Age-related changes in postural responses to backward platform translation

Area of Science:

• Biomechanics
• Human Movement Science
• Gerontology

Background:

• Postural control is crucial for stability, and age-related declines can increase fall risk.
• Understanding how older adults respond to external perturbations is vital for fall prevention strategies.

Purpose of the Study:

• To investigate age-related differences in postural responses to platform translation at varying velocities.
• To analyze the influence of linear velocity on center of pressure (CoP) and muscle activity (gastrocnemius and tibialis anterior).

Main Methods:

• Eleven young and eleven elderly healthy adults stood on a force platform with eyes closed.
• Backward platform translations at 10, 15, and 20 cm/s were performed.
• Center of pressure (CoP) displacements and EMG activity of gastrocnemius (GS) and tibialis anterior (TA) muscles were recorded.

Main Results:

• Elderly subjects showed increased maximal CoP responses and a scaling delay in CoP responses to platform velocity.
• Gastrocnemius muscle activity increased with platform velocity in both groups, but TA activity was velocity-independent.
• Early postural responses in the elderly involved significant co-activation of TA and GS muscles.

Conclusions:

• Elderly individuals demonstrate altered postural control strategies, including delayed responses and increased muscle co-activation.
• Increased body stiffening in the elderly may be a compensatory mechanism to maintain balance during external perturbations.