THE SR STANCE: SURFACE EFFECTS


A good segue to continuing my discussion of the SR Stance is to provide a tool that will enable the assessment of the effect of different surface densities and textures and footwear, orthotics and generic insoles on the small nerve proprioceptors in the plantar foot.

Most people assume that cushioning under the plantar foot is a good thing; that it provides comfort and helps protect the foot from shocks. Who needs footbeds? Everyone. It’s only common sense. Everyone knows the foot is weak. It needs support. Except, that none of this is true.

“With thousands of plantar receptors, the foot is also a proprioceptive-rich structure, containing thousands of small nerves that are sensitive to every subtle movement we make. Our ability to walk, run or jump is all initiated through stimulation of these nerves on the bottom of the foot (aka the plantar foot).

“Because of the smaller diameter these plantar nerves are able to send signals faster to the Central Nervous System, creating faster response times”.

– Barefoot Strong by Dr. Emily Splichal

“80% of our plantar proprioceptors are sensitive to vibration”    – Nigg et al

“With small nerve receptors sensitive to stimuli such as texture, vibration, pressure and skin stretch, the skin on the bottom of the foot is unique when compared to the skin on the top of the foot or the lower leg.

“As soon as we put on socks, orthotics  or shoes we block these highly sensitive small nerves on the bottom of the foot.”

– Barefoot Strong by Dr. Emily Splichal

What Dr. Splichal says is true of any form of arch support. Ski boots are arguably the worst form of footwear for blocking the highly sensitive small nerves on the bottom of the foot.

As Dr. Splichal explains, the power of neuromuscular activation that enables precise balance and movement originates from the ground and moves upward through the plantar foot.

An easy way to impart an appreciation of how the stability, density and texture of surfaces under the plantar foot or structures such as insoles, orthotics, ski boots, liners or any form of footwear, affect stance, balance and movement patterns is by doing a series exercises on one foot starting barefoot on a hard level, stable surface, then adding different materials between the plantar foot and the supporting surface and assessing their effect on balance.

Dr. Splichal demonstrates a series of exercises in her EBFA YouTube Fitness group called Best Surfaces for Barefoot Training – https://youtu.be/gvJjIi3h1Bs

There are some issues with the quality of this particular video, especially as it ends and the volume increases dramatically. So use caution, especially if you are wearing earbuds or headphones. This issue aside, Dr. Splichal’s demonstration is spot on.

Reference Surface

The reference surface for establishing a baseline should be solid, stable, level and uniform. Texture is important. The worst surfaces for small nerve stimulation are smooth and glass like. Through experimentation, I have found that the best surface in my home is the concrete floor in the mechanical room which is coated with an epoxy paint with fine sand imbedded in it. The worst surface is the smooth laminate in the main living area. Tile in the entry hall with a slight texture is somewhere in between.

The photo below shows textured surface concrete on the left, smooth laminate on the right.

textures

Balancing on One Foot

Although balancing on one foot in a process of alternating single limb support is our basic mode of locomotion, most people seldom engage in prolonged balance on one foot. In order to ensure accurate assessment of surface effect, the move from balance on two feet to balance on one foot should be rehearsed. In my patents, I refer to these two states as bipedal and monopedal support.

Start by standing relaxed on both feet in an upright stance. Start moving the pelvis towards one foot. The movement of the pelvis should be in an arc that is sideways and forward as if the side of the pelvis on the support leg is moving diagonally towards the little toe.

As the pelvis moves forward, relax the ankle and allow the weight (pressure) to move to the ball of the foot. Keep a small bend in the knee as Dr. Splichal advises in her video.

Move back to balancing on two feet. Then repeat the balance exercise on the other side.

Repeat the exercise until you can quickly find stable balance on each foot and maintain it with minimal effort for at least 20 seconds. This may take time if the muscles that are being recruited are weak and/or unbalanced.

When you are comfortable balancing on either foot, try the exercise on different stable, hard surfaces and compare the effect of the different surface textures on balance.

You may want to try the same exercise on carpet if it is available.

A Word about Pronation

A campaign of misinformation has created a widespread perception that any amount of pronation is unnatural, even dangerous and should be prevented with a supportive insole or orthotic. Some experts have taken the position that a small amount of pronation is desirable but that it should be restricted to a specific amount controlled by an orthotic.

In a future post, I will expand on my earlier discussions of the 3 foot types. While it is correct that both pronation and supination are abnormal, the context of abnormal is in bipedal stance. From a perspective of basic trigonometry, the leg must adduct (move towards center of the body) about 6 to 7 degrees in order for the foot to be positioned under the centre of gravity. The foot must rotate an equivalent 6 to 7 degrees about its long axis in order for its tripod points to become compliant with the supporting surface.  STJ joint coupling produces an equivalent amount of internal rotation of the tibia about its vertical axis. Eversion/internal rotation is called pronation.

The absurdity of what amounts to an all out war on pronation should become apparent from viewing the stick man figure below from my patents.

