Dragunas Andrew C, Gordon Keith E
Department of Physical Therapy & Human Movement Sciences, Northwestern University, Chicago, IL, USA; Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.
Department of Physical Therapy & Human Movement Sciences, Northwestern University, Chicago, IL, USA; Research Service, Edward Hines Jr. VA Hospital, Hines, IL, USA.
J Biomech. 2016 Sep 6;49(13):2662-2668. doi: 10.1016/j.jbiomech.2016.05.026. Epub 2016 Jun 1.
Body weight support (BWS) systems are a common tool used in gait rehabilitation. BWS systems may alter the requirements for an individual to actively stabilize by 1) providing lateral restoring forces that reduce the requirements for the nervous system to actively stabilize and 2) decreasing the stabilizing gravitational moment in the frontal plane, which could increase the requirements to actively stabilize. The goal of the current study was to quantify the interaction between BWS and lateral stability. We hypothesized that when able-bodied people walk with BWS: 1) the lateral restoring forces provided by BWS would reduce the requirements to stabilize in the frontal plane when comparing dynamically similar gaits, and 2) increasing BWS would decrease the stabilizing gravitational moment in the frontal plane and increase the requirements to stabilize when speed is constrained. Our findings partly support these hypotheses, but indicate a complex interaction between BWS and lateral stability. With BWS, subjects significantly decreased step width variability and significantly increased step width (p<0.05) for both the dynamically similar and Speed-Matched conditions. The decrease in step width variability may be attributable to a combination of lateral restoring forces decreasing the mechanical requirements to stabilize and an enhanced sense of position that could have improved locomotor control. Increases in step width when walking with high levels of BWS could have been due to decreases in the gravitational moment about the stance limb, which may challenge the control of stability in multiple planes.
体重支持（BWS）系统是步态康复中常用的工具。BWS系统可能会改变个体主动稳定的需求，具体方式如下：1）提供侧向恢复力，降低神经系统主动稳定的需求；2）减小额平面内的稳定重力矩，这可能会增加主动稳定的需求。本研究的目的是量化BWS与侧向稳定性之间的相互作用。我们假设，当健全人使用BWS行走时：1）与动态相似步态相比，BWS提供的侧向恢复力会降低在额平面内稳定的需求；2）当速度受到限制时，增加BWS会减小额平面内的稳定重力矩，并增加稳定的需求。我们的研究结果部分支持了这些假设，但表明BWS与侧向稳定性之间存在复杂的相互作用。使用BWS时，在动态相似和速度匹配条件下，受试者的步宽变异性均显著降低，步宽显著增加（p<0.05）。步宽变异性的降低可能归因于侧向恢复力降低了稳定的机械需求，以及增强的位置感可能改善了运动控制。使用高水平BWS行走时步宽增加，可能是由于支撑腿的重力矩减小，这可能会对多个平面的稳定性控制构成挑战。
