Gait balance control after fatigue: Effects of age and cognitive demand

Fatigue is a commonly mentioned symptom in older adults, and walking under the influence of fatigue frequently occurs in daily activities. Studies have reported individual effects from fatigue or cognitive demand on gait performance. However, the information on how fatigue and cognitive demand interact to affect gait balance control is still lacking.

How does fatigue affect walking balance control in young and older adults with and without performing a concurrent cognitive task?

We collected and analyzed motion data from 17 young and 17 older adults, who performed over-ground walking with and without a concurrent working memory test, before and after been fatigued by performing repetitive sit-to-stand movements. Three-way ANOVAs were used for statistical analysis with Age (young and older adults), Fatigue (pre- and post-fatigue), and Task (single-task and dual-task) as factors.

From pre- to post-fatigue, an increased gait velocity was observed during dual-task walking regardless of age (p = .02). Only young adults demonstrated a significant increase in mediolateral center of mass displacement (M-L CoM) at post-fatigue (p = .019). Accuracies of the working memory test were not affected by Age, Task, or Fatigue.

Our findings revealed that gait balance control, as measured by the M-L CoM, deteriorated post-fatigue in young adults. Older adults maintained their mediolateral body sway from pre-fatigue to post-fatigue. Fatigue effects were not further exacerbated during dual-task walking, and similar cognitive performance was maintained as performance fatigability increased.