Faculty of Rehabilitation, Kansai Medical University, 18-89 Uyama Higashimachi, Hirakata, Osaka 573-1136, Japan; Department of Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo Kyoto 606-8507, Japan.
Department of Human Development, Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe, Hyogo 657-0011, Japan.
J Biomech. 2023 Aug;157:111702. doi: 10.1016/j.jbiomech.2023.111702. Epub 2023 Jun 27.
To step over obstacles of varying heights, two distinct ongoing streams of activities-visual exploration of the environment and gait adjustment- were required to occur concurrently without interfering each other. Yet, it remains unclear whether and how the manner of embodied behavior of visual exploration is related to the synergistic control of foot trajectory to negotiate with the irregular terrain. Thus, we aimed to explore that how the synergistic control of the vertical trajectory of the swing foot (i.e., obstacle clearance) crossing an obstacle is related to the manner of visual exploration of the environment during approach. Twenty healthy young adults crossed an obstacle (depth: 1 cm, width: 60 cm, height: 8 cm) during their comfortable-speed walking. The visual exploration was evaluated as the amount of time spent in fixating the vicinity of the obstacle on the floor during the period from two to four steps prior to crossing the obstacle, and the strengths of kinematic synergy to control obstacle clearance were estimated using the uncontrolled manifold approach. We found that the participants with relatively weak synergy spent more time fixating at the vicinity of the obstacle from two to four steps prior to crossing the obstacle, and those participants exhibited greater amount of head flexion movement compared to those with stronger kinematic synergy. Taking advantage of this complex relationship between exploratory activities (e.g. looking movement) and performative activities (e.g. adjustment of ground clearance) would be crucial to adapt walking in a complex environment.
为了跨越不同高度的障碍物，需要同时进行两种不同的活动——对环境的视觉探索和步态调整——而不会相互干扰。然而，目前尚不清楚视觉探索的体现行为方式是否以及如何与协同控制足轨迹以适应不规则地形相关。因此，我们旨在探索在跨越障碍物时，摆动脚（即障碍物清除）的垂直轨迹的协同控制方式如何与接近障碍物期间环境视觉探索的方式相关。二十名健康的年轻人在舒适速度行走时穿过一个障碍物（深度：1 厘米，宽度：60 厘米，高度：8 厘米）。视觉探索评估为在跨越障碍物前两到四步期间，注视障碍物附近地面的时间量，使用非控制流形方法估计控制障碍物清除的运动协同的强度。我们发现，协同作用较弱的参与者在跨越障碍物前两到四步期间，在障碍物附近的注视时间较长，与具有较强运动协同作用的参与者相比，他们的头部前倾运动幅度更大。利用这种探索活动（例如看的动作）和表现活动（例如地面间隙的调整）之间的复杂关系对于适应复杂环境中的行走至关重要。
