Side-Steping - It's Not Just About Forward and Reverse Anymore!

So - tired of moving forward? Good - that can get quite boring, right? But don't think that just because you're feet are moving forward they aren't also moving side-to-side. Well, it's actually a lot more complicated than that. Unless you want to walk strictly like a robot, that is. You see, we humans have evolved to move in many directions, but especially forward - how else do you expect to get away from a sabertooth? You have to be able to run both fast, and possibly, for quite a while. This means you had better evolve in several directions - for strength, for speed, and for efficiency - energy efficiency, that is. You wouldn't want to run out of steam at the last second, would you? because that might be really bad - for you, not for that big pussy-cat!

Just as the foot needs to be able to adapt to the changing surface of the ground heel to toe, so does it need to adapt laterally and medially. The foot, in fact, is essentially an adaptable triangle, with the heel being one apex, and the first and fifth metatarsal heads being the other two. It is the job of all the other bones, joints, muscles, ligaments and nerves to make those two adaptable triangles work as efficiently as possible to keep the entire organism they support moving as smoothly and efficiently as possible. But for that to happen, they need to be interact properly with the other mechanisms proximally - that is, above them - so, the ankle, lower legs, knee joint, femur, and, most critically, the hip/pelvis/sacral components. Each plays a role that both affect and is affected by the joints above and below them.

And besides needing to interact according to some pretty basic mechanical concepts, they need to do so with a fairly high degree of symmetry - the right and the left have to work in near-mirror opposition. They have to do this with the nervous system firing in efficient and repetitive sequences, over and over, for your entire life. If just one part fails to work properly, however, the entire shebang can go off-kilter pretty quickly - just look what happens when you do something pretty basic like bang your shin on the coffee table!

First, you will hop on the un-banged side until you can sit down and rub the new contusion. When you are finally ready (no matter how reluctantly) to attempt to get back on your feet, you will try to put less weight and motion on the affected side, and thereby, limp. Limping is the most basic form of compensation - no, not like a paycheck, sad to say, but compensation as a method to relieve the temporarily impacted part. Now, odds are, you won't be limping very long, so unless you already have your back out of joint, this type of compensation - by limping - won't have any long-term negative impacts, and will only involve a few joint segments. But for this brief period, your body will still follow some basic rules until it is able to move without pain. At which point, you will go back to your "normal" way of ambulation.

Now, note I said "unless you already have your back out of joint," above. If you are already compensating for some other asymmetrical musculo-skeletal defect, then adding another level of compensation can have a decided impact on the pre-existing levels of compensation, possibly making the original issue, in this instance, your back spasms, much worse, which can really muddy the waters when the body works to deal with the new reason for additional compensation. But again, the basic rules apply - inner ear balance, and a level visual horizon.

But regardless of the reasons, compensation is largely an unconscious response and reaction to anything that modifies the symmetrical nature of human gait. It might start off conscious, as in the limping example above, but that is usually only the case when you respond to immediate trauma. The matter is, however, quite different when the asymmetry is from a birth defect, disease process, or early-infancy etiology (cause). Then, compensation is slow and steady, and can be influenced by a variety of other factors as to the degree of compensation, how many levels of the body it impacts, and what compensatory-related pathomechanics may result over time.

For our concern right now, lets just consider what happens when one foot is slightly different in the range of motion than the other. Say, your first ray - the first metatarsal and the big toe, or the Hallux. If you have a higher range of dorsiflexion and plantarflexion of the first ray on one side than the other, that side is likely to have a higher degree of pronation than the opposite side does, and this extra amount of pronation can have some pretty complicated compensatory reactions. (Dorsiflexion is movement upward, or toward the joints above the joints in question - plantarflexion is motion downward, toward the ground. So when you raise your big toe, or Hallux, you are dorsiflexing it, and when you point your Hallux downward, you are plantarflexing it. Just another little service we supply here at Definitions-r-Us!)

