Evolving sperm trajectory in the x-y plane of the pharmacologically treated cell in Fig. 1a (black curve). A red dot indicates the beginning of the journey and a green one the inhibitor addition (see also Fig. 1f). The yellow point corresponds to the moment when after an abrupt stopping for some seconds, the cell re-initiates with rapid flagellar shape changes with high curvature (see Fig. 1c,d). The blue point corresponds to the moment when the sperm clearly switches to a hyperactivated gait.