mistrail means to gallop in such a way that the rear hoof lands in line with the place where the front hoof on the opposite side landed.
Etymology
From mis- + trail.
verb
- To gallop in such a way that the rear hoof lands in line with the place where the front hoof on the opposite side landed.“again, the imprint of the posterior foot in question may be made in front or behind that the diagonal anterior foot, and then the horse mistrails himself (se dépiste) .”