We are very happy to announce that Jo Belasco, Esq. will be a presenter at the WINGS Foundation 2014 Soaring to New Heights Conference in Denver, CO, on September 26 and 27, 2014. She will be conducting a presentation entitled, “Itahoba Horse: The Power of Connection for Healing Trauma” on Saturday, September 27 at Denver Health’s Rita Bass Trauma and EMS Education Institute. We do not have the time yet. If you would like to register to attend the conference, please visit the conference page. If you would like to support the Itahoba Horse program that helps WINGS members, please visit the fundraiser page at Tapestry Institute.
Note: Subsequent to the posting of this announcement, the name of the program changed from Itahoba Horse to Horse Ibachakali after lengthy discussion with the Elders and Teachers of the Choctaw Language Program. Both “itahoba” and “ibachakali” mean “connected,” but the latter is more in line with the sense in which we mean it. We are grateful to the continuing efforts on behalf of the speakers in the Choctaw Language Program for helping us use precisely the right terms to convey the concepts manifested in our programs.
How does a horse who is outstanding in his field carry his weight? Well, if he’s out standing in his field, as opposed to trotting or running, he carries it on all four of his legs (bum-dum-ching). Here’s an example, to the left. Whatever this horse weighs, gravity is acting on his mass to pull it towards the earth with a calculable force. That force travels through each of his four feet to the ground. So a very simple way to begin thinking about force and stress at a horse’s hooves is to think about the force caused by gravity pulling on the whole horse’s body mass, and then simply dividing this force by four to estimate how much is supported by one of the hooves.
You can try this out for yourself on a bathroom scale. Stand on it with both feet and see what it says you weigh. Then balance yourself so you’re standing on it with just one foot, the other off the ground somehow. (Don’t balance yourself by touching a hand to the sink or a wall right now, as it will mess up your experience. You’ll do that in a moment for another reason.) Although you will see your weight wobble a bit on the scale as you move around to get to the one-footed position, in the end you will weigh the same amount. Only now you can feel that your weight is all being held up by that one leg and foot rather than two. Your body weight is your body weight, and it is going to push down the same amount on the scale whether it’s held up by one leg and foot or two of them. The difference is how much the leg/foot you’re standing on, that’s holding you, has to hold.
Now, put a hand on the bathroom sink while you’re standing on the scale. You will see your weight go down. That’s because you are supporting part of your weight through your arm and the sink, so less of your body weight is going through your legs to the floor. If a horse “leans” towards its front end, more weight goes through its front legs and less through its hind legs, just like you can lean more of your weight on the sink and watch the scales show you less and less weight going through your legs.
What you probably did not realize is that if you live in the United States and measure your weight in pounds, your bathroom scale does not measure your body’s mass, but the force with which your body’s mass is pressing down on the scale. A bathroom scale is a very simple type of machine that measures how much force pushes against it. A spring inside the scale deflects (gets squished) when you step on it and thereby apply force to it. A rack-and-pinion mechanism inside the scale turns the spring’s deflection into the motion of a needle on a dial, so that it points to a certain number of “pounds” depending on how far the spring has been deflected. So weight, in the US, in pounds is a measure of FORCE. (Also, see the section “spring scales” on this page about weighing scales.)
To explain how this happens, consider the equation for force, F = ma. F stands for the “force” an object exerts; “m” is the mass of the object; and “a” is that object’s acceleration. So the equation can be written in English, with specific reference to you on a scale, this way: the force your body exerts against the ground (or the scale) is equal to how much mass your body has, times how quickly your body is accelerating.
At this point, you are liable to say, “Wait a minute. My body is not accelerating if I’m simply standing on the bathroom scale.” But it is. The Earth’s gravitational attraction is pulling down on your body all the time. It pulls so hard that if your foot slips on some water as you get off the scale, you’ll crash to the tile floor hard enough to regret it. And it pulls so hard that when you hit middle age, various parts of your body start sagging down towards the earth’s surface because of gravity’s pull on them.
Gravity pulls on things enough to cause them to accelerate if they fall, and anything in freefall accelerates at exactly the same amount: 32 feet per second per second. That means that with each second that passes, the falling object goes faster than it did before. The diagram at the left (adapted from one on a UC Berkeley website) shows the position of a falling ball as gravity makes it go faster and faster, or accelerate, in free-fall. You can see where the ball is at the end of 1 second, 2 seconds, 3 seconds, and so on. Notice how much farther it goes in the 4th second. The speed of the ball, or its velocity, is recorded at the left as 32 feet per second at the end of the first second of its fall, and then 160 feet per second at the end of 5 seconds. You can see, here, what it means to say that gravity accelerates objects by pulling them towards the earth. The ball goes faster and then even faster, second by second, as it falls.
No matter what you drop, the speed of descent is going to be same. That’s what Galileo demonstrated in his famous experiment at the Leaning Tower of Pisa (which may have been just a thought experiment), where he dropped two objects of different masses from the balcony to see when they would hit the ground. “Common sense” held that the heavier object would fall faster. But in fact the two objects hit the ground at the same time. This is because the gravitational constant is simply and only 32 feet per second per second — mass isn’t in there at all. So the mass of the object gravity is pulling on has nothing to do with the speed at which it falls.
