Evaluation of pressure distribution under an English saddle at walk, trot and canter

REASONS FOR PERFORMING STUDY: Basic information about the influence of a rider on the equine back is currently lacking. HYPOTHESIS: That pressure distribution under a saddle is different between the walk, trot and canter. METHODS: Twelve horses without clinical signs of back pain were ridden. At least 6 motion cycles at walk, trot and canter were measured kinematically. Using a saddle pad, the pressure distribution was recorded. The maximum overall force (MOF) and centre of pressure (COP) were calculated. The range of back movement was determined from a marker placed on the withers. RESULTS: MOF and COP showed a consistent time pattern in each gait. MOF was 12.1 +/- 1.2 and 243 +/- 4.6 N/kg at walk and trot, respectively, in the ridden horse. In the unridden horse MOF was 172.7 +/- 11.8 N (walk) and 302.4 +/- 33.9 N (trot). At ridden canter, MOF was 27.2 +/- 4.4 N/kg. The range of motion of the back of the ridden horse was significantly lower compared to the unridden, saddled horse. CONCLUSIONS AND POTENTIAL RELEVANCE: Analyses may help quantitative and objective evaluation of the interaction between rider and horse as mediated through the saddle. The information presented is therefore of importance to riders, saddlers and equine clinicians. With the technique used in this study, style, skill and training level of different riders can be quantified, which would give the opportunity to detect potentially harmful influences and create opportunities for improvement.     

Usability of normal force distribution measurements to evaluate asymmetrical loading of the back of the horse and different rider positions on a standing horse

Pressure measurement devices in equine sports have primarily focused on tack (saddle pads and saddle fitting methods). However, saddle pressure devices may also be useful in evaluating the interaction and distribution of normal forces between the horse and rider, including rider position and riding technique. This study examined the validity, reliability, repeatability and possibilities of using a saddle pressure device to evaluate rider position. All measurements were performed using a standing horse. Validity was tested by calculating the correlation coefficient between measured normal force and the weight of the rider. Repeatability was tested by calculating intra-class correlation coefficients. The use of normal force measurements to evaluate horse–rider interaction was tested by adding a known weight to saddle or rider and collecting measurements with the rider sitting in four different positions.The device was found to be valid and reliable for force measurements when the measurement device was not replaced. The system could be used to determine the expected differences with added weight and in different rider positions. The normal force distribution measurement device proved to be a valid and reliable tool for studying the interaction between a rider and a static horse provided it is positioned carefully and consistently relative to both the horse and the saddle.     

Relationship between the forces acting on the horse's back and the movements of rider and horse while walking on a treadmill

Reasons for performing study: The exact relationship between the saddle pressure pattern during one stride cycle and the movements of horse and rider at the walk are poorly understood and have never been investigated in detail. Hypothesis: The movements of rider and horse account for the force distribution pattern under the saddle. Method: Vertical ground reaction forces (GRF), kinematics of horse and rider as well as saddle forces (FS) were measured synchronously in 7 high level dressage horses while being ridden on an instrumented treadmill at walk. Discrete values of the total saddle forces (FStot) were determined for each stride and related to kinematics and GRF. The pressure sensitive mat was divided into halves and sixths to assess the force distribution over the horse's back in more detail. Differences were tested using a one sample t test (P<0.05). Results: FStot of all the horses showed 3 peaks (P1‐P3) and 3 minima (M1‐M3) in each half‐cycle, which were systematically related to the footfall sequence of the walk. Looking at the halves of the mat, force curves were 50% phase‐shifted. The analysis of the FS of the 6 sections showed a clear association to the rider's and horse's movements. Conclusion: The saddle force distribution during an entire stride cycle has a distinct pattern although the force fluctuations of the FStot are small. The forces in the front thirds were clearly related to the movement of the front limbs, those in the mid part to the lateral flexion of the horse's spine and the loading of the hind part was mainly influenced by the axial rotation and lateral bending of the back. Potential relevance: These data can be used as a reference for comparing different types of saddle fit.     

