Modeling of human neuromuscular system in due consideration of nonlinearities in muscle contraction process

对脊椎动物的运动控制系统(神经肌肉系统)进行建模研究，以了解其肌肉骨骼系统的运动行为和/或将该模型应用于医学和工程应用。本研究提出的骨骼肌运动模型是一种与跨桥自行车系统协同工作的流变学模型。电机模型由两个Maxwell-和一个Voigt元件相互并联组成。权函数用于改变电机的粘弹性常数，使其与所产生的力成比例。对马达进行了等张缩短法和慢拉伸/缓释实验的数值模拟，计算了马达的能量释放。马达的力-速度关系呈双曲线，与肌纤维一样具有节能功能。…很好地反映了骨骼肌拉伸诱导的力增强和缩短诱导的力抑制更多的假设是，力产生能力对应于电机在缓慢拉伸/释放期间所遭受的机械冲量而增加/减少。然后，我们提出了一个肌肉收缩过程模型，该模型除了具有运动模型的上述缩短特征外，还具有从肌浆网释放钙的功能。钙释放的函数由脉冲响应的卷积积分表示。过程模型的输入是动作势，输出是力。首先在输入一排正弦脉冲(对应于动作电位)的情况下进行了数值模拟，并计算力的时间过程。骨骼肌典型的力产生行为，抽搐和破伤风，分别根据在肌肉纤维中观察到的输入信号的频率而发生。最后，在人体肱二头肌的力产生实验中，对五种力产生模式下的肌电信号进行了测量。将肌电信号数据输入肌肉收缩过程模型，模拟肌肉收缩过程中力的时间过程。所有的力产生模式的模拟结果与在力产生实验中得到的实验结果吻合得很好。结果表明，该模型对于分析和理解人类男性骨骼系统的动力学行为是非常有用的。较少

Modeling of the motion control system (neuromuscular system) of vertebrates is studied to understand the kinetic behavior of their musculoskeletal systems and/or to apply the model to medical and engineering uses. The motor model of the skeletal muscle proposed in this study is a rheological model that works in corporation with the cross-bridge cycling system. The motor model consists of two Maxwell- and one Voigt elements connected in parallel with each other. Weight functions are used to change the visco-elastic constants of the motor in proportion to the force generated. The numerical simulations of the isotonic shortening and the slow stretch/release experiments of the motor are carried out and the energy liberation is calculated. The force-velocity relation of the motor shows a hyperbolic curve and the energy saving function is possessed as in the muscle fibers. The stretch-induced force enhancement and shortening-induced force depression of skeletal muscle are well represented wi … More th an assumption that the force generation ability is increased/decreased corresponding to the amount of the mechanical impulse that the motor is suffered during the slow stretch/release. Then we propose a muscle contraction process model with the function of the Ca^<++> release from the sarcoplasmic reticulum in addition to the aforementioned shortening characteristics of the motor model. The function of the Ca^<++> release is represented by a convolutional integral of the impulse response. The input into the process model is the action potential and the output is the force. The numerical simulations are first carried out with the input of a row of single sinusoidal pulses (corresponding to action potentials) and the time course of force is calculated. The typical force generation behavior of the skeletal muscle, twitch and tetanus, take place according to the frequency of the input signal as observed in muscle fibers, respectively. Finally the measurements of the electromyogram (EMG) signals are made in the force generation experiments of human biceps brachii muscle with five kinds of force generation patterns. The EMG signal data are input into the muscle contraction process model and the time course of force is simulated. The simulation results for all of the force generation patterns coincide well with the experimental results obtained in the force generation experiments. It is confirmed that the model proposed here is quite useful for analyzing and understanding the dynamic behavior of human masculoskeletal systems. Less