Transcript travel time from sensory receptors to motor cortex

Motor Performance in Adults
© Gallahue, D.L., Ozmun, J.C., & Goodway, J.D. (2012). Understanding Motor
Development. Boston: McGraw-Hill.
McGraw-Hill/Irwin
© 2012 McGraw-Hill Companies. All Rights Reserved.
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
19-2
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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.)
19-3
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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)
19-4
- 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)
19-5
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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”
19-6
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Men (active older men have RT like nonactive young men)
Women (stronger older women have better
RT than weaker older women)
Physical activity (for many reasons positively
affects RT in older adults)
19-7
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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)
19-8
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Balance recovery decrements
- Slower muscle activation
- Additional muscle group activation
- Sequence reversal in muscle group
activation
- Simultaneous agonist/antagonist muscle
group activation
Visual & vestibular decrements
19-9
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Make environmental changes (surface area,
lighting)
Increase physical activity (improve leg
strength, increase joint flexibility, use
multiple sensory approach)
19-10
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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)
19-11
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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
19-12
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Segmental approach to getting out of chair or
bed
Make environmental modifications (ht of
objects, assistive devices, garments, lighting)
Increase community awareness & support
(crosswalks, benches, public restrooms)
19-13
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Automobile driving issues
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Elite Performance
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Visual functioning
Reaction time
Loss of independence
Master athletes (Table 19.4)
Assessment
Senior Fitness Test Manual
 Various scales of ADL
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19-14
A Physically Active Lifestyle Throughout
Adulthood Can Contribute Significantly to
the Slowing and Lessening of Decrements in
Motor Performance
19-15