Perceived sidedness and correlation to vertical movement asymmetries in young warmblood horses

Abstract

The prevalence of vertical asymmetries is high in “owner-sound” warmblood riding horses, however the origin of these asymmetries is unknown. This study investigated correlations between vertical asymmetries and motor laterality. Young warmblood riding horses (N = 65), perceived as free from lameness were evaluated on three visits, each comprising objective gait analysis (inertial measurement units system) and a rider questionnaire on perceived sidedness of the horse. A subgroup (N = 40) of horses were also subjected to a forelimb protraction preference test intended as an assessment of motor laterality. We hypothesized associations between vertical asymmetry and motor laterality as well as rider-perceived sidedness. Vertical asymmetry was quantified as trial means of the stride-by-stride difference between the vertical displacement minima and maxima of the head (HDmin, HDmax) and pelvis (PDmin, PDmax). Laterality indexes, based on counts of which limb was protracted, and binomial tests were used to draw conclusions from the preference tests. In the three visits, 60–70% of horses exhibited vertical asymmetries exceeding clinically used thresholds for ≥1 parameter, and 22% of horses exhibited a side preference in the preference test as judged by binomial tests. Linear mixed models identified a weak but statistically significant correlation between perceived hindlimb weakness and higher PDmin values attributable to either of the hindlimbs (p = 0.023). No other statistically significant correlations to vertical asymmetry were seen for any of the questionnaire answers tested. Tests of correlation between the absolute values of laterality index and asymmetry parameters (HDmin, HDmax, PDmin, PDmax) identified a weak correlation (p = 0.049) with PDmax, but when accounting for the direction of asymmetry and motor laterality, no correlations were seen for either of the asymmetry parameters. No convincing evidence of associations between vertical asymmetries and motor laterality were seen and further studies investigating motor laterality and the origin of vertical asymmetries are needed.

Determination of Equine Behaviour in Subjectively Non-Lame Ridden Sports Horses and Comparison with Lame Sports Horses Evaluated at Competitions

“…The development of objective methods of gait analysis and their widespread use in equine lameness assessments and analysis of gaits at pre-purchase examinations have begun to raise questions about what constitutes normality [ 14 , 15 , 16 , 17 , 18 , 19 ]. Measurable gait asymmetries outside the so-called normal ranges [ 20 , 21 ] have been identified in both Warmblood [ 18 ] and Standardbred [ 14 , 18 ] foals and in mature riding horses assumed by the riders to be working satisfactorily at both elite and non-elite levels [ 15 , 16 , 17 , 19 ]. It is not known with certainty whether this reflects innate non-pain induced asymmetry (sometimes referred to as motor laterality) [ 20 , 22 ], which may or may not predispose to subsequent development of pain-related gait changes, or is pain related.…”

Prevalence of movement asymmetries in high-performing riding horses perceived as free from lameness and riders’ perception of horse sidedness

“…Riders’ perceived sidedness of the horse can be quantified and investigated for its association with movement asymmetries. It has been done for a group of young horses perceived as non-lame by the owners [ 25 ]. No association between rider-perceived sidedness and vertical movement asymmetries was seen in that study, despite the horses having a high prevalence of movement asymmetries [ 25 ].…”

“…It has been done for a group of young horses perceived as non-lame by the owners [ 25 ]. No association between rider-perceived sidedness and vertical movement asymmetries was seen in that study, despite the horses having a high prevalence of movement asymmetries [ 25 ]. However, sidedness may also be affected by age, as size and anatomical proportions change over time [ 26 ], and by training [ 27 ].…”

“…Horses at higher competition levels can be assumed to exhibit less sidedness, given that riders strive to develop equal strength and suppleness in each direction so that the horse can perform the advanced movements required in dressage or the sharp turns required in show jumping. Additionally, riders competing at higher levels may be more skilled in assessing the sidedness of their horses compared with riders in the previous study on young horses [ 25 ]. The rider’s perceived sidedness and its relation to movement symmetry may therefore differ between high-performing horses and youngsters.…”

Pilot study of locomotor asymmetry in horses walking in circles with and without a rider

“…These asymmetries are usually evaluated during trotting and are measured in terms of asymmetrical vertical displacements of the head, withers and pelvis on the left and right diagonals ( Davidson, 2018 ; Reed et al, 2020 ). However, a recent study describes a weak association between rider-perceived sidedness to push-off lameness in trot ( Leclercq et al, 2023 ). Much less is known about movement adaptations in lame horses at the walk.…”