However, we all know intuitively that although a bowling ball and a tennis ball dropped from the Leaning Tower of Pisa might hit the ground at the same time, they will not hit the ground with the same force. We might be willing, if suitably encouraged, to stand where the falling tennis ball could hit us on the head. We would run like mad to get out of range of the shards of ball and pavement that would fly through the air from the much bigger force of impact with which the bowling ball would hit the ground. The force with which the tennis ball and the bowling ball hit the ground is described by the equation F = ma. Mass, m, is a part of Force. So the bigger the object that the earth’s gravity is pulling on, the more force that object applies to the ground. And this brings us back not only to the force at a horse’s foot, but our own bathroom scale.
American bathroom scales already factor in the acceleration due to gravity when we get on the scale. They do not measure our body’s mass. They measure the FORCE that results from gravity acting upon our body mass. That is what a pound measures on a bathroom scale in the U.S.
But, as you learned if you stood on the scale on just one foot long enough to do the exercise I described above, force isn’t the only thing that matters. Standing on the bathroom scale on two feet isn’t difficult. Standing for a long time on the bathroom scale on just one foot is. If you tried this part of the exercise, you might have noticed that you had trouble keeping your balance, that your joints hurt, and that your foot felt more “smashed” by having all your weight (force, remember!) on that one leg. The difference you felt was in the amount of stress that was in your foot.
In physics, stress is not a measure of how desperate you feel when you’ve missed a project deadline, have an overdue bill, and your car breaks down all on the same day. Stress is a measure of how much force is acting on a given area of an object. Stress, S, is also defined in an equation: Stress = Force divided by unit area. In other words, stress is how much force is being transmitted through any given part of an object. It is stress, not force, that causes structures to fail (if they fail). The area you measure — and this is important — is at a right angle to the force. So in your foot, the picture looks something like this:
What matters, in measuring the stress in your foot, is how much force is pushing down on it and how large the cross-sectional area is. In the picture on the left, we are looking at how much stress there is in the lower part of the shin area, just above the ankle. That’s where I’ve drawn a green ellipse that represents the cross-sectional area of the leg right at that point, as if you sliced through it horizontally. That plane is the one that the body’s weight, or force (the red arrow labeled “F”), is acting through. If the diameter of the person’s leg here is 3-1/2 inches (not too uncommon in a woman), then the area of the leg’s cross-section there is the area of a circle, pi times the radius squared. (Do I hear groans as thoughts of geometry flood back? Hang in there! We’re about to get back to horses, and this will all be worthwhile!) The radius of this part of the leg is half the diameter, or 1.75 inches, and pi times this radius squared is 9.6 square inches. So if our woman weighs 130 pounds, the stress this part of her leg is experiencing is 130 pounds divided by 9.6 square inches (because Stress = Force/area). That’s roughly 130/10, which is 13 pounds per square inch. That is the amount of stress going through this part of the woman’s leg in our example.
IF she is standing on one foot. If she is, all the force of her body (created by gravity acting on her mass) is being supported by one foot. But if she’s standing on TWO feet, then they are sharing the force. In that case, the stress in this part of the leg — the other one also being on the ground — is half her weight, or 65 pounds, divided by about 10 square inches, for just 6.5 pounds per square inch of stress. As you can see, stress is twice as high when she stands on one foot as when she stands on both — 13 pounds per square inch compared to only 6.5 pounds per square inch.
Let me pause here and say that if you’d like a reasonably good idea about how much stress this is, measure off a one-inch by one-inch square on a piece of paper. Look at how big it is. Now think about something that weighs 13 pounds — a medium-sized watermelon, for example. And imagine balancing the entire weight of that watermelon on that one-inch sized piece of paper. That’s how much stress is on the leg of that 130 pound woman if she stands on one foot. If she puts the other foot on the ground, the stress is half of that (about large cantaloupe-sized).
But remember we are heading for a horse’s HOOF here, not its leg. So let’s go on down to the part of a human leg and foot that is against the ground: the sole of the foot. How much stress is in that part of the body? The force or body weight is the same: it’s still 130 pounds if the woman is standing on just one foot, and 65 pounds (half of 130) if she’s standing on two. But the surface area of the sole of a foot is a lot bigger than the cross-sectional area of a shin. Look at the bottom of your own foot, and compare it to an imaginary slice through your shin bone, and you’ll see what I mean.
A common estimate for the surface area of the bottom of a woman’s foot is about 25 square inches. So our woman who weighs 130 pounds (who is, remember, exerting a FORCE of 130 pounds on her foot) experiences only 130/25 = 5.2 pounds per square inch of stress on the sole of her foot if she’s standing on one leg. And it’s half that — 2.6 pounds per square inch of stress — if she puts the other foot on the ground to hold up half the load.
Notice that the stress in the woman’s foot is much lower than it is in her shin, even though her weight (or force) is the same, regardless: she weighs 130 pounds. But since her shin has a smaller cross-sectional area than does the sole of her foot, the stress is higher there than in her foot: 6.5 pounds per square inch in her shin compared to 2.6 pounds per square inch in her foot (if she is standing on both of her feet). So now you understand one reason why it’s more common to hear of someone breaking their shin bone than breaking a bone in their foot. The basic stresses in a shin are higher than they are in the foot because the shin is smaller in diameter.
And now we can talk about force and stress in a horse‘s foot . . . er, hoof.
