Collisional mechanics of the diagonal gaits of horses over a range of speeds

Short Communication: changes in gait after 12 wk of shoeing in previously barefoot horses

Farriery can impact gait symmetry and lameness outcomes, but there is limited scientific data documenting these effects. We hypothesized that shoeing previously barefoot horses with plain stamp shoes on the hind hooves would increase gait symmetry, alter hock angles and increase range of motion, and improve lameness scores more than shoeing with traditional fullered shoes. At the start of the study, gait symmetry via wireless inertial motion sensors (IMS), kinematic gait analysis (hock angle and range of motion), and American Association for Equine Practitioner's (AAEP) lameness scoring were completed for 14 barefoot horses. Horses were then trimmed and hind hooves were shod (wk 0) in three-quarter fullered shoes or plain stamp style shoes. Horses were trimmed and re-shod at week 6. At the end of 12 wk, the IMS analysis, kinematic gait analysis, and lameness scoring were repeated. Differences between shod and barefoot values were calculated for each horse, and impact of shoe type was analyzed via t-test. Significance was determined at P ≤ 0.05. No differences were observed in the IMS scores, hock angles or range of motion, or AAEP lameness scores between horses shod in fullered or plain stamp shoes (P ≥ 0.08). As no variables were determined to be significantly different between the two shoe types, data from all horses were combined to analyze the differences between the barefoot and shod state. Shoeing increased the maximum angle of the right and left hocks (P ≤ 0.03) and the minimum angle of the left (P = 0.02) but not right hock (P = 0.23) relative to barefoot conditions. No differences in hock range of motion were observed in either hock. Lower AAEP lameness scores were observed in horses when shod compared with barefoot (P = 0.001). In conclusion, shoeing previously barefoot horses improved AAEP lameness scores and increased hock angles, regardless of the type of shoe.

Ground Reaction Forces of Dressage Horses Performing the Piaffe

Simple Summary

One of the most difficult movements performed by dressage horses is the piaffe, in which the horse raises and lowers alternating diagonal limb pairs while remaining in place. Piaffe is an artificial movement that requires good balance. Knowledge of the unique stresses on the horse’s limbs and body during the performance of the piaffe are needed to understand the mechanics of the movement and the implications for injury. In this study, we used force plates to measure ground reaction forces (GRFs) in the vertical, longitudinal and transverse directions in seven highly trained horses performing the piaffe. The results showed that the hindlimbs carried relatively more weight in the piaffe than in trot or passage, though the peak vertical GRF was significantly higher in the forelimbs. The forces acting in the horizontal plane showed considerable variability from step-to-step within individual horses. This was thought to represent the difficulty of maintaining balance when the horse stands on one diagonal pair of limbs.

Abstract

The piaffe is an artificial, diagonally coordinated movement performed in the highest levels of dressage competition. The ground reaction forces (GRFs) of horses performing the piaffe do not appear to have been reported. Therefore, the objective of this study was to describe three-dimensional GRFs in ridden dressage horses performing the piaffe. In-ground force plates were used to capture fore and hindlimb GRF data from seven well-trained dressage horses. Peak vertical GRF was significantly higher in forelimbs than in the hindlimbs (7.39 ± 0.99 N/kg vs. 6.41 ± 0.64 N/kg; p < 0.001) with vertical impulse showing a trend toward higher forelimb values. Peak longitudinal forces were small with no difference in the magnitude of braking or propulsive forces between fore and hindlimbs. Peak transverse forces were similar in magnitude to longitudinal forces and were mostly directed medially in the hindlimbs. Both the intra- and inter-individual variability of longitudinal and transverse GRFs were high (coefficient of variation 25–68%). Compared with the other diagonal gaits of dressage horses, the vertical GRF somewhat shifted toward the hindlimbs. The high step-to-step variability of the horizontal GRF components is thought to reflect the challenge of balancing on one diagonal pair of limbs with no forward momentum.

A Review of Biomechanical Gait Classification with Reference to Collected Trot, Passage and Piaffe in Dressage Horses

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. The objectives of this review were to describe the biomechanical characteristics that differentiate walking and running gaits, then apply these criteria to classify and compare the enhanced natural gait of collected trot with the artificial gaits of passage and piaffe as performed by highly trained dressage horses. Limb contact and lift off times were used to determine contact sequence, limb phase, duty factor, and aerial phase duration. Ground reaction force data were plotted to assess fore and hind limb loading patterns. The center of mass (COM) trajectory was evaluated in relation to changes in potential and kinetic energy to assess the use of inverted pendulum and spring-mass mechanics. Collected trot and passage were classified as running gaits according to all three criteria whereas piaffe appears to be a hybrid gait combining walking kinematics with running GRFs and COM mechanics. The hind limbs act as springs and show greater limb compression in passage and piaffe compared with trot, whereas the forelimbs behave more like struts showing less compression in passage and piaffe than in trot.