Department of Physical Therapy, Faculty of Medical Sciences, Teikyo University of Science, Uenohara-shi, Yamanashi, 409-0193, Japan.
Material Health Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo, 184-8588, Japan.
Sci Rep. 2022 Aug 1;12(1):13164. doi: 10.1038/s41598-022-17322-9.
The human being dynamically and highly controls the head-trunk with redundant mechanical structures to maintain a stable upright standing position that is inherently unstable. The posture control strategies are also affected by the differences in the conditions of sensory inputs. However, it is unclear how the head-trunk segmental properties are altered to respond to situations that require appropriate changes in standing posture control strategies. We used a data-driven approach to conduct a multipoint measurement of head-trunk sway control in a quiet standing position with differences in the conditions of sensory inputs. Healthy young subjects with 22 accelerometers attached to their backs were evaluated for head-trunk vibration during quiet standing under two conditions: one with open eyes and one with closed eyes. The synchronization of the acceleration and the instantaneous phase was then calculated. The results showed that the synchronization of acceleration and instantaneous phase varied depending on the visual condition, and there were some continuous coherent patterns in each condition. Findings were that the structural redundancy of the head-trunk, which is multi-segmental and has a high mass ratio in the whole body, must be adjusted adaptively according to the conditions to stabilize upright standing in human-specific bipeds.
人类通过冗余的机械结构动态地、高度地控制头-躯干，以维持固有不稳定的稳定直立站立姿势。姿势控制策略也受到感觉输入条件差异的影响。然而，目前尚不清楚如何改变头-躯干节段特性，以应对需要适当改变站立姿势控制策略的情况。我们使用数据驱动的方法，在感觉输入条件不同的安静站立位置进行多点测量头-躯干摆动控制。我们评估了 22 个加速度计附着在背部的健康年轻受试者在安静站立时的头-躯干振动，条件分别为睁眼和闭眼。然后计算加速度和瞬时相位的同步性。结果表明，加速度和瞬时相位的同步性取决于视觉条件，并且在每种条件下都存在一些连续的相干模式。研究结果表明，头-躯干的结构冗余性是多节段的，在整个身体中具有较高的质量比，必须根据条件进行自适应调整，以稳定人类特有的两足直立站立。