The effects of different saddle pads on forces and pressure distribution beneath a fitting saddle

Reason for performing study: Saddle pads are widely used in riding sports but their influence on saddle pressures is poorly understood. Objective: To evaluate the forces acting on the horse's back, and the eventual pressure distribution by using different saddle pads underneath a fitting saddle. Methods: Sixteen sound horses of different breeds and ages were ridden on a treadmill at walk and sitting trot. The horses were wearing a dressage saddle with a fitting saddle tree and 4 different saddle pads (gel, leather, foam and reindeer fur) successively. For comparison, measurements were made without any saddle pad. Right forelimb motion was used to synchronise the pressure data with the stride cycles. A pressure mat was used under the saddle pad to collect the kinetic data. Maximum overall force (MOF) and the pressure distribution in longitudinal and transversal direction were calculated to identify differences between the measurements with and without saddle pads. Results: A significant decrease in MOF was interpreted as improved saddle fit, and a significant increase as worsened saddle fit. Only the reindeer fur pad significantly decreased the MOF from 1005 N to 796 N at walk and from 1650 N to 1437 N at trot compared to without pad measurements. None of the saddle pads increased the MOF significantly when compared to the data without saddle pad. The pressure distribution in longitudinal and transversal direction was also improved significantly only by the reindeer fur pad at trot compared to no pad. Conclusion: This study demonstrated that a well chosen saddle pad can reduce the load on the horse's back and therefore improve the suitability of a fitting saddle.     

Saddle fitting,recognising an ill‐fitting saddle and the consequences of an ill‐fitting saddle to horse and rider

A saddle that does not fit either a horse or a rider correctly has potentially far reaching consequences for both horse and rider health. The saddle should be assessed off and on the horse, without and with a rider. The fit of the saddle for both the horse and rider must be evaluated. A well‐fitted saddle should distribute weight evenly via the panels to the horse's thoracic region, with complete clearance of the spinous processes by the gullet. The saddle should remain fairly still during ridden exercise at all paces. The saddle must also fit the rider to enable them to sit in balance. Signs of an ill‐fitting saddle include equine thoracolumbar pain, focal swellings under the saddle, ruffling of the hair, dry spots under the saddle immediately after exercise surrounded by sweat, and abnormal hair wear. If a saddle does not fit the rider, the rider may not be able to ride in balance with the horse, and this may induce equine thoracolumbar pain. A saddle of inappropriate size and shape for the rider may induce rider back pain, ‘hip’ pain, sores under the ‘seat bones’ and perineal injuries.     

Comparison of pressure distribution under a conventional saddle and a treeless saddle at sitting trot

It can be a challenge to find a conventional saddle that is a good fit for both horse and rider. An increasing number of riders are purchasing treeless saddles because they are thought to fit a wider range of equine back shapes, but there is only limited research to support this theory. The objective of this study was to compare the total force and pressure distribution patterns on the horse's back with conventional and treeless saddles. The experimental hypotheses were that the conventional saddle would distribute the force over a larger area with lower mean and maximal pressures than the treeless saddle. Eight horses were ridden by a single rider at sitting trot with conventional and treeless saddles. An electronic pressure mat measured total force, area of saddle contact, maximal pressure and area with mean pressure >11 kPa for 10 strides with each saddle. Univariate ANOVA (P<0.05) was used to detect differences between saddles. Compared with the treeless saddle, the conventional saddle distributed the rider's bodyweight over a larger area, had lower mean and maximal pressures and fewer sensors recording mean pressure >11 kPa. These findings suggested that the saddle tree was effective in distributing the weight of the saddle and rider over a larger area and in avoiding localized areas of force concentration.     

Effects of Large Saddle Panels on the Biomechanics of the Equine Back During Rising Trot: Preliminary Results

The saddle panels, directly in contact with the horse's back, are likely an important element to optimize the fitting of the saddle, the comfort of the horse, and subsequently, the pain management in dorsalgic horses. The aim of this study was to better understand the effect of the saddle panels on the horse's back, by evaluating a prototype saddle (comfort panels: CP) compared to a standard saddle (STD). The horse's back movements were measured using inertial measurement units (IMUs) fixed at the levels of thoracic vertebrae T6, T12, T16 (under the saddle) and lumbar vertebrae L2 and L5. The centers of mass (COMs) of the horse and the rider and limb's protraction-retraction angles, pressure between saddle and horse's back, and force on the stirrups were measured using respectively 2D motion capture, pressure mat and force sensors in the stirrup leather. Three horses were trotted at the rising trot (sitting: left diagonal-rider seated; standing: right diagonal-rider standing) by the same rider. To compare saddles, linear mixed-effects regression models were used. The estimated means (SE) were calculated. During sitting phase, pressure in the cranial and middle areas of the saddle significantly increased for CP compared to STD (+0.9 (0.2) kPa and +1.0 (0.1) kPa, respectively) whereas caudal pressure decreased (−1.8 (0.4) kPa). Concurrently, the range of motion of angles T12-T16 and T16-L2 under the saddle significantly increased (+1.8 (0.2)° and +2.3 (0.3)°, respectively). The results showed that modifications of the panels' shape not only affect the pressure distribution but also the kinematics of the thoracic and lumbar regions of the equine back.     