FIG 23A - 23BSystematic efforts aimed at immobilizing the joints of the foot and leg in the ski boot, usually in neutral STJ, prevent skiers from assuming a balanced (read: pronated) position on the outside foot and ski ski thus ensuring the existence of an unbalanced moment of inversion/external rotation force. In addition, studies have shown that restraining the ankle in a tightly fitting ski boot increases laxity of the knee under closed chain whole leg rotation by approximately 30% over lesser forms of ankle constraint.

In my next post, I will discuss a series of exercises for assessing the effect of the components of the ski boot, including different liner components and interventions that support the arch of the foot.


Dr Emily Splichal is a Podiatrist and Human Movement Specialist.

She is the Founder of the Evidence Based Fitness Academy (EBFA) and Creator of the Barefoot Training Specialist, Barefoot Rehab Specialist and Bare Workout Certifications for health and wellness professionals.

Her book, Barefoot Strong is available in print and ebook formats.

http://evidencebasedfitnessacademy.com/faculty.html

7 comments

  1. Ha! ha! I should have cured my ‘glazed eyes’ long ago and trained myself to read and comprehend better! Thanks for setting me straight on the barefoot business, glad you’re still at least one step ahead of me!! In admit I was being literal on that (you know not even socks so it wouldn’t work for me!) but realize that your goal is ‘minimalist’ ski boots which I have totally bought into. Checked out the patent thank you very much (just looked at the pictures I have to admit but plan on hiring someone to read it to me!) and see that it is very much what I’ve been gleaning from your posts over the past couple years. So while I wait for snow I’ll do some studying. I’m currently working on a new ‘restraint’ system for the boots but need to test it before I share it.

  2. When I imagine your stick figure walking that way, it is very odd and clunky with the head swaying to and fro, the spine going from side to side. This is so reductionist as to be absurd. Our bodies are systems and processes, not machines. Balance begins with core activation, then it works from the ground up. And just how do we ski barefoot?

    1. I suggest that you start by reading my last post (your comment suggests that you didn’t). Once you have done this, I suggest that you carefully read my key patent US 5,265,350. It is long. But it contains of valuable information. Here’s the Google link – https://patents.google.com/patent/US5265350A/en

      Then read through a good cross section of the many posts on this blog. When you find the place in any of my patents or posts on my blog where I say or suggest it is possible to ski barefoot, please let me know and provide a specific reference. Also please send me references to the the literature where the current immobilize the foot in ski boot principles were validated as sound and studies were conducted that conclusively demonstrated that it has the claimed to the human system and does not increase the risk of injury. Good luck.

    2. I’m all eyes and ears, waiting for you to share better information than what is presented on The Skier’s Manifesto. I started seeking better information about ski equipment shortly after becoming an instructor in the fall of 1992. At that point in my life, I physically couldn’t run but thankfully could still ski, sort of. By this I mean that by the end of the ski season my knee was almost too swollen for the brace I used and only anyone too stupid to love skiing more than their leg would return for another winter of that. That was stupid me. I learned very quickly that there was a direct relation between the individuals’ ski boots and how quickly they learned to ski because all I taught was beginners that year. Some of the best athletes (from their description of the sports and level of participation) got outskied by some of the least active people and that was a real head scratcher at first! So that’s when the quest began on improving boot fit for skiers; first by working at ski shops where I learned all the up to date methods of boot fitting etc. Well not all I guess, probably more because I’m a slow learner than because there were flaws in the system or so I thought. Was wrong about that turns out so since to my eyes the one major issue was fore/aft balance I dealt with that by inventing and skiing on an adjustable ramp/delta device which was to be a cure all. It really cured a lot of the knee issue by getting me out of the back seat but also isolated the fact that the biggest lack now was in reality in the ski boot. That was around 2000 when I started my quest to figure out how to fix the ski boots. I discovered a way of aligning the foot bones by adjusting the boot board and started working towards the rest of the boot from there. No longer being on snow the whole winter, progress was slow but fruitful. I had just come to the conclusion that THE BIGGEST flaw of ski boots was what it does to ankle flex when I was introduced to this blog. Fortunately, the author had been working on this subject of ski boots 3 times longer than I, has a Olympic downhill bronze medalist/ world cup winner on his resume, explaining things that I was just beginning to identify as issues and things I didn’t even know are issues. Integrating our two differing points of view together, 24 years later not only do I ski pain free, I can run again and walk pain free for the first time since 1974 in spite of 3 painful and turns out useless, knee operations pre 1992 that the only thing that the three doctors pretty much agreed upon was the continued deterioration of my knee with varying outcomes worse than what I was experiencing which was bad enough!! So if the information on this blog not only helps my skiing but also my every day ability to function on the lowest level of human bipedal locomotion; then I conclude that these things discussed here are based on fixed laws that aren’t applied to any foot wear much less ski boots.

