Academy for Engineering and Technology, Fudan University, 220 Handan Rd., Shanghai, 200433, China.
National Clinical Research Center for Geriatric Diseases (NCRCGD), Huashan Hospital Affiliated to Fudan University, No.12, Wulumuqi Middle Rd., Shanghai, 200040, China.
BMC Musculoskelet Disord. 2023 Oct 2;24(1):775. doi: 10.1186/s12891-023-06897-7.
Current studies on how external perturbations impact gait dynamics have primarily focused on the changes in the body's center of mass (CoM) during treadmill walking. The biomechanical responses, in particular to the multi-planar hip joint coordination, following perturbations in overground walking conditions are not completely known.
In this study, a customized gait-perturbing device was designed to impose controlled lateral forces onto the subject's pelvis during overground walking. The biomechanical responses of bilateral hips were simulated by subject-specific neuromusculoskeletal models (NMS) driven by in-vivo motion data, which were further evaluated by statistical parameter mapping (SPM) and muscle coactivation index (CI) analysis. The validity of the subject-specific NMS was confirmed through comparison with measured surface electromyographic signals.
Following perturbations, the sagittal-plane hip motions were reduced for the leading leg by 18.39° and for the trailing leg by 8.23°, while motions in the frontal and transverse plane were increased, with increased hip abduction for the leading leg by 10.71° and external rotation by 9.06°, respectively. For the hip kinetics, both the bilateral hip joints showed increased abductor moments during midstance (20%-30% gait cycle) and decreased values during terminal stance (38%-48%). Muscle CI in both sagittal and frontal planes was significantly decreased for perturbed walking (p < 0.05), except for the leading leg in the sagittal plane.
The distinctive phase-dependent biomechanical response of the hip demonstrated its coordinated control strategy for balance recovery due to gait perturbations. And the changes in muscle CI suggested a potential mechanism for rapid and precise control of foot placement through modulation of joint stiffness properties. These findings obtained during actual overground perturbation conditions could have implications for the improved design of wearable robotic devices for balance assistance.
目前关于外部干扰如何影响步态动力学的研究主要集中在跑步机行走过程中身体质心（CoM）的变化上。在地面行走条件下，关节的多平面协调的生物力学响应尚不完全清楚。
本研究设计了一种定制的步态干扰装置，在地面行走时向受试者的骨盆施加受控的侧向力。通过基于运动数据的特定于个体的神经肌肉骨骼模型（NMS）模拟双侧髋关节的生物力学响应，进一步通过统计参数映射（SPM）和肌肉协同激活指数（CI）分析进行评估。通过与实测表面肌电信号的比较，验证了特定于个体的 NMS 的有效性。
干扰后，主导腿的矢状面髋关节运动减小了 18.39°，随动腿减小了 8.23°，而额状面和横面的运动增加，主导腿的髋关节外展增加了 10.71°，外旋增加了 9.06°。对于髋关节动力学，双侧髋关节在中足（步态周期的 20%-30%）时表现出更大的外展肌力矩，在终末足（步态周期的 38%-48%）时减小。干扰行走时，矢状面和额状面的肌肉 CI 显著降低（p<0.05），除了主导腿在矢状面。
髋关节具有独特的时相依赖性生物力学响应，展示了其协调控制策略，以恢复因步态干扰而导致的平衡。肌肉 CI 的变化表明，通过调节关节刚度特性，可以实现快速、精确的足置控制，这一潜在机制对于平衡辅助可穿戴机器人设备的改进设计具有重要意义。这些在实际地面干扰条件下获得的发现可能对改善平衡辅助可穿戴机器人设备的设计具有重要意义。
