Adaptive control of gait stability in reducing slip-related backward loss of balance
Adaptive control of gait stability in reducing slip-related backward loss of balance
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DOI：
10.1007/s00221-005-0189-5
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发表时间：
2006-03-01
影响因子：
2
通讯作者：
Pai, YC
中科院分区：
文献类型：
--
作者：
Bhatt, T;Wening, JD;Pai, YC
运动和平衡控制系统中旨在改进预防跌倒的恢复策略的适应特性还没有被很好地理解。这项研究的目的是检验步态稳定性对重复滑动暴露的适应性控制，从而减少向后失去平衡(从而减少保护性步态)。14名年轻受试者在行走过程中经历了一次滑倒。所有滑移试验的滑移前和滑后稳定性分别是在触地(滑肢)和升起(对侧肢体)时，测量的重心(COM)状态，即相对于支撑底部(BOS)的位置和速度与数学预测的向后失去平衡阈值之间的最短距离。滑动前后稳定性的改善与平衡丧失的发生率从100%(第一次滑动)降至0%(第五次滑动)相关。虽然滑前稳定性的改善受到COM位置主动前移的影响，但滑移后稳定性的显著改善是由于BOS扰动强度的降低。BOS扰动强度的这种反应性变化是由于滑倒后制动冲量的需求减少所致，但这一需求受到滑滑开始前对姿势和步态模式(例如，重心、步长、平足着陆和膝关节屈曲增加)的主动调整的影响。这些发现表明了自适应控制的成熟过程。其特征是从依赖反馈控制进行姿势校正转变为受前馈控制的影响，前馈控制改善了预滑稳定性并改变了扰动强度，导致滑行或步行(>；0.05米或
The properties of adaptation within the locomotor and balance control systems directed towards improving one's recovery strategy for fall prevention are not well understood. The purpose of this study was to examine adaptive control of gait stability to repeated slip exposure leading to a reduction in backward loss of balance (and hence in protective stepping). Fourteen young subjects experienced a block of slips during walking. Pre- and post-slip onset stability for all slip trials was obtained as the shortest distance at touchdown (slipping limb) and lift-off (contralateral limb), respectively, between the measured center of mass (COM) state, that is, position and velocity relative to base of support (BOS) and the mathematically predicted threshold for backward loss of balance. An improvement in pre- and post-slip onset stability correlated with a decrease in the incidence of balance loss from 100% (first slip) to 0% (fifth slip). While improvements in pre-slip stability were affected by a proactive anterior shift in COM position, the significantly greater post-slip onset improvements resulted from reductions in BOS perturbation intensity. Such reactive changes in BOS perturbation intensity resulted from a reduction in the demand on post-slip onset braking impulse, which was nonetheless influenced by the proactive adjustments in posture and gait pattern (e.g., the COM position, step length, flat foot landing and increased knee flexion) prior to slip onset. These findings were indicative of the maturing process of the adaptive control. This was characterized by a shift from a reliance on feedback control for postural correction to being influenced by feedforward control, which improved pre-slip stability and altered perturbation intensity, leading to skateover or walkover (>0.05 m or