An absolute strength (force at break) value does not always cover all the information about the strength of a yarn. When a yarn is used in applications where it is subjected to a constant load for a prolonged period of time, the maximum load is often lower than the force at break. It is interesting and in some cases necessary to know what the maximum load is at a specified amount of time. We have equipment which is able to apply stress to yarns for long periods under controlable conditions like elevated temperatures. Another advantage to this measurement is that long term processes like creep become visible.