title: Head and pelvic movement symmetry in horses during circular motion and in rising trot.
abstract: Lameness examinations in horses often include lungeing and ridden exercise. To incorporate these exercises into the evidence-based decision making process aided by quantitative sensor based gait analysis, guideline values for movement asymmetry are needed. In this study, movement symmetry (MS) was quantified in horses during unridden and ridden trot on the straight and on the circle. Systematic changes in MS were expected as a result of the 'asymmetrical loading' caused by circular movement, the rising trot and the combination of the two. Out of 23 horses (age 4-20 years, height 13.3-17.2 hands), 13 presented within normal limits for head movement and 22 for pelvic movement. Inertial measurement units assessed MS of vertical head and sacral movement during trot in-hand, on the lunge and in rising trot (straight, left/right circle). Changes in MS between straight line trot and ridden exercise on the circle were more pronounced for the head than for the sacrum. The highest amount of asymmetry was observed during rising trot on the circle (symmetry index of the head: 1.23 for the left rein, 0.83 for the right rein; symmetry index of the sacrum 0.84 for the left rein, 1.15 for the right rein). Change in MS was significant between exercise conditions except for the difference between head displacement maxima. Horses had greatest asymmetry during rising trot on the circle, with MS values of comparable magnitude to mild lameness.
authors.affiliation: Department of Clinical Science and Services, Royal Veterinary College, University of London, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK.
authors.forename: Helen
authors.initials: H
authors.lastname: Robartes
authors.affiliation: Department of Clinical Science and Services, Royal Veterinary College, University of London, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK.
authors.forename: Harriet
authors.initials: H
authors.lastname: Fairhurst
authors.affiliation: Department of Clinical Science and Services, Royal Veterinary College, University of London, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK. Electronic address: tpfau@rvc.ac.uk.
authors.forename: Thilo
authors.initials: T
authors.lastname: Pfau
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D005684:Gait / Q000502:physiology*; D006257:Head / Q000502:physiology*; D006736:Horses / Q000502:physiology*; D010388:Pelvis / Q000502:physiology*
keywords: Circular motion; Equine; Inertial sensor; Movement symmetry; Rising trot