animals Review A Review of Biomechanical Gait Classification with Reference to Collected Trot, Passage and Piaffe in Dressage Horses Hilary M. Clayton 1,2,* and Sarah Jane Hobbs 3 1 Sport Horse Science, 3145 Sandhill Road, Mason, MI 48854, USA 2 College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA 3 Centre for Applied Sport and Exercise Sciences, University of Central Lancashire, Preston PR1 2HE, UK;
[email protected] * Correspondence:
[email protected]; Tel.: +1-517-333-3833 Received: 17 September 2019; Accepted: 2 October 2019; Published: 3 October 2019 Simple Summary: This paper reviews the biomechanical classification of diagonally coordinated gaits of dressage horses, specifically, collected trot, passage and piaffe. Each gait was classified as a walking gait or a running gait based on three criteria: limb kinematics, ground reaction forces and center of mass mechanics. The data for trot and passage were quite similar and both were classified as running gaits according to all three criteria. In piaffe, the limbs have relatively long stance durations and there are no aerial phases, so kinematically it was classified as a walking gait. However, the shape of the vertical ground reaction force curve and the strategies used to control movements of the center of mass were more similar to those of a running gait. The hind limbs act as springs with limb compression increasing progressively from collected trot to passage to piaffe, whereas the forelimbs show less compression in passage and piaffe and behave more like struts. Abstract: Gaits are typically classified as walking or running based on kinematics, the shape of the vertical ground reaction force (GRF) curve, and the use of inverted pendulum or spring-mass mechanics during the stance phase.