Mechanical and metabolic requirements for active lateral stabilization in human walking
Mechanical and metabolic requirements for active lateral stabilization in human walking
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DOI：
10.1016/j.jbiomech.2003.06.002
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发表时间：
2004-06-01
影响因子：
2.4
通讯作者：
Kuo, AD
中科院分区：
文献类型：
--
作者：
Donelan, JM;Shipman, DW;Kuo, AD
行走在横向上似乎被动地不稳定，需要主动反馈控制来保持稳定性。中枢神经系统可以通过调整内外侧脚的位置来控制稳定性，但可能会产生代谢成本。该成本随着狭窄的台阶而增加，并且可能影响优选的台阶宽度。我们假设身体的外部稳定会减少所需的主动控制，从而降低代谢成本和首选步宽。为了测试这些假设，我们使用弹簧从腰部向两侧拉动，为受试者在压力跑步机上以 1.25 m/s 的速度行走提供外部横向稳定性。十名受试者以规定的零步宽和他们喜欢的步宽行走，无论有没有稳定。我们使用间接量热法测量代谢成本，并根据力量跑步机数据测量步长。我们发现，在规定的零步宽下，外部稳定导致步宽变异性（均方根）降低 33%，代谢成本降低 9.2%。在优选的步宽条件下，外部稳定使受试者更喜欢窄 47% 的步宽，步宽变异性减少 32%，代谢成本减少 5.7%。这些结果表明，（a）人类行走需要主动横向稳定，（b）身体横向运动通过脚的内侧-外侧放置部分稳定，（c）主动稳定需要适度的代谢成本，以及（d）人类避免狭窄的步宽，因为它们不太稳定。 (C) 2004 Elsevier Ltd. 保留所有权利。
Walking appears to be passively unstable in the lateral direction, requiring active feedback control for stability. The central nervous system may control stability by adjusting inedio-lateral foot placement, but potentially with a metabolic cost. This cost increases with narrow steps and may affect the preferred step width. We hypothesized that external stabilization of the body would reduce the active control needed, thereby decreasing metabolic cost and preferred step width. To test these hypotheses, we provided external lateral stabilization, using springs pulling bilaterally from the waist, to human subjects walking on a force treadmill at 1.25 m/s. Ten subjects walked, with and without stabilization, at a prescribed step width of zero and also at their preferred step width. We measured metabolic cost using indirect calorimetry, and step width from force treadmill data. We found that at the prescribed zero step width, external stabilization resulted in a 33% decrease in step width variability (root-mean-square) and a 9.2% decrease in metabolic cost. In the preferred step width conditions, external stabilization caused subjects to prefer a 47% narrower step width, with a 32% decrease in step width variability and a 5.7% decrease in metabolic cost. These results suggest that (a) human walking requires active lateral stabilization, (b) body lateral motion is partially stabilized via medio-lateral foot placement, (c) active stabilization exacts a modest metabolic cost, and (d) humans avoid narrow step widths because they are less stable. (C) 2004 Elsevier Ltd. All rights reserved.