Barefoot science posts

THE ZEPPA TIPPING POINT PROBLEM

A recent post on The Foot Collective FaceBook page titled Humans aren’t meant to walk on ramps!, highlighted the problems caused by elevating the heel above the forefoot known in the footwear industry as drop. Like the author of the post, I also wear zero drop shoes like Xero and Lems exclusively  (with NABOSO insoles) and spend all of my time indoors barefoot. Like the author, I too have experienced an immediate, unnatural and a sense of disorientation in terms of a connection with the ground, when I have worn dress shoes and winter boots with moderate drop.

While some amount of boot board ramp angle or zeppa appears to necessary for a strong, tensioned stance (what I refer to as a planted or rooted stance), the amount of zeppa is turning to be much less than I originally thought. It may be less than 1.5 degrees total (zeppa + delta). Assuming zero delta, there appears to be a very narrow range within which zeppa is optimal after which a tipping point is reached in terms of adverse effects on the motor control and balance systems.

It has also become apparent that some racers are tuning ski response by adjusting binding delta. Zeppa and delta each have a different effect on ski response especially edge control and the ability of a skier to resist the forces acting on them in the load phase of a turn. I will discuss issue this in a future post.


Humans aren’t meant to walk on ramps!

Powerful post by TFC Educator @optimize.physiotherapy
👣
Why do most shoes have a heel on them?
This really hit home the other day when I put on my winter boots (because it snows in November in Canada). Being someone who goes barefoot all day at work and at home (and wears zero drop shoes), it was a very unnatural feeling. It really threw my walking off, and I noticed the effects immediately. It changed the way I walked, stood, and made me use different muscles.
Humans are meant to have a flat base. No other animal wears mini ramps on their feet, but we do. The problem is that your body adapts to having a heel on, and it works different from a biomechanical perspective in any given movement pattern (the higher the heel, the worse the effect…but even most casual, running, and gym shoes have heels)


One thing it really does is affect your ankle/foot function. It has a huge effect on ankle ROM and tissue tension around the ankle. The problem is, when you wear a heel all day at work/at the gym/walking around, your tissues adaptively shorten and you don’t require as much ankle ROM. But then you take your shoes off and walk, go up your stairs, squat down to get things around the house etc. This is where people have issues. Not only at the foot/ankle but all the way upstream at other joints



Ankle ROM is incredibly important, and walking on a ramped surface all the time is incredibly unnatural. So do yourself a favour and spend less time in heeled footwear or get rid of it altogether


The Foot Collective is a group of Canadian physical therapists on a mission to help humans reclaim strong, functional and painfree feet through foot health education.

The Foot Collective are empowering people with the knowledge they need protect their feet from the dangers of modern footwear and the guidance to fix their own feet.

http://www.thefootcollective.com

BEYOND BIOMECHANICS BY DR. EMILY SPLICHAL

The following post appeared on the Evidence Based Fitness Academy (EBFA) fitness blog on February 6, 2018 under the title Beyond Biomechanics | Addressing Foot Pain with Sensory Stimulation (1.).

I have reproduced the post with the kind permission of Dr. Emily Splichal under the title Beyond Biomechanics by Dr. Emily Splichal because her emphasis on the role of sensory stimulation of the plantar foot on foot, lower limb and function of the entire body has both direct application to and implications for, skiing.

I have a theory on what I call The NABOSO Effect that explains how I think NABOSO insoles improve dynamic stability in the biokinetic chain that I will discuss in a future post. I have been testing NABOSO 1.0 and 1.5 for months.


Beyond Biomechanics | Addressing Foot Pain with Sensory Stimulation – by Dr. Emily Splichal

I want you to picture a human foot.   Now picture a person standing barefoot, and then walking barefoot.   Do you see the foot striking the ground and flexing under impact, only to re-stabilize and push off just a few milliseconds later?

Often times when we think of human movement we can’t help but to be drawn to the thought of joints moving and muscles contracting.   Or in the case of foot function we are quick to consider the mechanics of flat feet, high arches, pronation and supination.   However when we delve deeper into the science of human movement there is more than meets the eye.

The Two Sides of Foot Function

When I teach on behalf of EBFA Global or speak to my patients I always emphasize that there are two sides to foot function (and dysfunction) – biomechanical and neuromuscular.    Now both play an important role in foot function which means that both must be appreciated – however to solely treat foot pain with just one belief system in mind is inherently flawed.

In most Podiatric Medical Schools we are taught foot function and foot pathology solely from a biomechanical perspective.

This means that every patient is tested for foot mobility and told to stand statically to determine arch height and foot type.   Based on this foot-focused biomechanical assessment and foot classification system the patient’s cause of injury and treatment protocol is determined.   Some of the favorite treatment recommendations include motion-controlled footwear and custom-posted orthotic both of which are prescribed with the hopes of controlling foot-focused biomechanics and thereby reducing their foot pain.

