Other Footwear Design Issues

Footwear doesn't just exist. Each design is a result of compromises, marketing and designer bias. Just because someone made certain choices doesn't mean they are automatically right for you. With the way a lot of footwear is now being made in Asia, it may

Footwear doesn't just exist. Each design is a result of compromises, marketing and designer bias. Just because someone made certain choices doesn't mean they are automatically right for you. With the way a lot of footwear is now being made in Asia, it may well be that some of it is quite UNsuitable for you. But not all. There are some good models on the market: you just have to be a bit choosey.

Effect of Shoe Weight

The issue of weight is real. Research has shown that wearing 1 kg on your feet makes you as tired as carrying about 6.4 kg on your back (""Energy cost of backpacking in heavy boots"", S J Legg & A Mahanty, Ergonomics 1986, vol 29, no 3, pp433-438). [My thanks to Jim Colton for providing a copy of the reference!] Other research (cited in that reference)has shown similar effects with a slightly lower factor (about 5). Either way, the weight of your footwear matters! So note that suede leather is usually lighter than full-grain leather, and heavy synthetic fabric (Cordura etc) is lighter than leather. Equally, big clumpy soles are obviously heavier than thinner soles.

Some uncontrolled 'research' in America (reported at Backpacking Light) suggests that 1 lb on your back costs 1 mile per day in distance travelled - for those who like to travel far and fast anyhow. That means that shaving (say) 250 g off your footwear is equivalent to shaving 1.75 kg off your back, and that is equivalent to reducing your daily travel by 6.2 km. Think about this - would you like to be able to travel 6 km per day further at no extra cost? Experience over a number of long trips seems to suggest this is for real.

One or two boot enthusiasts have commented that extra weight on your feet just make your legs stronger. This is a stupid argument, and was probably raised just to stir things along. The issue of weight is one to consider no matter what you choose to wear or carry.

Sole Materials and grip

What the sole is made of can make an significant difference to the grip given by any footwear. Boot wearers have reported significant changes in grip when the rubber in the sole has changed: the harder the rubber the longer the life but the poorer the grip. This is a trade-off. It can get worse: a synthetic rubber sole is used on some joggers, but many of these synthetics are extremely slippery when wet. One user (of an American brand of Approach shoe) claimed they made a wet footpath feel like ice. So beware of synthetic soles: avoid them if possible. Since the joggers are usually sold in sports shops rather than bushwalking shops, you may be on your own in assessing the material in joggers, but the label should tell you what materials have been used. You are probably safer going for the branded Approach and Trail shoes.

Good boot soles usually have a Vibram or similar pattern made from a carbon rubber: this material lasts well and grips very well. If the sole appears to have different coloured sections, that may indicate slightly different hardnesses. There may be harder rubber at the edge (for stiffness and life) and softer rubber towards the centre (for grip). On cheaper shoes the different colours may however be just for fashion. KTs have a soft carbon rubber sole over a high density foam for cushioning: the sole has a very good grip but does wear a bit faster. DVs have a strange rubber compound with fantastic grip but a shortish life. One person described the material as being like 'used pencil eraser'. This is a bit of an exaggeration, but claims for the excellent grip are not.

However, be warned. Old rubber can 'age', and become too hard, even slippery. Even the chewing gum on Volleys can go glassy with age, and when this happens they have no traction at all! Hopefully, you will do enough walking that you wear the soles out first.

Inner Soles and shoe construction

The original design for boots started with a heavy leather base or Foundation. Onto the top of this was sewn the Upper, and onto the bottom of it was attached a replaceable Sole. At first the replaceable sole was leather, with steel nails hammered into it for better life and grip. Ah, hobnails, tricounis, and endless arguments about the best nailing patterns. Later on the sole became rubber, or Vibram. Anyhow, what this gave you was a flat surface on the inside of the boot - and a pretty hard one at that. There is nothing wrong with a flat surface: try walking around at home in bare feet. (Half the world has bare feet.) In fact, I infinitely prefer a flat inner sole, and most good leather boots provide this. But there were some problems to be solved. Sometimes there was some space around the edge of the heel region, as shown here. This may have been due to the welt stitching, or because the upper needed to be wide enough to accommodate the wide ankle bone. And attaching the outer sole sometimes involved nails or screws, and after time these could protrude on the inside and stick into your foot. Rather painful of course. So, it became the done thing to have an Inner Sole glued to the Foundation, and this was also used to add strength to the sole of the boot. But it was still flat.

