The structures in service are subjected to loads whose amplitude varies most often over time. These differences in loading cycle levels will have a direct impact on the propagation of cracks that can lead to accelerations or slowdowns in the propagation speed of these cracks. Indeed, the delay of the propagation of a crack produced by the application of a simple overload depends on several parameters, such as the material, the loading, the geometry of the specimen and the environment. In this paper, study the influence of the loading parameters such as the load ratio, and the overload rate, on both crack propagation, propagation speed, number of delay cycle, is investigated by using the AFGROW code and the willenbourg model, which describes the delay after applying overloads.