Let’s consider a horse that weighs 1100 pounds. If this horse is standing at a tie rail and has 4 feet on the ground, each of those four feet carries about 1/4 of his total body weight, or 1100/4 = 275 pounds.
I have to pause here to point out that this means if you want to lift up his hoof to pick it out, and if he doesn’t do anything to change the situation, you are going to have to pull up against those 275 pounds to get that hoof off the ground. That’s what he’s putting through that leg and foot if he’s just standing there eyeing you. I point this out to remind you that horses are actually fairly cooperative. Most of them “lean away” when we go to pick up their hoof, and redirect a lot of their weight to the other three legs so we can lift the one we’re after. But a horse that’s determined not to pick up a foot can not only brace itself but lean more heavily on the foot the person wants to lift up. I’m sure you’ve seen a horse do this. And when you see that, you’re not looking at a force-and-stress problem, but a relationship one.
So, back to force and stress. We have a horse hoof with 275 pounds of force going through it. The amount of stress on the hoof is going to be this amount of force (275 pounds) divided by the area of the hoof. This means we need to estimate the area of the bottom of a horse’s hoof, that’s against the ground.
The Davis Boot company makes standard sizes of boots for horse hooves to soak in, and they provide the boot dimensions on their website. They say that “size 2” is for average horses but that the boots are intended to go over a bare (unshod) hoof and to fit loosely enough for soaking solutions to be added. So we’ll select the boot that’s one size smaller, the size 1, to represent the dimensions of our 1100 pound horse’s foot. That boot’s dimensions are 5-1/4 inches wide by 5-5/8 inches long. Notice that the boot is not perfectly round, but longer than it is wide. This reflects the shape of horse hooves, as you can see on the right.
Since the shape of a hoof is not a circle, we are going to average the two measurements (5-1/4 inches by 5-5/8 inches averages to 5.35 inches) to approximate a circle of roughly the same size. The radius (half the diameter) is therefore about 2.7 inches. We can now calculate the surface area using the standard “area of a circle equals pi times the radius squared” equation. Multiplying this out gives us a figure of about 23 square inches for the bottom surface of this hoof that is against the ground.
And now we can calculate the stress there. We have a hoof with 275 pounds of force going through it, and its area is 23 square inches. So the hoof is experiencing 275/23 = 11.9 pounds per square inch of stress. . . if all four feet are equally on the ground and the horse is not moving. That’s quite a bit more than the 2.6 pounds per square inch of stress that we calculated in a 130 pound woman’s foot if she’s standing with both feet on the ground. Notice why: the surface area of a hoof (23 square inches) is about the same as the surface area of the sole of a woman’s foot (25 square inches). Horses are carrying much more weight, and experiencing much greater forces, through feet that have about the same amount of surface area in contact with the ground that our feet do. Granted, horses have four feet instead of two to carry the load, but they also weigh a great deal more — even proportionally.
However, there is obviously far more to the story of stress in horse hooves than this. Horses don’t simply stand still at tie rails, and they often have only one or two feet on the ground at a given moment. Now that we have gone through this set of calculations, though, we can take things to the next step (pardon the pun!).
The slogan Jo (my business partner) and I use for our horse work is “Balance, Center, Connect.” This is the logo we designed for the first horse program we ever ran, which was at that time part of the work in which our non-profit, Tapestry Institute, was engaged. We coined the phrase to refer not only to our horses’ own best functional states, and to the states that allow us to have our best riding experiences, but also, purely and simply, to ourselves as human beings.
We all know it’s difficult for a person who’s not physically balanced to ride well. They continually throw their horse off-balance with their own off-kilter weight (which produces the “eccentric load” I talk about in my biomechanics seminars), accidentally asymmetrical hands and feet, or body stiffness that translates itself right into the horse. The same is true of being physically centered. And of course we need just the right amount of physical connection with the horse we’re riding to communicate responsibly as well as effectively.
But emotional balance matters, too. Who among us has not had a miserable time riding, fussing with our horse for being “difficult,” only to realize with a sudden pang of guilt that we went out to ride that day already angry or upset about something else? An emotionally unbalanced state communicates itself to our horses just as freely as it does to the humans around us, who can at least use spoken words to ask us to “lighten up” or “take a walk to calm down” before dealing with, and upsetting, them further.
When it comes to understanding how horses move and support themselves and their riders, it’s also important to balance differenttypes of knowledge. But doing so is extremely difficult because of our culture’s deeply-embedded assumption that logic, reason, and mathematics are the most valid ways of understanding reality. “Factual” information is seen as trumping any other type, “science” is seen as producing the most reliable facts, and information that is mathematical is seen as being the “best” type of science. Here’s an example of the result of this type of worldview.
Hilary Clayton, Ph.D., at Michigan State University’s College of Veterinary Medicine, has carried out studies on the biomechanics of bits. Clayton is a solid researcher who holds excellent credentials and has published a number of books. But her work can be a bit daunting for many people to read. Her biomechanics and physiology books, in particular, are ones I would personally select for my students to use if I was teaching a graduate course in biomechanics, but be reluctant to recommend as an easy-to-use resource for a rider who doesn’t want to get a graduate degree. Yet Clayton gets her work “out there” in clinics and talks — and is frequently misunderstood by people who are looking for “facts”, particularly mathematical ones they can hang their hats on with pride of knowledge.
