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Postural muscle onset and voluntary movement in the elderly
G E Stelmach1, L Populin, F Müller
1Motor Behavior Laboratory, University of Wisconsin-Madison 53706.
Neuroscience Letters
|September 4, 1990
Summary
Elderly individuals exhibit slower choice reaction times and potentially impaired postural systems, affecting movement initiation. This age-related difference in reaction time is more pronounced when standing and performing complex tasks.
Area of Science:
- Human movement science
- Gerontology
- Neuroscience
Background:
- Age-related changes in motor control and reaction time are significant.
- Postural stability is crucial for initiating voluntary movements, especially in older adults.
Purpose of the Study:
- To investigate age-related differences in reaction time (RT) during arm movements.
- To examine the influence of posture (sitting vs. standing) and task complexity (simple vs. choice reaction) on RT.
- To assess the role of postural muscle activation in age-related motor control deficits.
Main Methods:
- Young and elderly participants performed push and pull arm movements.
- Tasks included simple reaction (SR) and choice reaction (CR) conditions.
- Measurements included reaction time and ankle-stabilizer muscle activation.
Main Results:
- Choice reaction time (CRT) was longer than simple reaction time (SRT) in both age groups.
- Elderly subjects showed significantly slower RTs than young subjects, particularly under CR conditions while standing.
- Postural muscle onset was similar across conditions, but focal-muscle onset and RT showed age-related differences in the CR task.
Conclusions:
- The elderly may possess a compromised postural system that delays body stabilization before movement initiation.
- Age-related declines in motor control are exacerbated by increased task complexity and the need for postural adjustments.
- These findings highlight the importance of postural control in understanding age-related motor performance decrements.