SHMD219 HUMAN MOVEMENT
STUDIES
Producing Actions
TIME FACTORS THAT INFLUENCE
PRODUCING ACTIONS
Time Factors that Influence Producing Actions
• The brain strives to become efficient and
effective in perceiving movement situations and
producing actions.
• Three timing factors have an influence on
information processing.
1. The time needed to process information
2. The potential for a psychological refractory
period or delay in the time for processing
information.
3. The cognitive capacity to anticipate what will
happen in a movement situation.
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1.Time as a Feature of Information Processing
• So many skills involved in games require that
you time your actions correctly.
• There are several variables that affect the
timing of movement performance, these
include;
a) Reaction Time
b) Movement Time
c) Internal and External timing considerations.
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1.Time as a Feature of Information Processing
Reaction Time
1.Choice reaction time- the more choices the longer the processing
time. It is slower because of the time it takes to process
alternatives.
2.Complexity of the response-the more complex the movement
patterns the longer time it will take to organize the programs,
schemas and motor commands you need to activate the muscles.
3.The duration of the response- the amount of time it will take to
perform the movement influences the amount of time required to
organise the relationship of the programme-schema-command.
4.Type of stimulus-your reaction to kinaesthetic stimuli is the fastest
-your reaction to auditory stimuli will be faster by about 50
milliseconds than your reaction to visual stimuli.
- reaction to tactile stimuli is somewhere in between auditory and
visual stimuli
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1.Time as a Feature of Information Processing
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Movement Time
It is the amount of time it takes you to complete
the movement pattern.
It is measured from the first sign of action until
completion of the action.
Your reaction time + your movement time =
your response time.
If a movement is to be performed slowly
reaction time will be slower than when it has to
be performed quickly.
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1.Time as a Feature of Information Processing
Internal timing
• Defined as the coordination among the various
body parts during the performance of a
movement.
• When performing closed skills (skills performed
in relatively stable and unchanging
environments) you focus on your form.
• E.g. The coordination need in the high jumpeach of the body parts must move in a very
precise relationship to each other.
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1.Time as a Feature of Information Processing
External Timing
• It is the coordination of your movement patterns to the
dynamics of your environment.
• The natural dimensions of the environment such as the
size of the court.
• The artificial dimensions of the environment such as
the weight of the piece of the equipment.
• The human dimensions of the environment such as the
opponent’s style of defence.
• External timing is critical to success to in performing
open skills
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2. The Psychological Refractory Period
• In many movement situations there is continuous
change.
• This is called a dynamic environment.
• This means your are continuously perceiving and
your are continuously producing actions.
• Your system has a limit on how much information it
can process and how quickly.
• This limit is evident when you experience a delay in
how quickly you can respond to two closely placed
stimuli, and
• How quickly you can produce two separate actions.
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2. The Psychological Refractory Period
(PRP)
• It both cases the delay is described as the
psychological refractory period.
• Which is the delay in your system’s capacity to
process separate pieces of information.
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2. The Psychological Refractory Period
Delays in Responding to stimulus
• You can experience a delay in your ability to
respond in a situation when two stimuli are
presented closely together.
• For example: in basketball when an opponent is
dribbling the ball toward you, then fakes a move
to the left before going to the right,
• There is an amount of time between the fake
and the following action that is called the Inter
stimulus interval (ISI).
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2. The Psychological Refractory Period
Delays in Responding to stimulus
Interstimulus interval (ISI).
• If the ISI is long enough, you will have no
difficulty in responding to the first one and
second one successfully.
• If this interval is “just right” you will
experience a delay in processing the second
stimulus, which means you will not be able to
perform a response to it at the correct time
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2. The Psychological Refractory Period
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Delays in Responding to stimulus
Interstimulus interval (ISI).
You brain can only organise and initiate one action at a time.
You literally must wait until the first response is completed.
That is you cant plan a second response before you finish
planning and programming the first response.
You can see your opponent going to the right, but you can not
do anything about it immediately .
You are “stuck” moving in the direction of the fake and must
wait until your system clears that move before planning and
executing another move.
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2. The Psychological Refractory Period
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Delays in Producing Actions
You can not perform 2 separate actions at the same time.
When a motor programme plus a schema is joined with a
motor command and that command is issued ,it can be
regarded as a “chunk” or a burst of activity that exclusively
occupies several hundred milliseconds until the next one
can be generated.
This means that although information is provided
continuously, responses are generated in units.
When teaching complex skills they have to be taught in
parts.
If you want to teach a child to catch a ball while running,
she will run, then stop to try and catch the ball, then run
again: three separate actions separated by the
psychological refractory period.
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2. The Psychological Refractory Period
Delays in Producing Actions (cont…)
• But if you first make sure she knows how to
catch, then slow down the run and the speed
of the ball as it comes to her,
• You will find that the child’s system begins to
chunk running and catching into a combined
motor programme with a single schema that
can be processed as a single action.
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3.Anticipation
• One of the most effective ways of dealing with
delays in planning and programming movements
is through the process of anticipation.
• Anticipation is your ability to predict an event,
which means you can prepare for it by processing
information in advance.
• There are two types of anticipation:
a) Event anticipation (what will happen)
b) Temporal anticipation (when will it happen)
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3.Anticipation
Event Anticipation
• Your cognitive understanding of a situation is the foundation of your
ability to anticipate events.
• Based on your perception of selected spatial cues you may be able to
deduce what will happen next in the situation.
• Elite athletes spend time studying their opponents.
• They are building their knowledge about their opponents’
preferences and habits, so they will be able to predict what the
actions their opponents will take in different kinds of situations.
• Once the situation has been anticipated, the necessary program,
schema and schema can be assembled.
• This means that once the predicted stimuli occurs, all that is left is the
activation of the command.
• This is referred to as pre-programming movements.
• Activating a pre-programmed movement requires a fraction
of the time needed for the full processing of a response to
unanticipated stimuli.
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3.Anticipation (cont..)
Temporal Anticipation
• It works together with event anticipation.
• If you can predict when something will occur,
you can often get into position to execute your
pre-programmed response.
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3.Anticipation (cont..)
Cost of Anticipation
• Anticipation is an advantage because it helps
reduce the amount of time it takes you to
respond to a situation.
• It can be a disadvantage if you make a
mistake
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