Dionisio Valdeci Carlos, Almeida Gil Lúcio, Duarte Marcos, Hirata Rogério Pessoto
Laboratory of Clinical Studies in Physical Therapy, University of Ribeirão Preto, Ribeirão Preto, Brazil.
J Electromyogr Kinesiol. 2008 Feb;18(1):134-43. doi: 10.1016/j.jelekin.2006.07.010. Epub 2006 Oct 6.
The aim of this study was to investigate the kinematic, kinetic, and electromyographic pattern before, during and after downward squatting when the trunk movement is restricted in the sagittal plane. Eight healthy subjects performed downward squatting at two different positions, semisquatting (40 degrees knee flexion) and half squatting (70 degrees knee flexion). Electromyographic responses of the vastus medialis oblique, vastus medialis longus, rectus femoris, vastus lateralis, biceps femoris, semitendineous, gastrocnemius lateralis, and tibialis anterior were recorded. The kinematics of the major joints were reconstructed using an optoelectronic system. The center of pressure (COP) was obtained using data collected from one force plate, and the ankle and knee joint torques were calculated using inverse dynamics. In the upright position there were small changes in the COP and in the knee and ankle joint torques. The tibialis anterior provoked the disruption of this upright position initiating the squat. During the acceleration phase of the squat the COP moved posteriorly, the knee joint torque remained in flexion and there was no measurable muscle activation. As the body went into the deceleration phase, the knee joint torque increased towards extension with major muscle activities being observed in the four heads of the quadriceps. Understanding these kinematic, kinetic and EMG strategies before, during and after the squat is expected to be beneficial to practitioners for utilizing squatting as a task for improving motor function.
本研究的目的是调查当躯干运动在矢状面受到限制时，下蹲过程中及下蹲前后的运动学、动力学和肌电图模式。八名健康受试者在两个不同位置进行下蹲，即半蹲（膝关节屈曲40度）和半深蹲（膝关节屈曲70度）。记录了股内侧斜肌、股内侧长肌、股直肌、股外侧肌、股二头肌、半腱肌、腓骨外侧肌和胫骨前肌的肌电图反应。使用光电系统重建主要关节的运动学。通过从一个测力板收集的数据获得压力中心（COP），并使用逆动力学计算踝关节和膝关节扭矩。在直立位时，COP以及膝关节和踝关节扭矩有微小变化。胫骨前肌引发了这种直立位的破坏，从而启动下蹲。在下蹲的加速阶段，COP向后移动，膝关节扭矩保持在屈曲状态，且未观察到可测量的肌肉激活。当身体进入减速阶段时，膝关节扭矩朝着伸展方向增加，在股四头肌的四个头中观察到主要的肌肉活动。了解下蹲过程中及下蹲前后的这些运动学、动力学和肌电图策略，有望对从业者将下蹲作为改善运动功能的任务有所帮助。
