We have studied the dynamics of Au-induced nanowires on Ge(001) using scanning tunnelling microscopy. The ridges of these nanowires consist of buckled dimers that have their dimer bond aligned in a direction perpendicular to the nanowire direction. Neighbouring dimers have a preference to buckle in an opposite direction, leading to rows with a zigzag appearance. Dimers located at anti-phase boundaries continuously flip back and forth between their two buckled configurations. This process is thermally induced and occurs at an average frequency of 25 Hz at room temperature.