Patterns of good (VUCM, dashed line) and bad variance (VORT, solid line) (mean ± SE, 5 cats) computed for the limb orientation in space of 3 elemental variables. A: forelimb, regular walking. B: hindlimb, regular walking. C: forelimb, ladder walking. D: hindlimb, ladder walking. X's indicate 10% time bins of swing for which VUCM is significantly smaller than VORT (P < 0.05).