Age-related changes in posture response under a continuous and unexpected perturbation

Area of Science:

• Biomechanics
• Gerontology
• Neuroscience

Background:

• Aging significantly impacts functional performance and increases fall risk due to impaired posture control.
• Unexpected external perturbations challenge balance, revealing age-related deficits in control and recovery.

Purpose of the Study:

• To investigate age-related differences in balance control and recovery using a novel six-degree-of-freedom platform.
• To assess how older adults' posture control strategies differ from those of young adults under simulated real-life disturbances.

Main Methods:

• A novel movable platform and motion control protocol simulated unexpected disturbances.
• Center of Mass (COM) excursion, joint rotation angles, and electromyography (EMG) were recorded in 20 older and 20 young adults.
• Data were analyzed to compare balance reactive-recovery strategies between age groups.

Main Results:

• Older adults showed similar joint movement and COM excursion patterns but greater proximal joint rotation.
• Increased proximal joint rotation led to larger COM sway envelope and impaired posture recovery strategies in the elderly.
• Older adults exhibited lower muscle power and increased, potentially asymmetric, EMG activity for joint stability.

Conclusions:

• The novel platform and protocol effectively discriminate age-related balance impairments.
• Compensatory strategies for posture recovery are compromised in older adults due to biomechanical and neuromuscular changes.
• This approach can assess sensory, motor, and central adaptive impairments and serve as a training tool for individuals with posture instability.