Movement Symmetry Patterns During Lungeing in Trot on Hard and Soft Surface Differ Between Sound and Mildly Forelimb Lame Horses

Abstract

AimsLungeing on hard and soft surfaces is crucial to clinical lameness and prepurchase examinations. Here we 1) quantify movement symmetry (MS) in sound horses trotting on hard and soft surfaces, and 2) compare MS patterns for different rein and surface combinations between sound and mildly forelimb lame horses.MethodsTwenty‐three riding horses were equipped with an inertial sensor based gait analysis system and assessed in‐hand on the straight and during lungeing (10 m diameter circle), both on hard and soft surfaces. Assessment of rein (left/right) was performed in a randomised order. Seven published MS parameters (3 poll, 4 pelvis) were quantified from an average of 38 strides per condition. Horses were subdivided into 3 groups: control (9 horses), left (5) and right (9) forelimb lame. Statistical analysis was performed using paired samples t test, ANOVA and post hoc comparisons.ResultsFor control horses, only one MS measure was significantly different between the surfaces; Symmetry Index (P = 0.0122, increased asymmetry on hard ground). When comparing left and right forelimb lame horses, increased head movement asymmetry was found with the affected limb on the inside of the circle on both surfaces (P values between P = 0.0006 and P = 0.0481); circle and lameness induced asymmetry adding up. No differences in pelvic MS were identified between sound and mildly forelimb lame horses.ConclusionsSound horses show similar amounts of movement asymmetry during lungeing on hard and soft surfaces. Mildly forelimb lame horses show characteristic patterns of increased asymmetry in particular with the affected limb on the inside of the circle.Practical significanceThe observed differences between sound and mildly forelimb lame horses will contribute to higher specificity in identification of mildly lame horses based on objective gait analysis. It is recommended to include lungeing into objective gait assessments.AcknowledgementsWe are grateful to the owners of the horses that participated.Ethical animal researchThis project was granted ethical approval by the RVC Ethics and Welfare Committee as part of Hazel Mitchell's and Charlotte Jennings' final year research project and conducted with owners' informed consent. Sources of funding: RVC. Competing interests: None.