Force and pressure distribution beneath a conventional dressage saddle and a treeless dressage saddle with panels

The objective of this study was to compare forces and pressure profiles beneath a conventional dressage saddle with a beechwood spring tree and a treeless dressage saddle without a rigid internal support and incorporating large panels and a gullet. The null hypothesis was that there is no difference in the force and pressure variables for the two saddles. Six horses were ridden by the same rider using the conventional dressage saddle and the treeless dressage saddle in random order and pressure data were recorded using an electronic pressure mat as the horses trotted in a straight line. The data strings were divided into strides with ten strides analyzed per horse–saddle combination. Variables describing the loaded area, total force, force distribution and pressure distribution were calculated and compared between saddles using a three-factor ANOVA (P < 0.05).Contact area and force variables did not differ between saddles but maximal pressure, mean pressure and area with pressure >11 kPa were higher for the treeless dressage saddle. The panels of the treeless dressage saddle provided contact area and force distribution comparable to a conventional treed saddle but high pressure areas were a consequence of a narrow gullet and highly-sloped panels. It was concluded that, even with a treeless saddle, the size, shape, angulation, and position of the panels must fit the individual horse.     

A retrospective survey of riders' opinions of the use of saddle pads in horses

Horse riders have used layers between saddles and their horse's back since ancient times. Despite the apparent common usage of such layers, most research regarding pressures under horses' saddles seems to have been conducted without such layers present. An online survey of equestrian riders was conducted to quantify the use of such layers and how the layers behaved during use. This produced 1,011 responses from participants in 16 equestrian activities. More than 98% of respondents reported they used some form of layer between their horse's back and the saddle. Differences in layer usage were associated with the respondent's preferred riding discipline and the wither type of their horse. Compensation for perceived saddle fit problems was commonly cited as a reason for using layers. Although horse comfort was nominated by 87.5% of respondents as a reason for using a layer between saddle and the horse's back, many respondents (45%) reported using more than 1 layer. This often resulted in layers thicker than 1 cm, which paradoxically could compromise horse welfare. Half of the respondents reported that the layer between the saddle and the horse's back slipped during riding. Although some significant risk factors for this slippage were identified, they are deemed not to be definitive because of similar factors being identified by the group who did not report layer slippage. These results suggest that incorrect usage of layer between saddles and horses' backs can sabotage good saddle design and compromise equine welfare. Future research on the layers used between the saddles and horses' back is warranted. The question of whether using thicker layers can create greater pressure under saddles or improve rider–horse communication also needs to be investigated.     

An application of temperature mapping of horse's back for leisure horse‐rider‐matching

Leisure riding is a popular way of using horses however, unlike sport or racing horses, those are mostly not associated with one rider with high skills. Constant overload of equine musculoskeletal system causes pathologies, which are affecting horse mobility and decreases the horse‐rider communication. The aim was to propose the new scoring system of thermograph analysis as an aspect of differences in heat distributions on horseback before and after leisure ridings. The study was conducted on sixteen Polish warmblood horses, scanned with a non‐contact thermographic camera. Heat pattern of the thoracolumbar area was evaluated on thermograms taken before and after exercise. The criteria with point values for horse‐rider‐matching were created: heat points on the dorsal midline of saddle‐back contact area and degree of muscle unit overload. The results of thermograph analysis were compared with the results of a questionnaire on horse‐rider communication during riding in order to estimate the relevance of matching. The maximum score was obtained in 38.3% and 39.8% of combinations based on the thermograph analysis and questionnaire, respectively. Results of both scoring systems were strongly positive correlated (r = .937), demonstrating high sensitivity (61.72%) and specificity (90.23%) of the matching. The horse‐rider matching may improve horse comfort during leisure type of work.     

Saddle pressure measuring: validity, reliability and power to discriminate between different saddle-fits

Saddle-fit is recognised as an important factor in the pathogenesis of back problems in horses and is empirically being evaluated by pressure measurements in clinical practice, although not much is known about the validity, reliability and usability of these devices in the equine field. This study was conducted to assess critically a pressure measurement system marketed for evaluating saddle fit. Validity was tested by calculating the correlation coefficient between total measured pressure and the weight of 28 different riders. Reliability and discriminative power with respect to different saddle fitting methods were evaluated in a highly standardised, paired measurement set-up in which saddle-fit was quantified by air-pressure values inside the panels of the saddle. Total pressures under the saddle correlated well with riders' weight. A large increase in over-day sensor variation was found. Within trial intra-class correlation coefficients (ICCs) were excellent, but the between trial ICCs varied from poor to excellent and the variation in total pressure was high. In saddles in which the fit was adjusted to individual asymmetries of the horse, the pressure measurement device was able to detect correctly air-pressure differences between the two panels in the back area of the saddle, but not in the front area. The device yielded valid results, but was only reliable in highly standardised conditions. The results question the indiscriminate use of current saddle pressure measurement devices for the quantitative assessment of saddle-fit under practical conditions and suggest that further technical improvement may be necessary.     

