Walking and running are the most common means of locomotion in human daily life. People have made advances in developing separate exoskeletons to reduce the metabolic rate of walking or running. However, the combined requirements of overcoming the fundamental biomechanical differences between the two gaits and minimizing the metabolic penalty of the exoskeleton mass make it challenging to develop an exoskeleton that can reduce the metabolic energy during both gaits. Here we show that the metabolic energy of both walking and running can be reduced by regulating the metabolic energy of hip flexion during the common energy consumption period of the two gaits using an unpowered hip exoskeleton. We analyzed the metabolic rates, muscle activities and spatiotemporal parameters of 9 healthy subjects (mean ± s.t.d; 24.9 ± 3.7 years, 66.9 ± 8.7 kg, 1.76 ± 0.05 m) walking on a treadmill at a speed of 1.5 m s−1 and running at a speed of 2.5 m s−1 with different spring stiffnesses. After obtaining the optimal spring stiffness, we recruited the participants to walk and run with the assistance from a spring with optimal stiffness at different speeds to demonstrate the generality of the proposed approach. We found that the common optimal exoskeleton spring stiffness for walking and running was 83 Nm Rad−1, corresponding to 7.2% ± 1.2% (mean ± s.e.m, paired t-test p < 0.01) and 6.8% ± 1.0% (p < 0.01) metabolic reductions compared to walking and running without exoskeleton. The metabolic energy within the tested speed range can be reduced with the assistance except for low-speed walking (1.0 m s−1). Participants showed different changes in muscle activities with the assistance of the proposed exoskeleton. This paper first demonstrates that the metabolic cost of walking and running can be reduced using an unpowered hip exoskeleton to regulate the metabolic energy of hip flexion. The design method based on analyzing the common energy consumption characteristics between gaits may inspire future exoskeletons that assist multiple gaits. The results of different changes in muscle activities provide new insight into human response to the same assistive principle for different gaits (walking and running).

中文翻译：

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使用无动力髋外骨骼减少步行和跑步的代谢能量

步行和跑步是人类日常生活中最常见的运动方式。人们在开发单独的外骨骼以降低步行或跑步的代谢率方面取得了进展。然而，克服两种步态之间的基本生物力学差异和最小化外骨骼质量的代谢损失的综合要求使得开发一种可以减少两种步态期间代谢能量的外骨骼具有挑战性。在这里，我们表明使用无动力髋外骨骼可以通过在两种步态的共同能量消耗期间调节髋屈曲的代谢能量来降低步行和跑步的代谢能量。我们分析了 9 名健康受试者的代谢率、肌肉活动和时空参数（平均值 ± 标准；24.9 ± 3.7 岁，66.9 ± 8.7 kg，1.76 ± 0。05 m）在跑步机上以 1.5 ms-1 的速度行走，并以 2.5 ms-1 的速度在不同的弹簧刚度下跑步。在获得最佳弹簧刚度后，我们招募参与者在具有最佳刚度的弹簧的帮助下以不同速度行走和跑步，以证明所提出方法的通用性。我们发现步行和跑步的常见最佳外骨骼弹簧刚度为 83 Nm Rad−1，对应于 7.2% ± 1.2%（平均值 ± sem，配对 t 检验 p < 0.01）和 6.8% ± 1.0%（p < 0.01 ）与没有外骨骼的步行和跑步相比，代谢减少。除了低速步行（1.0 ms-1）外，在测试速度范围内的代谢能量可以在辅助下减少。参与者在拟议的外骨骼的帮助下表现出肌肉活动的不同变化。本文首先论证了使用无动力髋外骨骼来调节髋屈曲的代谢能量可以降低步行和跑步的代谢成本。基于分析步态之间共同能量消耗特征的设计方法可能会启发未来辅助多步态的外骨骼。肌肉活动的不同变化的结果为人类对不同步态（步行和跑步）相同辅助原理的反应提供了新的见解。基于分析步态之间共同能量消耗特征的设计方法可能会启发未来辅助多步态的外骨骼。肌肉活动的不同变化的结果为人类对不同步态（步行和跑步）相同辅助原理的反应提供了新的见解。基于分析步态之间共同能量消耗特征的设计方法可能会启发未来辅助多步态的外骨骼。肌肉活动的不同变化的结果为人类对不同步态（步行和跑步）相同辅助原理的反应提供了新的见解。