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Age, functional postural reflexes, and voluntary sway
G E Stelmach1, J Phillips, R P DiFabio
1Motor Behavior Laboratory, University of Wisconsin, Madison.
Summary
Older adults exhibit impaired coordination between postural reflexes and voluntary movement. Their muscle responses to disturbances during sway are slower, indicating age-related declines in motor control.
Area of Science:
- Gerontology
- Neuroscience
- Biomechanics
Background:
- Ageing is associated with changes in motor control.
- Understanding the interplay between postural reflexes and voluntary movement is crucial for fall prevention in older adults.
Purpose of the Study:
- To investigate age-related differences in the functional coupling of postural reflexes and voluntary sway.
- To analyze the timing and sequencing of muscle activity during postural control in young and older adults.
Main Methods:
- Electromyography (EMG) was used to record muscle activity.
- Participants (young and older adults) were subjected to horizontal postural perturbations during quiet stance and voluntary sway.
- Analysis focused on muscle onset timing, bilateral coupling, and stereotypical patterns of muscle activation.
Main Results:
- Older adults demonstrated poorer coordination between postural reflexes and voluntary movement.
- Stabilizing responses to postural disturbances during voluntary sway were significantly slower in older adults.
- Muscle activation patterns showed reduced bilateral coupling and less stereotypical organization in older adults.
Conclusions:
- Older adults exhibit a breakdown in the timing and sequencing of muscle activity.
- Functional coordination between postural reflexes and voluntary sway is compromised with age.
- These findings highlight age-related deficits in motor control crucial for maintaining balance.