“…In fact, this relationship is so standard that it is possible to determine the bounds of normal walking and use these to define abnormal locomotion (Schwartz et al, 2008;Lythgo et al, 2011;Dixon et al, 2014). A different, but equally consistent relationship exists for human running (Kurz et al, 2005;Perry and Burnfield, 2010;Hein et al, 2012;Floría et al, 2018). However, documenting the gait parameters used in a given circumstance does little to explain why these are the particular movement strategies (nearly) universally selected.…”