The use of artificial (man-made) materials to replace lost or damaged biological soft tissue has drawbacks, because the mechanical behavior of artificial materials fails to adequately mimic that of soft tissue such as ligaments, tendons, and skin. These natural materials exhibit large initial extension at small load, followed by a change to relatively little additional extension at rapidly increasing load, giving a J-shaped load versus extension curve. We have found that fibrous assemblies based on circular rings as a repeat unit can give both the J-shaped load versus extension curve and the high overall extension of many biological soft tissues. In addition, we have developed a criterion for design of and materials selection for the fibrous assembly. This criterion, which relates inherent properties of the material to the dimensions and extension ratio of the repeat unit, predicts the mechanical stability and recoverability of the repeat unit, and therefore of the fibrous structure composed of the repeat unit. The results of the study are promising for the development of soft tissue repairs or replacements of man-made fibers.