To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Movie S5. When a composite of Spandex fibers and PDMS matrix is subject to cyclic loading, fibers debond and slide against the matrix. Finally, the debond turns into a running crack. Stretchable materials of high toughness and low hysteresis Zhengjin Wang, Chunping Xiang, Xi Yao, Paul Le Floch, Julien Mendez, and Zhigang Suo PNAS. 2019. 116:5967-5972 DOI: 10.1073/pnas.1821420116 Download Original Video Browse All Videos »