In persons with calf muscle weakness, walking energy cost is commonly increased due to persistent knee flexion and a diminished push-off. Provided ankle-foot orthoses (AFOs) usually lower walking energy cost. To maximize the reduction in energy cost, AFO bending stiffness should be individually optimized, but this is not common practice. Therefore, we aimed to evaluate whether individually stiffness-optimized AFOs reduce walking energy cost compared to conventional AFOs in persons with non-spastic calf muscle weakness and, secondarily, whether stiffness-optimized AFOs improve walking speed and gait biomechanics. Thirty-seven persons with non-spastic calf muscle weakness using a conventional AFO were included. Participants were provided a new, individually stiffness-optimized AFO. Walking energy cost, speed and gait biomechanics were assessed, at delivery and 3-months follow-up. Stiffness-optimized AFOs reduced walking energy cost with 9.2% (−0.42J/kg/m, 95%CI: 0.26 to 0.57) compared to the conventional AFOs while walking speed increased with 5.2% (+0.05m/s, 95%CI: 0.03 to 0.08). In bilateral affected persons the effects were larger compared to unilateral affected persons (difference effect energy cost: 0.31J/kg/m, speed: +0.09m/s). Although individually gait biomechanics changed considerably, no significant group differences were found (p > 0.118). We demonstrated that individually stiffness-optimized AFOs considerably and meaningfully reduced walking energy cost compared to conventional AFOs, which was accompanied by an increase in walking speed. Especially in bilateral affected persons large effects of stiffness-optimization were found. The individual differences in gait changes substantiate the recommendation that the AFO bending stiffness should be individually tuned to minimize walking energy cost.

中文翻译：

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与神经肌肉疾病中的传统矫形器相比，刚度优化的踝足矫形器可改善步行能量消耗：一项前瞻性不受控制的干预研究

在小腿肌肉无力的人中，步行能量的消耗通常是由于膝盖持续屈曲和下推力下降而增加的。提供的踝足矫形器（AFO）通常可以降低步行能量消耗。为了最大程度地降低能源成本，应分别优化AFO的弯曲刚度，但这不是普遍做法。因此，我们旨在评估在非痉挛性小腿肌肉无力的人群中，单独进行刚度优化的AFO是否比传统AFO降低步行能量成本；其次，评估刚度优化的AFO是否改善步行速度和步态生物力学。包括37名使用常规AFO的非痉挛性小腿肌肉无力的人。为参与者提供了一个新的，经过单独刚度优化的AFO。评估步行能量成本，速度和步态生物力学，分娩时和3个月的随访中。刚度优化的AFO与传统AFO相比，步行能量成本降低了9.2％（-0.42J / kg / m，95％CI：0.26至0.57），而步行速度提高了5.2％（+ 0.05m / s，95％CI ：0.03至0.08）。与单方面受影响的人相比，在双边受影响的人中影响更大（差异影响能量成本：0.31J / kg / m，速度：+ 0.09m / s）。尽管个体步态的生物力学发生了很大变化，但未发现明显的群体差异（p> 0.118）。我们证明，与传统的AFO相比，单独进行刚度优化的AFO可以显着降低步行能量成本，并伴随步行速度的提高。特别是在双边受影响的人中，发现刚度优化的效果很大。