title: The effect of trotting speed on the evaluation of subtle lameness in horses.
abstract: Equine lameness is a significant and challenging part of a veterinarian's workload, with subtle lameness inherently difficult to assess. This study investigated the influence of trotting speed on perceived and measured changes in movement asymmetry. Ten sound to mildly lame horses were trotted at a 'slow', 'preferred' and 'fast' speed on a hard surface, both on a straight line and in a circle on left and right reins. Video recordings of the horses were visually assessed by six experienced equine clinicians. Vertical movement of head, withers and pelvis was derived from inertial sensor data and several features calculated. On the straight line, more horses were subjectively declared sound at higher speeds, whilst different objective asymmetry measures showed only slight and inconsistent changes. On the circle, speed had no significant effect on the subjective assessment, with an increase in objectively measured asymmetry at higher speeds possibly balanced by a decrease in sensitivity of the observers for this asymmetry. Horses visually examined for subtle lameness on the straight should therefore be evaluated at a slow speed. Trotting speed should be consistent on repeated occasions, especially during objective gait analysis on the circle, to avoid the interaction of treatment effects and speed effects.
authors.affiliation: Department of Veterinary Clinical Sciences, The Royal Veterinary College, North Mymms, Hatfield AL9 7TA, UK. sstarke@rvc.ac.uk
authors.forename: Sandra D
authors.initials: SD
authors.lastname: Starke
authors.forename: Kirsty J
authors.initials: KJ
authors.lastname: Raistrick
authors.forename: Stephen A
authors.initials: SA
authors.lastname: May
authors.forename: Thilo
authors.initials: T
authors.lastname: Pfau
mesh_terms: D000818:Animals; D005684:Gait; D006734:Horse Diseases / Q000175:diagnosis*; D006736:Horses; D007794:Lameness, Animal / Q000175:diagnosis*; D015588:Observer Variation; D014741:Video Recording
keywords: Gait analysis; Horse; Lameness; Speed; Trot