The pelvic sensor device contains an accelerometer that tracks vertical pelvic acceleration.
Right Forelimb Sensor
The right forelimb sensor device contains a gyroscope that measures angular velocity in the sagittal plane. It is used as an event marker to determine right forelimb stance. It is also used to calculate a median stride rate.
If the foot creates a depression or a divot in the ground, the surface should be considered soft. Soft preset surfaces = loose sand, grass/turf, soft/deep, mud, soft synthetic, soft (generic).
Stabilizing the Lameness
Following viewing the initial baseline straight evaluation, repeat the trial to confirm stability of lameness measurements!
the graphical representations of the trial data.
the variability of the lameness measure (Diff Max Head, Diff Min Head, Diff Max Pelvis, Diff Min Pelvis) from stride to stride over the course of a single data collection trial. Stride-by-stride variability is assessed in the Lameness Locator® report by comparing the standard deviation to the absolute value of the mean for that measure. If the standard deviation is significantly greater than the mean (currently this is arbitrarily set at 120% of the mean), the confidence in, or strength of evidence for, lameness (in limb, amplitude and/or timing) is reduced.
The Quantification (Q) Score
the Q score is a summary of the side, timing and amplitude of the asymmetry.
Total Diff Head (Vector Sum)
Can be considered the amplitude of total head movement asymmetry, taking into account both Diff Max and Diff Min of the head.
As the side and timing of forelimb lameness is dependent upon both Diff Max Head and Diff Min Head, this single variable can be more easily used to estimate the overall level of forelimb lameness.
Total Diff Head is the Vector Sum of the mean Diff Max and mean Diff Min values, and is calculated using Pythagorean Theorem (a2 + b2 = c2), where a is the value of Diff Max head, b is the value of Diff Min head, and c is Vector Sum. (a) is plotted on the X axis, (b) is plotted on the Y axis, and the hypotenuse that forms that triangle is the Vector Sum. Total Diff Head is indicated by the RED ray on the forelimb plot.
The Total Diff Head (Vector Sum) reference range is 0 to 8.5mm. The upper reference range value of 8.5 is derived from the VS calculation when Diff Max Head and Diff Min Head are at their upper reference range values of |6|. 62+62=VS2
Owner, horse, and trial specific data (including date, time and type of trial conducted).
Trial-to-trial variability = the variability of the mean lameness measure between two trials. I.e. is the measure repeatable? Trial-to-trial variability is assessed by comparing the lameness measures between two trials and whether they are within the 95% confidence intervals of repeatability. If a particular measure in two back-to-back trials is not within the 95% CI, then that lameness is not stable.