Anyone who’s been around horses for long knows that they sense the world in very different ways than we do. Their eyes, ears, noses and skin are more highly tuned than ours and perceive a range of information that human senses cannot detect. Their brains are focused on the external environment and do not permit them to mull internal plans, intents and thoughts. With all these differences, we might despair at the idea of ever really communicating well with a horse.
Yet there is one means of sensory communication that is fairly direct. It’s called proprioception, the sense of body awareness that tells you where your body is in space. With practice, your own proprioceptive nerves allow you to feel where your horse’s legs
are, how they are moving, whether his back is relaxed or tense, whether he is calm or frightened, how he changes in response to your physical pressure and release. Equine proprioception, in turn, permits a horse to sense the pressures, locations and tensions within their own bodies and ours. At any moment as he carries a rider, a horse with sharp proprioception knows not only where his legs are, but also where your legs are and what they’re doing.
Let’s suppose that when you bend your knee a little and press your calf against your horse’s side, he canters forward. Both of you have just made use of proprioception. Your brain sensed the amount of calf contraction that was necessary, then released that contraction smoothly just as the horse’s brain picked up your signal. Sensing your leg pressure, he changed gaits. His brain calibrated the speed of that gait according to the amount of pressure against his side. It’s like a very complicated close-contact dance with you and your horse fused in muscular coordination at the level of both brains.
Horse sports place unusually steep demands on the human proprioceptive system. All athletes have to control muscle contraction, but riders have to contract their muscles while simultaneously keeping them relaxed. We also must isolate muscles within a natural group, flexing some while loosening or neutralizing others. Equestrians need precise gradation of muscle tension to cue horses in smooth, gentle ways. Our brains need to sense not only our own joint angles, muscle lengths, tendon tension and postural balance, but also our horse’s joints, muscles, tendons and balance. Every athlete’s proprioceptive nerves work hard, but the rider’s are really huffin’ and puffin’.
You can improve your riding by beefing up the brain’s proprioceptive power. As a nice side effect, your horse’s proprioception also becomes further developed and your ability to communicate with him soars. These improvements require some attention, but they pay off in creating more precise aids; establishing a common balance between horse and rider; building the horse’s straightness, curvature, engagement and agility; and reducing the risk of human or equine injuries.
Most important, proprioceptive fitness helps your horse overcome the largest obstacle to training success: understanding what you want him to do. Too often, we assume horses are refusing to do what we want, when the real problem is that they don’t know what we want. Good proprioception makes our requests clear.
Life Without Proprioception
Proprioception is easy to take for granted because vision usually compensates for its mistakes. But give this a try: Stand on one foot with your eyes open. A little shaky maybe, but possible. Now stand on one foot with your eyes closed. Much harder, isn’t it? When you close your eyes, your brain has to rely on proprioception alone, without benefit of vision.
Without proprioception or the vision to overcome its loss, people fall into a heap. Seriously. Consider Ian, a man infected with a rare virus that attacked only his proprioceptive nerves, destroying their ability to send messages from his body to his brain. All other senses, plus his motor function, were intact. But without proprioception, Ian couldn’t sit up, stand, speak, drink or eat. His body
was floppy, like dead weight, and his brain didn’t know the position of his limbs or torso.
Only by virtue of vision and extreme determination did Ian teach himself to sit up and, later, stand. By staring at his feet, he learned to position them for an upright stance. Then, he’d look at his legs and get them in the right spot, and so on for the remainder of his body. Just to stand still, he had to learn consciously the visual position of each joint and muscle. Once all the parts were consciously placed, he could stand while staring at his body. If he looked away, closed his eyes or lost mental concentration, Ian collapsed like a string of spaghetti.
A normal human or equine brain receives proprioceptive signals from the body through muscle spindles, Golgi organs and joint angle receptors. Spindles are located inside the fibers that make our muscles strong. They allow the brain to monitor changes in the length of a muscle as we move and the speed of that lengthening process. Spindles are super-sensitive: They can pick up a difference of only .002 percent of the muscle’s total length. After detecting that minuscule change, they send impulses to the brain so that it knows what’s going on. These impulses arrive much more quickly than visual information does, so the brain can correct an error in muscle tension in less than half the time that vision would require. Which is good because it’s not often convenient---or safe---to be watching your leg instead of riding your horse!
