Riley P O, Schenkman M L, Mann R W, Hodge W A
Massachusetts General Hospital, Boston 02114.
J Biomech. 1991;24(1):77-85. doi: 10.1016/0021-9290(91)90328-k.
A sit-to-stand task is analyzed by a method which estimates the segmental and whole body center of mass (CoM) kinematics and kinetics using bilateral whole body kinematic data from nine healthy young female subjects. The sit-to-stand, or chair-rise, task is constrained with regard to chair height, pace, initial lower limb position and arm use. The chair-rise maneuver is divided into four phases; (1) the flexion momentum phase; (2) the momentum transfer phase; (3) the vertical extension phase; and (4) the stabilization phase; the first three are examined in detail here. The momentum transfer phase, which immediately follows lift-off from the seat of the chair, is the most dynamic portion of the event, demanding a high degree of coordination. This maneuver is analyzed in order to determine if trunk movement is used only to position the body center of gravity or if the trunk motion generates momentum which is important during the brief but critical period of dynamic equilibrium immediately following lift-off from the chair. Our evidence points to the latter case and indicates that inter-segmental momentum transfer is possible during this period.
采用一种方法对坐立任务进行分析，该方法利用来自九名健康年轻女性受试者的双侧全身运动学数据，估计节段和全身质心（CoM）的运动学和动力学。坐立任务，即从椅子上起身的任务，在椅子高度、节奏、下肢初始位置和手臂使用方面受到限制。从椅子上起身的动作分为四个阶段：（1）屈曲动量阶段；（2）动量传递阶段；（3）垂直伸展阶段；（4）稳定阶段；这里详细研究前三个阶段。动量传递阶段紧接从椅子座位上抬起后开始，是该动作最具动态的部分，需要高度的协调性。分析此动作是为了确定躯干运动是否仅用于定位身体重心，或者躯干运动是否产生动量，而该动量在从椅子上抬起后紧接着的短暂但关键的动态平衡期很重要。我们的证据指向后一种情况，并表明在此期间节段间动量传递是可能的。