      To get into specifics; what you are describing as head and spine movement completely describes how I used to ski; if I didn’t have every portion of my body aligned perfectly with great effort, I couldn’t make that next turn that I sorely needed because I was trying to ski all the best terrain on the worst knee. I skied just like Frankenstein’s monster except not as gracefully. Now I can ski like I can walk which is much better due to the following things I’ve also incorporated into my everyday foot wear that I got from this blog; Freeing up the ankle glide path, turns out that is a huge issue in our everyday foot wear even in something as flexible (as compared to ski boots) as rubber ‘barn’ boots. Removing ALL traces of arch support that is impeding arch movement in ALL my footwear was the final thing that got rid of my constant knee pain because it turns out that the slightest thing that impedes arch movement throws the whole leg out of alignment. Turns out I didn’t need 3 knee operations I just needed a lot of footwear operations. Turns out that my good knee was just as effected but because it didn’t hurt with every step I just didn’t know it and eventually would have probably become ‘worn out’ that knee also. I just discovered a couple of days ago that I can put my foot on the ‘bum’ knee side on a regular height stool and pull myself up standing on top of said stool with that leg. That my friend is a freaking miracle and I have no qualms, well actually my duty is to give credit where credit is due and it comes down to what I learned from this blog on ankle glide path, toe spread and removing arch impediments (drs. call it ‘support’) as the major revelations.

      That brings me to the barefoot part; while David I guess has as yet to figure out how to put us barefoot on skis I would like to admit that that is actually one of my goals; the ski boot is the singular biggest impediment to successful skiing and people can do all sorts of crazy stunts on skateboards and they ain’t doing it with skis boots. As one friend put it; my goal is to ‘sandalize’ ski boots; in other words make them fit like sandals. The more of the liner I remove, fearfully I admit at first, as outlined and tutored by this blog; the better I ski. My way of thinking is that maybe the smart thing to do is to toss the liner and simply add a few pieces of foam where needed in the shell and now I just have to figure out a few minor ‘issues’ because it’s kind of hard working on the inside of a ski boot. One option is to expand the boot to the size where I can actually work on the inside with scaffolding and ladders etc. and then shrink it back down to the correct size for the skier. Biggest reason I’m not really trying to perfect that idea is that even though foam sheets are inexpensive relative to lets say a custom foot bed; still seems like the cost would be higher than I want to spend on materials!! While I’ve worked in barns a lot of my life I’m also not sure I want to stick my nose that far into ski boots either!!

      1. “That brings me to the barefoot part; while David I guess has as yet to figure out how to put us barefoot on skis”.

        Actually I did with a concept I invented I call Beyond Barefoot or Better than Barefoot because it is simply not possible to affix the barefoot to a ski without some sort of drastic surgical procedure such as a stainless plate over the dorsum of the foot screwed through the foot to the ski. My US patent No. 5,265,350 describes in great detail a minimal ski boot that connects to the key mechanical points of the foot. The most important component is the device that applies a force to the dorsum of the foot that is substantially perpendicular to the transverse aspect of the ski base. The reason this is so importantis that it ensures that the small nerve plantar proprioceptors are maintained compliant loading in the tripod of the foot and that the small nerve plantar proprioceptors with the highest sensitivity under the ball of the foot are completely engaged.

  3. But which boot is best? Hard plastic, Apex soft boot, hard boots with tops buckles totally loosened? So many great ideas. I have been a barefoot/minimalist wearer for six years. I need a new pair of boots, is there any boot out there that you like?

    1. Roland, it is a case of what I am able to work with or what can be suitably modified. Since I value hands on experience, I started working with a small number of skiers and racers after I started this blog. To say that there are extreme challenges in attempting to create a functional environment for the foot and leg in any form of ski boot available is an understatement when you consider that the clearly stated objective is to render the foot, leg and lower limb dysfunctional. My quest to try and develop what amounts to a minimal ski boot first began in 1980. In my 1992 patent, I discussed all the features of a minimal ski boot in what amounted to a legacy effort because I was never confident that I would see this boot become reality even in my lifetime. If anything, the industry has redoubled its efforts in wrong direction.

      Over the last ski season, I put in many hours modifying two different ski boots and a series of liners for a ski pro whose only issue is large boned feet that have suffered considerable damage from ski boots. I could write an entire book on what had to be done. Suffice to say, I did not get the results I was striving for until the end of last season, and only then after the ski pro was able to obtain an older soft fabric Lange liner that I could gut. Now my efforts are unraveling because the soft Lange liners are disintegrating due to the heavy use of a season in Australia. The big problem is finding a liner that is soft enough to minimize foot function. I am running out of options because liners are becoming worse and harder and harder to modify.

      If you have been into barefoot for six years, I assume you are aware of the impending collision between evidence based science of the rapidly emerging minimalist camp and the camp that has a financial interest in maintaining the campaign of mis-information that the human foot is weak and flawed and incapable of functioning without the arch supports and other external appliances they promote and sell.

      I, myself, am a victim of extensive damage to my feet caused by the promotion of orthopedically correct supportive footwear as a child that resulted in my well intentioned mother ensuring that I was fit with these damaging shoes before I tried to take my first steps so that my weak feet would get the proper support they needed. The promotion of these shoes implied that it was tantamount to child abuse for parents who failed to get these shoes for their children. Although I am seeing some improvement with a comprehensive rehabilitation program, my feet may never function normally, the way they were intended to.

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