Dynamic arm swinging in human walking
Dynamic arm swinging in human walking
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DOI：
10.1098/rspb.2009.0664
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发表时间：
2009-10-22
影响因子：
4.7
通讯作者：
Kuo, Arthur D.
中科院分区：
文献类型：
--
作者：
Collins, Steven H.;Adamczyk, Peter G.;Kuo, Arthur D.
人类走路时倾向于摆动手臂，这是一种奇怪的行为，因为手臂在两足步态中没有明显的作用。使用肌肉来摆动手臂的成本可能很高，而且目前还不清楚身体其他部位的潜在益处是否值得这样的成本。为了检验这些成本和收益，我们开发了一个具有自由摆动手臂的被动动态步行模型。即使没有扭矩驱动手臂或腿，该模型也能产生与人类相似的手臂摆动步态。手臂相位与正常相反的被动步态也被发现，但这些步态从地面引起的反应力矩要大得多，这可能需要人类的肌肉力量。因此，我们假设这一时刻的减少可以解释手臂摆动的生理益处。对人类（n = 10）的实验测量表明，正常的手臂摆动只需要最小的肩膀扭矩，而有意识地保持手臂仍然需要多12%的代谢能量。在步态力学测量中，手臂摆动对垂直地面反应力矩的影响最大，没有手臂摆动的情况下，垂直地面反应力矩增加了63%。与正常手臂相反的走路方式只需要最小的肩部力量，但会放大地面反应力矩，导致代谢率增加26%。被动动力似乎使手臂摆动更容易，而减少垂直力矩的间接好处使其整体上值得。
Humans tend to swing their arms when they walk, a curious behaviour since the arms play no obvious role in bipedal gait. It might be costly to use muscles to swing the arms, and it is unclear whether potential benefits elsewhere in the body would justify such costs. To examine these costs and benefits, we developed a passive dynamic walking model with free-swinging arms. Even with no torques driving the arms or legs, the model produced walking gaits with arm swinging similar to humans. Passive gaits with arm phasing opposite to normal were also found, but these induced a much greater reaction moment from the ground, which could require muscular effort in humans. We therefore hypothesized that the reduction of this moment may explain the physiological benefit of arm swinging. Experimental measurements of humans (n = 10) showed that normal arm swinging required minimal shoulder torque, while volitionally holding the arms still required 12 per cent more metabolic energy. Among measures of gait mechanics, vertical ground reaction moment was most affected by arm swinging and increased by 63 per cent without it. Walking with opposite-to-normal arm phasing required minimal shoulder effort but magnified the ground reaction moment, causing metabolic rate to increase by 26 per cent. Passive dynamics appear to make arm swinging easy, while indirect benefits from reduced vertical moments make it worthwhile overall.