  Plenty of research on elastic interfaces has been done on systems where the
interface is pushed with a constant force. We studied the average velocity of
an interface under a sinusoidal driving in the creep region, considering both
short-range elastic systems, such as magnetic domain walls during a hysteresis
loop, and long ranged systems such as fractures. We obtained a modified version
of the creep velocity with approximate power-law behaviour and a material
dependent exponent for short ranged systems and simpler behaviour for
long-range elasticity. We discuss whether the model can be applied to fatigue
fractures, or if extra physics is needed.
