School of Engineering, University of Bradford, Bradford, United Kingdom.
Department of Physical Education, Federal University of Paraná, Curitiba, Paraná, Brazil.
PLoS One. 2024 Jul 23;19(7):e0307365. doi: 10.1371/journal.pone.0307365. eCollection 2024.
Understanding the contribution vision has to dynamic balance control may help in understanding where/why loss of balance occurs during everyday locomotion. The current study determined how body-centre-of-mass (BCoM) dynamics and postural stability when moving to and holding a single-limb-stance (SS) or an up-on-the-toes (UTT) position were affected by visual occlusion. From standing on a force platform, 18 adults (mean (SD) 26.7 (4.8) years; 1.73 (0.08) m; 84.0 (22.9) kg; 7 females) completed repeated trials (x3) with and without vision in which they moved to either a SS or an UTT position (order countered-balanced), and attempted to hold that position for 2 (SS) or 5 (UTT) seconds before returning to standing. UTT trials were also repeated at a fast speed, and SS trials were repeated using both the dominant and non-dominant limb. BCoM dynamics were assessed by analysing the displacement and peak velocity of the centre-of-pressure (CoP) when moving to and from the SS and UTT positions. Balance stability was the variability in the CoP displacement/velocity when holding these positions. Results indicate that under visual occlusion, the peak CoP velocity when moving to the SS or UTT position was reduced (ES, 0.67 and 0.68, respectively), suggesting greater caution. Both the variability in the CoP displacement/velocity when holding these positions and the peak CoP velocity when returning to flat-standing increased (SS: ES, 1.0 and 0.86, respectively; UTT: ES 1.26 and 0.66, respectively), suggesting, respectively, greater instability and poorer control. The poorer control in SS trials, occurred when returning to standing from the SS position held on the non-dominant limb, and correspondingly, the reduction in SS duration when vision was occluded was greater for the non-dominant limb trails (limb-vision interaction; p = 0.042). This suggests that movements initiated/controlled by the non-dominant limb are more reliant on visual feedback than those initiated/controlled by the dominant limb.
理解视觉对动态平衡控制的贡献有助于理解在日常行走中为什么会失去平衡。本研究旨在确定在进行单腿站立（SS）或踮脚尖（UTT）姿势时，身体质心（BCoM）动力学和姿势稳定性如何受到视觉遮挡的影响。18 名成年人（平均（标准差）26.7（4.8）岁；1.73（0.08）米；84.0（22.9）千克；7 名女性）从站立在力台上开始，完成了三次重复试验（x3），一次有视觉，两次无视觉，他们分别向 SS 或 UTT 位置移动，并尝试保持该位置 2（SS）或 5（UTT）秒，然后返回站立。UTT 试验还以快速速度重复进行，SS 试验分别使用优势和非优势腿重复进行。通过分析从中点压力（CoP）移动到 SS 和 UTT 位置时的 CoP 位移和峰值速度来评估 BCoM 动力学。当保持这些位置时，平衡稳定性是 CoP 位移/速度的可变性。结果表明，在视觉遮挡下，移动到 SS 或 UTT 位置时的 CoP 峰值速度降低（ES，分别为 0.67 和 0.68），这表明需要更加小心。保持这些位置时 CoP 位移/速度的可变性以及返回平卧位时的 CoP 峰值速度均增加（SS：ES，分别为 1.0 和 0.86；UTT：ES 分别为 1.26 和 0.66），这分别表明稳定性更差和控制能力更差。当从非优势腿支撑的 SS 位置返回站立时，SS 试验中的控制能力更差，并且当视觉被遮挡时，SS 持续时间的减少对于非优势腿的试验更大（肢体-视觉相互作用；p = 0.042）。这表明，由非优势腿发起/控制的运动比由优势腿发起/控制的运动更依赖于视觉反馈。
