Fig. 9. (A) Correlation coefficient between the total amount of rotation during a run and the angular position of the host’s head, tail and centre. The angular position of the host’s centre is the average of those of the head and tail. The host’s angular position from five frames before to three frames after the start of the rotation was used for analysis. (B) Total amount of rotation during a run as a function of the angular position of the host’s head 33 ms (one frame) before the start of the rotation.