Dr Gillian Tabor reviews a recently published paper on the effects of using balance pads.
In this paper, the research team measured the postural sway and multifidus cross-sectional area after standing a horse on pads for 5 minutes, 5 days a week for 4 weeks.
Cathcart, J., Ellis, K.L. and Moorman, V.J., 2024. Short term use of balance pads on postural sway and musculus multifidus cross sectional area in horses. Journal of Equine Rehabilitation, p.100006.
LINK TO PAPER HERE.
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Transcription
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Hello, this is Gillian Tabor, physio, and I’m here today to present some research that has recently been published in the Journal of Equine Rehabilitation. I’ve chosen this paper because I think it will be of interest to quite a few of our listeners, whether you are involved in therapy or bodywork or you’ve seen sort of recent trends on the internet for various tools that you can use when you’re training your horse.
So this paper is about the use of balance pads. So balance pads are the foam sort of squares or oval shapes that you can stand your horse on. So they’re placed underneath the horse’s feet. And they are sort of said to have a range of effects. Basically they provide a slightly unstable surface depending on the density of the foam. So some are sort of really quite firm and are almost sort of just like a solid step. And then others are a lot more squishier. And you can imagine, just like us, if we were standing on that kind of material, it changes the challenges to your balance. So the softer it is, the harder you have to work at balancing. Or if you’re relaxed, then you can have sort of quite a sway, a wobble on top of these pads. But if you want to try and keep yourself nice and still, you have to use various and muscular activity to try and maintain equilibrium. So we call that that movement, that wobble on the surface, postural sway. And there have been a number of papers up to this point investigating postural sway. Usually they are done on a force plate or on a pressure map. And what it does is it measures the trajectory of the center of pressure, which is a vertical line up to the center of mass of the horse and the center of pressure, effectively, um, sort of draws a shape on the floor in the base of support.
So much like in the old days, we used to have our we balance boards and you used to stand on it and you saw a red dot that was approximately between your feet. And if you leant forwards, the dot would move forwards, and if you leant back it would move backwards. And on those balance boards you could actually measure how good or how small your postural sway was. And we know with people that as you have weaknesses or pathology, neurological deficits or things like sort of osteoarthritis or frailty, as you get old, the amounts that that center of pressure moves actually increases. So you get a larger postural sway and that can link to actually the risk of falls in humans. And when we look at the equine research, there’s quite a body of literature that has described what happens to that postural sway if horses are either suffering from neurological deficits. So, you know, maybe they’ve got compression of the spinal cord. So, you know, there are a wobbler horse or they have been medically induced into sedation and that increases the postural sway. But recently, probably the last decade or so, you can look at products that you buy. So these pads that you put under the horse’s feet to either and this is sort of what confuses me a little bit about the genuine reason for using them is to whether you are looking to increase the postural sway, and in which case people talk about their horses going into sort of quite a soporific, relaxed state where they are swaying or wobbling and they seem really calm, and they talk about being tapped into that parasympathetic rest and digest state versus the actual use of them to try and recruit the postural musculature, to have the horse stood up on the platform, the foam pads to get them to work hard, to stand really still and in equilibrium, so to have a reduced postural sway.
So some of the research that’s gone before this paper that I’m going to talk about was a study, um, actually by. One of the co-authors in this current paper, but they looked at postural sway and horses that had lameness issues, and they found with rehabilitation that the actual postural sway reduced. They also measured the postural sway on a force plate, but with and without the horses standing on these balance pads, and found that after a program of rehabilitation, there was less postural sway both on the force plate, which is, um, you know, solid platform. And when stood on the balance pads on top of that force platform. So suggesting that the rehabilitation reduced the postural sway and that was being a good thing. This also aligned with changes in the size of the modified muscle. So modified. This is one of the deep stabilizers that lies along side. The spine is actually only one of the muscles that we consider being part of the core. Um, muscles. It’s not the only one, but it’s the one that’s easiest for us to measure because we can use ultrasound imaging to image the borders of the muscle so that you can actually measure the whole muscle cross-sectional area. And we know from studies where we’ve looked at the use of baited exercises.
So using carrot stretches, it actually has a benefit that it increases that size of the cross-sectional area where we know that if we’ve got pathology, we have a reduction in the size of the cross-sectional area of multiple kids. So it’s all sort of linked. Um, there is a big market for these balance pads. Um, you know, they’re not expensive in terms of, you know, buying a saddle or buying a lorry for your horse, but they are a piece of equipment that people would have to pay for. Uh, the ones that they used in this study were actually the sure foot pads, which you can find on the internet, but you can actually also buy pads that are, um, off of, um, companies like Amazon. You know, they call Pilates pads or yoga blocks. Um, the actual sort of density and the size of them is going to vary depending on whether you want your horse to be stood on a firmer surface or a softer surface. And whether you want to induce swaying to have that relaxing effect, or whether actually you are trying to recruit the postural musculature to actually work hard to stabilize the body in a sort of non loaded situation. So in that, um, stationary position and I won’t say static because they’re not standing static if they’re swaying, but they are stationary. They’re not moving their feet.