Beyond Biomechanics

The other side of foot function is one that is driven from a neuromuscular perspective and integrates the science of sensory stimulation and fascial systems.   In the case of neuromuscular function every patient would be assessed for sensitivity of plantar mechanoceptors as well as co-activation patterns between the foot and the core.  The role of minimal footwear, myofascial releasing, breathing patterns and compensation patterns more proximal would all be considered.

So which is more appropriate?  Well it depends.   In certain cases there will be a stronger argument towards a more biomechanical influence and in others it is more sensory.  This means it really is a marriage between the two approaches that provides the greatest patient outcome.

Sensory Stimulation in Foot Pain

My practice and Podiatry career is built around bringing an awareness to the important role sensory stimulation has on foot function and foot pain.

With every step we take impact forces are entering the foot as vibration.  This vibrational noise stimulates unique mechanoceptors on the bottom of the foot and is used to coordinate the loading of impact forces through coordinated contractions of the intrinsic (small) muscles of the bottom of the foot.   This co-contraction leads to a stiffening or strengthening response of the foot.

Researchers such as Nigg et al. and Robbins et al. have demonstrated a direct relationship between sensory stimulation of the plantar foot and intrinsic muscle strength concluding that one is necessary for the other.   This means that if our footwear or orthotics disconnect us from sensory stimulation – as in the case of cushioned footwear – this can actually weaken our foot making us susceptible to plantar fasciitis, Achilles tendinitis and stress fractures.

Beyond Vibration Stimulation

Vibration stimulation is an extremely important sensory stimulation that enters our foot however it isn’t the only stimulation.   Another important stimulation is the ability for our foot to determine texture and if a surface is rough or smooth.   This information is used to help maintain dynamic balance (think walking on ice).

Enter the merkel disk mechanoceptors.   These superficial sensory nerves are used to determine what’s called 2 point discrimination which is translated to roughness or the texture of a surface.  Surface texture and insole texture is one of the most studied aspects of foot stimulation and posture or gait.  From decreased medial lateral sway in patients with Parkinson’s or MS to reduced prefrontal cortical activity in atheltes post-concusion the applications are promising!

One area that hasn’t been focused on for sensory stimulation and foot function is foot pain.  I am here to change the awareness around this concept and share the powerful application of sensory stimulation and foot pain.

As we mentioned earlier sensory stimulation of the foot leads to a contraction of the intrinsic muscles of the foot.   Intrinsic muscle contraction is not only a criticial step in the damping of impact forces but has also been shown to increase the medial arch and build co-activation contractions in the core.

 The Evolution of Textured Insoles

In October 2017 Naboso Technology launched the first-ever commercially available textured insole!   Naboso Technology essentially brought the science of touch and years of textured insole research to the market place giving new hope to people with foot pain.

Available in two strengths – Naboso 1.0 (1mm texture) and Naboso 1.5 (1.5mm texture) Naboso Insoles are designed to be worn without socks (or at the most very thin socks).  They fit into all footwear, are freely movable in all planes of motion and are only 3mm thick.

FROM THE GROUND UP

Are you barefoot strong?


Learn more about the power of texture! – http://www.nabosostechnology.com

  1. https://barefootstrongblog.com/2018/02/06/beyond-biomechanics-addressing-foot-pain-with-sensory-stimulation/

 

NABOSO SURFACE SCIENCE INSOLE UPDATE

In June of this year, I posted on my beta testing experience with NABOSO surface science, small nerve, proprioception stimulating technology (1.).

Recently, I received the consumer version of NABOSO called NABOSO 1.0 shown in the photo below.

NABOSO 1.0 has a tighter grid than the NABOSO beta version I have been testing. The pyramid-like texture is also smaller.

The photo below shows NABOSO 1.o on the left and NABOSO beta on the right. The photo was taken before I trimmed NABOSO 1.0 to fit my shoes. 
Here is the information that came with my pair NABOSO 1.0 insoles.

I use both NABOSO 1.0 and NABOSO beta in my Lems Primal 2 and Xero Prio shoes. I immediately sensed better balance with the tighter grid of NABOSO 1.0. But I found it interesting after going back to NABOSO beta, after a period of time in NABOSO 1.o, that NABOSO beta felt more stimulating. Based on this subjective experience, I think there may be some advantage to switching back and forth between different texture grids. Hence my interest in the new NABOSO 1.5.

NABOSO 1.5 can be pre-ordered now for a reduced price of $30 US at orders@nabosotechnology.com

Disclosure: I do not receive any form of compensation from NABOSO or Dr. Emily Splichal. Nor do I hold any shares or have any financial interest in the company. The sole benefit I derive from NABOSO is to my feet and my balance and the efficiency of my movement.