Clayton’s work on horse bits was summarized and reported in Horse Science News in an article titled “Myler Bits Act Differently on Horses.” More than half of the three-paragraph summary was devoted to mathematical data, such as: “The jointed snaffle and Boucher bits both averaged 3.3 centimetres (1.3 inches) away from the teeth, whereas the Myler snaffle lay just 2 cm from the premolars. The other two Myler bits were located even closer, at 1.3 cm from the premolar teeth.” A reader studying this report is left with the comforting notion that “something important” has been learned about bits, particularly about the place in the mouth that myler bits sit compared to other bits, and that single-jointed snaffle construction and rein tension are somehow relevant factors. At the same time, I think it would be difficult for most riders to apply any of the information presented. I also think, from my years of doing public education with Americans who both respect and dislike science (thanks in large part to nasty grade- and high-school experiences) that most of the people who couldn’t make heads or tails out of what to do with this information would assume the problem was their own — that they didn’t know enough, or weren’t smart enough, to see at once how to apply it.
The trickier part of this is that I also know, from long experience, that there are people who do bitting clinics as part of their general horse business who, when they come across this numbers-filled article, will figure out a way to say that the figures support whatever view of bits they propound in their clinics. If you think people don’t do that, just watch the labels on (and ads for) products in the grocery store the next time there’s big news about a scientific study linking a particular nutrient or compound to some aspect of staying healthy. And it makes sense if you think about it — as long as the “facts” have been appropriately represented in the press to begin with. And that, as the PLoS Medicine article I just linked to shows, is the rub, right there.
On the other hand, take a look at this article summarizing Clayton’s bit research at Horse Journal on the Equisearch website. (That’s not a rhetorical statement. I really recommend you read the material to which I’ve linked.) This article, titled “Dr. Hilary Clayton Offers Many Prescriptions for Bits,” has an entirely different theme: “Dr. Hilary Clayton has been studying the way bits act on horses’ mouths for more than 20 years. But even after all those years of systematic research, she still says that ‘finding the right bit is more a matter of trial and error than a scientific process.'” The italics are my addition, to highlight the part of this statement I find particularly meaningful. The article then goes on to list some generalized findings that will come as a surprise to many horsepeople — one of which is that many horses prefer smaller-diameter to larger-diameter bits because their mouths are smaller than we think they are — and then quotes Clayton categorically stating that the rider has to figure out which bit their own horse is most comfortable using: “‘So the size and the shape of the bit is individual to every horse, meaning you have to keep trying until you find a bit they’re comfortable with”. This is repeated in the article’s last line, which concludes: “. . . Clayton still believes that finding the right bit for your horse is a matter of simply trying different bits.” Please notice that this research scientist is emphasizing the real value of experiential knowledge here, rather than “fact”-based knowledge, in two ways: (1) the rider is to use a personal trial-and-error method to try different bits and see how each one works, and (2) the rider is to assess each bit tested by using their own individual perception of howcomfortable their horse is with that bit in its mouth.
You don’t have to look far to find publications in which people who claim “horse expert” authority denigrate the very idea that horse “comfort” matters or that humans can assess a horse’s comfort. Further, such “experts” claim to use science, of all things, to give authority to their denigratation of experiential modes of understanding and to support their own fact-based system of information as not only best but also the only reliable source of knowledge. This is what leaves horsepeople feeling stuck, unable to get themselves and their horses out of situations that don’t feel right.
Yet here is a highly-credentialed research scientist who’s emphasizing experiential learning, the significance of a horse’s comfort, and the reliable ability of a horse owner to tell if their horse is comfortable or not. Given that the non-scientist “bit expert” who denigrates the horse owner’s experiential learning is claiming the authority of science (supposedly), then should not the actual scientist have the higher authority in this case? If so, then the paradoxical situation is that it is the scientist who turns over the tables on what type of knowledge has real value, placing the final authority squarely in the hands of a rider and the responses of her horse. And if that rider says, “But I don’t know about bits,” then look again at the article I linked to and you will see that it addresses this issue. Clayton points out the salient factors that usually impact bit comfort, that we need to pay attention to, including how high or low in the mouth the bit rides, whether it’s single jointed or has a flat area over the tongue, whether it touches the roof of the mouth, and the importance of paying as much attention as possible to the size of the mouth cavity since it’s not directly comparable to the horse’s body size. In other words, there are pieces of “factual information” she’s learned in 20 years of bit research, and she’s passing those on in order to give riders information about what to look for as we run our own tests. She is teaching us what to look at, how to see.
So that then we can make our own decisions.
That’s what science is about. It’s about learning what factors exist, since usually we aren’t aware of even a tenth of them in normal practice. It’s about learning which factors that we never even thought of are really important to pay attention to. And then it’s about learning how to integrate information about these factors into a much larger scheme of understanding the subject so that we can make personal decisions that are wise and informed. This is real science — which, interestingly, is based on trial-and-error (which is called “experimentation”) and personal assessment of results (which are called “sense-data”) — the two specific methods Clayton recommends horsepeople use to select the right bit for their own personal horse. Oddly enough, the fact-based, supposedly “science”-based system we find so often in the horse world, that tells us horse comfort is an illusion, that riders can’t possibly decide what’s best for their horse (but must hand over decisions to Experts), and that all horses in a certain discipline “must” use a particular bit because “we know” that bits work in such-and-such a way is actually not scientific at all. And I am saying that as a scientist with a doctorate from a major university, who has participated in policy discussions about the nature of science and of communicating science to the public in formal and informal education at the highest levels possible in the US.