So on to the paper. So the title of the paper is short term use of balance pads on postural sway and muscular small cross-sectional area in horses. It’s published in the New Journal Journal called the Journal of Equine Rehabilitation, and it is actually an open access paper. So I will put the link to the paper in the show notes, or you can Google it. I’m sure you can find it. The authors are Jessica Cathcart, Katherine Ellis, and Valerie Moorman, and they are producing this at the University of Georgia, the College of Veterinary Medicine, which is in the USA. So Katherine Ellis, as I said, has co-authored the paper on the postural sway in horses Rehabilitated with lameness.
And actually, I looked up the papers of Valerie Moorman and have seen that she is published on the use of technology to measure postural sway. And that is another thing that interests me of this paper, because I don’t have access to either pressure mats or force plates. Um, quick note if anybody out there has got a spare £100,000 and they’d like to pay for that to go into our research lab, that would be amazing. But in this paper they used another bit of technology. So going through the paper, as with all papers, the introduction provides the rationale for the study and gives a short literature review. And they talk about the motivators muscle and how it’s related to stabilization of the lumbar spine, which is, um, you know, quite sort of confidently understood in both the man and, um, horses. And then they talk about the research on standing on unstable surfaces. Um, they’re quite right. They say there’s no study evaluating the horse’s use of the balance pads alone. As I said, they were included in the study of lameness, but, um, that was a measurement tool rather than a, an actual effect generator.
So the object of the study was to evaluate the effects of short term use of balance pads in horses. How did they do this? Well, they, um, present their methods quite clearly. And I’ve read through and you, you could reproduce them, which is always a sign of a clear paper. You should be able to take the methods and copy them and see whether you get the same outcome. They actually had six horses in this study. They did provide a sample size six does sound quite low, but it’s quite common in these projects. It’s also, um, you know, it’s quite difficult both economically and uh, from a sort of monetary and a time wise to do this on larger sample sizes. But I would think that this would fall into the, um, sort of a pilot or preliminary study sort of size when it comes to sample size. But they use six mature, healthy quarter horses and these horses were on pasture turnout, so manage the same through the duration of the study. And it doesn’t say whether they are not being ridden, but I assume because they were on pasture turnout between the sort of intervention times they weren’t being ridden.
So what they did is five days a week for four weeks they stood the horses on firm balance pads. And as I said, these were the green shore foot pads from Murdoch method. So they had five minutes of on them. Um, if the horse sort of came off the pads, they put the horse back on again. So it was a total of five minutes each time they got a nice picture of a horse, um, tied up doing it. And uh, during the standing on the pads, the horses actually had access to food at chest height so that that would encourage them to stay on it before they did the study, they actually looked at whether the horses were lame. So for this they use objective gait analysis, which is good to know. They use the lameness locator. And there were actually a variety of lameness that they found. Um, and uh, they record these before. So at baseline and then at the end of the four weeks.
So how have they measured postural sway? And as I said, this interests me. And I’m going to look into this further, is that actually they put a portable media device, which happened to be an iPod touch strapped to the top of a roller in a forwards and backwards alignment, and it was set horizontally, and they used an app on it to measure the postural sway when the horse was stood on a hard surface, so on concrete, on flat ground, and then also when they were on the balance pads, they state that they tried to have the horses in a square stance, which is where the legs are orientated vertically, or the cannon bones are vertical. And they had 510 to 15 second trials for each of those conditions. So imagine actually that was um, you know, it’s fairly easy kit to use. It’s probably in the real term was six horses trying to, um, have them all stood well, obviously not at the same time, but have them stood there doing this measurement. Um, I would like to try it and practice and see how many attempts it took.
Um, they then extracted the data, um, because it was collected in a data logger and then were able to measure the amount of movement for analysis because they were interested in multiple videos. Um, they also had the equipment available to them. So they measured the cross-sectional area of multiple at, um, thoracic and lumbar levels. So they went T12, T14, T16, T18, L2 and L5, which um fit to previous studies. Um they talk about how they do that and they used the um, the methods that have previously been validated and published. They actually clipped the area of the skin above it so that they could know that when they went back four weeks later, um, they were able to remeasure the investigator, um, Catherine Ellis. It’s obviously experienced at doing this. She’s done this in previous studies as well. However, she was not blinded to the trial or what the horses were undergoing and actually an awful credit to the authors. They do actually talk about this in the discussion. The limitation is there was no control group and the measures were not blinded. The measure is coming from the lameness locator and the data logger on the horses roller to measure postural sway are obviously, um, they can’t be biased by the operator, but the ability to, um, bias multiple measures is, um, in previous studies, the person doing the measurements has also been blinded to either the group or the level or, um, the horse when they’ve been doing ultrasound imaging. So that’s the limitation. That’s why I think this, you know, should be titled a pilot or a preliminary study.
