The system developed in the USA in the 1980s by Susan Isernhagen, the Functional Capacity Evaluation (FCE), is a comprehensive kinesio-physical test of a person’s ability to perform work-related tasks. This method relies on the specially trained therapist’s expertise to determine maximum function by observing standardized functional criteria, i.e. prime movers (muscles), accessory muscles, body mechanics, speed, heart rate and other physical factors; subjective factors, such as pain reported by the patients and their observed pain behaviors, are recorded, but are not applied as primary evaluation criteria. The therapist determines when maximum effort has been reached and stops testing when implementation of the test activity becomes unsafe and dysfunctional. FCE has become increasingly firmly established in Germay over the last decade. Its role as a tool at the interface of medical and vocational rehabilitation is discussed.