All this being the case, my goal for this blog and for my seminars, both, is to share what I know about horse biomechanics and horse movement to help people learn how to see their horses better. I want to share information that helps riders see and appreciate the really astonishing power and subtlety of response that exists in a horse’s systems of adaptation to stress, and to learn what to look at when they assess how their horse is moving. I want to help people better understand the basic biomechanical adaptations of their own human bodies, to feel how subtly but profoundly those operate, and then use that information to understand the operation of those same systems in their horses’ bodies. And I want them to be able to use this information, even twenty or thirty years from now, with everything else they know about horses in general and their own horse in particular, to feel confident enough about their own authority to tell a trainer, when necessary: “No. I realize the method of moving you use on horses may work for many, but it’s not good for my horse. Thank you for your efforts to date, but I am discontinuing his training with you.”
The problem with my original blog post on force, stress, and the hoof was that it focused on numbers. It focused on calculations. It focused on apparent absolutes that really do not exist except in the most artificial situations imaginable (where, for example, a horse is literally not moving a muscle). And in doing all these things, it took us all to exactly the place I don’t want to go.
The first time I took it down, it was because I thought about all this. What I did was put it back up with a paragraph added near the beginning: “I want to say at this point that calculating, or even measuring, force in a living body is extremely difficult — sometimes impossible — for practical reasons having to do with the incredibly responsive systems of animal support, balance, and locomotion, and the fact that contraction in even a single muscle is generally along a wave that makes its force vectors change rapidly and dramatically. So the goal of this blog and the next is to look at things in just enough detail for you to get a working idea of the levels of load on horse hooves, and the sorts of things that impact those loads for better or worse.”
But the post still bothered me. Because I knew very well that my disclaimer — which was the real point of all the horse biomechanics work I do — was going to be monumentally outweighed by the correct but almost meaningless calculations I had gone to such great lengths to explain, about force and stress in the hoof. And finally I realized I have to go about explaining this a different way — one that focuses on the issues of subtlety and responsiveness in the horse’s living systems of adaptation. One that leaves the numbers out unless there’s an essential reason for them, and then makes very certain to keep them in perspective. One in which all the different ways of knowing about and understanding how horses move are in balanceand connected.
I close with the same Calvin and Hobbes cartoon with which I opened my ill-fated post of hoof stress calculations, this time focusing your attention on all the different ways of knowing that Hobbes combines to be an effective tiger. The laws of physics and the principles of biology are important factors, but so are art and ethics. All I can say is: right on.
So now I’m in balance again, not focused all to one side of things with purely intellectual and mathematically-based knowledge. And I’m centered once more, squarely in the framework of the goals I have for this blog, my seminars, and my life work in general. The result, I hope, is that I’m better connected to you, the reader.
And NOW we can go on to consider force and stress in the hoof . . . this time, in a way that has a little more meaning, and meaning you can use.
See you next week.
This post was a featured blog entry on BarnMice, Jan. 2, 2013.
You can take the title of this blog as meaning either or both of two things: horses that are moving (in which case the word “moving” is an adjective), or the things a person does to move a horse (in which case the word “moving” is a gerund). The two things are related, which will turn out to be the theme of this blog.
This entry is the joint product of two people: myself as the anatomist and biomechanics scientist, and my business partner Jo Belasco as professional trainer. Jo and I have worked on what might be called “applied horse biomechanics” together for over ten years now, and although I wrote the words you see here, they only came into existence after lengthy conversations with her and discussion about this very post.
The impetus for writing this entry was that a horse friend wrote me in response to my post about the walk, saying that although he’s heard many trainers insist that a horse cannot move the leg it’s standing on, and that cues to move a specific foot need to be provided when that foot is off the ground, he doesn’t see how this can be so. “If it were true,” he wrote, “there would be no way to start a horse from the stop. Maybe the ‘rein or seat’ qualifiers are important here, but I had a horse that was so forward he would move if you simply relaxed the reins. . . All with no reference to influence with the foot on or off the ground.”
My friend’s comments made me think about the glib way we all short-cut biology to smoosh terms around in ways that give them meaning they were never meant to have, and the impact such short-cuts have on how we think about and deal with horses. So here’s some additional thought about the walk and the training practice of learning to cue a horse’s foot when it’s off the ground.
When people say you can’t move a horse’s foot unless it’s not on the ground at the time, they are really making a short-cut statement. The real statement should be: “If you cue a horse to move its foot when that foot is bearing weight at the time, the horse won’t be able to respond immediately and/or in the way you’ve asked. And because horses move quickly, even at a walk, if you cue them any later than the moment you feel their foot come up, you will be too late. They will have put their foot back on the ground before they have a chance to respond. Furthermore, you want to cue them early enough that their foot is not only still in the air, but able to be redirected to come down somewhere else than where it would have gone otherwise.” Yes, that’s a lot to say, but of course it’s why we speak in a short-cut.