So what did they find? Well, um. Five of the horses had a moderate hind limb lameness. Um, and then after the treatment there was a variety. So two no longer had hind limb lameness, but three were the same. And the one that wasn’t lame at the start actually had a mild left front limb lameness. Um, so I don’t think there’s anything conclusive from that with regards to whether balance pass has an effect on lameness because of those changes. So they then report on the postural sway. And they say that between baseline and four weeks there was a significant decrease in the medial lateral. So side to side and forward backwards range of motion after the four weeks. So what I’d be interested to know, um, when they report on these is actually the effect size of that change of range of motion. So we know there’s a decrease and it is statistically significant. But it would be really good if um, authors could present the, uh, clinical significance. So you know, what is biologically useful in terms of those number and the data that they present. So there are some nice images of long gizmos and they present the data in tables. But there was not a significant effect of time on the median motivator asymmetry.
Um, although there was a slight difference at different locations, but there wasn’t a significant effect of time and spinal location at spinal, um, location on the asymmetry. So what did they conclude? They from their data, they can say that there was a change in the postural sway after the four weeks, uh, compared with the baseline. And that was demonstrated by a reduction in that range of motion. And they suggest that that is an improvement in postural stability. Um, there is some sort of ongoing discussion wider than this paper as to what you mean by stability and how much stability is good, and at what point does stability become stiffness. Um, that’s an interesting question. And does it depend on the starting range of motion as whether you want a different change in that? For instance, if you have a, a horse that has a reduced range of motion, are you looking to create mobility? Or if you have a horse that’s hypermobile, are you looking to create stability?
So that is a sort of a complex. Broad discussion point that, um, I, I sort of think about when I see the words postural stability, but, um, it is quite conclusive that the range of motion did reduce and they were able to measure it with this tool, uh, resting on the horse’s back, which I think is quite nice. It would be interesting to know whether or not the the change in the postural sway then affects the spinal motion during gait. From this study, we can see that it didn’t really have a conclusive effect on the lameness. But actually, if we could then put our Mus on the horse’s back or use 3D motion capture, what would be happening to the actual flexion and extension ranges and the sort of actual displacement values, either in a sort of up, down or side to side movement of the horse’s back, you’d expect perhaps there would be less side to side, some less medial lateral movement. But does this result in an increased or eventual movement? And does this occur in the whole body, throughout the spine, or in specific areas around the spine? I don’t know, I’m just sort of hypothesizing. And it’s an extension from this preliminary study, the hypothesis from the authors that the multifarious cross-sectional area would be greater.
It was only sort of partially supported and it was only significant both sides at T 14. But T14 is an interesting part of the horse’s body. It’s right underneath where we sit. And also it’s an area that has been highlighted as a more frequently diagnosed with back pathology. So, you know, is this an area that’s more likely to have a change. The other factor is that they only did four weeks. And when we think about the studies that have used baited exercises, certainly the the one from, um, Doctor Narelle Stubbs that looked at 12 weeks when I did my racehorse study and motivators, we looked at six weeks. So this is sort of quite a short time to see hypertrophy so that muscle growth. So maybe, maybe if it was increased the study had a longer duration, maybe we’d see a change of muscle dimensions. And actually that is something that is discussed in the final section of this paper. So they talk about the, um, limitations of the study, saying that there was only one type of pad that was used. Um, they talked about whether or not they were in a standing square position. And they also self critiqued about the fact that the cross-sectional area measurements were performed by a single unblinded observer, which might introduce bias. So I always like to see that the authors have recognized that there are limitations to the study’s methodology.
Um, there always will be, um, may not be completely possible to blind or randomize. Um, but what would have been nice with this paper, we have, you know, another group of horses that were measured, um, on the, on the hard surface and on the pads at baseline, then didn’t do any intervention and then measured again on the hard surface and on the pads so that then you could see whether it was an effect of multiple standing on the pads or whether it was just that, um, you know, one time that they learned to stand more still on the pads. Um, so there are, you know, there’s potential for this train of study line to be taken further. And yeah, I’ll be looking out to see whether or not these authors have more in the pipeline. But sort of in conclusion, it’s interesting to show that there obviously are changes when the horses are standing on the pads. Um, there’s there was no reports of any side effects, any danger to them. Um. 1s You know, I’m not recommending everybody rushes out there and buys buys the pads. But if you’ve got them and you use them or you, um, have somebody that, um, recommends them, then they may be, um, you know, useful addition to providing some sort of training, uh, stimulus, some movement variability.
However, at the moment, we don’t know the bigger picture. You know, how does this fit into how the horse moves dynamically? And what effect does this have on function? And then also if you’ve got a horse that has an underlying pathology, is that a good thing or a bad thing to use these pads? Um, these are all questions that I’m throwing out there. I wouldn’t expect this, you know, this one paper to answer them. Um, but it always is a sort of stimulus for further thought processes and further discussion.
So, um, please do read the paper if you are interested in it. If you’ve got any comments or you want to discuss it further, then obviously please do get in touch. Um, and I look forward to continuing the discussion. So thank you very much for listening.