Evaluation of the presence of house dust mites in horse rugs

A sample of fourteen horse rugs and two saddle blankets stored in south western Sydney, Australia, an area of known high dust mite prevalence in the human environment, were analysed for the presence of house dust mites. Dust samples from the rugs, blankets and 16 control sites were collected using a vacuum cleaner with a modified attachment and filter. Dust mites were extracted using an adapted floatation technique. Eight rugs and all control samples were positive for mites, which were confirmed to be house dust mites of the genus Dermatophagoides. This study confirms that exposure to house dust mites from horse rugs can occur, indicating that house dust mite allergen reactivity on intradermal and serum allergy testing in atopic horses may represent true dust mite hypersensitivity. Nevertheless, quantification studies will be necessary to ensure that there is adequate mite exposure for development of hypersensitivity, and further evaluation of immunological responses, avoidance and provocation, and specific immunotherapy are required to confirm the clinical relevance. To the authors’ knowledge, this is the first study to document the presence of house dust mites in the equine environment.     

Effects of girth, saddle and weight on movements of the horse

REASONS FOR PERFORMING STUDY: Although the saddle is seen as one of the biggest causes of back pain, and weightbearing is seen as an important aetiological factor in 'kissing spine' syndrome (KSS), the effects of a saddle and weight on the back movements of the horse have never been studied. OBJECTIVE: To determine the effects of pressure on the back, exerted by tack and weight, on movements of the horse. HYPOTHESIS: Weight has an extending effect on the horse's back and, as a compensatory mechanism to this extension, an alteration in pro- and retraction angles was expected. A similar but smaller effect was expected from a saddle only and a lungeing girth. METHODS: Data were captured during treadmill locomotion at walk, trot and canter under 4 conditions: unloaded; with lungeing girth; saddle only; and saddle with 75 kg of weight. Data were expressed as maximal extension, maximal flexion angles, range of motion of L3 and L5 and maximal pro- and retraction angles of the limbs. RESULTS: At walk and trot, there was a significant influence on back kinematics in the 'saddle with weight' situation, but not in the other conditions. Overall extension of the back increased, but the range of movement remained the same. Limb kinematics changed in the sense that forelimb retraction increased. At canter, both the 'saddle with weight' and 'saddle only' conditions had a significant extending effect on the back, but there was no effect on limb kinematics. CONCLUSIONS AND POTENTIAL RELEVANCE: Weight and a saddle induce an overall extension of the back. This may contribute to soft tissue injuries and the KSS. The data from this study may help in understanding the reaction of the equine back to the challenges imposed by man when using the animal for riding.     

Kinematics of saddle and rider in high‐level dressage horses performing collected walk on a treadmill

Reasons for performing the study: The kinematics of the saddle and rider have not been thoroughly described at the walk. Objective: To describe saddle and rider movements during collected walk in a group of high‐level dressage horses and riders. Methods: Seven high‐level dressage horses and riders were subjected to kinematic measurements while performing collected walk on a treadmill. Movements of the saddle and rider's pelvis, upper body and head were analysed in a rigid body model. Projection angles were determined for the rider's arms and legs, and the neck and trunk of the horse. Distances between selected markers were used to describe rider position in relation to the horse and saddle. Results: During the first half of each hindlimb stance the saddle rotated cranially around the transverse axis, i.e. the front part was lowered in relation to the hind part and the rider's pelvis rotated caudally, i.e. in the opposite direction. The rider's seat moved forwards while the rider's neck and feet moved backwards. During the second half of hindlimb stance these movements were reversed. Conclusion: The saddles and riders of high‐level dressage horses follow a common movement pattern at collected walk. The movements of the saddle and rider are clearly related to the movements of the horse, both within and outside the sagittal plane. Potential relevance: The literature suggests that the rider's influence on the movement pattern of the horse is the strongest at walk. For assessment of the horse‐rider interaction in dressage horses presented for unsatisfactory performance, evaluations at walk may therefore be the most rewarding. Basic knowledge about rider and saddle movements in well‐performing horses is likely to be supportive to this task.     

