Kinesiology Program, Arizona State University, 550 N. 3rd Street, Phoenix, AZ, 85004, USA.
Ann Biomed Eng. 2018 Feb;46(2):318-323. doi: 10.1007/s10439-017-1957-7. Epub 2017 Nov 13.
The inverted pendulum model predicts that the major challenge for neural control of the upright posture is the inherent instability of the body due to the center of mass (COM) being above the base of support (BOS). If so, even slight elevation of the COM may substantially destabilize posture. The destabilizing effect of heavy load positioned above the COM has been demonstrated. We examined sensitivity of posture to light (1-5% of body weight) load by placing weights on the shoulders and assessing functional reach distance in the forward, right, and left directions and postural sway during quiet stance. At each load level, the quiet stance task was tested with and without vision. The 1% of body weight load significantly shortened reach distance in the forward direction. It also increased postural sway. Interestingly, additional weight did not result in further deficits. The results support high sensitivity of postural stability to COM elevation that increases the challenge for neural control of posture and that can potentially be used for early detection of declines in postural stability.
倒立摆模型预测，由于重心（COM）高于支撑基础（BOS），因此神经控制直立姿势的主要挑战是身体固有的不稳定性。如果是这样，即使 COM 稍有升高也可能会使姿势严重不稳定。已经证明了位于 COM 上方的重物的失稳效应。我们通过在肩部放置重物，并评估向前、右和左方向的功能伸展距离以及在安静站立时的姿势摆动，来检查姿势对轻（1-5%体重）负荷的敏感性。在每个负荷水平下，在有和没有视觉的情况下测试安静站立任务。1%体重的负荷显著缩短了向前伸展的距离。它还增加了姿势摆动。有趣的是，增加额外的重量不会导致进一步的缺陷。研究结果支持姿势稳定性对 COM 升高的高度敏感性，这增加了对姿势神经控制的挑战，并且可能可用于早期检测姿势稳定性的下降。
