School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
Gait Posture. 2011 Jun;34(2):279-84. doi: 10.1016/j.gaitpost.2011.05.017. Epub 2011 Jun 15.
Stair edges provide important visual cues for appropriate foot placement on the stair and balance control during stair descent. Previous studies explored age-related changes in stepping performance and balance control during stair descent and included fit older adults. The present study investigates both age- and frailty-related changes to stepping parameters and Centre of Mass (COM) control during stair descent and how these measures are affected by visual factors. Older adults were split into two groups containing participants with the lowest (LROA, n=7) and highest (HROA, n=8) combined scores on tests of balance and confidence to negotiate stairs. Data were also collected from younger adult participants (YA, n=8). Kinematic data were collected from participants while they descended stairs under combinations of ambient light (bright and dimmed) and stair edge contrast conditions (high and low). A three (group) × two (illumination)×two (contrast) ANCOVA was performed with average stair walking speed as covariate. HROA cleared the stair edge vertically (p=0.001) and horizontally (p<0.001) with less distance than LROA. Dimmed ambient light resulted in decreased step length in HROA (p=0.006) compared to bright lighting. High stair edge contrast led to reduced vertical COM acceleration variability in HROA (p=0.009) and increased distance between COM and anterior base of support (p=0.017) in LROA. YA increased horizontal foot clearance (p=0.011) when stair edge contrast was high. We conclude that the aforementioned differences in stepping behaviour shown by HROA may contribute towards an increased risk of tripping and that high stair edge contrast has a beneficial effect on balance control in older adults.
楼梯边缘为适当的脚部放置提供了重要的视觉线索，并有助于在楼梯下降过程中保持平衡。先前的研究探讨了与年龄相关的楼梯下降时的步幅表现和平衡控制变化，并纳入了适应能力强的老年人。本研究调查了年龄和脆弱性相关的步幅参数变化以及在楼梯下降过程中重心（COM）的控制变化，以及这些措施如何受到视觉因素的影响。老年人分为两组，一组包含平衡和信心测试综合得分最低（LROA，n=7）和最高（HROA，n=8）的参与者，另一组包含平衡和信心测试综合得分最低（LROA，n=8）的参与者。还从年轻成年参与者（YA，n=8）收集数据。当参与者在环境光（明亮和调暗）和楼梯边缘对比度（高和低）的组合下下楼梯时，收集参与者的运动学数据。进行了三（组）×二（照明）×二（对比度）的 ANCOVA 分析，以平均楼梯行走速度为协变量。HROA 比 LROA 更垂直（p=0.001）和水平（p<0.001）地清除楼梯边缘。与明亮照明相比，调暗的环境光导致 HROA 的步长缩短（p=0.006）。高楼梯边缘对比度导致 HROA 的垂直 COM 加速度变异性降低（p=0.009），LROA 的 COM 和前支撑基础之间的距离增加（p=0.017）。当楼梯边缘对比度较高时，YA 增加了水平脚部间隙（p=0.011）。我们得出结论，HROA 表现出的上述步幅行为差异可能导致绊倒的风险增加，而高楼梯边缘对比度对老年人的平衡控制有有益影响。