OK, next time, we will follow this problem in greater detail. Why, you ask? Why do I need to be confused by all this detail? Well, if you want to understand your own feet, and you don't want the medical professionals you have to deal with to hold all the cards, having a working knowledge of how your feet work - or don't - will put some of the power back in your own pocket. The aim is to enable you to understand your feet, your footwear, your orthotics, and why they work, or don't, and what you can do to make sure they do work better. And you should definitely consider asking questions - having more knowledge helps you ask better questions.

Even if it's just to fluster the doc!

Your Shoes, Part Deaux - Translation and Mediation

To continue with the sole and heel a bit, it helps to think of the foot from the point of view of the ground itself. You leave a real impression on it, you know. Well, at least when it's the bare earth. But there are several things that occur when you take a step, besides what your body appears to be doing. First, there is the force of gravity. When your foot hits the ground, it does so with motive force (that's the part you put into it,) and gravitational force (that's the part gravity's force upon your body adds to the mix.) You might think the earth doesn't notice such an insignificant force as your stepping on it, but in fact, it does so through something called the "ground reaction force." Essentially, this is the effect of you pushing on the earth and the earth pushing back. And it is this ground reaction force that helps propel you on to your next step, as well as contribute to the responding shock wave that occurs as your foot impacts the ground. Various factors can amplify or reduce the degree of impact - body weight, shoe materials, heel height and shape, and your specific biomechanics.

It helps to view the heel and sole of your shoes, and, when they are included in the mix, your orthotic devices, as mediators or translators between the shape and composition of the type of ground you are walking on, and your specific bio- or patho-mechanics. That is, these interceding materials (sole, heel, orthotic) either reinforce the interaction, or change it. Think of what happens when you walk on a sidewalk that is tilted toward the street, as most are (to varying degrees.) If the street is to your right, then your right foot is lower than your left relative to perpendicular - you are no longer walking at 90 degrees to the earth, but offset by x-degrees. And, because you are bi-pedal, it forces one leg into a longer relationship with the ground, and the other leg into a shorter one. Of course, you could try to walk at 90 degrees to the tilted sidewalk, but that is not a simple proposition (I'll explain this more later.) The altered shape of the sidewalk has changed your entire biomechanics - temporarily, of course. But for the most part, our bodies can adapt to such a (relatively) short-term change - we are an adaptive animal. And it is the way our bodies were evolved to deal with uneven surfaces that makes us unique among bi-pedal creatures.

But here's the problem - we walk on uneven surfaces less frequently than on hard, flat, unyielding surfaces due to the modern world's obsession with paving and other materials to "manage" our interactions with the planet we walk upon. So that great adaptive mechanism of our body deals less with continually changing forces and more with repetitive forces. Concrete, wood, tiles, etc., all produce more direct and harsh ground-reaction forces than the bare earth ever does. And, we pay a price for this with every step we take. When we add to this mix poor biomechanics, as we clubbies are pretty good at doing, we have even more negative impact - on joints, muscles, tendons, ligaments - and this can lead to early arthritic changes due to this "translation" of force and response. But what it we insert something between our feet and the ground? Let's start with our shoes.

As I said in the last post, the heel raises your rear foot higher than your forefoot. It therefore changes the relationship of your body's center of gravity (COG) relative to the ground - it shifts the COG forward. This causes your body to make certain adjustments, all quite subtle, but clearly measurable. First, you bend your knees slightly, which per,its your pelvis to settle back a bit, thereby keeping your spine aligned perpendicular to the ground. If your body didn't make these adjustments, you would feel like you were always falling forward. Obviously, that would be hard to tolerate for very long. It turns out there are two things the body must maintain according to their specific original designs - our inner-ear balance, and our visual horizon line. If the visual horizon appears un-level, we will always adjust our posture and gait to restore this visual perception of the horizon - side to side, as well as forward and backward. That 90 degree relationship to the ground is critical to our being able to function in relative comfort, so the body is designed to compensate in many ways to maintain that relationship.

