Figure 1.

Illustration of vertical head and pelvis movement over a stride cycle and definitions of symmetry measures for head (HDmin, HDmax) and pelvis (PDmin, PDmax). Typical examples of a right forelimb (RF) lame horse (top, poll) and of a left hindlimb (LH) lame horse (bottom, sacrum) are shown. The movement patterns are used based on published evidence on fore‐ 14 or hindlimb 26 lameness. For ease of interpretation, positive values of HDmin and PDmin (representing patterns commonly seen in right forelimb or hindlimb lame horses) are referred to as HDmin_right and PDmin_right, negative values as HDmin_left and PDmin_left. Positive values for HDmax and PDmax represent typical patterns of right forelimb and right hindlimb lameness, negative values of left forelimb and left hindlimb lameness. The grey bars labelled LF, RF, LH, RH indicate the limb in contact with the ground at the time of the measured displacement minima (min_1,poll, min_2,poll, min_1,sacrum, min_2,sacrum) for ease of interpretation of sidedness of observed asymmetries between the 2 halves of the stride. The stride cycle here starts at approximately foot contact of the RH limb.