Let’s consider, first, where this idea comes from, which is ostensibly the nature of the step cycle. A step cycle is the complete range of motion made by a limb from the time it leaves the ground to begin a step, through the time it advances and comes down again to the ground and bears weight, until it leaves the ground again to take a new step. The sequence of still images below shows one complete step cycle of the left hind limb of the same horse that was pictured in the walking blog I posted on October 12. The screen grabs are from the same slow-motion video I used there. The blue arrow I’ve added to the first frame shows the foot coming up off the ground to begin the step cycle. It’s a little hard to see that the heel is up in that image because of the way I reduced it to fit on the page. But the heel is up off the ground where the blue arrow is.
You will notice several things in this sequence, if you look closely, all of which give you a little better understanding of the walk. First, the horse is moving its body forward (the whole point of walking) by pushing the foot back against the ground during part of the step cycle. So the position of the foot we’re watching changes with respect to where the horse is. When the foot is coming up off the ground in the first frame, it looks to be about 4 feet to our right of the vertical wooden post, which is at that time behind the middle of the horse’s neck. Mid-way through the step cycle, in frames 6 – 9, the horse’s left hind foot is fully on the ground and supporting weight. It has been brought forward about 2 feet, so now it is only about 2 feet to the right of that post. At this point, the post is behind the horse’s withers (in 6) and then the end of the back (9). By the time we get to the last frame, where this back left foot comes up off the ground again, it’s still about 2 feet to the right of the post — but now the horse has advanced so far forward that the post is behind its rump.
Many trainers say a rider could ask this horse to move that back left foot in about frames 1 through 3, when it’s come up off the ground and has not yet been set back down. So they teach riders “feel” of the feet so they can tell when that particular foot is in the position shown in frames 1 through 3 — and that’s when they cue the horse to set that foot down someplace other than they were about to put it. These trainers believe that if the horse is asked to redirect that foot between frames 6 and 11, the horse won’t be able to respond even if it wants to because it is standing on that foot and therefore unable to move it (unless it breaks its gait by hitching or stumbling). In the case where you are asking a loping or cantering horse to change its lead, there is even the possibility that it will respond on one end (that can respond at that moment) but not the other (which can’t), with the result that it cross-leads if you ask for a change of lead while the back foot that needs to move is on the ground.
Because of my biological background, I was actually suspicious of this idea for quite a while. The reason is that neurological researchers spend a lot of time considering what they call Reaction Time (or “RT”, because of course it has to have a catchier and geekier name than just “Reaction Time” if you study it in your lab). To get an idea of the level of discussion about how long it takes a body part to respond to a stimulus, and the kinds of factors that impact this response, here are abstracts of a couple of scientific papers on the subject from the National Academies of Science and the American Psychological Association. What you will see, besides the designation “RT” and other jargon that might make you reach for a pain reliever, is that moving a foot in response to a cue is not a simple matter of stimulus-response. There is a lot that affects how quickly a motor response is expressed when any animal hears, sees, or feels something — which is to say that how quickly a horse moves a foot in response to the touch of a heel or rein is not a simple matter of picking the “one right part” of the step cycle to offer the cue (stimulus).
Researchers in RT want to know how quickly a human being can respond to switch off power to an engine if an alarm sounds, for instance, so most of the work on Reaction Time is on human beings. If you wade through those abstracts, you will see that their work suggests that a person’s reaction time can vary according to things like practice, the kind of stimulus presented, how many response options exist (in other words, do you have to decide whether to flip the lever or push the button, or is there only one choice), the nature of the on-going task or activity, and how much attention is being paid to specific parts of the environment. Just to show you how important these factors are, visualize for a moment the memory of an experience I’m sure you’ve had — a sudden loud noise or sharp motion startles a horse, which proceeds to leap straight up into the air with all four feet at once. It might have had all its feet on the ground a split second before, but the nature of these other factors changed its “normal” Reaction Time dramatically.
Most of us hope we don’t generate that kind of reaction in our horses. The point is that when we talk about “when our horse can move a foot in response to our cue,” we are actually talking about Reaction Time whether we realize it or not. And, given that we are, it’s a much more complex phenomenon than we imagine. A lot of things, including training, can impact how quickly our horse responds to a stimulus-cue. Furthermore, even though the Reaction Time for a foot placed squarely on the ground may be longer than if it was in the air when we cue it, that Reaction Time still exists. A foot that is on the ground when we cue it can and will (if the horse chooses) react to our cue when it come up off the ground a few seconds later.
In the worst case scenario, the horse might react to the cue with a different foot and get a bit tangled up, which is how it’s said that cross-leading can happen by accident, or the delay of responding with the correct foot might lead to a bit of ungainly movement. But most of us who ask at the “wrong” or “sub-optimal” time don’t usually wind up with our horses tripping all over themselves. Usually what we get is movement in the direction we want, just a bit later than we asked for it — which is actually usually ok with us. Few of us are engaged in activities that require our horse to move a particular foot at a particular time in order to, say, keep from falling into a hole in the ground. So a little-bit-late response is just fine.
