During weaving, warp yarns are subjected to dynamic loading before stress relaxation during a loom stop. A test method is presented for simulating this behaviour. There are three types of relaxation curves - simple relaxation, inverse relaxation and mixed relaxation - depending on the previous load history of the yarn. The residual force can be calculated at infinite time in a relaxation test from a model for the tensile curve of spun yarns. There seems to be good correlation with the results of tests made using this method.