Abstract
Background: During walking, the center of mass (CoM) oscillates up and down in the sagittal plane. In the late-stance phase, as the CoM descends, its vertical velocity decreases before foot contact, indicating active neural balance control, which we refer to as CoM braking. Young adults tend to increase braking while maintaining step length and speed when performing a cognitive task, such as subtracting numbers. In contrast, older adults maintain consistent braking by reducing step length and speed. This study examined the effects of walking at constant self-selected, slower, or faster speeds on CoM braking and cognitive performance. Methods: Healthy young and older adults walked on a level motorized treadmill at various imposed speeds, with and without engaging in a subtraction task. Previous research has shown that such cognitive tasks can interfere with balance control. Subjects received no instructions to prioritize either task. The order of conditions was randomized. A 3D motion analysis system captured walking performance at 120 Hz, with subtraction proficiency measured as responses per minute. Results: Both young and older adults maintained braking at preferred and slower speeds while subtracting. However, older adults showed decreased braking at faster speeds (p < .05). Despite a significant reduction in the influence of speed on CoM braking during subtraction, the older group produced decreased subtraction proficiency across conditions (p < .05). Although they made more subtraction errors while walking, they managed to maintain accuracy by slowing their subtraction speed. The braking index was more sensitive (-.8, Hotelling’s T-square) than step width (.71) and step length (.28) in differentiating the effects of dual-tasking between the groups, especially at faster walking speeds. Conclusion: These results suggest that balance control during walking is complex and affected by aging, speed constraints, and dual-tasking difficulty. The young group’s ability to maintain CoM braking during fast walking indicates improved attentional focus under dual-task conditions. Clinicians should consider these findings when working with clients on gait and dual-task training.
Recommended Citation
Chong, Raymond; Moore, Victoria; Sampson, Hope Brown; Spears, Heather; and Do, Manh-Cuong
(2025)
"Age-related balance control changes in constrained-speed gait during a concurrent cognitive task,"
Asian Journal of Physical Therapy: Vol. 2:
Iss.
2024, Article 1.
Available at:
https://digitalcommons.lmunet.edu/ajpt/vol2/iss2024/1
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