I will be testing NABOSO insoles in my ski boots this winter in conjunction with toe spreaders starting with NABOSO 1.0. I will report on my experience in a future post.


  1. http://wp.me/p3vZhu-27v

WHO NEEDS FOOTBEDS? NO ONE

There are some who can benefit from footbeds or orthotics and some who do actually need them. But these groups are the rare exception. And they are unlikely to be skiers.

Orthotics. The pros / cons of orthotics in today’s society!

In a recent YouTube video (1.), Podiatrist & Human Movement Specialist, Dr Emily Splichal, explores the concept of orthotics and their role in today’s society. Dr. Splichal doesn’t pull any punches when she says:

“…..I have been through the conventional podiatric school and been fed pretty much the bullshit from podiatry of how every single person needs to be in orthotics, that our foot is not able to support itself without orthotics……if we do not use orthotics our foot is going to completely collapse  and you are going to lose your arch…….”

“……Our foot is designed to support itself. If we actually needed orthotics, we would be born…..we would come out of the womb, with orthotics on our feet.”

Meantime, The Foot Collective  asks (2.) Are you promoting weak feet?

  • Anything you use for artificial support at the feet (footwear with arch support & orthotics) your brain takes into account and accommodates for it.
  • That means if you provide your foot support your brain shuts down the natural arch supporters to reduce un-necessary energy expenditure.
  • Stop using support to help with pronation and understand why your feet pronate in the first place – because they are weak.
  • Strong feet = strong foundation = strong body.

The Real Source of Support for the Arch

Ray McClanahan, D.P.M. offers a perspective on the issue of Arch Support in his post on the CorrectToes blog (3.)

Are Custom Footbeds and Orthotics better than stock insoles?

In his post of August 20, 2017, Custom Foot Orthotics; No Better Than Stock Insoles (4.), Rick Merriam, of Engaging Muscles, explores the issue of orthotics in depth.

Prior to being told that supportive insoles are the way to go, I think it’s safe to say that all of those people didn’t know what they didn’t know.

The erroneous assumption that every skier needs footbeds or orthotics was made at a time when little  was known about the function of the foot and lower limb, especially in late stance. I was one of those who didn’t know what I didn’t know when initially when down the ‘the foot needs to be supported in skiing’ road up until I realized what I didn’t know and took steps to acquire the requisite knowledge.

Footbeds; is anyone checking what they do?

In 2000, I formed a company called Synergy Sports Performance Consultants (5). Synergys’ product was high quality information. One of my partners, UK Podiatrist, Sophie Cox, was trained by Novel of Germany and was one of the few experts in the world at that time on the Pedar system. Synergy did not make and/or sell footbeds or orthotics. Instead, we checked the effect of footbeds on skier performance. We performed a quick footbed check for a minimal fee of $20 using the sophisticated Novel Pedar pressure analysis technology.

Synergy was one of the first companies in the world to use the Novel Pedar pressure analysis system synchronized to video to acquire data on skier performance and analyze the captured data.  The Synergy team with diverse expertise studied the effect of ski boots and custom insoles on skier performance and identified functional issues in the body that needed to be addressed. It was a common finding that custom footbeds were significantly compromising skier performance, especially the ability to create the necessary platform under the foot on which to stand and balance on the outside ski.

Synergy offered a comprehensive 5 Step Performance Program that started with a footbed check. A key component was item 2., the Biomechanical Check.

With increasing recognition of the negative effect of most footwear on the user and criticism of the unproven claims made for footbeds and orthotics coming hard and fast, credibility in skiing is rapidly going downhill. It is time for proponents of custom insoles for ski boots to support their claims with solid evidence, especially evidence supported with data acquired during actual ski maneuvers. The technology to do this has existed since at least the year 2000.


  1. https://youtu.be/CIRf9WHmMXI
  2. http://www.thefootcollective.com
  3. https://www.correcttoes.com/foot-help/articles-studies/arch-support/
  4. http://www.engagingmuscles.com/2017/08/20/custom-foot-orthotics/
  5. DIGITAL SALVATION FOR THE SOLE [BACK TO THE FUTURE] –  http://wp.me/p3vZhu-24g

ERROR IN LAST POST ON EVERSION

In my last post, I erroneously stated that the sole turns inward, towards the center of the body, in eversion. I meant to state that the sole turns outward, away from the center of the body, in eversion.

I have revised the paragraph in my post so it reads correctly.

In order for the torso and Center of Mass to stack vertically over the ball of the foot, the sole of the foot must turn outward, away from the center the the body. This is called eversion. It is enabled by the joint that lies below the ankle called the sub-talar joint. The sub-talar joint is tied to the tibia where it acts as a torque converter. When the foot everts or inverts, the sub-talar joint translates this on an approximately 1:1 ratio into internal or external vertical axial rotation of the leg.

