Force direction patterns promote whole body stability even in hip-flexed walking, but not upper body stability in human upright walking
Force direction patterns promote whole body stability even in hip-flexed walking, but not upper body stability in human upright walking
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DOI：
10.1098/rspa.2017.0404
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发表时间：
2017-11-01
影响因子：
3.5
通讯作者：
Blickhan, Reinhard
中科院分区：
文献类型：
--
作者：
Mueller, Roy;Rode, Christian;Blickhan, Reinhard
将地面反作用力引导到全身质心上方的焦点，可以促进人类和动物步态的全身稳定性，类似于物理钟摆。在这里，我们展示了人类髋部弯曲行走时的情况也是如此。对于所有上半身方向（直立、25 度、50 度、最大），焦点远高于整个身体的质心，表明其与步行的一般相关性。随着上半身倾斜度从 25 毫米均方根偏差 (RMSD) 增加到 43 毫米，力作用线与焦点的偏差增加。对于直立步态的上半身，所产生的力也在焦点附近传递（净力的作用线和焦点之间的 RMSD 为 17 毫米），但该点位于其质心下方 18 厘米。虽然这种行为模仿了不稳定的倒立摆，但它会导致根据周期性上半身运动产生交替符号的扭矩，并且可能通过保持较小的髋部扭矩来降低直立步态的代谢成本。上半身的稳定是其他机制的结果，例如：髋部反射或肌肉预反射。
Directing the ground reaction forces to a focal point above the centre of mass of the whole body promotes whole body stability in human and animal gaits similar to a physical pendulum. Here we show that this is the case in human hip-flexed walking as well. For all upper body orientations (upright, 25 degrees, 50 degrees, maximum), the focal point was well above the centre of mass of the whole body, suggesting its general relevance for walking. Deviations of the forces' lines of action from the focal point increased with upper body inclination from 25 to 43mm root mean square deviation (RMSD). With respect to the upper body in upright gait, the resulting force also passed near a focal point (17 mm RMSD between the net forces' lines of action and focal point), but this point was 18 cm below its centre of mass. While this behaviour mimics an unstable inverted pendulum, it leads to resulting torques of alternating sign in accordance with periodic upper body motion and probably provides for low metabolic cost of upright gait by keeping hip torques small. Stabilization of the upper body is a consequence of other mechanisms, e.g. hip reflexes or muscle preflexes.