Transcript continued - Human Kinetics

Sensory Contributions to
Skilled Performance
Chapter 3
Objectives
Explain the contributions and limitations of
a closed-loop model of movement control
Understand the various ways that sensory
information is used in movement control
Discuss the various roles of vision in
movement control
Understand how sensory contributions to
movements are part of a conceptual
model of motor performance
Preview
How is a rugby player able to watch the
ball leave a teammate’s hand with a few
tenths of a second of viewing time and
realize she must turn her back on the ball
and cut sharply in one direction to catch
it?
She predicts the ball’s flight correctly,
visually focuses on it, times the ball’s
arrival into her hands, and compensates
for other external factors by grasping the
ball with two hands.
(continued)
Preview (continued)
How is so much accomplished in such
a short time?
How are corrections made during
skilled performance?
Overview
Processing vast amounts of information
quickly and accurately and making
effective adjustments as needed
Processes that allow performers to detect
patterns of information in the environment
and use the information to predict future
actions
The neuromuscular system, the
conceptual model of motor performance,
and principles of visual control as they
relate to movement
Exteroception
From the environment
Outside of the body
Highly visual
Proprioception
Information that comes from within
the body, largely from the muscles
and joints
Interoception:
From Inside the Body
Kinesthesis—Sensory information coming
from the motor system that signals
contractions and limb movements
Vestibular apparatus—located in inner
ear; information about balance, posture,
and orientation
Muscle spindle—located in skeletal
muscle; sends information about muscle
length to CNS
(continued)
Interoception: From Inside
the Body (continued)
Golgi tendon organs—located
between muscle and tendon; provide
information about force in the
muscles
Cutaneous receptors—located in
the skin; detect pressure,
temperature, and contact
Closed-Loop Control System
Involves the use of feedback and
error detection and correction
processes to maintain the desired
goal
Used to control slow and deliberate
movements
(continued)
Closed-Loop Control System
(continued)
Good for detecting slow movement
Not good for explaining rapid
movement
Does not account for discrete tasks
(continued)
Closed-Loop Control System
(continued)
Comparator—error detection
Executive—brain; determines
actions to take to reach goal
Effector—carries out decisions
Feedback—provides information on
current state
Open-Loop Control
Response selection and response
programming require considerable
time and attention.
In the closed-loop conceptual model,
corrections occur a few hundred
milliseconds after an error occurs.
The error signal is processed in the
stimulus-identification stage.
(continued)
Open-Loop Control
(continued)
A movement correction is chosen in
the response-selection stage.
Modifications to the movement are
organized and initiated in the
response-programming stage.
Compensations for Muscle
Movements
M1—monosynaptic
Most rapid, unconscious, one
synapse, little environmental impact,
inflexible
M2—polysynaptic
Longer muscle, adjusts more than
M1, higher-level function, knee-jerk,
sensory, can’t modify once begun
(continued)
Compensations for Muscle
Movements (continued)
Triggered reaction
Wineglass effect, learned, conscious,
cutaneous receptors
M3—voluntary reaction time
Voluntary; affected by instruction,
anticipation, and stimulus responses;
supported by Hick’s law
Visual Systems
Focal—Identifies objects in center of
visual field; is conscious and affected
by light
Ambient—Detects orientation of
body in environment; is
nonconscious and peripheral
Optical Flow
Detects movement of patterns of
light from the environment
Perceives motion, positions, timing,
stability, velocity, and direction
Vision
How does vision affect balance?
Visual dominance—visual
information dominates information
coming from the other senses
Visual capture—visual information
attracts a person’s attention more
easily than other forms of
information