For those with an interest in boot construction, I would draw your attention to the little pink/purple bit at the stitching, outside the boot. This was the 'welt': an extra bit of leather added to reinforce the main part of the boot against the stitching. This is the source of the term 'welt-stitched'. It is seldom seen these days, although the American Danner boots are still built this way. And I have not shown the inner steel reinforcing usually included in heavier boots these days. You can't have everything. It should be noted in passing that the stiff sole sticking out at the sides does hold a pair of trekking crampons rather nicely.

Later on the design of the sole became a bit more sophisticated. The upper was tucked inside and stitched inside, and a rubber rand was welded around the outside. This put the edge of the boot much closer in, which is an excellent thing for any sort of climbing boot. Improvements in gluing technology meant that the screws could be eliminated and the sole glued to the Foundation. This is a common design in real boots today. But the need for an Inner Sole remained, otherwise there would have been a severe dent in the middle of the boot sole, in between the edges of leather. This would have been most uncomfortable.

Modern Joggers and Approach shoes are a bit different: typically they have a sole which is molded. On the good ones the molding includes the traditional sole and the rand as well. Inside this, or on top of it, there may be some molded stiff EVA foam of fairly high density for cushioning, and on top of this there is some sort of inner sole, also molded. The whole lot is glued together, and often the edges of the uppers are interleaved during the gluing. In the picture to the right the sole is below the thin red line, and the black stuff above that line is the layer of EVA foam. On top of that there is a thin bluish layer: the inner sole, but in this case it is quite light as the EVA layer is thick. Then there is a loose footbed. The upper part is in two layers: an outer layer which is what you get to admire, and a separate inner layer or synthetic liner which is the real strength member. The outer layer handles the inevitable abrasion so it isn't just for show. The liner is generally a synthetic non-woven fabric, highly bonded and water-resistant, and usually quite strong. Embedded in the toe region and visible as a white line there is (sometimes) a stiffened Toe Cap. There is also a stiffened heel cup (which is very essential), but this is not really visible in this picture. Finally at the top there is a padded ankle-surround. One hesitates to call the whole design a monocoque construction, but the analogy is there.

However, not all joggers and Approach shoes are built this way: the cheaper joggers skip some of the interior components, especially in the sole construction, and just have the fashion appearance. As you might guess, the cheaper ones can fall apart rather easily. I have seen ones which had the thin rubber sole and a non-waterproof fibreboard inner sole, with almost nothing in between them. They were not bad in the dry at first, but a total disaster once they got wet and the fibreboard went mushy. Street fashion.

This diagram shows a more recent development: the inclusion of a 'Foot Bed'. I imagine they were introduced to provide a bit more cushioning between the foot and the ground. In this sense they can be quite useful. After a while the designers decided to embellish the design, which started out flat. They started to add a curl at the edge. This was meant to help centralise the heel within the shoe, which might be useful if your foot has a very narrow heel but the shoe doesn't. However, whoever designed many of these things appears to have lost sight of the shape of the human foot and gone overboard with the size of the curl. That, or they have feet quite different to many bushwalkers.

If you look at the diagram you will see that the edge of the wearer's heel (in blue) overlaps the edge of the footbed (in red) right in the corner. I have drawn it this way because this is what happens inside some joggers and even some Approach shoes. Of course, what really happens is that the foam foot bed gives away or yields to the heel. So what's the problem?

The problem is that now you have excess pressure just at the edge of the heel. For an hour or to this does not matter, but over a period of several days of hard walking, especially on a track, the heel starts to object, and you, the wearer, get blisters around the edge of your heel. It does not happen in general with flat inner soles; just with these shaped ones.

The situation is actually getting worse in some shoes. The curl at the back edge of the foot bed is initially splayed outwards when new. When the foot bed is jammed into the shoe the edge of the curl is compressed, and may even form little creases around the back of the heel. Needless to say, this simply hastens the creation of blisters. If you don't believe me, have a look inside some shoes at a gear shop. You will see these little creases soon enough. You know now what those lumpy creases will do to your feet after a day's walking, don't you?

An allied problem is the inclusion of a huge lump of foam curled up under the arch of the foot. This is called an arch support It is a concept which was introduced in the 90s by some crazed American Marketeers. They wanted a technical edge or gimmick over the competition, and hit on this idea. These days it is recognised by performance experts and sports doctors as a Fundamentally Bad Idea. It just gives you RSI in the muscles and tendons under your foot. What else do you expect when something compresses a hard-working muscle all day? You should shun these completely if you value your feet. If the shoe shop attendant tries to tell you they are 'essential', reflect on how little he (or she) knows about feet, and what sort of 'training' he has been given, and go elsewhere.

