To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Movie 1 Example of a subject walking on part of the trail (approximately the second half of the trail). Preferred walking speed on rough terrain: is it all about energetics? Koren Gast, Rodger Kram, and Raziel Riemer Journal of Experimental Biology 2019. 222:None-None; doi: 10.1242/jeb.185447 Download Original Video