Background and Purpose: 

Energy minimization is thought to underlie the naturally selected, preferred walking speed; however, people post-stroke walk slower than their most economical speed, presumably to optimize other objectives, such as stability. The purpose of this study was to examine the interplay between walking speed, economy, and stability.

Methods: 

Seven individuals with chronic hemiparesis walked on a treadmill at 1 of 3 randomized speeds: slow, preferred, and fast. Concurrent measurements of speed-induced changes in walking economy (ie, the energy needed to move 1 kg of bodyweight 1 ml O₂/kg/m) and stability were made. Stability was quantified as the regularity and divergence of the mediolateral motion of the pelvic center of mass (pCoM) during walking, as well as pCoM motion relative to the base of support.

Results: 

Slower walking speeds were more stable (ie, pCoM motion was 10% ± 5% more regular and 26% ± 16% less divergent) but 12% ± 5% less economical. Conversely, faster walking speeds were 9% ± 8% more economical, but also less stable (ie, pCoM motion was 17% ± 5% more irregular). Individuals with slower walking speeds had an enhanced energetic benefit when walking faster (r_s = 0.96, P < 0.001). Individuals with greater neuromotor impairment had an enhanced stability benefit when walking slower (r_s = 0.86, P = 0.01).

Discussion and Conclusions: 

People post-stroke appear to prefer walking speeds that are faster than their most stable speed but slower than their most economical speed. The preferred walking speed after stroke appears to balance stability and economy. To encourage faster and more economical walking, deficits in the stable control of the mediolateral motion of the pCoM may need to be addressed.

Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, https://links.lww.com/JNPT/A416).

中文翻译：

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中风后步行速度、经济性和稳定性之间的相互作用

背景与目的： 

能量最小化被认为是自然选择的首选步行速度的基础；然而，中风后的人走路比他们最经济的速度慢，大概是为了优化其他目标，比如稳定性。本研究的目的是检验步行速度、经济性和稳定性之间的相互作用。

方法： 

七名慢性偏瘫患者以 3 种随机速度中的一种在跑步机上行走：慢速、首选速度和快速速度。_{同时测量速度引起的步行经济性变化（即移动 1 公斤体重 1 ml O 2} /kg/m所需的能量）和稳定性。稳定性被量化为行走期间骨盆质心 (pCoM) 中外侧运动的规律性和发散性，以及 pCoM 相对于支撑底部的运动。

结果： 

较慢的步行速度更稳定（即，pCoM 运动的规律性提高 10% ± 5%，发散性降低 26% ± 16%），但经济性降低 12% ± 5%。相反，较快的步行速度经济性提高 9% ± 8%，但稳定性也较差（即，pCoM 运动的不规则性提高 17% ± 5%）。步行速度较慢的个体在步行较快时具有增强的能量优势 ( ​​rs = 0.96, _P < 0.001)。神经运动障碍更严重的个体在走得更慢时具有增强的稳定性益处 ( rs = 0.86, _P = 0.01)。

讨论和结论： 

中风后的人似乎更喜欢比他们最稳定的速度快但比他们最经济的速度慢的步行速度。中风后首选的步行速度似乎可以平衡稳定性和经济性。为了鼓励更快、更经济的步行，可能需要解决 pCoM 中外侧运动的稳定控制缺陷。

视频摘要可从作者那里获得更多见解（参见视频，补充数字内容 1，https://links.lww.com/JNPT/A416）。