Fujisawa Hiroyuki, Suzuki Hiroto, Murakami Kenichi, Kawakami Shingo, Suzuki Makoto
Department of Rehabilitation, Faculty of Medical Science and Welfare, Tohoku Bunka Gakuen University, Japan.
J Phys Ther Sci. 2016 Jan;28(2):613-20. doi: 10.1589/jpts.28.613. Epub 2016 Feb 29.
[Purpose] The purposes of this study were first to analyze the multijoint dynamics of downward squatting, and to examine the contribution of interaction torque and muscle torque to net torque, and second, to examine mechanisms of movement control. [Subjects] The subjects were 31 healthy men with a mean age of 21.0 ± 1.2 years (range, 19-24 years). [Methods] Squatting tasks with the trunk in two positions, an erect and anterior tilt position, were performed by the subjects. Net, interaction, muscle, and gravity torque were calculated according to the Lagrange equation using 3D tracking data. [Results] The contribution ratio of interaction torque to net torque was approximately 90%, irrespective of the joint and task. In contrast, muscle torque showed complicated behavior to compensate for gravity torque. A combined muscle and gravity torque profile showed flexion or dorsiflexion immediately after the initiation of the movement, and it later changed to extension or plantar flexion. [Conclusion] The torque that contributes almost exclusively to the net torque was interaction torque. The combination of muscle and gravity torque at the knee joint and the hip joint is important for movement control, independent of the starting position.
[目的] 本研究的目的一是分析下蹲动作的多关节动力学，研究相互作用扭矩和肌肉扭矩对净扭矩的贡献；二是研究运动控制机制。[对象] 研究对象为31名健康男性，平均年龄21.0±1.2岁（范围19 - 24岁）。[方法] 受试者在躯干处于直立和前倾两种姿势下进行下蹲任务。利用三维跟踪数据，根据拉格朗日方程计算净扭矩、相互作用扭矩、肌肉扭矩和重力扭矩。[结果] 无论关节和任务如何，相互作用扭矩对净扭矩的贡献率约为90%。相比之下，肌肉扭矩表现出复杂的行为以补偿重力扭矩。肌肉扭矩与重力扭矩的组合曲线在运动开始后立即显示为屈曲或背屈，随后转变为伸展或跖屈。[结论] 几乎完全对净扭矩有贡献的扭矩是相互作用扭矩。膝关节和髋关节处肌肉扭矩与重力扭矩的组合对于运动控制很重要，与起始姿势无关。
