Henry S M, Fung J, Horak F B
Physical Therapy Department, University of Vermont, Burlington 05405, USA.
IEEE Trans Rehabil Eng. 1998 Mar;6(1):32-42. doi: 10.1109/86.662618.
The purpose of this study was to compare and contrast postural responses to lateral and A/P surface translations by quantifying joint positions, bilateral three-dimensional (3-D) ground reaction forces, and lower limb and trunk muscle electromyographic (EMG) activity. Subjects stood on a movable platform which was randomly translated in four different directions. The kinematic patterns in response to lateral and anterior/posterior (A/P) surface translations were similar in that there was a sequential displacement and reversal of the shank/thigh and then trunk segments. While the body center of mass (CoM) was displaced equally in response to lateral and A/P translations, equilibrium was maintained by redistributing the vertical forces and changing the shear forces exerted against the support surface. These force responses were bilaterally symmetrical for A/P translations but not for lateral translations. With respect to EMG activity, the first muscle activated was the proximal tensor fascia latae for lateral translations whereas the distal muscles were recruited first for A/P translations. Results from this study suggest that control of postural equilibrium may be similar for A/P and lateral translations, although specific differences in patterns may reflect various biomechanical constraints of the trunk and the lower extremities associated with the two planes of movement.
本研究的目的是通过量化关节位置、双侧三维（3-D）地面反作用力以及下肢和躯干肌肉肌电图（EMG）活动，比较和对比对侧向和前后（A/P）表面平移的姿势反应。受试者站在一个可移动的平台上，该平台在四个不同方向上随机平移。对侧向和前后（A/P）表面平移的运动模式相似，即小腿/大腿和躯干节段存在顺序位移和反向。虽然身体重心（CoM）对侧向和A/P平移的位移相等，但通过重新分配垂直力和改变作用于支撑表面的剪切力来维持平衡。这些力反应对于A/P平移是双侧对称的，但对于侧向平移则不是。关于EMG活动，对于侧向平移，首先激活的肌肉是近端阔筋膜张肌，而对于A/P平移，首先募集的是远端肌肉。本研究结果表明，A/P平移和侧向平移的姿势平衡控制可能相似，尽管模式上的具体差异可能反映了与两个运动平面相关的躯干和下肢的各种生物力学限制。
