Simonsen E B, Dyhre-Poulsen P, Voigt M, Aagaard P, Fallentin N
Institute of Medical Anatomy Section C, Panum Institute, University of Copenhagen, Denmark.
Scand J Med Sci Sports. 1997 Feb;7(1):1-13. doi: 10.1111/j.1600-0838.1997.tb00110.x.
The present study investigated factors that contribute to the formation of a previously reported knee joint flexor moment during the stance phase of walking. Contradictory results have been reported on this flexor moment, which some but not all individuals exhibit. Seven healthy male subjects were high speed filmed while walking across a force platform, and EMG recordings were obtained from five leg muscles. To investigate segment interactions, net joint moments about the ankle, knee and hip joint were calculated by inverse dynamics and each term in the equation used for the moment calculation was evaluated during the time-course of the step cycle. To test the hypothesis that net joint moments are balanced by an external moment formed by the resulting ground reaction vector multiplied by the perpendicular distance to the actual joint, external moment arms were calculated by the floor reaction force vector approach (FRFV). Contrasting two subjects with different net joint moments about the knee and ankle joint revealed that the knee joint flexor moment could not be explained by an opposite external moment. The external moments were calculated by a simplified method (FRFV) in which the point of force application is incorrect for joints above the ankle joint. However, at the ankle joint the net joint moment was always opposed by an external moment of opposite polarity. A detailed examination of the equation used for the net joint moment calculation showed that a knee joint flexor moment can be caused directly by a large plantar flexor moment about the ankle joint. For example. the soleus muscle can pull the tibia and generate an extensor moment about the knee joint, which in turn has to be opposed by a knee flexor moment from the hamstring muscles. Otherwise the desired joint angles cannot be obtained during human walking. It is therefore suggested that the kinematics regarding how the foot is placed on the ground may influence the net ankle joint moment, while the moment patterns about the knee and hip joint are determined by segment interaction and the requirements for controlling the direction of the resulting ground reaction vector. In vertical jumping it is advantageous to generate extensor moments about the knee and hip joint simultaneously, while in horizontal locomotion this would result in inefficient vertical movements.
本研究调查了在步行站立阶段促成先前报道的膝关节屈肌力矩形成的因素。关于这种屈肌力矩的报道结果相互矛盾，部分但并非所有个体都表现出该力矩。七名健康男性受试者在走过测力平台时进行了高速拍摄，并记录了五条腿部肌肉的肌电图。为了研究节段间的相互作用，通过逆动力学计算了踝关节、膝关节和髋关节的净关节力矩，并在步周期的时间进程中评估了用于力矩计算的方程中的每一项。为了检验净关节力矩由地面反作用力矢量乘以到实际关节的垂直距离所形成的外部力矩平衡这一假设，采用地面反作用力矢量法（FRFV）计算了外部力矩臂。对比两名膝关节和踝关节净关节力矩不同的受试者发现，膝关节屈肌力矩无法用相反的外部力矩来解释。外部力矩是通过一种简化方法（FRFV）计算得出的，在该方法中，对于踝关节以上的关节，力的作用点是不正确的。然而，在踝关节处，净关节力矩总是被极性相反的外部力矩所抵消。对用于净关节力矩计算的方程进行详细检查发现，踝关节处较大的跖屈力矩可直接导致膝关节屈肌力矩。例如，比目鱼肌可牵拉胫骨并产生膝关节伸肌力矩，而这反过来又必须由腘绳肌产生的膝关节屈肌力矩来抵消。否则，在人类行走过程中无法获得所需的关节角度。因此，有人提出，足部与地面接触方式的运动学可能会影响踝关节净力矩，而膝关节和髋关节的力矩模式则由节段间的相互作用以及控制地面反作用力矢量方向的要求所决定。在垂直跳跃中，同时在膝关节和髋关节处产生伸肌力矩是有利的，而在水平运动中，这将导致垂直运动效率低下。
