The benefit of using ‘yearling rollers - Dr. Russell Mackechnie-Guire asks if a roller is a harmless piece of equipment? -scientists discover performance inhibiting spinal pressure under rollers
/Dr. Russell Mackechnie-Guire
![[opening image]Photo credit North Lodge Equine[HEADLINE]Scientists discover performance inhibiting spinal pressure under rollers[STANDFIRST]Reducing pressure under the saddle, bridle and girth has been found to significantly improve performance, and…](https://images.squarespace-cdn.com/content/v1/517636f8e4b0cb4f8c8697ba/1600857095099-SLWYE5I6YL6ON0SMGO1Q/opening+image_lo.jpg)
Reducing pressure under the saddle, bridle and girth has been found to significantly improve performance, and now the roller has been scientifically tested.
Lost training days, treatment and medication for back problems are time consuming and costly, so optimising equine spinal health from early on is an essential consideration in improving equine health and welfare. When a young horse is started, one of its first experiences is to have tack on its back, initially a lungeing roller. The roller, a seemingly harmless piece of equipment and its effect on the horse, has previously been overlooked. However, it has now come under scientific scrutiny by the same research team that investigated the impact of pressure distribution under the saddle, bridle and girth on equine health and performance.
Their recent study used high-tech pressure mapping to examine the pressures exerted on the horse’s back during lungeing (see technology panel). Localised areas of high pressures were consistently recorded under the roller on the midline of the horse’s back directly over the spinous processes in the region of the 10th and 12th thoracic vertebrae (T10-T12, see anatomy panel).
High pressure directly in this region, as seen under a conventional roller, is likely to cause the horse to seek a compensatory locomotor strategy and adopt a posture where the back is stiffened and hollowed, resulting in an extended spine. Previous research has shown that back function and gallop kinematics are compromised by a stiffened spine.
Studies have demonstrated that pressure-relieving modifications in a saddle result in increased stride length and hip flexion, along with a greater femur-to-vertical angle (indicating that the hindleg is being brought forward more as the horse gallops). Reducing saddle pressures leads to a marked improvement in the horse’s locomotion, allowing it to gallop more efficiently.
A modified roller that removes pressure will allow the back to function without restriction.
The roller is positioned over the part of the back where the front half of the saddle sits; by applying these principles, modifying the roller to remove pressure would allow unhindered back function.
The equine back is an essential component of the locomotor apparatus, transferring biomechanical forces from the hindlimb. So, a modified roller will not only result in improved locomotion and performance but will also have long-term spinal health benefits.
Strong start
In racing, where lungeing is primarily used prior to backing, what we do to and the equipment we use on the young horses in the preparatory stages are likely to have a significant impact on the development of the horse’s posture, back health and locomotion.
If a young horse begins the training process of being lunged with a roller that exerts pressure directly on the spine at T10-T12, it will develop a strategy to compensate for the discomfort. Then, as the horse progresses to a saddle—which similarly exerts high pressure in the same area—it is inevitable that this will have an effect on the locomotor system. The horse’s athletic performance will be significantly compromised before it even gets on the track.
Innovative pressure-relieving modifications in tack design have demonstrated improved locomotion when pressure is reduced. Identifying and replacing any equipment that has limiting effects on locomotion or development could have long-term benefits for the longevity and performance of the horse. This applies particularly to the lungeing roller as it is the first piece of tack a youngster has on its back. It is essential that the horse does not develop a locomotor strategy to compensate at this stage.
Under pressure
Pressure mapping during lungeing
Conventional roller - 35kPa pressure directly on the spine at T10
Conventional roller & side reins - pressure consistent at T10 but increases at T11 and T12 to 45kPa
New roller design, even with side reins - all pressure is removed from the spine]
In a recent study, horses were lunged on a 20-metre circle on both reins in trot and canter wearing a roller fitted with pads. In canter, peak pressures were seen each time the inside forelimb was in stance (on the ground). In trot, pressure peaks occurred each time a forelimb was in stance phase.
Given that the horse is experiencing high pressures under the roller directly on the spine in the region of T10-T12 in every repeated motion cycle (stride), it is inevitable that a compensation strategy will develop.
When trotting and cantering with no attachments, such as side reins or training aids, peak pressures under the centre of the roller were found to be similar to those seen under the saddle with a rider on board. Studies have shown pressures over 30kPa can cause back discomfort. In this study, researchers measured pressures up to 35kPa directly on the midline of the horse’s spine, in every stride, with just a roller and pad.
With side reins attached, the location of the peak pressure was brought further towards the front edge of the roller. Essentially, the pull of the side reins caused a ridge of pressure under the front half of the roller, and the readings increased to 45kPa.
Compensation costs
Compensatory gait strategies lead to asymmetric forces which have a negative effect on limb kinematics (movement). The consideration here is that the horse is experiencing these locomotor compromises before the back has been conditioned to manage the increased forces, and before a jockey has even sat on its back.
It remains to be shown whether the compensatory gait and asymmetric forces caused by early roller pressure manifest as lameness or loss of performance later on. There is a coexisting relationship between back problems and limb lameness, but evidence is still being gathered as to which one comes first. Researchers are investigating to what extent loss of performance and lameness issues might be traced back to these ‘training and backing’ experiences. It is therefore essential that young horses are started with correctly fitting equipment to limit any long-term effect.
Lungeing for rehab
In addition to the backing process, lungeing also occurs during other influential periods of a horse’s life, including rehabilitation after surgery. Post-operative recommendations for kissing spines can often include lunge work with training aids to induce spinal flexion and opening up of dorsal spinous processes. …
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