High foot elevation during obstacle crossing is viewed as a conservative strategy in older adults, but excessive foot elevation may result in large mediolateral center of mass (CoM) displacement. Since an incorrect transfer of CoM can lead to balance loss during locomotion, both appropriate foot elevation and CoM position must be controlled and coordinated by adjusting body segment positions. However, no studies have revealed time profiles of CoM position by coordinated segment movements and the relation of foot elevation with CoM position during obstacle crossing. Twenty-five healthy older adults crossed an obstacle (depth: 1 cm, width: 60 cm, height: 8 cm) during comfortable-speed walking. Synergy indices were calculated during lead- and trail-limb swing using uncontrolled manifold analysis. High synergy index values indicate a strong multi-joint kinematic synergy, or co-fluctuations in segment movements, to control CoM position. The maximum foot heights of the swing limbs were calculated as the maximum vertical distance between the most distal foot point and the ground. In the mediolateral direction, synergy index values during early lead-limb swing were significantly greater than during early trail-limb swing, and in the vertical direction, large synergy index values were found during early- and mid-swing phases. Moreover, maximum trail-foot height was correlated to vertical synergy index during early phase. CoM position was not well controlled by a kinematic synergy during trail-limb swing and the low control of CoM position was observed with great trail-foot height. The results suggest that a conservative strategy with great trail-foot height would not always be helpful for successful obstacle crossing.

在老年人中，越过障碍物时高脚抬高被认为是保守的策略，但是过高的脚抬高可能会导致较大的中外侧重心（CoM）移位。由于不正确的CoM传递会导致运动过程中的平衡损失，因此必须通过调整身体部位的位置来控制和协调适当的脚抬高和CoM位置。但是，尚无研究揭示协调障碍物移动过程中协调运动位置的时间分布以及障碍物穿越过程中脚高与协调运动位置的关系。25名健康的老年人在舒适的速度行走过程中越过障碍物（深度：1厘米，宽度：60厘米，高度：8厘米）。使用不受控制的歧管分析计算前肢和后肢摆动过程中的协同指数。较高的协同指数值表示强烈的多关节运动协同效应或段运动的协同波动，以控制CoM位置。将摆动肢体的最大脚高计算为最远端脚点与地面之间的最大垂直距离。在前外侧方向上，铅前肢摆动早期的协同指数值显着大于在后肢上肢摆动初期的协同指数值，而在垂直方向上，在早期和中期摆动阶段发现了较大的协同指数值。此外，最大的后足高度与早期阶段的垂直协同指数相关。在后肢摆动过程中，CoM位置不受运动学协同作用的很好控制，并且在较大的后脚高度处观察到对CoM位置的控制较低。