Abstract：
Vision, as queen of the senses, plays a critical role in guiding locomotion. Little is known about the effects of vision on gait coordination in terms of variability. The uncontrolled manifold (UCM) approach offers a window to the structure of motor variability that has been difficult to obtain from the traditional correlation analysis. In this study, we used the UCM analysis to quantify how the lower limb motion is coordinated to control the center of mass (COM) while walking under different visual conditions. We also probed how synergy strength evolved along the stance phase. Ten healthy participants walked on the treadmill with and without visual information. Leg joint angle variance with respect to the whole-body COM was partitioned into good (i.e., the one that kept the COM) and bad (i.e., the one that changed the COM) variances. We observed that after vision was eliminated, both variances increased throughout the stance phase while the strength of the synergy (the normalized difference between the two variances) decreased significantly and even reduced to zero at heel contact. Thus, walking with restricted vision alters the strength of the kinematic synergy to control COM in the plane of progression. We also found that the strength of this synergy varied across different walking phases and gait events in both visual conditions. We concluded that the UCM analysis can quantify altered coordination of COM when vision is blocked and sheds insights on the role of vision in the synergistic control of locomotion.
摘要：
愿景,作为感官女王，在指导运动中起着至关重要的作用。就变异性而言，关于视觉对步态协调的影响知之甚少。不受控制的流形（UCM）方法为运动变异性的结构提供了一个窗口，这从传统的相关分析中很难获得。在这项研究中,我们使用UCM分析来量化在不同视觉条件下行走时下肢运动如何协调以控制质心（COM）。我们还探讨了协同力量是如何沿着姿态阶段演变的。十名健康的参与者在有或没有视觉信息的情况下在跑步机上行走。腿部关节角度相对于全身COM的方差被划分为良好(即，保留COM的那个)和坏(即，改变COM)方差的那个。我们观察到视力消除后，在整个站立阶段，两种差异都增加了，而协同作用的强度（两种差异之间的归一化差异）显着降低，甚至在脚跟接触时降低到零。因此，视力受限的步行会改变运动学协同作用的强度，以控制前进平面中的COM。我们还发现，在两种视觉条件下，这种协同作用的强度在不同的行走阶段和步态事件中有所不同。我们得出的结论是，当视力受阻时，UCM分析可以量化COM的协调性改变，并揭示了视力在运动协同控制中的作用。
