Fig. 7.

Mass normalized translational jumping energy ($E_N$) for different types of slips (Trial Details and Slip Energy). (A) Locust: males only. (B) Robot: SLIP foot at a 45° surface angle. † Data are from the SLIP-none foot. (C) Simplified model (Slip Energy) for determining the ratio of translational and rotational energies in the event of a type-1 slip. (D) Locust: estimated $E_N$ as a function of the position, within the jumping cycle, in which a type-1 slip occurs. Assumed jumping angle is 45°. Energy regions (planting, early, middle, or late) are shown for an approximate leg length of 20 mm. Approximate position for the included type-1 (one leg) slip data from A is shown. Notes: Work is measured from jump initiation to foot separation, where each slip type is composed of slips from approximately the early knee angle region, to accentuate the energy losses, and covers all materials in which the behavior was observed. *P $\le$ 0.05; **P ≤ 0.01; ***P $\le$ 0.001; n.s., not significant. Variables: number of trials, n; contact-type jump, C; and non-contact-type jump, N.