As for our inner ear - if you've ever had the misfortune to have an inner- ear infection, and get vertigo, you will understand quite easily why it is so important. If our "vestibular balance" is thrown out of whack by vertigo, we cannot properly perceive where the ground is from one step to the next. So too should our biomechanics get off-kilter, and we will adapt, or compensate, in order to eliminate this imbalance. So by changing the relationship between the ground and the body, via heels, orthotics, or via the shape of the ground, our body uses this idea of compensation to mediate that relationship.

Try this little experiment - tape some materials, say, some stacked cardboard, to the sole of your shoes - same amount, both shoes, but not to your heels. Use enough to make the soles higher than the heels. Now, walk around the room a few minutes. What do you notice? Your knees? Your hips? Your back? How about your balance - what happens there? What this does is to reverse the usual experience of having your shoe's heels higher than the soles, and now you can see the demands any change to your relationship to the ground makes on your body. But don't continue this experiment too long - it will actually cause your kees to "hyper-extend" and can cause some real issues over time. back in the 70's, a shoe called the Earth shoe tried to convince everyone this was a better way to walk, just because that is how your foot acted when you walk on the beach. But how much time do you actually spend walking on the beach?

OK, next time, we'll look at what happens when you alter the relationship between your body and the ground side-to-side. For now, you have enough information already to do your own experiments -  observe how you walk, and try to get a sense of how one side of your body might respond differently than the other side - more impact at heel strike, more or different muscle use on one leg as compared to the other. Observe your pain - is it greater in one area on one foot than on the other. If you are a uni-clubby, this should be an easy experiment, compared to us bi-clubbies, but even with bi-CF, there will be some differences. See you soon.

Are those Shoes on Your Feet, or Are You Just Fixin' To Dance?

OK, here we go with another "what the heck IS that, anyway" post. Most people think of shoes as something they buy at a store, or on-line, and to make themselves acceptable in mixed company - or not, depends, I suppose, on one's particular proclivities. For some, its all about the sexy, while for others its all about the function. That's one of the things that makes shoes somewhat problematic - we want them to "do" things they can only do in our imaginations. But the bottom line (an obvious pun when we speak about shoes) is the issue of utility and function. We'll leave the sexual aspects for another post (and then, only if you ask real nice.)

Until about midway through the Roman Empire, shoes were essentially not much more than flat sandals, of moccasins, or mukluks - somewhat climate-defined coverings to protect the foot from the harsh touch of the earth, and the often harder touches of cold and wet conditions. But sometime in the middle of the Roman Empire, some wise fella had a brainstorm - if he added extra material under the heel portion of the sandal, thereby elevating the heel a small amount higher than the rest of the foot, those hearty and bloodthirsty Centurions could out-march pretty much every barbarian horde in the known world, and be less fatigued by the time they needed to raise their swords and lop off some body parts. This was the first known shoe modifications with a clear, and quite effective, functional outcome.

Now, history shows that shoes began to really go to absurd lengths, er, heights in the Middle Ages, with some shoes recorded as high as 20 inches - the original platform shoes. And even today, the high heel remains one of the mainstays of fashion, and as fraught as ever with sexual subtext. But the raised heel has also become something even more utilitarian, and depending on design and basic shape, can provide significant advantages for people with a wide array of foot problems. They can also, as we will see, create foot problems, and we will explore this, as well, in future posts.

The heel, being named for the part of the foot where it is most closely aligned, serves not merely to elevate the rear part of the foot over the level of the sole, but also serves to either increase or decrease the shock wave of the heel when it strikes the ground. It can do this based on shape and on the materials from which it is made. The primary problem is, it can do one or the other really well, or it can do both, but less well. But it can seldom do both really well. This is because there is a trade-off, between the need to cushion against the impact, and the need to remain stable side-to-side so that the foot is not unbalanced as it transfers the load of the body from the heel, to the midfoot, to the forefoot, and then allows the heel to leave the ground in preparation for swinging through to the next phase of gait. Too soft a material will cause poor stability; too hard will transfer more shock. Therefore, a trade-off is the primary determinant for the design of the heel.

Next time, we will look at materials, used to make the heel and sole of shoes, and how various materials impact functional outcomes. And remember - if you have any questions, just post them in the Comments section. Till then, don't forget to dance!