An increased risk of falling is associated with changes in gait while dual-tasking. The degree to which gait stability is altered during walking is influenced by an individual’s cognitive and postural capacity, and the difficulty of the presented tasks. However, it is unknown how greater walking task difficulty affects gait stability in younger and older adults when dual-tasking. The purpose of the current study was to determine the effect of walking task difficulty on gait stability in younger and older adults while performing a difficult audiospatial task. Ten younger [mean (SD) age 30.8 (6.6) years; 5 women] and 10 older [66.8 (5.7) years; 6 women] healthy adults walked on a treadmill at their preferred walking speed [younger 4.8 (0.4) ms⁻¹, older 4.5 (0.5) ms⁻¹) on either a level, or downhill slope both with and without responding to an audiospatial task. Step width, step width SD and mediolateral centre of mass displacement were calculated to determine changes in gait, and response time and accuracy were calculated to determine secondary task performance. Results indicated that older adults displayed a consistently greater step width (p ≤ 0.015) and maintained their mediolateral centre of mass displacement (p > 0.05) while walking downhill and responding to the audiospatial task, compared to downhill walking only. In contrast, younger adults maintained a regular step width during both level and downhill dual-tasking compared to level and downhill walking only (p > 0.05), however displayed a lower mediolateral centre of mass displacement during level dual-task walking compared to level walking only (p = 0.013). When the difficulty of the walking task was greater, older adults increased their step width, which increased their stability.

双重任务时步态的变化与跌倒的风险增加有关。步行过程中步态稳定性改变的程度受个体的认知和姿势能力以及所提出任务的难度的影响。但是，未知的是，双任务时较大的步行任务难度如何影响年轻人和老年人的步态稳定性。本研究的目的是确定步行任务难度对年轻人和老年人的步态稳定性的影响，同时执行困难的音频空间任务。十岁以下[平均（SD）年龄30.8（6.6）岁；5名妇女]和10名年龄较大的[66.8（5.7）岁；6位女性]健康的成年人以自己喜欢的步行速度[跑步机4.8（0.4）ms ^-1，老年人4.5（0.5）ms ^-1），无论是否响应音频空间任务，都可以在水平或下坡上进行。计算步幅，步幅SD和中外侧质心位移来确定步态的变化，并计算响应时间和准确性来确定次要任务的执行情况。结果表明，老年人显示始终如一更大步骤的宽度（p  ≤0.015）和保持它们的质量位移（的中间外侧的中心p  > 0.05），而步行下坡和响应audiospatial任务相比，下坡行走只。相比之下，相比仅在水平和下坡行走中，较年轻的成年人在水平和下坡双重任务期间均保持规则的步幅（p > 0.05），但是与仅使用水平行走相比，在水平双任务行走过程中显示出较低的中外侧质心位移（p  = 0.013）。当步行任务的难度更大时，老年人会增加步幅，从而增加稳定性。