Proposal of a Neuromusculoskeletal Model Considering Muscle Tone in Human Gait

In an aging society, it is increasingly important to solve problems related to human gait. One of these issues is the relationship between gait and muscle tone. In this study, we propose a neuromusculoskeletal model that can be used to represent and evaluate the movement changes generated by changes in muscle tone in human gait using computational simulations. The model is based using a musculoskeletal model with 70 muscles and a neurological controller model that can represent muscle tone. As a hypothesis to judge the validity of the model, a high muscle tone makes it difficult to maintain gait and makes the stride length narrow. A total of 1470 parameters were optimized for 3 days for each trial with varying muscle tone. As a result under the condition of high muscle tone, the gait maintenance time became shorter, and the stride length became narrow compared with the experimental value. Therefore, the hypothesis used to judge the validity of the model that gait maintenance becomes difficult and stride length becomes narrow under high muscle tone was proved. In addition, the tendency for changes in the angle of the knee joint, the distance traveled by the center of the foot pressure, the number of times the foot touched the ground, the distance the foot swung forward, the regularity and periodicity of each gait, and the bimodality of foot pressure were evaluated and confirmed to be natural. From these results, we conclude that the neuromusculoskeletal model for gait proposed in this study was proper.