Abstract: The present invention relates to a method of fatigue testing an elongate specimen, such as a wind turbine blade, comprising: calculating a service life damage sum at one or more locations on at least one respective first section of an elongate specimen, responsive to at least one strain time history associated with the specimen; determining a predicted test damage sum at the one or more locations for each of a plurality of predetermined test blocks separately applicable to the specimen; and selecting at least one test block associated with the plurality of predetermined test blocks based on a comparison of the predicted test damage sum with the service life damage sum for each of the one or more locations, wherein the selected at least one test block is applicable to the specimen to cause a test damage sum at each of the one or more locations that at least substantially matches the service life damage sum at each of the one or more locations.