The Ground You Walk On

When you stop to consider the shear variety of possible biomechanics alignments found among clubbies, you have to be somewhat in awe the degree to which we are able to adapt, and still (most of us) walk upright at all. And while the shoes and orthotics that we nearly all wear can to a greater or lesser degree help improve that alignment, and thereby reduce the pathomechanics we also have to contend with, there is another element of the equation that is easy to overlook, and even when we do ruminate on it, we tend to minimize it's importance.

I am talking about the surfaces we walk on - the ground beneath our feet. Now, in the modern world, most of the people in the developed world, that is, walk on relatively level, and usually quite hard, surfaces. Concrete, wood, tiled floors, pavement - substances that are designed to support a lot of wear and weight for a long time. But they are NOT designed to absorb shock, or, more correctly, impact. Shock is a response to impact. and quite interestingly, there remains no consensus definition of shock as it applies to the human body. Some call it "ground reaction force," which is the preferred term in biomechanics, but that still barely describes what shock is.  And then, there are all the surfaces that are not level, not rigid, not "altered" from their natural condition.

Grass, dirt, gravel, sand, rock - all of these present other impacts on the human gait, and thus, have a somewhat more dramatic effect on biomechanics. Now, if one walks on grass that is relatively level, and as long as the ground beneath the grass is neither too wet, nor too dry, the effect on gait, especially on impact is far more gentle and forgiving than concrete. But change the leveling factor - make it a 3 degree slope - not very much, but enough that, when we walk on it, the very angle we are on relative to the slope changes our biomechanics in relationship to the surface. If, for example, we are walking directly up the face of the slope, then our Achilles gets a greater workout, and our anterior muscles have to work harder to keep us upright relative to gravity - we walk at a slight forward leaning angle relative to the angle of the slope. But if we walk down the slope, all that muscle and tendon action reverses, because we are now fighting the pull of gravity in such a manner that we have to make greater use of our decelerator muscles. Think how it feels after you've had to walk down a large number of stairs, several  stories worth, and you'll understand this much better.

But let's go the other way - let's walk across the face of the slope. Now, depending whether we are walking with the up-slope to our right or to our left, we will have one leg that is shorter, functionally, than the other. This is going to put more stress on the up-slope leg, because you are going to have to either walk at a tilt - something that is very hard to do, especially as the slope becomes steeper - or walk with the up-slope knee flexed. This also presents a major energy expenditure. That is, it's difficult to keep up for long without causing fatigue, and eventually, pain. And likewise at any angle you walk on that slope relative to its vertical direction, say, at forty-five degrees from the vertical. Any angle off the vertical will demand some form of compensation by the body.

The same holds true for any surface - soft or rigid - when you are required to walk at an angle off the level plane. If you throw another spanner into the works - uneven surfaces like rocks, gravel, or sand - the mechanics get even more fraught with complexity, and thus, place a greater energy demand on the body. Sand is especially problematic, as it's density is highly variable. Anyone who has walked on a beach knows this - the dryer the sand is, the harder it is to walk on for any length of time in comfort. while wet sand, which is far more compacted, offers more support. Gravel, especially on a slope, can shift unexpectedly, and will place sudden demands on the firing of the musculature to maintain balance, and thus, place higher energy demands.

But lets go back to so-called level, rigid surfaces. Besides the floors inside buildings, the other surface we walk on most frequently is sidewalks. Now, sidewalks, except where they are obviously cracked and buckled, seem the height of reliable surfaces upon which to trod. But the next time you walk down one, try to close your eyes for a few steps, and maintain a straight line of gait. It's really not so easy, because nearly all sidewalks, if they were built according to code, have a slant to them, to permit water to shed during rain. Perfectly sensible, right? But this sensibility forces all who walk upon the sidewalks to compensate for that slope - remember - you are walking perpendicular to the line of the slope, so one leg is now shorter (the up-slope leg), while the other leg is longer (the down-slope leg.) For people with so-called "normal" biomechanics (there is really no such thing - the term of art is "Neutral biomechanics" a kind of averageing principal - I'll eventually post a definition of this idea, but for now, back to the sidewalks) there is no problem - their compensatory mechanisms can handle it without any problem.

But we clubbies, along with almost anyone with a handicap that affects their gait, are not so blessed. We can tolerate these surface insults, if you will, for brief periods (some briefer than others, of course) but that period can also vary depending on our current state of pain - what works for us today might prove far more uncomfortable tomorrow. But, we must get around, and short of adapting by making our legs into telescoping mechanisms, we are just going to have to deal.

But what does this all have to do with our footwear and orthotics? Well, first of all, never, and I really mean never, test a new pair of shoes or orthotics on anything other than completely level ground. This of course seems like common sense, but I have seen people do otherwise without giving it any thought. And when I say level ground, I am also talking about the shoes you are currently wearing, when you go to get a new pair of orthotics. If your shoes are worn, no matter how good the orthotics might be, the results will be less than ideal. This is because, from the perspective of the orthotics, your shoes represent un-level surfaces. Think of it like this - when its merely your feet, and the ground, that is one kind of relationship, mechanically. Place a shoe between your foot and the surface, and now, that relationship has to include the balance of the shoes.. When you further intervene in that relationship with an orthotic, the mechanics change yet again. The idea is to make it a positive change, but if the shoes themselves are unbalanced - edge wear, compression, breakdown of the uppers on the soles - then you are making the orthotics work on uneven ground, and thus,increasing the energy burden, not to mention offsetting the muscular balances laterally, medially, anteriorly, and posteriorly. Essentially, you're going to cause something to hurt. Most likely - your body.

So, word to the wise clubbies out there - never go to get new orthotics, or even have your old ones adjusted, while wearing shoes that show obvious signs of wear. Just wastin' your time, and making your chiropractor work harder. And as for you skiers out there? See ya on the slopes!