Abstract：
The mechanism by which postural threat induced by standing at a high height causes a decrease in the amplitude and an increase in the frequency of postural sway might involve voluntary control (VC) to avoid swaying, rather than conscious balance processing, in which postural threat directs conscious balance processing. This study aimed to clarify the differences between VC and conscious balance processing during quiet standing. Twenty-seven healthy young adults were instructed to stand with their feet placed together and keep their eyes open. The standing task was performed under three standing conditions: relaxed, VC, and high-conscious movement processing (high-CMP). The center of pressure in the anteroposterior (AP) and mediolateral (ML) directions was measured using a stabilometer to assess differences in postural control. The results indicated that the mean power frequency (MPF) ML and high frequency (HF) ML were higher in the VC condition than in the high-CMP condition. In the VC and high-CMP conditions, compared with the relaxed condition, MPF AP was higher, whereas the root mean square AP and low frequency AP were lower. These results show that the sway amplitude is lower, and the frequency is higher in both the VC and high-CMP conditions compared with those in the relaxed condition; however, the frequency is higher in the VC condition than in the high-CMP condition, suggesting that the VC condition is similar to postural control under the postural threat condition.
摘要：
站在高处引起的姿势威胁导致振幅减小和姿势摇摆频率增加的机制可能涉及自愿控制（VC）以避免摇摆，而不是有意识的平衡处理，姿势威胁指导有意识的平衡处理。本研究旨在阐明安静站立时VC和有意识平衡处理之间的差异。27名健康的年轻人被指示站立，双脚并拢并睁大眼睛。站立任务是在三种站立条件下进行的：放松，VC,和高意识运动处理（高CMP）。使用稳定仪测量前后（AP）和中外侧（ML）方向的压力中心，以评估姿势控制的差异。结果表明，VC条件下的平均功率频率（MPF）ML和高频（HF）ML高于高CMP条件。在VC和高CMP条件下，与放松的条件相比，强积金AP较高，而均方根AP和低频AP较低。这些结果表明，摇摆幅度较低，与放松条件相比，在VC和高CMP条件下的频率更高；然而，VC条件下的频率高于高CMP条件下的频率，表明VC条件类似于姿势威胁条件下的姿势控制。
