparation

Chapter 2

Overview

In chapter one we talked about the abilities (or ‘hardware’) that people bring with them to motor performance

In chapter two we address the processes (or software) people use when attempting skilled movements– If you will work with individuals with physical or

mental challenges, the performance problems are often caused by impairments in one or more of the processes

Information Processing Model

Input – Stim. ID - Resp. Select. – Resp. Program. - Output - Feedback 

Stimulus Identification Stage

Stage 1: Has a stimulus been presented and what is it?– Environmental information is analyzed through

senses– Performers categorize the information according to

patterns Types of objects, pattern of movement, colors

Response Selection Stage

Stage 2: What response, if any, should be made to the stimulus?– Based on the identification of the stimulus, the

performer translates the information to the possible forms of movement output to be made

A decision is made

Response Programming Stage

Stage 3: Let’s get ready to do something!– The motor system is organized for the production of

the desired movement Get the brain and spinal cord ready for movement, get a

plan of action to control the movement ready, send a plan to the muscles to contract in the proper order and with the proper amount of force and timing

The End Result

Output!– Execution of the movement determined to be

appropriate The execution can be successful or unsuccessful

– The next component of information processing is important to the next attempt to be made

Feedback!

As movement is initiated, intrinsic feedback can be used to make adjustments to the movement (if time permits)

Intrinsic and extrinsic feedback that occurs after the output occurs should influence the next attempt

What differences in processing demands might exist for open and closed skills?

Practical Application

Describe the information-processing activities that might occur through the three stages for a soccer goalie.

Describe the information-processing activities that might occur through the three stages for an individual who uses a walker and gets out of bed in the middle of the night to answer the phone in the kitchen.

Components of Response Time

 

Preparing a Response

Reaction Time (RT)– Interval of time between the moment that a stimulus is

presented to when a response is initiated. Is a good indicator of the speed and effectiveness of decision

making

Indicative of the amount of time needed to prepare a response.

Influenced by several factors.– Number of choices

– Strategies to create or reduce uncertainty to response

Factors that influence RT

Number of stimulus response alternatives

– Simple vs. choice RT

Hick’s Law

– Relationship between the number of movement choices and the time needed to prepare a response

– The higher the degree of uncertainty in a given situation, the longer the time needed to decide which response to make

In choice RT, RT is a measure of the time needed to detect the stimulus, decide which response to make, and initiate the movement

Relationship Between Number of Stimulus-Response Alternatives and RT

An Important Strategy

An important strategy that athletes use to slow down their opponent’s decision making is to increase the number of SR choices– Increase the number of different pitches– Increase the variety of spiking positions from a

setter– Increase the variety of serves in racquetball or

tennis

Stimulus Response Compatibility

The extent to which a stimulus and its required response are naturally related – Low SR compatibility = increased response time– High SR compatibility = decreased response time

Lo SR: showing a forehand stroke, but does forehand drop shot Hi SR: presentation of a red light, the foot puts on the brake

Practice and SR Compatibility

Amount of practice– The greater the amount of practice, the shorter the

choice RT Extreme amounts of practice, high level performers can

become almost automatic

Nature of practice– When the same SR combinations are practiced,

choice RT becomes faster

Dealing with decision-making delays

Anticipation!– The more predictable a stimulus, the quicker and

more accurately a response can be made

Related to reducing the number of response choices as possible options are narrowed down

Types of Anticipation

Spatial event anticipation

– Predicting what will happen in the environment

Temporal anticipation

– Predicting when an event will happen

Effective anticipation

Regularity of events affects our capability to predict

– Precues: warning signal or action given by a person to help us predict

‘telegraphing’ a movement

“always” done in a particular way

Costs of Anticipation

Cost/benefit tradeoff: 80% probability = decreased RT

If wrong prep, RT will be slower as you must ‘unprepare’ the movement

If wrong movement is initiated: even longer response delay– Must inhibit incorrect response, prepare the correct

response, and execute in the correct fashion

Psychological Refractory Period (PRP)

The Fake in Sports

For fakes to be effective they must:– Appear to be identical to the expected action– Precede the goal movement by 60-100ms– Be employed infrequently

Creating or reducing uncertainty

Having a large number of choices to perform will increase uncertainty in opponent

Facilitate skill learning by decreasing the number of alternate responses (start with a more closed skill environment)

With increased practice, performers can begin to approach automatic processing

When practice uses the same S-R combinations, choice RT becomes faster

Reducing response time

Successful performance may not always come by reducing movement prep time

– Slow responses may be the result of prolonged movement time

Increase movement speed Reduce length of movement (shorten backswing)

Alternate view: give more time to respond by increasing distance or changing to slower equipment

Attention: Processing Limitations

Limited attentional capacity

Drive a car

Sing a song

Drive a car

Sing a song Apply Make up

Performance is hindered orTask may be ignored

Attention: Processing Limitations

Bottleneck theory

– Stimuli that need a response are processed is serial fashion

– A bottleneck can occur if too much information must be processed; response time slows down

Attention: Processing Limitations

- Sometimes people will focus on external sensory events (another person’s movement),

– sometimes they focus on internal mental operations (what they need to do next),

– sometimes they focus on internal sensory info (how their body feels)

– Very difficult to focus on more than one of these sources at a time (pat head and rub stomach?)

Limited Attentional Capacity

Stand with dominant side next to the desk. Lift your non-dominant foot slightly off ground

and make a figure 8. Repeat continuously. Keep making the figure 8 with foot. Trace a

numeral ‘6’ on the desktop with your dominant hand index finger.

What happened when you attempted to perform the two tasks simultaneously?

– What does this say about attentional capacity?

Attention

Things to consider:

– Environmental and task complexity: as complexity increases, attentional space for additional tasks is reduced

– Skill level: Beginners have trouble focusing on more than one thing at a time; give sufficient practice before adding new tasks

– Number of cues: focus on one cue at a time

Practical Application

For a skill of your choice, explain how you might design the learning environment to reduce the attentional demands on the learner.

Attention

Selective attention: being able to focus on one specific stimuli even though there are lots of stimuli in the environment

– ‘tailgate party phenomenon’

We are able to focus on relevant stimuli and disregard irrelevant stimuli– Successful motor performance is dependent on

person’s ability to attend to meaningful information

Read the bold print

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Decision making and arousal

Arousal and anxiety are common aspects in daily situations– If one thinks the demands exceed his/her capability

to meet them, the situation becomes more threatening and anxiety is experienced

Level of arousal is an important determinant of performance especially if the situation requires fast and accurate decision-making

Arousal and nature of the task

A task requiring fine muscle control or important decision-making, prefer lower arousal level

Skills with large muscle actions or lower level of cognitive complexity, better performed at higher arousal level

Arousal: Inverted U Principle 

As a task increases incomplexity, lower arousal levels will be optimal.

Higher arousal levels are better fortasks that requirelittle attention or decision-making.

Cue Utilization Hypothesis

Under low arousal, attentionfocus is broad. Toomuch competition for attention resourcesmay result in slow movement response and hindered performance.

Over-arousal can narrow the focus too much, so the performer misses some relevant stimuli. Performance may be hindered.

Perceptual narrowing

Practical Application

From your own experience, generate a list of the following:– Irrelevant stimuli that might draw the attention of an

individual with low arousal and thereby affect overall performance.

– Professions that might find individuals susceptible to poor decision-making when perceptual narrowing occurs.