Methods, applications and limitations of gait analysis in horses

Over the last 30 years, the increase in interest in horses for racing and riding activities has stimulated scientific research in equine locomotion. This paper presents a review of the measurement methods and their applications used to assess equine locomotion. After describing gaits and velocity-related changes in stride variables, the current applications of gait analysis are presented. The economic consequences of lameness justifies the great effort now being put into lameness quantification and prevention. To improve breeding and reduce the costs of training, early performance evaluation tests for each discipline are proposed. After extensive fundamental and methodological research on the various aspects of equine locomotion, the horse industry should benefit from the applications of gait analysis by improving the profitability of racing and riding activities.     

The horse–saddle–rider interaction

Common causes of poor performance in horses include factors related to the horse, the rider and/or the saddle, and their interrelationships remain challenging to determine. Horse-related factors (such as thoracolumbar region pain and/or lameness), rider-related factors (such as crookedness, inability to ride in rhythm with the horse, inability to work the horse in a correct frame to improve core strength and muscular support of the thoracolumbar spine of the horse), and saddle-related factors (such as poor fit causing focal areas of increased pressure) may all contribute to poor performance to varying degrees.Knowledge of the horse–saddle–rider interaction is limited. Traditionally, saddle fit has been evaluated in standing horses, but it is now possible to measure the force and pressure at the interface between the saddle and the horse dynamically. The purpose of this review is critically to discuss available evidence of the interaction between the horse, the rider and the saddle, highlighting not only what is known, but also what is not known.     

FEASIBILITY AND SAFETY OF CONTRAST‐ENHANCED ULTRASOUND IN THE DISTAL LIMB OF SIX HORSES

Vascular alterations play important roles in many orthopedic diseases such as osteoarthritis, tendonitis, and synovitis in both human and equine athletes. Understanding these alterations could enhance diagnosis, prognosis, and treatment. Contrast‐enhanced ultrasound (CEUS) could be a valuable method for evaluation of blood flow and perfusion of these processes in the equine distal limb, however no reports were found describing feasibility or safety of the technique. The goal of this prospective, experimental study was to describe the feasibility and safety of distal limb CEUS in a sample of six horses. For each horse, CEUS of the distal limb was performed after intravenous injections of 5 and 10 ml, as well as intra‐arterial injections of 0.5 and 1 ml contrast medium. Vital parameters were monitored and CEUS images were assessed qualitatively and quantitatively for degree of contrast enhancement. None of the horses had clinically significant changes in their vital parameters after contrast medium injection. One horse had a transient increase in respiratory rate, and several horses had mild increases of systolic blood pressure of short duration after intravenous, but not after intra‐arterial injections. Intra‐arterial injection was possible in all horses and resulted in significantly improved contrast enhancement both quantitatively (P = 0.027) and qualitatively (P = 0.019). Findings from this study indicated that CEUS is a feasible and safe diagnostic test for evaluation of the equine distal limb. Future studies are needed to assess the clinical utility of this test for horses with musculoskeletal diseases.     

A promising surgical approach to equine glaucoma

The preceding case report by Wilson et al. (2015) describes the surgical placement of a Baerveldt glaucoma shunt in a glaucomatous equine eye that had been refractory to aggressive medical and repeated surgical therapies yet maintained functional vision. Shunt placement surgery successfully maintained vision and intraocular pressure in the normal range in the affected eye. This is the first report of long‐term successful glaucoma filtration surgery in a horse. Glaucoma shunt placement shows promise for maintaining vision and comfort in equine eyes affected with glaucoma. There is much to be learned in terms of the most appropriate implant type for the equine eye, the risk of complications such as ocular hypotony or tube fibrosis, and the utility of combination therapy with transcleral cyclophotocoagulation and implant placement, but with the report of one case in which gonioimplant placement has been associated with intraocular pressure control for over one year, further investigations appear warranted. This case provides a glimmer of hope for long‐term treatment of a painful, blinding disease that has traditionally carried a poor prognosis in horses.     

Validity of saddle pressure measurements using force-sensing array technology--preliminary studies.

Back pain is a common and poorly understood clinical problem. An important factor in this regard is the induction or exacerbation of back pain from badly designed or poorly fitting saddles. This study used a pressure-sensing mat to investigate saddle fit. The aims of the study were to confirm the accuracy and reliability of the force-sensing array technology when used to measure pressure beneath the saddles of horses, and to collect some initial data from normal healthy horses with well-fitting saddles. Experiments were undertaken to establish that a linear relationship existed between the total force (weight) exerted and the pressure measured beneath the saddle, using both a wooden horse and a live horse in the standing position. Further studies were performed to demonstrate that characteristic changes of the centre of pressure occur while horses move at the walk, sitting trot, rising trot, and canter.