I apologize for any confusion this may have caused.

OUTSIDE SKI BALANCE BASICS: STEP-BY-STEP

In view of the positive response to my recent posts and comments I have received, I have decided to take a step-by-step approach to explaining the mechanics and biomechanics of balance on the outside ski.

I am going to start the process by comparing balance on one foot to balance on two feet. I refer to balance on one foot as monopedal stance (one foot) and balance on two feet as bipedal stance (two foot). The graphics are for illustrating general principles only.

The graphic below shows monopedal stance on the left and bipedal stance on the right. Orange hash marks delineate the alignment of major body segments. Black reference lines on the right leg of both figures show the angle of the leg in relation to the ground.

In order to transition from a balanced position in bipedal stance to a balanced position in monopedal stance, either the foot must move towards the L-R center of the torso or the torso must move towards the foot that will become the stance foot, or a combination of the 2 movements must occur. The central issue is the amount of inertia acting on the torso. In skiing, due to the degree of inertia, the new outside foot of a turn is normally guided into position under the torso as the skier or racer approaches the fall line in the top of a turn.

Moving the foot into position under the Centre of Mass so it stacks in line with the ball of the foot usually takes an inward movement (adduction) of the leg from the pelvis of 6 to 7 degrees. In the upper left figure in monopedal stance, the leg is adducted 6.5 degrees and has formed a varus or outward leaning angle with the ground.

If the leg only adducted, then the sole of the foot would end up at an angle of 6.5 degrees with the ground and the figure would end up on the outer edge of the foot; on the little toe side. In order for the torso and Center of Mass to stack vertically over the ball of the foot, the sole of the foot must turn outward, away from the center the the body. This is called eversion. It is enabled by the joint that lies below the ankle called the sub-talar joint. The sub-talar joint is tied to the tibia where it acts as a torque converter. When the foot everts or inverts, the sub-talar joint translates this on an approximately 1:1 ratio into internal or external vertical axial rotation of the leg.

When the foot everts, the subtalar joint rotates the vertical axis of the leg towards the center of the body an equivalent amount; in the subject case, 6.5 degrees.

The combination of eversion/internal vertical axial rotation of the leg is called pronation. If either of these actions is interfered with, or worse, prevented, it is impossible to create the alignment necessary to stack the torso and Center of Mass over the ball of the support foot.

The consistently stated objective of footbeds is either to limit or even prevent pronation. Put another way, the whole idea of footbeds is to make it difficult or even impossible to balance on the outside foot and ski.

If this issue is not crystal clear, please post comments as to what is needed.

ADDENDUM TO THE ORIGINS OF KNEE ANGULATION

The intent of my last post was to create an awareness of the lower limb alignment indicative of stability and how a lack of stability, whether intrinsic or caused by footwear, especially ski boots, will cause a skier to default to the use of knee angulation in what will be a failed attempt to hold the edge of the outside ski.

A skier will be unable to develop the requisite biomechanics to balance on their outside ski if they lack stability in barefoot monopedal stance under the minimal challenges associated with a flat, level unperturbed surface. If they lack lower limb/pelvic stability, there could endless combinations of causes which is why I listed a number of resources to help address this deficiency.

If a skier/racer exhibits good to excellent  stability under this basic test and they become unstable with the addition of any form of footwear, it suggests, but does not unequivocally prove, that the footwear is the cause. In more 4 decades of working with skiers and racers at all levels, I have consistently found that I can turn monopedal stability off and on at will. That I can do this without limitation, is indicative of cause and effect. In the 2 world class racers I am presently working with, even a small change in a liner or the over-tensioning of a shaft buckle or power strap has an immediate and noticeable effect on outside limb/pelvic stability and balance.

A key exercise I like to use with racers and elite skies I am working with is the vertical stacking exercise shown in the graphic below. This exercise is performed by starting from bipedal stance with the feet stacked under the heads of the femurs and the head and torso vertical and then making fluid arcing movement of the COM over the ball of the big toe while keeping the torso and head stacked vertically and the pelvis and shoulders horizontal as indicated by orange vertical and horizontal references in the graphic below. The torso should be aligned with the transverse or frontal plane, square with the foot.

A lack of stability in the biokinetic chain is typically evidenced by a drop of the opposite side of the pelvis and a leaning in the opposite direction of the torso and/or the head or both. While this reduces the load on the pelvis side of the  leg it creates a myriad of issues. Inside hip drop will cause the inside leg of a turn to assume the load as the skier inclines thus creating further instability on the outside leg.

Elite skiers and racers like Shiffrin are able to get over it (find stability on their outside foot and ski) in milliseconds. This enables them to retract the inside foot and ski with knee flexion as they incline into a turn similar to the mechanics cyclists use when they corner; outside leg extends, inside leg retracts.

The vertical stacking exercise is best performed in front of a mirror.