Fig. 2 . Movements of the femoro-tibial joint and body during a jump by a freely moving adult male captured by high-speed images at 1000 frames s^-1. (A) Plot of hind-leg femoro-tibial angle and femur/body joint movements, changes in height of the body and angle of the body relative to the ground. Time zero was taken as the point when the hind legs left the ground and the insect became airborne. Tibial extension takes 40 ms. The inset diagrams are tracings from single frames, at the times indicated, to show body posture, leg movements and the way the various measurements were made. The vertical lines show when the front and hind legs are lifted from the ground. (B) Bending of the tibia of a hind leg during the jump plotted in A at the times (in ms) indicated. Horizontal lines indicate ground level. The degree of bending is measured as the distance from the centre of the tibia to a line (chord) joining the femoro-tibial and tibio-tarsal joints. The values (in mm) are given in the right-hand column. The drawings are tracings from single images in the jump.