Skeletal muscles possess the combinational properties of high fatigue resistance (1,000 J/m²), high strength (1 MPa), low Young’s modulus (100 kPa), and high water content (70 to 80 wt %), which have not been achieved in synthetic hydrogels. The muscle-like properties are highly desirable for hydrogels’ nascent applications in load-bearing artificial tissues and soft devices. Here, we propose a strategy of mechanical training to achieve the aligned nanofibrillar architectures of skeletal muscles in synthetic hydrogels, resulting in the combinational muscle-like properties. These properties are obtained through the training-induced alignment of nanofibrils, without additional chemical modifications or additives. In situ confocal microscopy of the hydrogels’ fracturing processes reveals that the fatigue resistance results from the crack pinning by the aligned nanofibrils, which require much higher energy to fracture than the corresponding amorphous polymer chains. This strategy is particularly applicable for 3D-printed microstructures of hydrogels, in which we can achieve isotropically fatigue-resistant, strong yet compliant properties.

骨骼肌具有高抗疲劳性（1,000 J/m ²）、高强度（1 MPa）、低杨氏模量（100 kPa）和高含水量（70至80 wt%）的综合性能，这是迄今为止尚未实现的在合成水凝胶中。类似肌肉的特性对于水凝胶在承重人造组织和软装置中的新兴应用来说是非常理想的。在这里，我们提出了一种机械训练策略，以实现合成水凝胶中骨骼肌的对齐纳米纤维结构，从而产生组合的肌肉样特性。这些特性是通过训练诱导的纳米原纤维排列获得的，无需额外的化学修饰或添加剂。水凝胶断裂过程的原位共焦显微镜显示，抗疲劳性是由对齐的纳米原纤维的裂纹钉扎引起的，与相应的无定形聚合物链相比，断裂需要更高的能量。该策略特别适用于 3D 打印的水凝胶微观结构，我们可以在其中实现各向同性的抗疲劳、坚固且合规的特性。