Spindles are powerful enough to create illusions. When scientists zap the correct spindles with electrodes, the brain thinks that its arm is bending backward at the elbow or that its knee is bending forward. Some illusions are so strong that people
report feeling their lower
leg fold upward until the foot touches the front of their hip. The brain can’t distinguish between a neural signal that comes from a real stimulus and one that comes from a fake stimulus.
Located where tendons meet muscles, Golgi (“GOAL-jee”) tendon organs monitor muscle tension. They tell the brain how much force is being exerted on a muscle based on the degree to which it is flexed. When a horse pulls on the bit, Golgi tendon organs in your hands, arms and shoulders signal the amount of force that is exerted against the reins as well as the amount of force you are returning. This information reminds you to stop the pull by releasing pressure, which in turn relaxes the horse.
Spindles and Golgi organs send instant messages to your brain, while your horse’s proprioceptors send similar information to his brain. Suppose you correct your horse after misbehavior with a sharp, fast contraction of the calf or a bump with your heel. The horse’s proprioception signals his brain that this intense burst is quite different from gradual leg pressure. The brain translates varying signals into different content: The sharp bump scolds: “Hey, whatcha doin’, buster?!” The gradual rise in pressure encourages: “OK, now let’s canter....”
Joint angle receptors come into play when our joints are suddenly straightened or bent. To accommodate the horse’s center of gravity, we close our hips in the air over a jump. This deeper flexion is communicated to the brain through nerves located inside the hip’s joint capsule. Some angle receptors adapt quickly to joint flexion, signalling only that a change has occurred. Others adapt slowly, telling the brain that this new joint position is being held in place.
Proprioceptive nerves of all types enjoy a special fast lane to the brain. It’s a highly insulated portion of the spinal cord that allows signals to travel much more quickly than do bodily indicators of touch, temperature and pain. Rapid signalling of proprioceptive information is required for efficient feedback to nerves that cause muscles and joints to move. We don’t want to be twiddling our thumbs waiting for the brain’s instructions while ducking low branches on a runaway horse.
Proprioception sounds almost simple when we analyze each step independently. But even the most basic equestrian movement---say, one leg’s pressure ---puts many different nerves to work. One human leg contains 43 major muscles from hip to ankle. To squeeze a horse’s barrel, each muscle must sit at the proper location while flexed or relaxed to varying degrees. Thousands of proprioceptive nerves are sending messages to the brain simultaneously when you press your horse’s side with one leg. And we’re not even counting all the tendons, ligaments and joints that are involved in such a “simple” movement.
Before we can tune proprioception, we have to find inaccuracies in the way our brains perceive body locations. The fact that brains adapt quickly is both a blessing and a curse: It permits us to align our bodies by retraining our brains, but it also allows temporary misalignments to become ingrained. Many events can cause temporary misalignment---an injury, the physical compensation that allows it to heal, repetitive misuse or sloppy form. With time, our brains grow accustomed to the alteration, accepting it as the new normal.
Proprioceptive training teaches our brains to demand alignment rather than accepting an uneven body position. Why bother? Because our horses pick up every imbalance and alter their bodies, and then their brains, to accommodate it. Soon horse and rider are listing to the side or stepping short with one leg while both brains say everything’s hunky-dory. Every trainer knows the surprise with which clients greet a well-timed video: “I’m leaning that far back?? It sure doesn’t feel that way.”
Proprioceptive assessment is available through physical therapists and advanced athletic trainers. Most of them aren’t familiar with our sport, though, and fail to recognize exactly how we use body awareness to communicate with our mounts. You can stay home and assess for free with the help of a friend. Closed eyes are important throughout assessment because we want to test proprioception without benefit of vision---after all, we can’t ride and watch our shoulders at the same time. Ask your friend to view your stance from front, sides and rear, then jot down any discrepancies in alignment or the direction, extent or coordination of movement. Assessment takes a while, so you might want to spread sessions over several days.
First, put on fitted clothing and have your friend consider joint alignment as you stand comfortably with your feet hip-width apart, eyes closed and arms at your sides. Are your shoulders even on an imaginary horizontal line? What about your elbows, wrists, hips, knees and ankles? From the side, are your ears, hips, knees and ankles in a vertical line? Is your spine straight, with your weight distributed evenly along the heels and balls of your feet?
