Effect of Ankle-Foot Orthosis Stiffness on Muscle Force During Gait Through Mechanical Testing and Gait Simulation
Effect of Ankle-Foot Orthosis Stiffness on Muscle Force During Gait Through Mechanical Testing and Gait Simulation
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DOI：
10.1109/access.2021.3095530
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发表时间：
2021
期刊：
影响因子：
3.9
通讯作者：
Masataka Yamamoto;Koji Shimatani;Hitoshi Okano;H. Takemura
中科院分区：
文献类型：
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作者：
Masataka Yamamoto;Koji Shimatani;Hitoshi Okano;H. Takemura
踝足矫形器（AFO）的力学测试和步态测量是确定个体AFO刚度大小的关键。然而，在步态过程中的肌肉力量的刚度大小的影响的信息是有限的。本研究旨在探讨踝足矫形器刚度与步态时踝关节肌力的关系。利用六轴机械臂对AFO的刚度进行了机械测试，通过改变弹簧常数来调节刚度大小。为每个跖屈阻力（PFR）和背屈阻力（DFR）功能设置五个刚度条件。采用骨骼肌模型和AFO模型研究了PFR和DFR对步态中踝关节肌力的影响。通过步态模拟计算胫骨前肌（TA）和小腿三头肌（TS）的肌力。角-力矩关系显示了每种条件下的磁滞回线。PFR和DFR条件之一与其他条件显著不同（对于所有条件，p < 0.05）。按刚度较低的顺序，在无刚度条件下归一化的峰值TA肌力中的每个PFR贡献率分别为8.4%、10.8%、11.3%、13.5%和15.3%;而每个DFR对峰值TS肌力的贡献率分别为16.2%、20.9%、25.3%、29.8%和30.5%。通过力学测试以及步态模拟，证明了AFO刚度的大小降低了步态过程中所需的踝关节肌肉力。这项研究可以有助于更有效的步态康复使用AFO以及AFO制造定制刚度为个人步态功能。
Mechanical testing and gait measurement for ankle-foot orthosis (AFO) are crucial for determining the AFO stiffness magnitude in an individual. However, information on the effect of the stiffness magnitude on the muscle force during gait is limited. This study aimed to investigate the relationship between the AFO stiffness and ankle muscle force during gait. The AFO stiffness was mechanically tested using a six-axis robot arm. The stiffness magnitude was adjusted using different spring constants. Five stiffness conditions were set for each plantarflexion resistive (PFR) and dorsiflexion resistive (DFR) function. The effect of the PFR and DFR on the ankle muscle force during gait were determined using musculoskeletal and AFO models. Tibialis anterior (TA) and triceps surae (TS) muscle forces were calculated through gait simulation. The angle-moment relationships display hysteresis loops for each condition. One of the PFR and DFR conditions differed significantly from the others (for all, p < 0.05). In order of lower stiffness, the each PFR contribution ratio to the peak TA muscle force normalized in the no-stiffness condition was 8.4%, 10.8%, 11.3%, 13.5%, and 15.3%; while the each DFR contribution ratio to the peak TS muscle force was 16.2%, 20.9%, 25.3%, 29.8%, and 30.5%, respectively. Through mechanical testing as well as gait simulation, it was demonstrated that the magnitude of the AFO stiffness decreased the required ankle muscle force during gait. This study can contribute to more effective gait rehabilitation using AFO as well as AFO fabrication with customized stiffness for individual gait function.