The Effect of Horse Velocity on the Output of an Inertial Sensor System

Abstract

Horse velocity has previously been demonstrated to influence both subjective and objective evaluation of lameness, especially in horses with mild lameness. As horse velocity is not always tightly controlled either within or between successive lameness examinations and horse-mounted sensor systems are becoming more commonly used in clinical practice, it is important to understand the influence of horse velocity on the results of these sensor systems. One inertial sensor (IS) system is widely available and commonly utilized to complement the subjective lameness examination. The objective of this study was to determine if horse velocity had an effect on the kinematic output from this commercial IS system. Twelve horses with at least one lame limb were examined with the IS system during a single daily high-speed treadmill exercise session. Horses were examined at the trot at 3.0, 3.5, and 4.0 m/s, in random order. Stride rate, maximum and minimum differences in head position (HDMax, HDMin), vector sum (VS), and maximum difference in pelvic position (PDMax) and minimum difference in pelvic position (PDMin) were analyzed using mixed-model analysis of variance with significance at P < .05. Horse velocity had a significant effect on stride rate (P = .0025) and one variable of hindlimb lameness (PDMin) (P = .0234). Horse velocity resulted in no significant differences on forelimb lameness kinematics (HDMax, HDMin, VS). Horse velocity may have an impact on assessment of hindlimb lameness as determined by this system, making it more important to control velocity in these cases.