The second part is more entertaining. Keeping your eyes closed, extend your arms straight out to the sides. Are your hands level? Bring both index fingers together way out in front of you. Do they touch? Now bring your arms back out to the sides and touch each index finger to the opposite big toe. Quickly, please! Your proprioception needs to work right now on a horse, not after a bunch of forethought and consideration. Did your finger connect accurately with each toe? Touch each elbow to the same-side hip joint, moving in a sideways downward arc. Arms out to the side again, and bend one elbow to touch that index finger to the same-side ear. Place the sole of each foot on the front of the opposite knee, one after another. Continue these tests as your friend chuckles and looks for discrepancies from various angles.
Part three involves standing with your back one inch away from a wall. Move your left shoulder back to touch the wall, then your right shoulder.
Do the same with each cheek of your fanny, each heel and each elbow. Lift each shoulder an inch toward the same-side ear; lift each hip joint an inch toward the shoulder. Then face the wall and bring each shoulder, hip and knee toward it by an inch. You can experiment with all sorts of movements, while your friend watches for misalignment or faulty neural measurement.
The next test assesses postural balance---something that’s mighty important as we riders go whipping around a barrel or flying over an in-and-out on huge animals with centers of gravity that differ from ours. Stand arm’s length from a wall and hold your arms out to the sides with your eyes closed. When you feel balanced, stand on one foot for 30 seconds, then the other. Which foot is most stable? Try it with your arms hanging straight down. If that’s too easy, stand on your toes. Touching a solid object, stand on your heels. Ah, that one’s tough, isn’t it? If you can stop laughing long enough, try standing on one heel to see if you’re more stable on one side than the other.
Check weight distribution by placing two weight scales on the floor about hip distance apart. Calibrate the two scales so that each reads the same weight for a given object. Then close your eyes and stand comfortably with one foot on each scale. If your weight is distributed evenly across both legs, the scales should read the same on each side.
For the fifth section of proprioceptive assessment, we need to explore the brain’s awareness of muscle tension. Find a 10- to 20-pound object you can hold in two hands---hand weights are fine if you have them, or just use some books, a grooming box, a supplement tub, whatever’s handy. (Leave the 50-pound feed sacks for another time.) The average woman needs about 10 pounds of weight for this test, and the average man needs around 20. Adjust the amount for your personal size and strength. Then stand on one foot and center the extra weight over that leg. Gradually bend the knee, bringing your seat down toward the floor, then back up gradually onto your tiptoes. Now try it with the other leg. Are they on par in strength, flexibility, range of motion and balance? Try similar movements by lifting the object with your arms and back, comparing sides as you go.
Finally, seek differences in flexibility by stretching the same muscles on each side of your body independently. When we stretch, let’s say, both legs simultaneously, one leg’s flexibility often compensates for the other leg’s stiffness. So we want to test the proprioceptors and neurons that control each leg separately. Once you’ve assessed the flexibility of your arms, neck, upper back, mid back, low back, waist, abs, hips, thighs, calves and Achilles tendons, begin to rotate each major joint independently: the left hip, the right; the left shoulder, then the right, and so on. Ask your friend to identify disparities in the flexibility of each muscle group as compared to its counterpart, and in each joint’s range of motion.
Almost everyone finds discrepancies---places where your brain says, for example, that your left shoulder is in horizontal line with the right when in fact it’s an inch higher. Your brain has adapted to an uneven body position and is providing incorrect proprioception. Wherever you find something askew, repeat the movement without trying to correct it. We want to see whether it’s a consistent imbalance in your proprioceptive system or just a mistake.
Once you’ve identified your proprioceptive errors, you’re ready to do something about them. In the second installment of this series, we’ll talk about why subtle misalignments are so detrimental to good riding and how to correct them. Many simple techniques can be used to train your proprioception---they’re not tiring or difficult, and they don’t require much time. I’ll see you next time. Till then, I’ll be standing on my head trying to touch my little toe to the back of my neck. Quickly.
This article first appeared in EQUUS issue #449, February 2015.