Induction of paired bends by mechanical deformation resulted a response of bend relaxation (BR). Response of a demembranated sperm at 1.7 μM ATP following to paired bend formation by axial needle movement. Sequential images of this movie are shown in Fig. 1B (Bend relaxation, BR). Numbers at the bottom right indicate time in seconds. Induction of bending for 2 seconds (16:19:34-16:19:36) was followed by bends translation to the distal region of the flagellum in 43 seconds (16:19:36-16:20:19). Scale bar: 10 μm.