Or at least, this is what I thought until I saw a Tom Dorrance video about learning to move a horse’s feet individually while riding it. In this particular video, Tom Dorrance worked with some riders and their horses and a pattern of tires laid on the ground, to help the humans figure out how to tell where the horse’s feet were at all times and respond to their horse and the tires. The point of the exercise was to develop feel. The demonstration of feel was that the rider could move a horse’s foot exactly and precisely at the time desired, to the place desired. So there was discussion in the video about feeling when the foot came up off the ground and giving the cue then, as is standard in this type of training. The result was astounding and unexpected. Remember, I was pretty jaundiced about the idea that a cue has to be tied so closely to the step cycle because I had a healthy respect for the complexity of Reaction Time.But every rider who engaged in this exercise, and learned how to feel where the feet were and to cue them at the “appropriate” times developed an incredibly light and responsive riding relationship to the horse s/he was on.
Jo uses some of Tom Dorrance’s methods when she gives riding instruction, and she’s the one who developed the closed-eyes on a bareback horse walking exercise I described in my previous post. Sure enough, she found — and I saw it was so — that when people learned to feel their horse’s feet coming up off the ground and paid attention to it enough to cue them “at the right time,” they got light and responsive movement from the horse. I also saw other trainers working on teaching the same “learn to feel when the foot comes up and cue it then” method in clinics in a variety of riding disciplines, and again I saw that when riders began to develop feel of their horse’s foot positions, a light and responsive relationship blossomed into existence. The uniformity of this response shocked and amazed me, especially given the huge variation in different trainers’ means of explaining and teaching the concept. But as long as the rider finally learned to feel the horse’s feet, the response materialized. So clearly something important was going on. But what?
Remember that we know Reaction Time is not solely or even primarily dependent on the timing of the stimulus or cue, but instead a complex phenomenon. So we have an “effect” here, which is a light and responsive horse, the “cause” of which cannot be, biologically, simply applying the stimulus at precisely the right time. To find the actual cause, we must consider what else all these experiences have in common. And what they have in common is this: the human learns to feelwhere the horse’s feet are all the time, and learns it so well that a cue can be offered at one particular point in the step cycle of one particular leg. Notice which words are in bold and italics. It’s about what the human learns.
A human who learns to feel where his or her horse’s feet are is thinking about, and even physically connected with, the horse. That human’s mind is no longer inside their own ego and their own intention — at least for a while. Instead, they are focusing on the horse. They are feeling the horse, quite literally. And Jo and I both suspect, very deeply, that what happens is that this change in focus and concentration allows the horse and rider to communicate simply and effectively in an entirely different way than the one we usually think of as “stimulus-response.” Which means, of course, that Reaction Time is irrelevant. What matters is simply the development of feel. And an exercise in which you learn where your horse’s feet are — with such precision that you can cue one at one particular place in the step cycle — will teach you that. But the exercise is not about cuing the horse. It’s about teaching the human to feel.
If you read Tom Dorrance, Bill Dorrance, or Ray Hunt you will see that this is pretty darned close to the way they talk about “feel”. And given that they coined the concept, at least in contemporary equine society, that’s enough for me to take it as a “good fit” to the only explanation I can see for what happens in these riding exercise — given that the neurobiological “reason” usually given (Reaction Time) is actually not valid. Did Tom Dorrance know this when he used a line of tires to teach a rider how to tell where his horse’s feet were, and how to move each foot at just the right time? Was he actually and simply trying to teach “feel” in a reliable way? Yes, I think he was.
In my walking blog, when I suggested ways a person could develop feel of their horse’s walking foot positions, my thought was that I’d give lip service to the “reason” this is usually said to be a good thing to do: Reaction Time, or “you can’t move a foot that’s not off the ground.” It was, after all, good enough for Tom Dorrance in that clinic I saw in a video. But my real thought was that anyone who did that exercise would develop proprioceptive awareness of the horse they were sitting on. And I do believe, after all I’ve seen and after the training work Jo has done to explore this, that if you do this exercise you will develop your sense of “feel” and, as a result, start to develop a relationship of light responsiveness between you and your horse.
If it works better for you to skip all the talk about “feel” and use the short-cut of thinking that you can’t move a foot that’s on the ground, that’s fine. You will still learn where your horse’s feet are and when to cue a foot to move. And that will get you light and responsive movement from your horse. But you’ll need to pretend you don’t know about the complexities of Reaction Time if you do that — which is ok by me. The complexities of the natural world get abridged in common understanding all the time, largely for the reason of generating actions that have simple and predictable outcomes that seem to be based in science. But, as is usually the case in all such situations, understanding the science a little better actually takes you to a place you might not expect to wind up.
So if your horse already knows how to “go” and all you have to do is relax the reins, you’re in good shape in lots of ways. But an exercise that teaches you to feel where your horse’s feet are, well enough that you can cue one foot at one particular place in the step cycle, will still give you something new that’s worth developing: feel. Horses already know how to walk, after all. It’s we humans who have to learn how to go along for the ride without messing them up.
This post was a featured blog entry on BarnMice, Nov. 22, 2012.
Sometimes the best way to understand how your horse moves is to mindfully experience how your own body moves. This is called experiential learning. When I used to teach comparative anatomy and functional anatomy in the university, I always told my students that the number one tool we all have to understand how animals move is our own bodies. See if you don’t discover something really cool about horse movement by trying this exercise in experiential learning.
What you need to do is read the next four paragraphs (down to the break in the text), and then set your computer aside and get down on the floor on your hands and knees. Yes, really. Don’t just think about it, and don’t ask someone else (like your teenager) to do it so you can watch them. You need to experience this for it to have the substantial learning impact it can have.