If your current footwear does not have a good inner sole it may be worth adding one, or even replacing a poor one. This is different from adding an orthodic support: that requires skilled medical assistance. The obvious question is where would you get a 'good inner sole'? You can buy a range of these from Sports Stores, but you will need to try several out very carefully before choosing one. Many are a structural disaster never intended for use by bushwalkers, so you need to throw them away if they are anything less than completely satisfactory: remember the 3C rule! I would strongly recommend you select a flat one: that way you won't have the problems of blisters at the edges. Also, make very sure that adding the inner sole or footbed does not now make the size of shoe you have a bit too small. After all, those layers of foam take up volume.

Uppers

We have covered the rest of the shoe: what about the uppers? Well, in boots the uppers are usually leather. Good boots will have a lining inside the leather to conceal the stitching and present a nice smooth face to the wearer's foot. The better the leather, the longer the life of the boot. The better the care you take of the leather (Sno-Seal!), the longer the life. Some padding around the ankle and possibly under the tongue is usually nice, to prevent rubbing. The tongue may have a leather gusset down each side to help exclude water: this too is nice as long as it is thin leather. So far, very traditional. Hey, a well-made pair of boots are an artistic creation.

Joggers and Approach shoes are a different matter - or rather, anything with a molded cup sole is. The reason is that the upper here is molded into the sole during manufacture, and may be made of quite different materials. Take a walk through a sports shoe shop or even a bushwalking shop and look at all the different styles of uppers. Why are there so many; how do they do it? The brief answer is that they aren't all different: what you see on the outside is just the equivalent of a paint&trim job on a car.

Take a dead jogger and cut it in half - or look at the picture of the chopped one above. You will find a non-woven synthetic fabric inside the shoe, under the jazzy outer layer. This is the strength member. This is what holds your foot inside. The many bits of trim and leather and synthetic adorning the outside are just there as trim: they do not hold the shoe together.

Well, true, but not the entire story. The outer layer does have one function: it is a sacrificial layer protecting the inner layer of non-woven fabric from the scrub and rocks. The outer layer takes the abrasion, gets worn and damaged, while the inner layer continues to hold the shoe together. In particular, the strange rubberised fabric around the front of many Approach shoes does a heroic job protecting the insides from abrasion. You need this whole outer layer - but try to pick one with some strength. In particular, avoid outer layers ones which look like a coarse loose-weave fabric. Scrub can tear such loose fabrics open quite easily. Light suede leather is pretty good here, and so is well-anchored Cordura.

There is a very subtle feature which you will learn to recognise after wearing out many pairs of Approach shoes. Very often there is a layer of leather around the edge, above the sole, and then fabric above this. When you flex your foot you will see the stiff leather concertina at the flex-point, next to the widest bit of your foot, on either the inside or outside edge. This places a high loading on the stitching right there, and it is common for the stitching to fail just there - or for the fabric to wear out and tear just there. Well, if you do a lot of walking, anyhow. But some designs have the leather come up a little higher, so the acute stress point doesn't happen. If you can get shoes which don't have the high stress design, and you maintain the leather with Sno-Seal, the shoes may give you a longer life.

I guess I had better point out that our beloved DVs don't fit this description very well. In some places there is just a single layer of canvas. Ah well, but they are very light and have a superb grip.

Socks, wonderful things

One very important part of your footwear is the layer between your skin and the shoe: your socks. Now some walkers claim to be satisfied with bare feet in DVs, but for most of us the sock is an under-valued item. Quite seriously, a good sock is worth whatever it cost. But what features should it have?

In general, warmth is not an issue. A sock will not 'keep' your foot warm, despite advertisements to the contrary. If you have adequate blood flow down your legs and through your feet, they will be warm. If you are walking hard, there will be plenty of blood flow. In fact, most Australian walkers wish their feet were cooler! Of course, wearing shorts in a howling icy gale may mean the lower part of your legs could be less than toasty warm: be reasonable!

What the sock should do is provide a buffer between your soft skin and the harder shoe fabric. A very thin sock is not enough for this for most people: a thick sock with a generous terry-towelling loop structure on the inside is. You can also use a sock which is just a very thick knit, but this will not be as soft. A good idea here which some walkers use is to put a very light nylon sock under the main sock: it sticks to the skin and takes most of the rubbing which would otherwise be between the skin and the thick sock. The author has used the 'Gobi Wigwam' liner socks to good effect: these are found in good bushwalking shops. However, most any thin close-fitting synthetic sock should do.