Run Like an Elephant

If you’ve ever had anyone tell you that you run like an elephant, thank him, because research from the Journal of Experimental Biology reveals that pachyderms have very efficient motion.

“While human runners exert peak force of three times their body weight, an elephant hits the ground with at most 1.4 times its weight,” reported the journal, and that even at top speed, “an elephant’s center of mass moves up and down only a centimeter.”

Figure 8 of the study tells us:

Fig. 8. The percentage recovery (%R) (A), phase shift between minima of kinetic energy (E_k) and potential energy (E_p) (B) and relative amplitude of work done to accelerate the centre of mass (COM) forwards (W_f) and positive work done against gravity (W_v) (C) as a function of speed. The phase shift shows an average value of ~180 deg. at low and intermediate speeds, which is typical of an inverted-pendulum walk. At the highest speed, energy curves are almost completely in-phase (~10 deg.), which is typical of a bouncing mechanism. The W_v/(W_v+W_f) ratio decreases from ~0.7 to ~0.2 with increasing speed, averaging about 0.6 at the speed where %R is maximum.

This is good to know.