Get on your hands and knees, supporting yourself. In other words, you don’t want to crawl like you’re scooting under barbed wire. War games are next week. (OK, not really. But don’t scoot.) Then just crawl across the floor as far as you can without hitting the furniture. Don’t think about it; just do it.
Once you’ve done that, and have your rhythm established, turn around and go back the other way, still crawling, but this time just pay attention to — but do not try to control — the order in which your hands and knees hit the floor. I suggest you choose your left knee to start with as you make mental notes, and that you then notice what hits the floor next after your left knee, then next after that, and so on. Do it several times so that you have a good idea of the pattern that exists when you crawl. You can even stop and jot that pattern down.
Now go crawl. :-) I will skip some lines here so you can’t easily see what I write next, and can instead scroll down to it after you do the crawling exercise.
Unless something really interesting has happened (and bodies are interesting things, that surprise us sometimes), your order of motion was left knee, then left hand, then right knee, then right hand. Of course, if you started by paying attention to the right hand coming down first, then the sequence would be right hand, left knee, left hand, right knee, right hand, and so on. But the sequence is still identical. It is that you put down the back “leg” (knee) on one side, and this is followed by putting down the front “leg” (hand) of that same side, and then you put down the back leg of the other side, which is then followed by the front leg of that other side.
Note: It is very important to realize that the sequence is always the same, but that it will at first look different if you “start” with a different foot. Each time a front foot comes down and hits the ground, the next foot that comes forward will be the hind foot of the opposite side. But this is then followed by the forefoot on the same side.
Here’s what it looks like in a walking horse, in slow motion. These images are stills edited from a video by British videographer “Mike Snail”, who posts his work series at Youtube under “Slow Motion Connection.” I left in the time stamp information so you can see the sequence of things.
Starting with the left hind foot touching the ground…
Then the left front foot touches the ground…
Then the right hind comes forward and strikes the ground…
And finally the right front foot strikes the ground.
The entire clip is at youtube, here. I strongly urge you to watch it, paying close attention to the sequence in which the feet strike the ground.
Now of course the point of all this is to go back and compare the horse’s sequence of limb movements at the walk to your own sequence of limb movements at a crawl. They are identical: left rear to left fore to right rear to right fore. And they are identical to crawling in a human baby as well. It is thought that this similarity is due to neurological homology — that the firing mechanisms that activate the limb muscles in that particular pattern are literally the same in both horses and humans. In fact, Susan Patrick and two other researchers published a paper in the Journal of Neurophysiology in 2008 suggesting the structural/ functional pattern of the nerves that activate crawling and walking is so conservative that it’s the same in almost all quadrupeds — which is to say, in every animal with four legs. (Note: In biology, “conservative” means it has not changed evolutionarily. It has remained the same over vast spans of time during which other structures have evolved and changed. For more discussion of homology in gaits, see the previous blog post.)
What does this mean for you, as a horseperson who wants a better experience with your horse? It means you have an inborn mechanism that allows you to understand where your horse’s feet are. You have probably been told by at least one trainer, on a DVD if nothing else, how important it is to know where your horse’s feet are as it moves. (That’s because it’s only really possible to move a foot with rein or seat if that foot is off the ground at the time, not supporting the horse’s weight. You can’t move a foot someone is standing on.) And if so, you’ve probably also been told one or more complicated ways to learn how to tell where your horse’s feet are. But, as long as you’re willing to use your experiential knowledge, you’ve got all the tools you need right inside your own body.
Here’s a suggestion: crawl around some more. Get a good “feel” for your own body. (Yes, I am suggesting that good “feel” for your horse begins with good “feel” of yourself.) Then go out to your horse and ask someone to hold its lead line for you, and just halter it. Then do one of two things: (1) get on your horse with its normal saddle, but place your hands on the withers right in front of the saddle, as far down the slope as you can in that position, or (better yet!) (2) get up on your horse bareback and lay your hands on the withers on each side, on the sloping area. Remember that if a friend is holding your horse’s lead line, you don’t need to worry about holding the reins. Then close your eyes and pause, for a moment, to remember — as viscerally as you can — how it felt to crawl. Fix that in your mind. You can even let your legs and arms twitch a little bit as you remember their motion.
Then have your friend slowly lead your horse forward at a walk.
What you want to do here is focus on the similarity between the four feet your horse is moving and the pattern of your own limb motion when you crawled. If you can let those two “walking feelings” overlap in your mind and in your body-awareness, you will suddenly have very strong “feel” for your horse’s feet. And although at first you will be focused on when each foot hits the ground, the awareness will grow to the point that if you just turn your mind a little bit, you will know when each foot comes up off the ground to swing forward.
If it helps, particularly if you are on your horse bareback, you can lean forward so that you are oriented with your back more parallel to your horse’s back when you do this, which will overlap your fore and hind limbs more completely with your horse’s fore and hind limbs.
Either way, with a saddle or without, this exercise allows you to use your own body’s proprioceptive senses to feel your horse. Your horse, in other words, becomes an extension of your own body.
And how cool is that?
Many thanks to my business partner Jo Belasco for the work she’s done with bareback riders who have their eyes closed as they learn to feel a horse’s feet at a walk.
This post was a featured blog entry on BarnMice, Nov. 19, 2012.