Postural Stability When Grasping an Object While Standing: Younger and Older Adults (Fallers and Non-Fallers)

Area of Science:

• Biomechanics
• Gerontology
• Motor Control

Background:

• Postural stability is crucial for daily activities, particularly for older adults.
• Reaching and grasping tasks challenge postural control, increasing fall risk in older populations.
• Understanding age-related changes in postural control during dynamic tasks is essential for fall prevention.

Purpose of the Study:

• To investigate postural stability, measured by the margin of stability (MoS), during reaching and grasping.
• To compare MoS in younger adults (YA), non-fallers (OA), and fallers (FOA) across varying task difficulties.
• To analyze differences in MoS dynamics (minimum, maximum, timing) between age and fall groups.

Main Methods:

• Forty-five participants (YA, OA, FOA) performed reaching and grasping tasks.
• Six conditions manipulated task difficulty using base stability and obstacles.
• Anterior-posterior (AP) and medial-lateral (ML) margin of stability (MoS) were computed between movement onset and object contact.

Main Results:

• Older adults (OA) showed smaller MoS than younger adults (YA) in both AP and ML directions.
• Fallers (FOA) exhibited a smaller minimum MoS in the ML direction compared to YA.
• FOA had an earlier minimum MoS in the AP direction and adopted a more cautious strategy than YA.

Conclusions:

• Both non-fallers and fallers demonstrate impaired postural control during standing reach-to-grasp tasks.
• Fallers employ a more cautious strategy, adjusting MoS earlier to enhance stability before grasping.
• These findings highlight age-related and fall-specific alterations in dynamic postural control during functional movements.