Six out of ten showjumping horses were assessed as having back issues in a British study that drilled down into their performance over fences.
The study team used clinical assessments as well as high-speed motion capture technology to assess a range of factors around their condition and jumping performance.
The researchers who undertook the Animal Health Trust study detected elements of unevenness − asymmetry − which had the potential to contribute to injury risk.
An asynchronous push-off with the hindlimbs − that is, each leg pushing off at a slightly different time − was seen in three horses. A range of landing issues were also identified among the horses.
“We have identified a number of features of jumping horses that have not previously been described, and that potentially should be considered in injury prevention, diagnosis and management,” equine orthopaedic specialist Dr Sue Dyson and her colleagues reported in the journal Equine Veterinary Education.
The study team noted that there was limited knowledge about the causes of musculoskeletal injury in showjumpers.
They set out to describe features of the turn, approach and jump in the 10 competitive showjumpers, believed by their riders to be sound. They related these results back to the clinical evaluation carried out beforehand by Dyson on each of the horses in the hope of identifying features that may predispose them to injury.
The horses, comprising nine Warmbloods and one Irish Sports Horse, were all in active showjumping training and competition, competing at heights of 1.2 to 1.6 metres. They were aged 6 to 10, with body condition scores ranging from 6 to 7 on the 9-point scale. All were ridden in their usual tack by their usual professional riders. Two riders rode two each, and a third rode the remaining six.
Saddle-fit was assessed by master saddler Mark Fisher. Riders were asked to warm each horse up as they would normally and were told that 20 minutes were available.
The riders and their mounts were asked to jump an upright and a parallel fence four times off the left and right reins respectively, after the riders had warmed up their horses to their satisfaction. The test was undertaken on an outdoor arena with a rubber-based surface.
Real-time and high-speed motion capture was undertaken to assist in the analysis. A detailed subjective assessment of the gait of each horse was performed during the warm-up, on the turn, the approach, and all phases of the jump.
The study team reported that six of the horses had pain or abnormal muscle tension in the thoracolumbar region. A seventh horse had swelling and abnormal hair wear under the front of the saddle.
In five horses, the back muscles were poorly developed; three of them had pain or abnormal muscle tension, including one which showed low-grade hindlimb lameness when being led. Four of these horses showed a poor quality canter when ridden.
Seven saddles were used among the 10 horses. Saddle fit was considered poor in six horses, with the problems including being too wide, unstable and bridging. The saddles were consistently placed too far forward, although most moved backwards to some extent during riding. The saddles were girthed unevenly, with the girth attached to the front two straps on the left and the rear two straps on the right. Flocking was variable, and excessively hard in one saddle used on two horses.
The warm-ups by the riders ranged from 5 to 10 minutes. During warm-up, Dyson noted that six horses were consistently above the bit in both trot and canter. One showed low grade left hindlimb lameness. Six had a poor quality canter, three of whom performed flying changes incorrectly, and intermittently bucked and kicked out to the left. Two horses bucked and kicked out on landing.
When it came to the jumping test, consistent saddle slip to the outside was seen in six of the horses. The cantle of the saddle repeatedly bounced on two horses on the approach and in five horses on take-off, all ridden by the same rider.
All horses consistently leant their entire trunk inwards on the turn towards the approach and in three horses this lean persisted in the approach strides. There was generally a greater lean of the inside hindlimb on the turn, with angles of 49–60 degrees recorded.
Looking at the approach stride and take-off, the hindlimbs were placed to the ground simultaneously in preparation for take-off in just over a quarter of the 80 take-offs monitored in the study. The hindlimbs drifted left or right during the jump in four horses, reflecting their asymmetrical push-off.
A range of anomalies were noted on landing, from horses landing on the incorrect forelimb (left if turning right and right if turning left), as well as incidents of a horse holding its head up on landing, bucking and kicking out. Only two horses landed consistently with the correct forelimb leading relative to the direction in which the horse had to turn after the fence.
“Repetitive overload through asymmetrical use of the left and right canter leads, inadequate warm-up, and limb instability could potentially predispose to injury,” Dyson and her colleagues wrote.
“Contrary to our hypotheses, the horses in the current study did not land with similar frequency with the left or right forelimb leading,” the researchers reported. “In addition, there was more variability within and among horses in their approach and jumping technique than anticipated.”
They noted in their conclusion: “Although considerable variations in gait and jumping technique were seen within and among horses, trunk lean and hindlimb lean were consistent features on the turn, placing asymmetrical loads on the musculoskeletal system.
“Repeated landing with a preferred forelimb leading may result in chronic overload,” they warned.
The high incidence of poorly fitting saddles and movement of the saddle was disturbing, given the influence that saddle fit can have on performance.
“Recognition of pain-related gait abnormalities with appropriate interventions may have the potential to enhance jumping performance and reduce the risk of injury.”
A subjective descriptive study of the warm-up and turn to a fence, approach, take-off, suspension, landing and move-off in 10 showjumpers
S. Dyson, C. Tranquille, V. Walker, R. Guire, M. Fisher and R. Murray
Version of Record online: 19 DEC 2016 | DOI: 10.1111/eve.12699