Transcript Chapter 20 - McGraw Hill Higher Education

Chapter 20
Motor Performance in Adults
© Gallahue, D.L., & Ozmun, J.C.. Understanding Motor Development.
McGraw-Hill
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Key Concept
An Adult’s Motor Performance
Depends on the Interaction of a Wide
Variety of Variables, Some of Which
Can Be Manipulated With Ease While
Others Are Resistant to Change
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Factors Affecting Adult
Motor Performance
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State of individual physiological systems
(musculoskeletal system, CNS, sensory
systems, circulatory/respiratory systems)
Specific environmental conditions (light,
temperature, contact surface, etc.)
Specific task demands (speed, accuracy,
strength, endurance, flexibility etc.)
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Reaction Time (Figure 20.1)
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Reaction time (RT): the time delay from
the initial stimulus to start of the initial
movement response
RT’s Fractionated components
- Reception time (travel time from
external stimuli to sensory
receptors)
- Integration time (travel time from
sensory receptors to motor cortex)
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Reaction Time (cont.)
- Motor overflow time (travel
time from motor cortex to first
electrical activity in the
muscles
- Motor time: (travel time from
first electrical activity to
actual initiation of movement)
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Variations in RT
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Changes under different conditions
- Using multiple response choices
- Using varying sensory system
- Changing stimulus intensities
Age influences
- Peaks in early to mid-20’s
- Regresses gradually with age
- Practice & familiarity minimizes age
differences
- “Speed-accuracy trade-off”
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Aging, Physical Activity
and RT
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Men (active older men have RT like
non-active young men)
Women (stronger older women
have better RT than weaker older
women)
Physical activity (for many reasons
positively affects RT in older
adults)
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Mechanisms of Balance
and Postural Control
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Postural muscle response synergies (the
timing & sequence of muscle activation)
Sensory systems (use of visual, auditory,
prospective cues)
Adaptive systems (modifications based on
sensory input & motor output)
Muscular strength (ankles, knees, hip)
Joint flexibility (range of motion)
Body morphology (biomechanical influences
of ht, wt, leg & foot length, center of mass)
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Aging, Balance and
Postural Control
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Balance recovery decrements
-
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Slower muscle activation
Additional muscle group activation
Sequence reversal in muscle group
activation
Simultaneous agonist/antagonist
muscle group activation
Visual & vestibular decrements
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Improving Balance and
Postural Control
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Make environmental changes
(surface area, lighting)
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Increase physical activity (improve
leg strength, increase joint
flexibility, use multiple sensory
approach)
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Falls (Table 20.1)
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Falls occur in 30% >65 years old
20-30% suffer moderate to severe
injuries (hip fractures & head
traumas)
Increase in fear & depression
Why do they occur? (physiological
factors, environmental factors,
task requirement factors)
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Aging and Gait Changes
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Swing phase changes
Support phase changes
Period of double support changes
Stride length changes
Toe-floor clearance changes
Speed changes
Possible pathological changes
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Aging and Activities of
Daily Living
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Perform some tasks segmentally
Make environmental modifications
(ht of objects, assistive devices,
garments, lighting)
Increase community awareness &
support (crosswalks, benches,
public restrooms)
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Aging and Physical Activity
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Learning new skills (table 20.2)
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Emphasize active rather than passive
learning
Focus on procedures not just
concepts
Provide for extended practice time
Growing old isn’t for sissies
-
Competition can be good
Master athletes (table 20.3)
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Concluding Concept
A Physically Active Lifestyle
Throughout Adulthood Can
Contribute Significantly to the
Slowing and Lessening of
Decrements in Motor Performance
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